Rev_WRMP

Dŵr Cymru Welsh Water

Revised Draft Water Resources Management Plan

October 2011

TABLE OF CONTENTS

INTRODUCTION, SUMMARY, AND CONSULTATION PROCESS .......................................................................... 1

CHAPTER 1. WATER RESOURCES MANAGEMENT PLANS ............................................................ 11

1.1 Why we prepare plans .......................................................................................................... 11

1.2 Our approach to the development of this plan ...................................................................... 11

1.3 Our 2008 plan........................................................................................................................ 11

1.4 Other Developments since the 2008 Plan ............................................................................ 12

1.5 Strategic Links ....................................................................................................................... 14

1.6 Compliance with Welsh Government Direction ..................................................................... 15

CHAPTER 2. SUPPLYING WATER IN OUR AREA .............................................................................. 17

2.1 Water resources in our supply area ...................................................................................... 17

2.2 Water Resource Zones - General ......................................................................................... 19

CHAPTER 3. WATER SUPPLY CAPACITY ........................................................................................... 25

3.1 Deployable Output ................................................................................................................ 25

3.2 Resource Developments during 2005-2010 ......................................................................... 27

3.3 Other changes since the 2008 Draft Plan ............................................................................. 27

3.4 Outage ................................................................................................................................... 27

3.5 Levels of Service (LoS) ......................................................................................................... 29

3.6 Operational use of water ....................................................................................................... 31

3.7 Water Transfers..................................................................................................................... 31

3.8 Elan Builth ............................................................................................................................. 32

3.9 Non-Potable Supplies ........................................................................................................... 32

3.10 Other customers .................................................................................................................... 32

3.11 Water Available for Use ........................................................................................................ 32

CHAPTER 4. THE DEMAND FOR WATER ............................................................................................ 34

4.1 Baseline demand .................................................................................................................. 34

4.2 Population forecasts .............................................................................................................. 36

4.3 Property Forecasts ................................................................................................................ 38

4.4 Household Demand .............................................................................................................. 39

4.5 Non Household Demand ....................................................................................................... 40

4.6 Distribution Input ................................................................................................................... 41

4.7 Managing Demand ................................................................................................................ 45

CHAPTER 5. TARGET HEADROOM ...................................................................................................... 53

5.1 Calculating Target Headroom ............................................................................................... 53

5.2 Risk Profile ............................................................................................................................ 54

5.3 Baseline and Final Planning .................................................................................................. 54

5.4 Work carried out since the 2008 Draft Plan .......................................................................... 54

CHAPTER 6. THE HABITATS DIRECTIVE AND THE IMPACT ON WATER ABSTRACTIONS ...... 56

6.1 The Habitats Directive ........................................................................................................... 56

6.2 Review of Consents (and Restoring Sustainable Abstraction programme) .......................... 56

6.3 The impact of Review of Consents upon Resources ............................................................ 65

CHAPTER 7. UNCERTAINTY REGARDING THE EFFECTS OF CLIMATE CHANGE ..................... 67

7.1 How we approach climate change ........................................................................................ 67

7.2 The impact on supply ............................................................................................................ 68

7.3 The Impact on Target Headroom - Supply ............................................................................ 70

7.4 The Impact on Target Headroom – Demand ........................................................................ 74

CHAPTER 8. THE SUPPLY DEMAND BALANCE ................................................................................ 76

8.1 Calculating the Supply Demand Balance .............................................................................. 76

8.2 The projected Supply Demand balance ................................................................................ 76

8.3 Brecon Portis ......................................................................................................................... 78

8.4 Pembrokeshire ...................................................................................................................... 79

8.5 South East Wales Conjunctive Use System (SEWCUS) ...................................................... 81

8.6 North Eyri Ynys Mon ............................................................................................................. 82

CHAPTER 9. OPTION APPRAISAL ........................................................................................................ 83

9.1 Our approach to appraising the options ................................................................................ 83

9.2 Identifying the feasible options .............................................................................................. 84

9.3 Feasible List .......................................................................................................................... 85

9.4 Environmental and Social costing ......................................................................................... 89

9.5 Selecting the preferred option ............................................................................................... 91

9.6 Optimisation model ............................................................................................................... 91

9.7 Preferred Options for Addressing Supply Demand Deficits (Without Incorporating the Full Range of UKCP09 Climate Scenarios in Target Headroom) ............................................................ 92

9.8 Preferred Options for Addressing Supply Demand Deficits, Incorporating the Full Range of UKCP09 Scenarios in Target Headroom .......................................................................................... 97

9.9 Sensitivity ............................................................................................................................ 103

CHAPTER 10. ENVIRONMENTAL APPRAISAL ................................................................................... 107

10.1 Introduction .......................................................................................................................... 107

10.2 Strategic Environmental Assessment ................................................................................. 108

10.3 Habitats Regulations Assessment ...................................................................................... 109

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Dŵr Cymru Welsh Water Revised Draft Water Resources Management Plan, October 2011

Introduction, Summary, and Consultation Process

One of our most important responsibilities, as provided for under the Water Industry Act 1991, is to

ensure that we can always meet the reasonable water needs of our customers now and into the

future. And, like all other water companies, we are required periodically to produce a Water

Resources Management Plan which demonstrates how we plan to balance supply and demand over

the following 25 years. Although companies had produced Water Resources Plans on a voluntary

basis for several years previously, the amendments to the 1991 Act which were made by the Water

Act 2003 introduced for the first time a statutory requirement for companies to produce Water

Resources Management Plans (WRMPs).

As part of our preparation for the 2009 regulatory price-setting process, we submitted a Draft Water

Resources Management Plan to the Welsh Government in March 2008. Following a Direction from

the Welsh Government in January 2009, the Plan was published for consultation on 15 January 2009.

However, it did not complete the full statutory process as it was never formally approved by the Welsh

Government, primarily due to fact that, in certain important respects, it was overtaken by events,

notably the need to consider the impact of the Habitats Directive.

This document is therefore a revised draft of our Plan for the period up to 2035, and sets out for

consultation how we intend to achieve the required balance between supply and demand. Our aim is

to do so efficiently so that water bills are no higher than they need to be and the impact on our

environment is minimised. In order to develop the plan, we have projected the future demand for

water from our customers, we have calculated how much will be available from current sources, and,

where there is a shortfall, looked at all the ways of increasing supply and reducing demand so as to

arrive at the best overall package of solutions.

In general, we are currently in a relatively strong position on water resources. Wales has a

comparatively wet climate and we abstract for public water supply just 3% of effective rainfall (which

compares with much higher figures in parts of the South East of England, for example). Demand for

water and the amount of water we abstract has fallen by a quarter over the last 15 years (as a result

of halving of leakage and falling industrial demand for water) and we are forecasting more or less flat

demand for water from our customers over the coming 25 years. This is based on Government and

local authority projections of population and properties, and assumes no major upturn in the demand

for water from heavy industry. All our 24 water resource zones currently have a surplus of supply

over demand in both a normal and a Dry Year.1

However, we do not expect this situation to persist. Much of this document is concerned with the

significant changes in our water resources position that we are expecting in the coming years. We

have to plan and cater for likely and possible changes in the years ahead, and for this Plan those are

greater and more serious than they have been for the last two or more generations.

Specifically, the Plan has been prepared so as to take account of two very significant influences:

the results of the Environment Agency Wales‟ “Review of Consents” exercise which it has

undertaken in the light of the European Habitats Directive. A significant feature of this

process is that it entails the application of a “precautionary principle” under which potential

adverse impact of abstraction is presumed unless evidence is available to the contrary, which

typically is not the case; and

1 A “Dry Year” is defined as a year that is characterised by low rainfall and unconstrained demand. The Dry Years that we have

experienced and which are incorporated in our modelling include 1976, 1984, and, for some zones, 2003.

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an updated assessment of the possible impact of climate change on the water environment in

Wales, as set out in the latest UK Climate Change Projections published in 2009 (“UKCP09”),

which may both reduce the amount of water we have available to supply, and increase

demand from our customers.

Together, these two developments could very significantly reduce or eliminate our water resource

surpluses, in some zones creating deficits that could require significant investment to address. For

example, in our South East Wales Conjunctive Use System zone (“SEWCUS”) which covers much of

South East Wales, the Review of Consents process alone will reduce our Deployable Output by

nearly 20%, the equivalent of what we need to meet the needs of consumers in the whole of Cardiff.

More generally, the resultant tightening of our water resource position means that surpluses that we

currently have cannot be regarded as being available to support long term economic development.

For example, on the basis of the projections set out in this plan water is unlikely to be available to

supply the new Wylfa power station on Anglesey, and new resources would probably be required to

facilitate any further industrial development in Milford Haven.

We want to test our understanding and current thinking with all who have an interest in the water

industry and the environment in Wales. We want our customers and other stakeholders to engage

with us on the challenges we face in maintaining a balance between supply and demand for water

and how we propose to meet them. And if there is one key message we want to get across from this

discussion and consultation it is that Wales does not have an abundance of water for public water

supply and that we all need to value our water resources much more than in the past.

The feedback we receive will not only assist us in shaping the final Plan, but will also influence our

approach to the next draft Water Resource Management Plan, due in 2013.

Structure of draft Plan

This document is structured as follows. Chapter 1 sets out the context within which the revised draft

plan has been prepared, and the processes that have been applied. Chapter 2 provides a summary

of the key features of our region and the water supply industry in general that are particularly relevant

for water resources planning. Chapter 3 then explains the primary measures of water supply

capacity, namely “deployable output” and “water available for use” (including the role of “outage”), and

Chapter 4 describes the main elements of the demand for water in our region together with the basis

on which we have forecast demand out to 2035. Chapter 4 also summarises our approach to the

management of leakage (leakage being one component of the “demand” for water) and the promotion

of water efficiency, both of which will continue to play important roles in our water supply strategy over

the Plan period. Chapter 5 then explains “Target Headroom”, the buffer that we build into our

projections to allow for error and uncertainty for the purposes of determining when there is deemed to

be a supply demand “deficit”.

Chapters 6 and 7 describe two exceptional influences on our water resources position over the Plan

period. These are respectively the notification we have had from the Environment Agency that it has

reviewed some of our licences and wants us to make significant “sustainability reductions” in the light

of the Habitats Directive (reductions that we are assuming will come into effect in 2020), and the latest

projections for climate change. Chapter 8 brings together the projections of demand, Target

Headroom and Deployable Output to present the „supply demand balance‟ for each of our 24 water

resource zones for the period to 2035. We show that, but for the effects of the Habitats Directive

related review of our consents and climate change, we would be projecting no supply demand deficits

over the next 25 years, but when they are taken into account deficits appear in some zones during the

plan period.

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Chapter 9 then sets out how we have approached the evaluation of options for closing these deficits.

These options range from increasing the storage available in our reservoirs to encouraging our

customers to use water more efficiently. It shows how we have evaluated the options to arrive at a

preferred list of viable solutions to the projected deficits. It sets out our initial estimates of the likely

financial and carbon cost of progressing each of these options and the possible impact on customer

bills.

Finally, Chapter 10 summarises the environmental appraisals we have commissioned in connection

with, and to support this Plan. A glossary of terms is included with the supporting Annexes.

Building the Uncertainty Surrounding Climate Change into this Plan

The biggest challenge we faced in preparing this plan was the question of how we should incorporate

the latest climate change scenarios, “UKCP09”,into our projections, and particular the uncertainty

around the central projections. We are the first water company to use UKCP09 scenarios in the

preparation of a water resources management plan, and the Environment Agency‟s guidance on how

they should be incorporated is still under development. Following “best practice” in dealing with the

uncertainty around climate change, we found that the UKCP09 scenarios had a very dramatic effect

on the supply demand position in some parts of our region, notably the large South East Wales

Conjunctive Use System zone that relies extensively on the River Usk and the Wye. From a baseline

position in which the zone would be 75 megalitres per day (Ml/d) in surplus in 2035, the Review of

Consents takes the zone into a small 3 Ml/d deficit and incorporating the median climate change

scenarios in calculations of Deployable Output extends this to 12 Ml/d. Allowing for the full range of

UKCP09 scenarios on uncertainty in Deployable Output in Target Headroom, however, takes the

projected deficit to 104 Ml/d by the end of the Plan period.

Faced with this dramatic effect, we considered three options:

A. plan on the basis of the full range of UKCP09 scenarios and present the options for

addressing supply-demand deficits such as the one for SEWCUS referred to above;

B. use the full range of UKCP09 scenarios, but discount their effect on a sliding scale,

progressively more deeply the further into the future one is projecting. The rationale for this

approach, which is used by several companies and is acknowledged in the Environment

Agency‟s guidance, is that the more distant the uncertainty, the more time and scope there is

available in the meantime to deal with it; or

C. calculate and disclose the effects on Target Headroom of the full range of UKCP09 scenarios,

but plan to address supply-demand deficits that exclude them.

We did not adopt option B because we believe it has the unhelpful characteristic of blurring the

quantification and the management of uncertainty. We do not think that it makes sense to plan

investments for an artificial scenario that acknowledges what it is that you think is going to happen but

only addresses a part of it on the grounds that it is a long way into the future. We prefer to be explicit

as to the magnitude of the risks we face, and to address them using considered judgement.

We have evaluated in general terms what option A would mean for our investment plans. Chapter 9

presents our view of what they would entail, including the prospect of significant investment in

desalination in South East Wales. We have not, however, followed option A in arriving at the final

planning solutions for the purposes of this document, and have applied option C instead. Whilst we in

no way understate the importance and potential impact of climate change on our future water supply

position, given that the application of UKCP09 is a developing area, given that the potential supply

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demand deficits driven by uncertainty around climate change do not manifest themselves for several

years, and given that we are due to prepare our next draft Plan at the same time as the other water

companies in 2013, we have chosen in this document to confine our projections to the supply demand

deficits that we are most confident we will have to address during the Plan period, and the least cost

way of dealing with them. We do, however, present for information supply demand projections using

the full range of UKCP09 scenarios in Target Headroom, and what would be the preferred means of

addressing deficits under this alternative approach.

In the meantime, we believe that we will be in a position to take a much more definitive view of the

likely magnitude of such deficits and how they can best be addressed when we embark upon the next

water resource management planning exercise in a year or so.

The Timing of Licence Adjustments under the Review of Consents

It is also worth highlighting that we have assumed, for the purposes of this Plan, that the licence

amendments in the South East Wales Conjunctive Use System zone will not be formally put in place

until 2020. Having said that, the sustainability reductions would not put the zone into deficit straight

away - rather, according to current modelling, they would leave a small planning surplus for the time

being. The size of the reductions contemplated is so dramatic that we consider that it would be

prudent to carry out further detailed work on the way that the zone is operated in order to ensure that

it is fully robust to such radical changes.

Our Strategy Summarised

The key elements of our overall strategy can be summarised as follows:

regional leakage is expected to fall from 190.45 Ml/d in 2010-11 to 184.08 Ml/d in 2014-15.

This strategy is in line with the targets agreed with our economic regulator, Ofwat. As part of

the option selection process for addressing supply demand deficits we have considered

options involving more reductions in leakage. However, none have been selected because of

their comparatively high costs;

the promotion of a wide range of water efficiency activities for both our domestic and business

customers. For the period 2010-15 we will continue with our full suite of baseline promotion

activities;

the installation of water meters at all new properties and those households who opt to be

metered under our free meter option scheme. We will continue to meter all new business

customers and carry out selective metering on high water use unmeasured business

premises;

for Pembrokeshire, where the deficit has been driven by the potential impacts of climate

change and the significant impact of sustainability reductions being proposed by the

Environment Agency, we are proposing to reinstate a currently licence-exempt groundwater

source and carry out a network scheme that will enhance the connectivity of the zone. This is

the most economic solution for the zone;

in the Brecon – Portis water resource zone where the Environment Agency wants us to

reduce our abstractions from the River Usk at Brecon, we plan to supplement the available

flow in the river with additional releases from the Usk reservoir, when required; and

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in the South East Wales Conjunctive Use System zone, where we must address the effects

of the Agency‟s review of our abstractions on the protected habitats in the Wye and the Usk,

plus the effects of climate change on Deployable Output. We plan to reinstate two reservoirs

that we have not used for public water supply for some time, namely Wentwood and Grwyne

Fawr, and to build new treatment works for both sources.

For the Preferred solutions in the three deficit zones, the total capital cost is estimated at £35.7m with

a total operating cost, in the entire planning period, of £9.1m. We estimate that this will add

approximately £5 to our average bills in today‟s prices by the end of the Plan period.

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Questions we are asking

We would like comment and feedback on this Revised Draft Water Resources Management Plan so

that we can ensure that the Final Plan takes account of as many stakeholder views as possible. We

will also take account of further advice from our regulators in preparing the Final Plan, which we

expect to publish in Spring 2012.

In developing this plan we have followed a structured process, as described in this document. We

summarise below the findings we have reached and ask specific questions on which we would

welcome feedback.

Q1 Are there any important issues that have not been adequately considered in our

assessments of the future water supply and water demand position?

At the start of this process we have identified the Level of Service we will guarantee our customers

namely:

not more than once in every 20 years, on average, for a hosepipe ban, and

not more than once every 40 years, on average, for Drought Orders/ Permits.

We view the imposition of rota cuts and standpipes as unacceptable.

Q2 Is our target level of service, i.e. the frequency of water restrictions and other drought

powers, acceptable, and does it strike the right balance between the needs of customers and

the environment?

We have described how we calculate the amount of water we can supply and how we forecast the

demand for water, and have concluded that all our water resource zones are projected to be in

surplus for the whole of the 25 year Plan period, unless the projected effects of climate change and

the review of our consents that the Environment Agency has carried out in the light of the Habitats

Directive are taken into account.

We have highlighted that the Environment Agency‟s review of our licences and the resultant

modifications it intends to make to our abstractions for both water resource and fish entrainment

impacts require investment by Welsh Water and would increase the bills paid by our customers.

Under the Habitats Directive, the Environment Agency is obliged to use “best available data” which in

the case of the impacted rivers is sparse. Without this data, the Agency has adopted the most

stringent “precautionary principle”, based on a generic approach.

Q3 Should we undertake further research work into whether it can be demonstrated that there

is “no adverse impact” from our abstractions on sites protected by the Habitats Directive?

We believe that there may be a case for a programme of scientific investigation that would allow us

better to define what each of the features in sites protected under the Habitats Directive need in terms

of river flow. This might reduce the number of sites where a lack of scientific evidence combined with

the default “precautionary principle” has resulted in the Environment Agency seeking reductions in the

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volumes of water we remove from Habitats Directive sites. This would also give us confidence that the

investment suggested in this plan would be beneficial, and deliver value for money.

Q4 If we are to undertake further research how might this best be done and what would be the

sensible areas to focus on?

Notwithstanding the above, the Environment Agency has the responsibility to decide what

amendments are required to our licences. Our primary role is to identify, as a result of their

conclusions, the options available to us to ensure we continue to provide sufficient water to our

customers in line with the commitments we have given. We have described how we have identified

our preferred options and these have been summarised in chapter 10.

Q5 Are the options we have identified the most appropriate ways of securing future water

supplies? Are they both robust and flexible?

Q6 Are there any alternative options that we should consider and why might these be better

than the ones we have identified?

As set out above, we have chosen not to reflect uncertainty surrounding the full effects of climate

change on Deployable Output in our central projections, but we have evaluated what they would look

like and what impacts they have on the least cost strategy for balancing supply and demand.

Q7 Do you agree with our treatment of climate change uncertainty? If not, what alternative

approach do you advocate?

After identifying the options for meeting supply demand deficits we have also described how we have

undertaken environmental assessments of our Plan.

Q8 Does our environmental assessment, outlined in our Strategic Environment Assessment

and our Habitats Regulations Assessment, identify the most relevant potential impacts of the

proposed options?

Finally we highlight that the financial impact of our preferred options is a total cost of £35.7m in capital

expenditure and a total operating expenditure over the plan period of £9.1m, which would mean a bill

increase of around £5 per household in today‟s prices.

Q9 Do you think our proposals represent good value for money?

Of course, as well as these specific questions we welcome comments on any aspects of our Plan. If

you are within our supply area, please write to the Welsh Government at the following address:

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Olwen Minney,

Water Policy Manager

Water Policy Branch

Welsh Government

Cathays Park

Cardiff CF10 3NQ

[email protected]

Comments may be sent by post or email. It would be helpful if the subject title in your email or letter

includes the words “Representation on Dŵr Cymru Welsh Waters‟ Revised Draft Water Resources

Management Plan”.

We will inform you through our Statement of Response how we plan to take your comments into

account in preparing our Final WRMP.

Future Challenges

There are a number of key areas that will present great challenges for us and the rest of the water

industry over the next 5-10 years. We have summarised these in the following table along with our

intended approach to dealing with these challenges.

mailto:[email protected]

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Issue Going Forward

Climate Change

We have taken a pragmatic approach to the adoption of the latest UK

climate chamge projections (“UKCP09”) in advance of accepted

industry guidance. By the time we prepare the next draft Plan in 2013,

however, it is likely that the Environment Agency will have set out its

position on how UKCP09 scenarios should be incorporated in water

resource management planning, especially Target Headroom. This

may impact on the deficit position.

Water Framework Directive

In December 2009 the first round of River Basin Management Plans

were published setting out the actions and strategies for rectifying

those water bodies currently failing their objectives. During our current

(2010-2015) investment programme we anticipate that investigations

that are underway into these failures could lead to further modifications

to our operations being required.

We are on the steering group of a key UK water industry research and

development project2 and will therefore contribute to decisions

affecting how we should meet the Directive in our current and future

investment programmes.

Restoring Sustainable

Abstraction Programme

(RSAp)

The Environment Agency‟s Restoring Sustainable Abstraction

Programme is ongoing within Wales and we are aware there are a

number of sites that the EA wishes to investigate further to assess

what impact our operations are having upon the ecological integrity.

We remain concerned regarding further investigations in this area and

encourage the Agency to share this with us and allow us to work

together.

Review of the Plan

In preparing this Revised Draft Plan we have undertaken many detailed studies. However, water

resources planning is a dynamic process and we are committed to reviewing the key elements of the

Plan, almost on a continual basis.

In particular, between now and the Final Plan we will take account of consultee responses and

regulatory and industry developments in preparing our Final Plan. This feedback will also play a

significant role in shaping our preparatory work for the draft Plan we intend to publish in 2013.

We also intend over the next two years to:

review in full our demand forecasts (in particular taking account of the high demands

experienced during the summer of 2010);

2 UKWIR research project reference WR33 on Heavily Modified Water Bodies

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revise our Economic Level of Leakage assumptions in line with Ofwat requirements for water

company investment programmes for 2015-2020;

review and update the inflow sequences on which we base our deployable outputs;

revise our water resources models and drought triggers to account for changes in legislation

that prescribe the restrictions we can apply during droughts (this may impact on the

Deployable Output of some our water resource zones); and

maintain our supply demand balances in line with industry best practices.

All these elements are likely to change the supply demand balance in some water resource zones

and change the overall aspect of the water resources management plan for our 2015-2020

investment programme.

Finally, we will continue to discuss and review the key elements of the Plan through our close working

relationship with the Environment Agency and other stakeholders. We expect to publish our Final

Plan in Spring 2012.

More generally, it is clear that the next few years will see a considerable amount of further work on

the challenge of meeting water resource objectives in Wales, including in particular the creation of an

improved evidence-based understanding of the impact of our abstractions on the environment. It is

vital that the major strategic decisions that we make are the right ones both for current and future

generations, and to this end we will seek to work yet more closely and openly with our stakeholders,

especially our regulator the Environment Agency, over the medium term.

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Chapter 1. Water Resources Management Plans

The purpose of this chapter is to set out the legal context within which this revised draft Plan has been

prepared and how we have approached the task of putting it together. This includes a description of

how our work has evolved since the previous plan in 2008, and how it links in, at a strategic level, with

Government and regulatory policies and requirements.

1.1 Why we prepare plans

Under the Water Industry Act 1991 all water companies are required to provide customers with a

reliable supply of water for domestic and business purposes. Although companies had produced

Water Resources Plans on a voluntary basis for several years previously, the amendments to the

1991 Act which were made by the Water Act 2003 introduced for the first time a statutory requirement

for companies to produce Water Resources Management Plans.

Under these provisions, we are required to prepare a draft Water Resources Management Plan and

to consult with our customers and with other stakeholders as to its content. We regard this as a

highly important exercise for our business: the security of water supplies is of paramount importance

to our customers, and the way in which we achieve this can have significant implications for the costs

we incur and hence the bills customers pay.

1.2 Our approach to the development of this plan

The planning of long term water supplies is not a discrete task that takes place every few years:

rather, we review on a continual basis our water resource position, the future requirements of our

customers, and how they can best be met at least cost to them and at minimal impact to the

environment. This plan therefore represents a “snapshot” of our most up-to-date thinking. It has

been prepared in accordance with guidance provided by the Environment Agency3 and, notably, takes

into account the effects of the review of consents that the Agency has undertaken in the light of the

Habitats Directive(see chapter 6 for details) and includes a full consideration of the latest projections

of the effects of climate change (see chapter 7).

As set out in chapters 8 and 9, we have identified three Water Resource Zones where we are

expecting a supply-demand deficit during the Planning period. In order to determine how best these

can be addressed we have identified and costed all the possible options for increasing supply and/or

reducing demand, including a full evaluation of their environmental, social and carbon costs.

It is important that we understand the potential environmental and ecological impact of any plans we

put forward. We have therefore undertaken a “Strategic Environmental Assessment” (SEA) and a

“Habitats Regulations Assessment” (HRA) of our preferred options for addressing the deficits. These

are described in more detail in Chapter 10.

1.3 Our 2008 plan

This is not the first water resources plan we have produced. Every 5 years each water company

publishes a Business Plan following a very detailed review of all its future service and expenditure

needs, including those relating to water resources. Our economic regulator, the Water Services

3 Water Resources Planning Guideline (WRPG) (EA, November 2008)

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Regulation Authority, “Ofwat”, uses this information when setting price limits for the following five

years. The last review of price limits was completed in 2009 when Ofwat set price limits for the period

2010-2015.

As part of our preparation for the price-setting process, we submitted a Draft Water Resources

Management Plan to the Welsh Government in March 2008. Following a Direction from the Welsh

Government in January 2009, the Plan was published for consultation on 15 January 2009. The 2008

Draft Plan was also included as part of the Business Plan we submitted to Ofwat later the same year,

although its interim status was recognised given that it was still subject to consultation at the time.

The 2008 Draft Plan did not complete the full statutory process as it was never formally approved by

the Welsh Government. This was primarily due to fact that, in some respects, the Plan was overtaken

by events, in particular the need to consider the impact of the review of our consents that the

Environment Agency has undertaken in the light of the European Habitats Directive.

1.4 Other Developments since the 2008 Plan

As well as the impact of the Habitats Review of Consents, this Plan also takes into account other

significant developments since 2008. These include updated information – e.g. on demand (see

chapter 4), and the projected effects of climate change (see chapter 7) – and feedback on our 2008

Plan from our main stakeholders. Table 1.1 below presents a summary of the main points of

difference between this revised draft plan and our 2008 Plan: detail on each topic will be found in the

relevant chapters of the remainder of this document.

2008 Draft

Plan Revised Plan Reason for Change Chapter

Supply

demand

deficits

Six of our Water

Resources Zones were

previously forecast to be

in deficit and are now

forecast to be in surplus

during the planning

period. Three zones are

now presented as having

forecast supply deficits.

We have revised our demand forecasts and

leakage strategy. We have also reflected

the latest predictions about climate change

impacts (UKCP09) and taken account of

proposed modifications to some abstraction

licence modifications that may be needed to

meet the Habitats Directive.

4,6,7

Strategic

Environmental

Assessment

Fully updated

Different options have been assessed to

reflect changes in predicted supply and

demand in some zones.

Representations received from the

Countryside Council for Wales highlighted

several areas that required amending/

updating.

10

Habitats

Regulations

Assessment

Fully updated

Our Habitats Regulations Assessment now

incorporates the outcomes of the

Environment Agency‟s review of our

consents.

10

Page | 13


2008 Draft


Different intervention options have been

assessed to reflect changes in predicted

supply and demand in some zones.

Representations received during the last

consultation exercise from the Countryside

Council for Wales, Natural England,

Environment Agency and the Wye & Usk

Foundation highlighted several areas that

required amending/ updating.

Outage Allowances updated

Assumptions have been reviewed against

actual data. Outage review is a continuous

process.

3

Operational

Use & Losses Allowances updated

We have improved our data collection and

reflected the results of a detailed pilot study

of operational use at water treatment works.

3

Climate

Change Use of UKCP09

Updated projections of climate change for

the UK were produced in 2009 and analysed

in preparation for this plan.

7

Sustainability

Reductions Reductions incorporated

From our consultation on the 2008 Draft

Plan one of the main issues highlighted was

the exclusion of the Environment Agency‟s

proposed sustainability reductions because

they had not yet been notified to the

company. This Revised Draft takes full

account of the reductions.

6

Target

Headroom

Updated forecasting

around the demand

components of

Headroom. Full review

of headroom allowance.

The Environment Agency raised concerns

over large Headroom allowances in some

zones. We have fully reviewed our

uncertainty assumptions in these zones,

particularly those regarding climate change

5

Demand Demand forecast fully

revised and updated

Changes in demand forecasts caused by

effects of the current economic recession

and changes in the rebasing of the data

used in the forecasts from 2007-08 to 2008-

09.

4

Costing of

Options

Capital and operating

costs updated in line with

Welsh Water‟s Unit Cost

Database (UCD)

To ensure full consistency with Welsh

Water‟s investment programme, all aspects

of our Resource and Production schemes

have been reviewed and re-costed,

9

Environmental Additional categories To ensure a full assessment of the 9

Page | 14


2008 Draft


& Social Costs added to assessment environmental and social costs associated

with the implementation of water resource

schemes, we have ensured that all options

now use the same categories for

Environmental and Social costs

Carbon

Costing

Carbon emissions

updated

To ensure consistency with Welsh Water‟s

2010-2015 business plan all our resource

schemes‟ embedded and operational

emissions have been recalculated.

9

Table 1.1 – Updates since 2008 Draft Plan

1.5 Strategic Links

We operate in the broad policy framework that has been set by the Welsh Government. We have

tried to ensure that we have full regard to its key strategies and policies in preparing the plan. We

also work closely with the Environment Agency, and have discussed details of this plan with it,

particularly the effect its proposed changes to our licences because of the Habitats Directive. We

have also consulted with the Countryside Council for Wales and Natural England, particularly

regarding the Strategic Environmental Assessment and Habitats Regulations Assessment so we can

be confident that we have considered all the key environmental issues. We have summarised in Table

1.2 the main strategies and plans that have helped to shape our thinking in developing this document.

Organisation Document Links to this Plan

Welsh

Government

Strategic Policy Position

Statement on Water

(2011 update)

Sets out the Welsh Government‟s vision on how water

resources should be managed in Wales

Welsh

Government

Social and

Environmental

Guidance to Ofwat

Gives the Welsh Ministers‟ guidance to Ofwat on how it

should undertake its duties in relation to the Welsh

Government‟s objectives.

Welsh

Government

One Wales: One Planet

– The Sustainable

Development Scheme

of the Welsh

Government

We need to have due regard to the Welsh

Government‟s sustainable vision for Wales where

“land, freshwater and marine environment is best

managed to provide the services of food, wood, water,

soil, habitats and recreation”.

Welsh

Government

People, Places, Future:

The Wales Spatial Plan

2008 Update

The Spatial Plan aims to safeguard and protect Wales‟

natural and historical assets whilst enhancing their

resilience to climate change.

Welsh

Government

Climate Change

Strategy for Wales

The Welsh Government‟s vision on tackling climate

change in Wales and what it expects from industry.

Welsh

Government

Environment Strategy

for Wales

95% of internationally designated conservation sites to

be in favourable condition by 2010

Page | 15


Organisation Document Links to this Plan

Welsh

Government

A Low Carbon

Revolution: The Welsh

Government Energy

Policy Statement

This policy statement sets out the Welsh Government‟s

ambitions for low carbon energy in Wales.

Welsh

Government

Planning Policy Wales

(Edition 3)

Sets out the land use planning policies of the Welsh

Government and the key policy objectives for Local

Development Plans in Wales which reflect the

sustainable development agenda.

Environment

Agency Wales

Water for People and

the Environment: Water

Resources Strategy for

Wales

Sets out how the Agency believes water should be

managed in Wales until 2050 and lists actions and

measures water companies should undertake to

achieve its Vision.

Environment

Agency Wales

Water Resources

Strategy for Wales –

First Action Plan

Sets out the required actions for the relevant parties to

deliver the Agency‟s Water Resources Strategy.

Environment

Agency Wales Regional Action Plans

Localised plans containing actions the Agency wants

water users to take to achieve their national strategy

aims.

Environment

Agency

approved by

Welsh Ministers

River Basin

Management Plans

How the Environment Agency will implement the

European Water Framework Directive and the

measures it wishes to implement for water bodies to

achieve “good status/ potential”.

Environment

Agency

Catchment Abstraction

Management Strategies

Sets out water resource availability status across

surface water/ groundwater catchments in England and

Wales. This determines the Agency‟s licensing policy.

Ofwat

Preparing for the future

– Ofwat‟s climate

change policy statement

Sets out Ofwat‟s expectation that companies will plan

for the impacts of climate change upon their supply and

demand balances within the water resource planning

framework.

Local Councils

Regional Development

Plans/ Spatial

Strategies

These set out Councils‟ aspirations for development in

their area.

Table 1.2 – External Strategies and Plans we have considered

1.6 Compliance with Welsh Government Direction

Throughout the preparation of this Plan we have complied fully with the joint Department for the

Environment, Food and Rural Affairs/ Welsh Government Water Resources Management Plan

Direction (2007). The specific Direction items are covered in the following report sections:

the planning period (item no. 2) - Introduction section;

the frequency of customer restrictions (planned and actual) (item no. 3a) – section 3.5;

the option appraisal methodologies (item no. 3b) – Chapter 9;

Page | 16


the requirement to undertake carbon accounting (item no. 3c) – section 9.4;

how account has been taken of climate change (item no. 3d) – Chapter 7; and

the estimation of household demand (item no. 3e) – section 4.4.

Page | 17


Chapter 2. Supplying Water in our area

This chapter provides factual background on our water supply area It explains some of the critical

issues we must consider and describes how our assets have been developed and managed to ensure

that we can provide a reliable supply of water to our customers.

2.1 Water resources in our supply area

Welsh Water delivers water supply services to most of Wales and some parts of England, including

most of Herefordshire. In total we supply water to around 3 million people, of which over 40% are

concentrated in the south east of Wales in the Cardiff and Newport area and much of the remainder is

located in the main population centres around the coast. These are in sharp contrast to the sparsely

populated areas of mid-Wales, where population densities are amongst the lowest in the UK.

Wales has a relatively wet climate when compared to other parts of the UK. We estimate that we only

use some 3% of rainfall, on average, for public water supply, which compares to 50% in parts of

South East England. However, the regional picture masks important geographical differences within

our supply area: for example, at up to 3,000mm per annum, rainfall in Snowdonia can be more than

four times the levels recorded in the border areas and Herefordshire, where 700mm per annum is

typical.

The diversity of our water supply systems reflects these regional variations. Most comprise discrete

small-scale local supplies, of which we have a considerable number, with only South East Wales

being served by the sort of large scale multi-source integrated network that is typical in many other

water company areas.

Our main sources of water are our 65 impounding reservoirs. These are linked closely to our five

major river regulation schemes: on the Rivers Wye and Usk in the south east of Wales; the Rivers

Tywi and Cleddau in the south west; and the River Dee in the north.

On average we abstract from the environment around 800 million litres a day (Ml/d) for public water

supply. This normally increases by around 15 - 20% during the summer. During periods of extreme

conditions – long hot summers or sudden thaws following freezing weather – the demands on our

supply systems can increase by over 25%, and in some localised areas by nearly 50%.

Figure 2.1 illustrates this variability and highlights the peaks in demand we experienced during the

warm summer of 2006 and the very cold period just before Christmas 2010.

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Figure 2.1 – Variability of water volume put into supply

Underlying these short term variations is a long term steady decline in overall water demand (see

Figure 2.2). This is primarily due to the decline of heavy industry, particularly in South Wales, and the

significant reduction in leakage from our networks over the past fifteen years.

Figure 2.2 – Declining trend in water supplied

750

800

850

900

950

1000

Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar

Average Monthly Company Distribution Input (Ml/d)

2006-07 2007-08 2008-09 2009-10 2010-11

Page | 19


Against this background, and notwithstanding a general perception that Wales has an abundant

supply of water, our future water supply strategy faces a number of challenges, as set out in the

remainder of this document.

2.2 Water Resource Zones - General

Our water supply area is divided into 24 Water Resource Zones (WRZs). These zones are defined as

the largest area in which all resources can be shared, and hence they represent a group of customers

who receive the same Level of Service. The WRZs essentially define the limits of the areas beyond

which water supply becomes increasingly uneconomic with the current supply infrastructure. The

landscape of our supply area means that each of these WRZs is fairly self-contained, and the scope

to move water between zones is extremely limited.

Figure 2.3 shows our 24 WRZs, of which the largest is the South East Wales Conjunctive Use System

zone (SEWCUS) which covers 40% of our customers, and the second largest is Tywi Gower, which

covers another 20%. By contrast, the 8 smallest zones together cover just 1.5% of our customers.

Table 2.1 below presents further details on each of the 24 WRZs.

Figure 2.3 – Water Resource Zones

Page | 20


WRZ No. WRZ name Area (km2)

Population served (‘000)

4 Water delivered (average, Ml/d)

5 Main Source of water

North Wales

8001 North Eyri Ynys Mon 1,336 121 41 Reservoir storage

8012 Clwyd Coastal 152 80 22 Reservoir storage

8014 Alwen Dee 1,142 155 45 Reservoir storage

8020 Bala 391 4 1 Reservoir storage

8021 Tywyn Aberdyfi 68 5 1 River abstraction

8026 Blaenau Ffestiniog 332 6 2 Reservoir storage

8033 Barmouth 85 5 2 Reservoir storage

8034 Lleyn Harlech 648 35 14 Reservoir storage

8035 Dyffryn Conwy 841 90 29 Reservoir storage

8036 South Meirionydd 584 7 Reservoir storage

South West Wales

8201 Tywi Gower 3,524 691 179 Reservoir storage

8202 Mid & South Ceredigion 1,780 62 18 Reservoir storage

8203 North Ceredigion 469 31 9 Reservoir storage

8206 Pembrokeshire 1,699 118 40 Reservoir storage

South East Wales

8101 Ross on Wye 198 19 6 Bulk supply import

8102 Elan Builth 1,229 18 5 Reservoir storage

8103 Hereford 1,258 127 32 River abstraction

8105 Llyswen 353 9 2 River abstraction

8108 Brecon Portis 447 12 4 Groundwater abstraction

8106 Monmouth 104 13 3 River abstraction

8107 Pilleth 366 8 2 Groundwater abstraction

8110 Vowchurch 250 6 2 Groundwater abstraction

8111 Whitbourne 354 15 5 River abstraction

8121 SEWCUS 2,756 1276 361 Reservoir storage

TOTAL 20,366 2915 829

Table 2.1 – Water Resource Zones – Key Facts and Figures

The following sections present further detail on each of our three sub-regions: North Wales, South

West Wales, and South East Wales.

4 Source: Table 10 June Return 2009

5 Based on average water delivered Table 10 June Return 2006 – 2009 with estimated zonal leakage included.

Page | 21


2.2.1 Water Resource Zones - North Wales

The ten WRZs in North Wales serve half a million people living mainly in Chester and Deeside,

Anglesey, the Bangor and Caernarfon area and the north coastal strip from Llandudno to Prestatyn.

They also supply some large non-potable customers in the area, notably on Deeside.

The WRZs in North Wales vary from very small areas supplied entirely from run-of-river abstractions

to larger zones supplied from a combination of impounding reservoirs, run-of-river abstractions and

groundwater sources. Some parts of North Wales experience a significant influx of tourists during the

summer months, which increases the demand for water. As a consequence, the systems that supply

these areas have to be able to meet these peaks whilst operating at lower levels during the remainder

of the year. Rainfall across North Wales varies from upwards of 3,000mm per annum on the

mountains of Snowdonia to 1,200mm per annum around the coastline of North Wales and Anglesey.

The supply of water in North Wales may be significantly affected in the next few years by the potential

development of a major new power station at Wylfa on Anglesey. When finally confirmed, the power

station will require a substantial volume of water in a zone that is comparatively supply-constrained,

and this will alter the complexion of water resource planning in the area. Although these plans are not

sufficiently crystallised to be taken into account in this Plan, it is likely that they will be a central

feature in the next draft Plan, due in 2013.

2.2.2 Water Resource Zones - South West Wales

The WRZs across South West Wales serve 0.9 million people living mainly in Swansea, Llanelli,

Carmarthen and the coastal towns and villages from Pembroke to Cardigan. We also supply and

support several large non-potable customers in the Pembroke Dock/ Milford Haven area. Much of

South West Wales experiences a significant influx of tourists during the summer months, which

increases the demand for water.

Rainfall across South West Wales varies from a low of 1,047mm per annum at Nevern on the north-

west Pembrokeshire coast to a high of 2,220mm per annum in the uplands of the Rheidol valley in

Ceredigion. Rainfall in the main Tywi catchment averages around 1,600mm per annum.

The WRZs in the region can be divided into two categories; small zones with relatively simple supply

systems in the north west of the area (eg. North Ceredigion and Mid & South Ceredigion) and the

more complex conjunctive use zones in the southern part of the region (eg. Pembrokeshire and Tywi

Gower).

One of the most significant zones in South West Wales – Pembrokeshire – is expected to require

investment to meet a supply-demand deficit during the Plan period. A diagram of the zone is

presented in figure 2.4 below.

Bolton Hill Water Treatment Works is fed from the Eastern and Western Cleddau and supplies water

to the southern half of the zone including Haverfordwest, Pembroke, Milford Haven and Tenby.

Preseli Water Treatment Works, fed from Llys-y-fran Reservoir and the Eastern Cleddau (via

Rosebush Reservoir), supplies the northern, more rural area and can also be used to supply water

into Haverfordwest.

Page | 22


Figure 2.4 – Pembrokeshire

2.2.3 Water Resource Zones - South East Wales

The WRZs across South East Wales serve 1.5 million people living mainly in Cardiff, Newport and the

South Wales valleys. They also serve several large non-potable customers.

Rainfall across South East Wales varies from as little as 700mm per annum in the eastern parts

around Hereford to some 2,200mm per annum in mid-Wales and the uplands of the South Wales

valleys. The main lowland urban areas such as Cardiff receive around 1,200mm per annum, slightly

under the average for Wales.

Within this sub-region, the South East Wales Conjunctive Use System zone (SEWCUS) is our largest

and most complicated WRZ. As set out in chapter 8 significant investment may be required in this

zone during the Plan period.6 A schematic diagram of SEWCUS is presented in Figure 2.5 below.

6 One other small zone in the South East also requires minimal investment, but this is negligible by comparison.

Page | 23


Figure 2.5 – The South East Wales Conjunctive Use System SEWCUS

There are several upland raw water reservoirs in the Brecon Beacons that can feed this zone,

including: Talybont (shown in Figure 2.6 below, capacity 11,668 Mega Litres) which supplies the Usk

Valley communities of Crickhowell and Abergavenny; Pontsticill (capacity 15,753 ML) which supplies

areas of the South Wales Valley; and Beacons/Cantref/Llwynon (total capacity 8,572 ML) which

supply Merthyr Tydfill and the area south towards Cardiff.

The other major sources of raw water are the Rivers Usk and Wye. The former is used to fill

Llandegfedd Reservoir (capacity 23,609 ML) near Cwmbran which in turn feeds Sluvad Water

Treatment Works. It can also feed Sluvad and Court Farm Water Treatment Works directly. The River

Wye is used to supply Court Farm Water Treatment Works. These Water Treatment Works feed the

main urban areas of Newport and Cardiff.

In addition there are a number of smaller reservoirs and Water Treatment Works that can supply

water in this zone.

Page | 24


Figure 2.6 – Talybont Reservoir

Page | 25


Chapter 3. Water Supply Capacity

The purpose of this chapter is to set out how we calculate the amount of water we can supply in each

WRZ. This is a function of the “Deployable Output” of our water resource assets together with the

allowances and adjustments that are made for the operational losses that are inherent in the

treatment and of water,7 outages, and transfers.

3.1 Deployable Output

Deployable output (DO) is the maximum quantity of water from a source, a group of sources, or from

a bulk supply, that can be sustained during a Dry Year. Output can be constrained by:

abstraction licence conditions;

the capacity of assets (pumping stations, treatment works, mains);

water quality factors; or

environmental needs, for example freshet releases.

We have assessed Deployable Output in accordance with Environment Agency guidelines and best

practice methodologies8 and have specifically carried out in-depth modelling to re-assess Deployable

Output in the 15 of our 24 WRZs where the supply system is complex. In the other 9 WRZs this has

not been necessary, either because the zone is served by a simple, single source, or because

Deployable Output is effectively capped by abstraction licence conditions.

For the modelling of the 15 complex zones we have used our “WRAPSim” software. This tool

examines how well a water supply system would perform in meeting demands under a variety of

historical climatic conditions and seeks to optimise the operation of the system.

A complete re-assessment of Deployable Output for all zones was undertaken during the preparation

for the 2008 Draft Plan. The key activities involved in this were:

an up-to-date review of the operational network and constraints;

a review of our demand modelling, and peak demand in particular: high peak demand during

the summer can limit Deployable Output later in the year;

a complete re-evaluation of the information available on reservoir inflows, including a review

of all available historical data and the identification of the most appropriate source of

information on inflows for use in the planning process;

update of the model data on inflows to 2007 where available;

the development of eight new rainfall-runoff models and improvements to existing ones; and

7 Losses from the distribution system are part of leakage and are included in “demand”, as described in chapter 4 below.

8 Surface Water Yield Assessment (National Rivers Authority, 1995); Reassessment of yield methodology (EA, 1997); A Unified

Methodology for Determination of Deployable Output from Water Sources (UKWIR and EA, 2000).

Page | 26


a re-assessment of the Emergency Provision requirements.9

The notable feature of this work was the analysis of 2006 demand. Although overall demand for

water in 2006 in Wales was considered to be normal, most WRZs experienced exceptional peak

demands. We have built these unusual demand patterns into our projections going forwards.

We set out the methodologies used in the re-assessment of Deployable Output in our 2007 June

Return to our economic regulator, Ofwat. Comments made by the Environment Agency in November

2007 have been addressed as part of our ongoing dialogue with the Agency and have been reflected

in our technical work as appropriate.10

In addition, since November 2007, we have continued to update the following components:

our assessment of peak demands, and how they relate to normal demand;

reservoir and catchment inflows, following updates of Environment Agency data; and

the baseline models we use to incorporate the actions and triggers defined as “actions” in our

Drought Plan.11

This is in line with our Company policy on Level of Service and is in

accordance with Environment Agency methodology.

We will continue to update and refresh our planning tools to reflect up-to-date experience, notably the

drier than average conditions that characterised the early summers of 2010 and 2011.

3.1.1 Groundwater Sources

A review of groundwater source yields has also been completed in accordance with national best

practice guidelines.12

As a result of the natural landscape and geology of Wales, groundwater

accounts for just 5% of the total water supplied. Most groundwater sources are operated

conjunctively with surface water sources and are used intermittently. However, some small sources

are always in use and provide constant supplies to local areas that cannot be supplied by other

means.

3.1.2 Emergency Storage

An emergency storage allowance has been incorporated into our Deployable Output assessments, in

accordance with Environment Agency methodology. This provides the reserve of water that is

considered necessary in view of the uncertainty regarding the duration and severity of droughts. The

emergency storage allowance adopted has been set at 30 days, which is in the middle of the range

(15-45 days) suggested by the Environment Agency guidance.

3.1.3 Dead Storage

Dead storage is the volume of water in a reservoir that lies below the lowest draw-off point and

therefore cannot be abstracted under normal operating conditions. A review of dead storage

9 As set out in the EA‟s 1997 “Re-assessment of Water Company Yields”.

10 See, in particular, “Deployable Output Values for Draft 2007 Water Resources Management Plan (WRAPSim modelled

zones)”: Entec, November 2007. 11

Final Drought Plan (DCWW, 2009, awaiting Direction to publish from WG). 12

The Methodology for the determination of outputs of groundwater sources (UKWIR, 1995b); A methodology for the determination of Groundwater Sources (UKWIR, 1995); Critical Period Groundwater yield (UKWIR/EA 2001).

Page | 27


allowances has been undertaken using data collected from bathymetric surveys and the results have

been incorporated in the Deployable Output calculations. Appropriate linkages with the Drought Plan

have been made where it is considered that dead storage may be used in drought conditions.

3.2 Resource Developments during 2005-2010

As part of the re-assessment of Deployable Output, we identified a number of capital schemes which

would improve the security of water supplies and bring about improvements. These schemes include

those originally identified in anticipation of our 2005-2010 investment programme and a number of

additional resource schemes that were implemented during that period. These are detailed in Annex

1.

3.3 Other changes since the 2008 Draft Plan

With three exceptions, there have been no further updates to our assessment of Deployable Output

since the 2008 Draft Plan.

First, we found that the efficiency of the abstraction from Llys-y-Fran reservoir could be improved,

increasing the Dry Year Annual Average Deployable Output from 77 Ml/d to 79.12 Ml/d. Details are

set out in the supporting technical report.13

Second, prompted by the dry summer of 2010, a number of operational measures were taken in the

SEWCUS WRZ to ensure continuity in the provision of services to all our customers. These changes,

mainly relating to network configuration, were incorporated into the SEWCUS WRAPSim model and

the annual average Deployable Output increased from 465 Ml/d to 477 Ml/d as a result. Details are

set out in the supporting technical report.14

Third, following the completion in March 2009 of a scheme in North Eyri Ynys Mon to improve security

of supply, details of the final delivered outputs of the project were incorporated into the WRAPSim

model, which had previously relied on theoretical design information. Annual average Deployable

Output decreased from 52.8 Ml/d to 51.0 Ml/d as a result.15

3.4 Outage

3.4.1 Background

Outage is defined as the temporary loss of Deployable Output due to planned and unplanned events

in a Dry Year (or drought period). An allowance for outage is required in order to recognise that at

any given time some assets will temporarily be out of action for one reason or another. It is important

to estimate outage for each WRZ individually: this is done by taking a pragmatic view of the potential

future reduction in Deployable Output that could be caused by asset failures and/ or operational

problems.

The estimation of outage is based on records of past events which resulted in a loss of Deployable

Output O and an assessment of the risks of unplanned events occurring in the future. We have used

13

“2010 Review of Consents Supply Assessment in Pembrokeshire Water Resources Zones, Final Report” (Entec, Jan 2011).

14 “2010 Review of Consents Supply Assessment in SEWCUS Water Resources Zones, Final Report” (Entec, Jan 2011).

15 “North Eryri Ynys Mon WRAPSIM changes to DO Model”: Welsh Water, October 2010.

Page | 28


best practice UK Water Industry Research (UKWIR) methodology16

in accordance with the

Environment Agency‟s Guideline, to determine the outages for all of our WRZs.

3.4.2 Our estimation of outage

Since 2005 we have gathered outage data on a monthly basis at Water Treatement Works level,

classified in accordance with the six main categories set out in the UKWIR report. This enables us to

carry out an annual assessment of outages and their causes. The six categories are:

algae – where this may be present in the raw water, affecting quality at source;

planned outage – these are known planned maintenance activities, and are divided into those

that would take place even in a drought situation and those that could be delayed until a non-

drought period;

power failure – this highlights areas where temporary and back-up generation is not adequate

to maintain operation;

source pollution – where, for example, there is a risk that a river could be contaminated due to

a spillage;

system failure – events where equipment has failed; and

turbidity – again, affecting raw water quality.

The methodology we use assesses the probability of events occurring by looking at the duration and

magnitude of observed events; we have modified this by adding information on the frequency with

which these events occur. The monthly data we collect are fed directly into this assessment.17

The

final outage estimate derived from this process is ultimately presented as a reduction in Deployable

Output. We have assessed outage at WRZ level for both annual average and critical period18

scenarios.

In assessing outage, we ensure that there is no double counting of Water Treatement Works losses

or operational use that is accounted for elsewhere. As part of updating our analysis, we found that

some double-counting had previously occurred in relation to turbidity which, as well as being

accounted for in outage, had been identified as a cause of significant higher operational use

associated with increased filter washing caused by greater turbidity. Consequently, our assessment

of outage has been reduced in some WRZs.

3.4.3 Changes since the 2008 Draft Plan

Since publication of the 2008 Draft Plan we have carried out a two-stage review of outage to take

account of new evidence from the monthly data collection exercise.

In Stage 1 we compared the estimates and assumptions on which our outage assessment was based

against actual up-to-date evidence, and made adjustments where significant differences were

observed, taking into account Dry Year influences where appropriate. We also considered allowing

16

“Outage Allowances for Water Resource Planning”: (UKWIR, 1995). 17

“Review of Outage Assumptions for Post Draft Water Resources Management Plan”: November 2008 Entec, 2009. 18

This is the period of peak demand within the Dry Year.

Page | 29


for events that were considered possible even if there had been no actual occurrence during the

period over which monthly data had been collected.

In Stage 2 we examined our Drinking Water Safety Plans and the risks identified within them relating

to source pollution. Where there is a risk of source pollution that had not been captured using the

actual events database, our outage assessment was amended accordingly.

Our outage calculations have been updated in this Plan for those WRZs that have been subject to

reductions in Deployable Output as a result of implementing the outcomes of the Environment

Agency‟s consent review exercise: outage has also been updated for North Eyri Ynys Mon zone

because this is the other significant WRZ there has been a re-assessment of Deployable Output.19

3.5 Levels of Service (LoS)

A key role in Water Resources Planning is played by the frequency with which a hosepipe ban or a

Drought Order/ Permit would be expected to be required in order to maintain water supplies, the

“Level of Service”.

We believe that it would be wrong for us to plan for a level of service that would guarantee there

would never be any customer restrictions as this would require enormous investment in additional

water resource assets (principally reservoirs) which would be used very infrequently. This would

require much higher levels of customer bills, which we do not consider could be justified, and would

be environmentally unacceptable.

The Company has accordingly set its minimum overall level of service as follows:

not more than once in every 20 years, on average, for a hosepipe ban, and

not more than once every 40 years, on average, for Drought Orders/ Permits.

We view the imposition of rota cuts and standpipes, which represent more severe restrictions on

customer use, as unacceptable. This is for several reasons, notably the risk to public health that rota

cuts and standpipes entail.

In practice the actual current level of service in each of the 24 WRZs varies and is shown in Table 3.1.

To ensure compliance with the Water Resources Management Plan Direction (2007) and as

requested by the Agency in their Statement of Response Advice Report to the Welsh Government on

our 2008 Draft Plan, for each WRZ we have assessed the impact of each resource option upon the

level of service. We have ensured that all intervention options are compliant with our current level of

service and the reported increases in DO reflect this. However, where appropriate, changes to level

of service as a result of the options have also been considered.

It is theoretically possible to increase the Deployable Outputin a zone by lowering the level of service.

Changes to our overall level of service are therefore one of the options when we are considering how

to address supply demand deficits.

19

“R143 NEYM outage update Nov 2010” Entec UK Limited, November 2010.

Page | 30


Water Resource Zone Levels of Service

20 (years)

Hosepipe Ban Drought Order/ Drought Permit

8001, North Eyri Ynys Mon 1 in 24 >1 in 48

8012, Clwyd Coastal 1 in 22 1 in 43

8014, Alwen – Dee 1 in 29 1 in 43

8020, Bala >1 in 84 >1 in 84

8021, Tywyn – Aberdyfi >1 in 48 >1 in 48

8026, Blaenau Ffestiniog 1 in 24 1 in 48

8033, Barmouth 1 in 48 >1 in 48

8034, Lleyn – Harlech 1 in 24 1 in 48

8035, Dyffryn – Conwy 1 in 29 1 in 86

8036, South Meirionnydd >1 in 48 >1 in 48

8101, Ross on Wye >1 in 33 >1 in 33

8102, Elan – Builth >1 in 33 >1 in 33

8103, Hereford Conjunctive Use System >1 in 33 >1 in 33

8105, Llyswen >1 in 33 >1 in 33

8106, Monmouth >1 in 33 >1 in 33

8107, Pilleth >1 in 33 >1 in 33

8108, Brecon – Portis >1 in 33 >1 in 33

8110, Vowchurch >1 in 33 >1 in 33

8111, Whitbourne >1 in 33 >1 in 33

8121, SEWCUS >1 in 33 >1 in 33

8201, Tywi Conjunctive Use System 1 in 36 >1 in 36

8202, Mid & South Ceredigion 1 in 23 >1 in 69

8203, North Ceredigion 1 in 35 1 in 69

8206, Pembrokeshire 1 in 36 >1 in 36

Table 3.1 – Actual Level of Service

20

Note that “> 1 in 33” denotes a better level of service than 1 in 33, not a frequency that is greater than 1 in 33. Also, it should be pointed out that “>1 in 33” refers to those situations where we have records for the last 33 years, during which there have been no restrictions.

Page | 31


3.6 Operational use of water

Water can be lost during the routine operation of raw water mains and water treatment works. Overall

we estimate some 3% of water is lost in this way.

3.7 Water Transfers

3.7.1 Potable supplies

There is some limited scope to transfer water, both raw and treated, between particular parts of zones

in our area and in the form of bulk supplies between ourselves and neighbouring water companies. A

summary of our transfers is shown in Table 3.2.

Export from Import to Maximum Volume

(Ml/d)

Alwen Dee WRZ Dee Valley Water 0.16

Lleyn Harlech WRZ* Barmouth WRZ 1

Severn Trent Water South Meirionydd WRZ 0.45

South Meirionydd WRZ Severn Trent Water 0.12

Severn Trent Water Ross-on Wye WRZ 9

Hereford WRZ* Whitbourne WRZ 0.33

Hereford WRZ* Ross on Wye WRZ 1

Tywi Gower WRZ SEWCUS WRZ 14.08

*Schemes delivered in AMP4 to increase inter-zonal transfer capability

Table 3.2 – Water Transfers

Further details of three of these transfers are provided below.

Tywi Gower to SEWCUS

Our latest assessment of the maximum level at which water can be transferred from Tywi Gower to

SEWCUS is based on WRAPSim modelling that takes into account changes made to the supply

system following the dry summer of 2010 (as described in section 3.3 above) and confirmation of the

capacity of the network to deliver transfers at a higher level. This is one of the reasons for the change

in Deployable Output for the South East Wales Conjunctive Use System, “SEWCUS”, described in

section 3.3 above.

Alwen Dee to Dee Valley Water

The River Dee is a regulated source that is managed in accordance with the Dee General Directions

which are the responsibility of the Environment Agency, supported by the three major water

companies in the area (Welsh Water, Dee Valley, United Utilities) and British Waterways Board. As

part of this complex arrangement we also export a small amount of water to Dee Valley Water in the

lower part of the Dee system which enables them to supply domestic properties in that area.

Severn Trent Water to South Meirionydd

The landscape of South Meirionydd WRZ and the limited small-scale supplies in the area can make

supplying water a challenge. Hence, it is beneficial to both us and Severn Trent Water (whose supply

boundary is on the border with the South Meirionydd WRZ) to have an “exchange” of water in certain

Page | 32


locations. There is an import into the zone from Severn Trent Water of 0.45 Ml/d, and an export from

the zone to Severn Trent Water of 0.12 Ml/d.

3.8 Elan Builth

Since the 2007 June Return we have modified the reporting of Elan Builth WRZ so as to show only

the Welsh Water abstraction allowance (around 5 Ml/d) within this zone and not the significantly

greater proportion exported to Severn Trent Water (up to a maximum of 386.4 Ml/d) from the Elan

reservoirs. This amendment was agreed with the Environment Agency for the 2008 Draft Plan and

removed any discrepancy relating to the reporting of Deployable Output of a Severn Trent source

which is within their, and not our, control.

3.9 Non-Potable Supplies

In addition to supplying domestic and non-domestic customers with potable water, we do in certain

instances and locations supply large industrial users with water that has not been treated to potable

standards but that is suitable for their purposes. There are two zones where these supplies share

water resources assets with potable water supply systems and where the non-potable supplies are

relevant to the calculation of Deployable Output.

Pembrokeshire WRZ

In this WRZ we supply a number of industrial users of water in and around the Milford Haven area,

mostly involved in the oil refinery, natural gas and power generation industries. The water is primarily

used for tank cleaning and cooling purposes. The supply of non-potable water is taken account of

directly within Deployable Output in this zone, as both potable and non-potable supplies are drawn

from the same raw water source. At present the supply of water for industrial purposes equates to

approximately 27 Ml/d.

The South East Wales Conjunctive Use System (SEWCUS) WRZ

We also supply non-potable water to industrial customers in the SEWCUS zone. As in

Pembrokeshire, this water is directly accounted for within Deployable Output as it is primarily supplied

from raw water sources that are also used for domestic supply.

3.10 Other customers

There are a number of other Industrial customers that are supplied with non-potable water through

discrete supply systems. These do not affect the supply demand position in any of our WRZs

because they do not share assets with potable water supply systems and therefore do not affect

Deployable Output. Further details of these supplies are reported to Ofwat and the Environment

Agency on an annual basis.

We also provide a non-potable bulk supply to Albion Water. This water is not accounted for within our

supply demand balance for the Alwen-Dee WRZ because the supply system currently shares no

assets with our potable supply systems (although the non-potable resource could fairly readily be re-

deployed for potable use if necessary in the future).

3.11 Water Available for Use

Water Available for Use is defined as the volume of water available once we have adjusted

Deployable Output for outage, transfers and operational losses, and provides the figure we use for

planning purposes as the amount of water we can expect to be able to supply. It is Water Available

Page | 33


for Use that provides the figure that, if exceeded by the sum of Demand and Target Headroom (see

below) signifies that a zone is in deficit.

Page | 34


Chapter 4. The Demand for Water

This section provides a summary description of how we compile forecasts of the demand for water.

We begin by establishing a baseline position and then, by looking at factors such as projections of

population and household occupancy, we calculate how demand for water may change.

Full details of how we have prepared our demand forecasts can be found in our Technical Report,

Demand for Water Resources 2010.21

4.1 Baseline demand

Baseline demand forecasts include our current demand management policies (Section 4.6) but

exclude the effects of any additional demand management measures identified by the option

appraisal (Chapter 9). This approach is in full accordance with the Environment Agency guidance

(2008).

For the purposes of preparing our demand forecasts we chose 2008-09 as the base year, as this was

the latest year for which actual data was available when we embarked on the planning process. In

line with Agency guidance (2008) though, the years 2006-07 and 2007-08 have been retained and

shown in the supporting Water Resource Planning Tables to enable comparison between the 2008

Draft Plan, this Plan and the expected Final Plan.

4.1.1 Base Data – population and properties

Base year population for each WRZ was derived by adding one year‟s growth to 2007 estimates,

verified by reference to data published in 2008 by the Office of National Statistics and the Welsh

Government.

Base year property numbers are as reported in our 2009 June Return to Ofwat, and are derived from

extracts from Welsh Water‟s Customer Accounting System. Using information on customer

addresses, we are able to allocate properties to WRZs, categorised into measured, unmeasured,

households and non-households.

Occupancy rates are based upon a 2003 customer survey, supplemented by an annual zonal review

based upon metered consumption data and additional data obtained from customers as part of meter

option requests. In some areas the number of second homes is high and it is necessary to take this

into account.

To establish base year consumption for each customer type we use data from our Domestic

Consumption Monitor22

. The primary purpose of the Monitor is to enable our Company to determine

unmeasured household Per Capita Consumption. During 2008-09, Welsh Water undertook a review

of its current unmeasured Per Capita Consumption strategy. A revised strategy was developed to

build upon the existing monitoring areas to improve the geographical representation of the Domestic

Consumption Monitor. This will provide more robust estimates of unmeasured Per Capita

Consumption in the 24 WRZs in the future. Work has begun to select additional monitoring areas

21 “Technical Report, Demand Forecasts for Water Resources Plan 2010”: Welsh Water, 2010. 22 Our Domestic Consumption Monitor involves recording the consumption pattern of a fairly large number of homes over an

extended period of time. The aim is to produce a quantitative understanding of water consumption for various household types. The large number of houses and time period of the monitor allow trends and seasonal patterns to be investigated. Our DCM complies with Industry Best Practice.

Page | 35


following a best practice review23

to bring the total number in the Domestic Consumption Monitor up to

approximately 150. As part of this process, the current areas will also be reviewed to ensure that they

comply with the UK Water Industry Research „best practice‟ guidance and thus remain suitable for

inclusion in the Domestic Consumption Monitor.

4.1.2 Unmeasured Per Capita Consumption (pcc)

For 2008-09, the regional annual average unmeasured Per Capita Consumption was derived from 15-

minute logged data from the Domestic Consumption Monitor with a total population of 66,554 in

unmeasured households. There has been no change to the methodology used to calculate

unmeasured Per Capita Consumption since the Draft Water Resource Management Plan was

published. However, to simplify the data collection and data checking processes and to allow for the

eventual addition of new monitoring areas, both the 15 minute flow data and base data are now input

to and processed in the corporate Leakage Monitoring and Reporting System software which

calculates the unmeasured Per Capita Consumption using the verified data.

Analysis of data from the Monitor produced an unadjusted annual average unmeasured household

Per Capita Consumption value of 154 l/h/d for the base year. After various adjustments, as set out in

on June 2009 Return to Ofwat (notably those made as part of the overall reconciliation of the water

balance) the figure we reported and have used as the basis for our demand forecasts is 160.1 l/h/d.

For each WRZ, unmeasured Per Capita Consumption was calculated by multiplying regional

unmeasured Per Capita Consumption by the ratio of measured Per Capita Consumption for the zone

to regional measured Per Capita Consumption. Measured Per Capita Consumption data from a single

year (2008-09) has been used to estimate ratios for each zone.

23

„Best Practice for Unmeasured Per Capita Consumption Monitors‟ (99/WM/08/25), UKWIR 1999

Page | 36


4.1.3 Measured Per Capita Consumption

Total measured water delivered (household and non-household) is constrained to reconcile with the

total volume derived from the income received.

The 2008-09 initial estimate of measured household Per Capita Consumption (as recorded) was

119.4 l/h/d. This was derived by dividing the consumption recorded by over 340,000 meters, adjusted

to reconcile with income, by the population in billed measured households. In the 24 WRZs, values

ranged between 109.6 l/h/d (Elan Builth) and 131.0 l/h/d (Whitbourne).

The average consumption per property in 2008/09 was 200 l/pr/day. This is 10 l/pr/day higher than the

equivalent 2006-07 figure. Consumption at property level is subject to more detailed analysis in which

trends in average consumption by groups of household types are tracked.

The corresponding estimate of measured household Per Capita Consumption for 2008-09, after

adjustments, was 124.2 l/h/d.

4.1.4 Non-Household Per Property Consumption

Non-household consumption is predominately measured, with only 10,000 properties (less than 1% in

terms of volume) remaining unmetered within our supply area. Our Compulsory Metering Policy is that

all non-household premises will be on a metered charge basis and these have been built into the on-

going metering programme. It is estimated that we will transfer around 500 properties per year on to

a metered basis. We derived the unmeasured non-household per property consumption estimate by

examining the consumption records of customers that have been compulsorily metered over the last

nine years. This produced a figure for 2008-09 of 487 l/pr/day.

4.1.5 Normalisation of Base Year

Finally, it was necessary to make adjustments to base year demand estimates to reflect the extent to

which the base year was not “normal”. Using regression techniques to explore the relationship

between consumption and weather (rainfall and temperature) we identified that 2008-09 was

comparatively wet, and adjusted the demand components upwards accordingly.

4.2 Population forecasts

4.2.1. Local Authority Projections

There are two projections of population available to us: one provided by the Welsh Government,

which is based on 2006 population estimates; and one provided by the Office of National Statistics.

These generate different figures for population growth, the first projecting an annual increase of

around 17,000 and the latter forecasting slower growth of 14,600 per annum. In accordance with

Government guidance24

on how to address this discrepancy we have used the Office of National

Statistics figures for total population and the Welsh Government projections to divide overall totals

between WRZs.

4.2.2 Migration

The biggest driver of population growth in Wales is likely to be inward migration. However, this is

expected to be slower in the short to medium term than the levels observed in recent years. Our

24

“Statistics for Wales – Local Authority Population Projections for Wales (2006-based) Summary Report”.

Page | 37


projections therefore assume a lower level of migration over the next few years, returning to trend

after 2015.

4.2.3 Insets

An inset appointment is made where an existing supplier is replaced by another supplier of water or

sewerage services for customers in a specified area; an inset appointment can only be made for part

of a current supplier‟s area. Two inset appointments have been made in our water supply area, but it

is not possible to forecast the extent to which further inset appointments will be made in our area in

the future. However, from the point of view of water resource management planning, the important

point is that while insets will affect the number of customers we serve they will not affect our demand

forecasts because we will almost certainly still supply the water. We have also assumed that

household and customer demand characteristics will be unaffected by the making of inset

appointments.

4.2.4 Non-household Population

Non-household population (e.g. resident in prisons, university campuses, military bases) is forecast to

rise slowly, directly in line with the increase in the level of non-household properties forecast for the

period.

4.2.5 Population Forecasts

Future estimates of population in metered households are based on forecast numbers of new

properties, optant,25

and selectively metered households, multiplied by projected occupancy rates.

Similarly, average occupancy rates in non-household properties are multiplied by the number of

forecast non-household properties. The remaining population from the overall population forecasts is

allocated to the unmeasured household stock.

25

Customers who have chosen, or opted, to be metered.

Page | 38


Figure 4.1 shows the historical and projected population forecasts for the different customer

categories.

Figure 4.1 – Population Forecasts

4.3 Property Forecasts

4.3.1 Projections

We have based our forecast of the rate of change in the number of household properties within our

area on trends from the last 9 years. We estimate that there will be 9,000 new household

connections in a “normal” year. However, given the current state of the regional economy we are

currently experiencing lower new connection rates, and have reflected this in our near term forecasts.

From 2012-13 we forecast the level of new households built in our region to return to normal levels,

and over the ten years 2015-25 we are forecasting an element of “catch-up”, with new household

connections increasing above the long term normal level for a temporary period.

4.3.2 Government Statistics on Property Numbers

In June 2009, the Welsh Government published household projections for Wales at a National and

Local Authority Level. In addition, a number of Local Authorities have published Local Development

Plans. Our property forecasts for the 2008 Draft Plan for the Herefordshire area were based on

information received from Hereford County Council. Our revised forecasts take account of the latest

revisions to the Regional Spatial Strategies.

Page | 39


4.3.3 Insets and Non-households

As mentioned earlier there may be a trend to customers in new properties in Wales being served by

inset appointee companies, but we nonetheless include these in our forecasts, because we expect to

have to supply them with water, whether directly or through an intermediary.

The level of non-household properties is forecast to continue to rise slowly throughout the planning

period at a steady rate of 200 properties per year. The already low level of unmeasured non-

households is forecast to continue to fall over the planning period.

4.3.4. Metered/ Unmeasured Split

The proportion of household customers on a metered supply will continue to rise. All new

connections to our network are required to be metered and we continue to see unmeasured

customers opting to have a meter installed at a steady rate. Overall, we estimate that the number of

customers opting to be charged on a measured tariff will continue at 2.5% of the number of

households remaining unmeasured at the start of each year.

Figure 4.2 shows historical and projected household forecasts for the period 2000-01 to 2034-35.

Figure 4.2 - Household property forecasts

4.4 Household Demand

Figure 4.3 shows the historical and projected household demand forecasts for the period 2000-01 to

2034-35, for both the normal and Dry Year forecasts. The shape of this curve reflects the interaction

between the upward pressure on demand caused by population and property growth, and the

downward pressure on demand caused by metering. The margin between Dry Year and normal

demands varies from zone to zone, but averages across our region at approximately 4%.

Page | 40


„Normal‟ year forecasts of unmeasured and measured household demand were calculated by

multiplying together the forecasts of population and Per Capita Consumption. The zonal Per Capita

Consumption forecasts applied were derived by multiplying the regional forecasts by the zonal

unmeasured and measured Per Capita Consumption ratios (section 4.1).

Figure 4.3 - Household Demand Forecasts

4.5 Non Household Demand

4.5.1 Economic Sectors

We have been monitoring the measured water consumption of 13 sectors of economic activity for

over 12 years, and use this data as the basis for forecasts of future demand, as well as for other

purposes such as the estimation of night use allowances in leakage reporting.26

4.5.2 Non-household Demand

Our forecasts of non-household measured water delivered have been made by extrapolating past

trends. Our analysis of demand by sector has now been in place for over 10 years and provides a

basis for forecasting that we consider to be at least as robust as the approach used previously under

which consumption was defined as a function of future changes in economic conditions.

Longer term forecasts of non-household demand are notoriously difficult to make. In the demand

forecasts prepared for the Plan, we are forecasting that the rate of decline in demand will gradually

slow after 2014-15. There have been some large reductions in non-household demand in recent

26 NB: as a result, the WRP8 tables for the Revised Draft Plan will be completed using the Company‟s own sector headings

rather than those specified by the EA. However, in broad terms the headings are very similar.

Page | 41


years but we believe that the levels reached towards the end of the planning period are approaching a

long-term minimum.

Figure 4.4 presents our forecasts of non-household demand for both the normal and Dry Year

scenarios.

Figure 4.4 – Non Household Demand Forecast

4.6 Distribution Input

Normal year forecasts of Distribution Input27

were derived by summing the Component forecasts

described in the previous sections and adding forecast total leakage to produce forecasts for each of

the 24 WRZ‟s for each year up to and including 2034-35.

„Dry‟ year and „Critical Period‟ forecasts for the 24 WRZ‟s were derived by applying „peaking‟ factors

to the Normal year forecasts to account for the expected increase in demand in whole „dry‟ years and

during shorter (for example, one week) periods of increased demand (Critical Periods). Our peaking

factors have been derived from analysis of demand data from 2002 to 2007. Since this is currently our

most accurate period of demand data, any attempts to lengthen this record to match the longer

hydrological records (typically from the early 1970‟s) would introduce great uncertainty into the

results.

Analysis undertaken within the demand forecast report also confirmed that 2003-2006 events used at

zonal level were dry year events and have been selected accordingly depending upon the zone. As

agreed with the Agency, this record will be improved as more data becomes available and/ or when a

dry year event occurs which would trigger a re-assessment of demand. For example, during 2010 we

experienced a significant prolonged period of dry weather. Analysis of this data and its impact on

water demand will commence shortly.

27

This is the volume of water, whether expressed on a zonal or company basis, that is delivered into supply, into the distribution

network.

Page | 42


Further results and peaking factors for each zone and the analysis process are discussed in detail in

our demand forecasting report21

.

Figure 4.5 shows the historic and projected distribution input forecasts for the period 1992-93 to 2034-

35 for both the normal and dry year forecasts. Tables 4.1 and 4.2 show the „Dry‟ and „Critical Period‟

forecasts for all 24 WRZ‟s for the years 2014-15, 2024-25, 2034-35. The 2008-09 values are actual

Distribution Input values as reported in our 2009 June Return to Ofwat.

Figure 4.5 Distribution Input Forecasts

Page | 43


Zone No. Zone 2008-09 (Ml/d)

2014-15 (Ml/d)

2024-25 (Ml/d)

2034-35 (Ml/d)

8001 North Eryri/ Ynys Mon 40.84 37.10 36.11 35.76

8012 Clwyd Coastal 21.68 20.23 20.35 20.78

8014 Alwen/ Dee 44.62 45.29 42.94 42.05

8020 Bala 1.33 1.43 1.42 1.44

8021 Tywyn Aberdyfi 1.26 1.28 1.26 1.27

8026 Blaenau Ffestiniog 1.83 1.76 1.78 1.82

8033 Barmouth 1.62 1.69 1.73 1.80

8034 Lleyn/ Harlech 13.60 12.42 12.27 12.32

8035 Dyffryn Conwy 29.51 29.20 28.93 29.19

8036 South Meirionnydd 2.62 2.40 2.46 2.54

8101 Ross-on-Wye 5.95 6.33 6.49 6.77

8102 Elan/ Builth 4.67 5.05 5.13 5.27

8103 Hereford CU Area 32.53 37.71 38.07 39.70

8105 Llyswen 2.38 2.57 2.73 2.90

8106 Monmouth 3.49 3.77 3.87 4.00

8107 Pilleth 2.52 2.55 2.63 2.73

8108 Brecon/ Portis 3.98 4.79 4.81 4.90

8110 Vowchurch 2.24 2.41 2.48 2.60

8111 Whitbourne 4.77 5.33 5.48 5.71

8121 SEWCUS 361.27 352.33 353.19 363.12

8201 Tywi CU Area 178.76 180.69 180.15 183.99

8202 Mid & South Ceredigion 18.47 17.92 18.25 18.68

8203 North Ceredigion 8.62 9.42 9.71 10.02

8206 Pembrokeshire 40.20 42.09 41.74 41.97

Region 828.75 825.75 823.97 841.33

Table 4.1 Zonal Dry year Distribution Input Forecasts

Page | 44


Zone No. Zone 2008-09 (Ml/d)

2014-15 (Ml/d)

2024-25 (Ml/d)

2034-35 (Ml/d)

8001 North Eryri/ Ynys Mon 40.84 43.61 42.44 42.04

8012 Clwyd Coastal 21.68 24.36 24.51 25.02

8014 Alwen/ Dee 44.62 56.35 53.43 52.33

8020 Bala 1.33 1.86 1.85 1.87

8021 Tywyn Aberdyfi 1.26 1.92 1.88 1.90

8026 Blaenau Ffestiniog 1.83 2.05 2.06 2.11

8033 Barmouth 1.62 2.89 2.96 3.07

8034 Lleyn/ Harlech 13.60 15.24 15.05 15.11

8035 Dyffryn Conwy 29.51 32.89 32.60 32.88

8036 South Meirionnydd 2.62 2.99 3.06 3.15

8101 Ross-on-Wye 5.95 8.11 8.31 8.67

8102 Elan/ Builth 4.67 6.47 6.58 6.75

8103 Hereford CU Area 32.53 46.23 46.68 48.68

8105 Llyswen 2.38 3.08 3.27 3.48

8106 Monmouth 3.49 4.42 4.53 4.70

8107 Pilleth 2.52 3.13 3.24 3.37

8108 Brecon/ Portis 3.98 5.44 5.47 5.58

8110 Vowchurch 2.24 3.14 3.23 3.39

8111 Whitbourne 4.77 6.25 6.42 6.70

8121 SEWCUS 361.27 401.21 402.19 413.50

8201 Tywi CU Area 178.76 220.01 219.35 224.02

8202 Mid & South Ceredigion 18.47 22.61 23.02 23.57

8203 North Ceredigion 8.62 11.36 11.71 12.08

8206 Pembrokeshire 40.20 55.13 54.67 54.97

Region 828.75 980.76 978.53 998.94

Table 4.2 Zonal Critical Period Distribution Input Forecasts

Page | 45


4.7 Managing Demand

Demand management plays a vital part in maintaining the security of water supplies, and can

contribute significantly to ensuring that water is managed in the most sustainable and cost effective

way.

This section describes the ways in which we look to manage demand, including water efficiency

strategy, leakage control, metering and tariff policies. Our baseline strategies for demand

management are built into the demand projections presented above.

4.7.1 Water efficiency

We have a duty to promote the efficient use of water by all our customers. To achieve this, we

provide information to customers about:

the sensible use of water in the home and garden;

how to conduct a self-audit of household consumption;

the availability of cistern and other water-saving devices;

the availability of supply pipe leakage detection/ repair;

how to report a leak; and

how to get further information.

Welsh Water launched its Water Efficiency Strategy in May 2007, building on an established water

efficiency programme and ensuring alignment with the Welsh Government‟s Environment Strategy

(Environmental Outcome number 14).

We believe that there is a need to move public perception away from thinking that Wales will always

have plenty of water and to encourage wiser and more efficient use of water. Our Water Efficiency

Strategy sets out the activities and initiatives that are in place and planned to promote the efficient

use of water. These include the provision of information to customers, as detailed above, and a

comprehensive programme of educational activities. In addition, our strategy fully reflects the

principles behind Ofwat‟s Water Efficiency Initiatives.28

There are 10 good practice headings within

the Register, and these are detailed below:

cistern displacement devices;

household water audits;

commercial water audits;

customer education/awareness;

other water efficiency initiatives;

metering;

water butts/composters/trigger hoses;

28

Water Efficiency Initiatives – Good Practice Register (Ofwat, 2007).

Page | 46


retrofitting toilets and showerheads;

collaborative R&D (Research and Development); and

supply pipe repair/replacement.

A summary of our activities in each of these areas can be found in Annex 2.

4.7.2 Efficiency Targets

We have been promoting the efficient use of water by our customers for a number of years.

However, 2010 saw the introduction of mandatory targets by Ofwat and a notably more prescriptive

approach to what the promotion of water efficiency should entail.

We can choose to use water efficiency measures within our demand management strategy for a

specific water resource zone as part of our overall planning approach to water resource management

when the analysis indicates that it makes economic sense. If we use water efficiency measures as a

solution to address supply/demand issues then Ofwat monitors our progress in delivering them by

setting a “Sustainable Economic Level of Water Efficiency” target.

We are also obliged, through the newly-introduced Ofwat targets, to deliver a saving of 1.31 Ml/d

across the company in each reporting year. This is to be achieved through defined approaches to

water efficiency and is described as our “Base Service Water Efficiency” target.29

The Base Service

Water Efficiency element of water efficiency is separated into two further categories relating to the

mode of delivery, namely “Hard” and “Soft” option measures.

Delivering “Hard” options”

“Hard” measures relate to the installation or distribution of water-saving equipment. Such equipment

aims to reduce consumption by technological means. Under Ofwat‟s target mechanism hard

measures are permitted to contribute up to 70% of the overall target, which for us equates to around 1

Ml/d of water saved. The reason for this high percentage is that the evidence underpinning

technological measures for reducing water consumption is well-documented, and is regarded as

relatively robust.

To deliver these targets, we aim to deliver cost-beneficial savings across the entire customer base

whilst building on the evidence we compile to demonstrate the effectiveness of water efficiency.

During the first year of the target we have:

provided water-saving welcome packs to customers opting for a water meter;

undertaken a collaborative project with key stakeholders in Wales to understand the links

between water and energy efficiency and social behavioural change where affordability is a

key consideration;

provided water efficiency audits for schools and installed water-saving devices;

29

Ofwat‟s PR09/20 paper (December 2008) sets out its position on water efficiency and has set companies two-part targets;

base service water efficiency (BSWE) and the sustainable economic level of water efficiency (SELWE). The BSWE is the minimum activity Ofwat expects companies to undertake, whilst the SELWE is additional water efficiency activity above the base level.

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provided water efficiency audits and equipment installations in public health care sector

buildings, helping health authorities to manage their water footprint and reduce their costs;

assisted business customers with water audits and made recommendations for managing

water more efficiently, including help with the implementation of hard technological measures;

assisted tertiary education providers in managing their water consumption in places where

there is high demand, such as halls of residence;

collaborated in a UK-wide promotion with a major retailer and energy provider for the

distribution of free water-saving packs to customers;

provided free Hippo bags to all customers on request; and

provided a web-based water butt incentive scheme.

Throughout the remainder of our current 2010-2015 business plan period, we will continue to work to

identify the most effective approaches to water efficiency promotion across our customer base.

Linking “soft” and “hard” option measures

It is widely recognised that technology alone cannot deliver the optimal water efficiency strategy and

that other drivers of consumption such as behaviour, seasonality, culture and affordability influence

the demand for water. We are committed to ensuring that technological measures are supported by

“soft” approaches aimed at influencing individual or corporate use.

Delivering “soft” options

Soft option measures relate to the promotion of water efficiency through education or communication

programmes. Historically this is the approach to water efficiency promotion we have tended to use.

For example, during the recent “spring droughts” of 2010 and 2011 we moved quickly to reinforce the

message for customers to “use water wisely” through press releases, website updates, and so forth.

Within the mandatory targets, soft options can contribute the remaining 30% of the target. The lower

percentage recognises that the evidence of the effect that educational or communication campaigns

have on consumption is somewhat limited.

Overall, our education programme currently contributes around 90% of the 0.3 Ml/d annual reduction

required under the soft component of the mandatory target. We believe that this focus on education

is the most sustainable and cost-beneficial approach to the promotion of water efficiency.

4.7.3 Delivering our Water Efficiency Strategy

We have set up a Water Efficiency Working Group to deliver water efficiency projects: it is normally

held on a monthly basis.

We acknowledge the Ofwat mandatory target approach and, in accordance with the legislative

requirements in Wales, have consulted (in February 2009) with the Welsh Government as to how our

strategy for the promotion of water efficiency in Wales should be aligned with its overall sustainability

objectives.

It is our intention to maintain and to further the approach of promoting water efficiency through

communication and education in line with our current strategy whilst developing and expanding other

activities to ensure the year-on-year target reduction of 1.31 Ml/d continues to be achieved. Where

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necessary, our strategy will be revised in the future in line with any new guidance issued by the Welsh

Government in relation to its sustainability objectives.

4.7.4 Leakage Strategy

With more than 27,000km of pipelines and more than 1 million customer connections on our network,

leakage is inevitable. It is critical for a water company to know how much water is leaking from its

assets and to have good operational knowledge of where that leakage is occurring.

We have an aged network, with many pipes over 100 years old. Fresh leaks are continually breaking

out; we require sustained leak detection and repair procedure simply to maintain leakage at current

levels. A substantial quantity of leakage is classified as “background leakage”, the aggregation of

losses from all the fittings on the network. These leaks are generally small and difficult to find, and

would usually be expensive to repair given the modest quantity of water saved.

We are committed to meeting our leakage targets and have reduced total leakage from 329 Ml/d in

2001-02 to 190 Ml/d in 2009-10, a reduction of 42% in 8 years. Detection, repair and optimisation of

leakage solutions are an integral part of the Environment Agency‟s Guidelines, primarily as a way of

reducing demand. The Guidelines state that we should:

demonstrate how the company‟s leakage appraisal is built from data on District Meter Area

source leakage and cost information to produce WRZ assessments of the Economic Level of

Leakage30 and thereby an overall leakage strategy at the company level;

detail the company‟s current leakage policies that are built into the baseline demand forecast;

and

not rely on a single assessment of ELL projected across the planning period.

Economic Level of Leakage

The Economic Level of Leakage can be broken down into Short Run Economic Level of Leakage or

Long Run Economic Level of Leakage, depending on which planning horizon is chosen. Short Run

Economic Level of Leakage is the leakage target to be achieved in the short term i.e. 5 years or so,

based on current leakage levels. The Short Run Economic Level of Leakage is updated in each five

yearly Periodic Review of water price limits to account for, for example, efficiency savings in the

previous 5 years. Our Short Run Economic Level of Leakage only includes current active leakage

policy activities and provides baseline leakage levels used in the demand forecasts across the

planning period.

For WRZs identified as being “in surplus”, Short Run Economic Level of Leakage and Long Run

Economic Level of Leakage values are equal. However, for deficit WRZs, the least cost planning

process identifies the least cost scheme(s) to meet the deficit. Such schemes may include further

reductions in leakage to levels below the Short Run Economic Level of Leakage, using more intensive

leakage control techniques or policies. If that occurs, the resulting leakage level in the zone is then

the Long Run Economic Level of Leakage and attainment of this target will require leakage reductions

below the Short Run Economic Level of Leakage either during or following the initial 5 year period.

30 ELL is determined as the point where the incremental benefit of additional leakage control is just offset by the incremental

cost of carrying it out i.e. it is not cost beneficial to undertake further leakage control as the cost of undertaking the work is greater than the equivalent cost of the „lost‟ water (that can be supplied from the other sources).

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In accordance with Ofwat guidance (Ofwat, 2008), the Economic Level of Leakage should now

correctly be referred to as the “Sustainable Economic Level of Leakage” in recognition of the fact

that the methodology should take account of the environmental, social and carbon-related costs and

benefits of leakage control, not just the water company‟s “private” costs and benefits. Since 2007 our

methodology for calculating Economic Level of Leakage has taken full account of these external

costs, and is therefore consistent with “sustainable” Economic Level of Leakage. The Economic

Level of Leakage targets for the whole company and by WRZ are shown in Table 4.2.

Zone 2010-11 (Ml/d)

2011-12 (Ml/d)

2012-13 (Ml/d)

2013-14 (Ml/d)

2014-15 (Ml/d)

Whole Welsh Water supply area

190.45 188.10 186.20 184.77 184.08

North Eryri/ Ynys Mon 8.55 8.16 7.83 7.56 7.37

Clwyd Coastal 4.55 4.37 4.23 4.10 4.02

Alwen/ Dee 7.48 7.57 7.65 7.71 7.76

Bala 0.48 0.48 0.48 0.48 0.48

Tywyn Aberdyfi 0.15 0.14 0.13 0.12 0.11

Blaenau Ffestiniog 0.51 0.59 0.59 0.59 0.59

Barmouth 0.37 0.37 0.37 0.37 0.37

Lleyn/ Harlech 3.64 3.53 3.44 3.36 3.31

Dyffryn Conwy 8.11 7.98 7.86 7.77 7.71

South Meirionnydd 0.75 0.72 0.69 0.67 0.66

Ross-on-Wye 1.55 1.51 1.48 1.46 1.45

Elan/ Builth 1.29 1.31 1.32 1.34 1.35

Hereford CU Area 6.91 7.11 7.29 7.46 7.61

Llyswen 0.59 0.61 0.62 0.64 0.65

Monmouth 1.00 1.03 1.05 1.07 1.09

Pilleth 0.76 0.77 0.77 0.78 0.78

Brecon/ Portis 1.60 1.67 1.74 1.80 1.84

Vowchurch 0.725 0.74 0.75 0.76 0.77

Whitbourne 1.251 1.24 1.23 1.22 1.22

SEWCUS 81.56 79.98 78.68 77.67 77.11

Tywi CU Area 41.07 40.87 40.72 40.62 40.61

Mid & South Ceredigion 4.84 4.71 4.60 4.51 4.46

North Ceredigion 2.28 2.38 2.47 2.55 2.61

Pembrokeshire 10.36 10.28 10.21 10.17 10.14

Table 4.3 - ELL targets by WRZ for AMP 5

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Current Leakage Policy

Our current baseline leakage policy complies with industry best practice. It follows the approach to

leakage optimisation outlined by the Department for Environment, Food and Rural Affairs, Ofwat and

the Environment Agency in 2002,31

supplemented by various reports published by Ofwat as part of

detailed reviews of certain aspects of the optimisation methodology (Ofwat, 2007) as well as its work

on “sustainable” Economic Level of Leakage, as referred to above.

The Tripartite study identified two principal methods of modelling leakage management costs:

the “BABE” approach (based on the use of a theoretical model identifying optimal intervention

frequencies); and

the “MELT” approach, which uses empirical information on leakage savings and costs to

determine directly both the natural rate of rise in leakage32 and the marginal costs of leakage

control.

Both methods are considered valid and during 2007 we switched from the use of the BABE

methodology to the MELT approach, using our Sustainable Achievable Leakage Targets model. The

methodologies embedded within Sustainable Achievable Leakage Targets are in line with industry

best practice. Full details can be found in the supporting report.33

District Meter Area coverage

Our current leakage strategy is implemented across the whole of our distribution network, which is

divided into 916 District Meter Areas. The flows into and out of the District Meter Areas are

permanently monitored, recorded and quality-controlled. In addition, service reservoir seepage and

trunk main losses are monitored, reported and quality-controlled at the WRZ level.

Information systems and databases

The flows into and out of all our District Meter Areas are permanently monitored and recorded, with

raw data transferred on a daily basis to our database system, LIBRA (Leakage Identification,

Balancing, Reporting and Abstraction). The data is then transferred into our bespoke Leakage

Monitoring and Reporting Software. This software is used for quality control, targeting/ranking and

reporting leakage. The system produces reports on a monthly basis, at District Meter Area,

operational area, WRZ and company level.

In addition to flow data, the information contained in daily “activity sheets” and DMA information packs

are now entered into our bespoke Leakage Monitoring and Reporting Software, enabling zone

specific leakage/ cost assessments and benchmarking of efficiency and costs to be carried out.

Pressure Management

31 “Best Practice Principles in the Economic Level of Leakage Calculation”: report commissioned by the Tripartite Group

consisting of Defra, the Environment Agency, and Ofwat. 32 The natural rate of rise (NRR) in leakage may be thought of as the continuing increase in leakage that would occur in the

absence of any leak repairs. It is made up of two components – the breakout of new leaks in the network plus the growth (increase in volume) of existing leaks. Of this total NRR, a proportion will comprise visible (customer-reported) leaks, which will be duly repaired. 33 “Determining the Short Run Economic Level of Leakage for AMP 5”: RPS, 2008.

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Background leakage levels can be controlled by managing the pressure in the network. We have

undertaken considerable pressure management activity in recent years, and continue to sustain

savings by maintaining the status quo in areas where pressure is well-managed while working to

identify circumstances where further pressure management opportunities may exist.

New Property Forecasts

Property numbers within our area are projected to grow by an average of 0.65% per year over the

planning period. As a consequence there will be an expansion of the distribution network, which will

mean a corresponding increase in leakage.

Baseline Leakage

The initial Short Run Economic Level of Leakage value we derived from the optimisation process was

184.89 Ml/d. Analysis of zonal level values indicated lower levels, relative to current leakage, in 12 of

the 24 WRZs. We then used these preliminary values in our demand forecast and thereby identified

which WRZs were expected to go into deficit during the plan period.

It is inevitable that the revised leakage targets for 2014-15 will involve higher leakage levels in some

WRZs and lower levels in others, relative to the current position. However, in line with recent

regulatory guidance, for the two deficit WRZs where Sustainable Achievable Leakage Targets

indicated that rising leakage profiles would be appropriate, the Short Run Economic Level of Leakage

values have been constrained at the current zonal levels of leakage (in l/prop/d).

These constraints result in a reduction in the company level value by 0.81 Ml/d, producing a final

Short Run Economic Level of Leakage for 2014-15 of 184.08 Ml/d (including trunk mains and service

reservoir leakage). This value is 1.9 Ml/d higher than the figure calculated for the 2008 Draft Plan

(182.2 Ml/d).34

Future planned leakage reductions

Enhanced leakage reduction is a critical component of our Plan to maintain the supply demand

balance and reduce our CO2 emissions. For deficit WRZs, Sustainable Achievable Leakage Targets

was not used to determine the cost of leakage intervention schemes. This is because Sustainable

Achievable Leakage Targets utilises the current leakage policy costs that are consistent with short run

Economic Level of Leakage and not the costs of adopting more intensive leakage control

technologies that might be cost effective in contributing to deficit reductions.

An alternative methodology was used to derive the private and external costs of three alternative and

successively more intensive leakage control policies. These policies are:

reductions in detected leak run times – this option essentially increases the amount of

leakage detection resource made available;

location, operating and sounding of all fittings - this option targets previously undetected

leakage from all fittings, not just those that are visible without excavation; and

34

Note: out-turn leakage in 2010-11 was 199 Ml/d, higher than our leakage target of 190 Ml/d. This was the result of

exceptional weather conditions, notably the extreme “freeze-thaw” period in December 2010, and is expected to be recovered well in time for our end-AMP5 target of 184 Ml/d in 2014/15.

Page | 52


installation of permanent correlator noise loggers – this option helps leakage teams

detect leaks quicker and to identify leaks that are not usually detected through conventional

means.

Details on how we assessed whether or not these policies were the best way to address supply

demand deficits are contained in Chapter 9.

4.7.5 Metering

As noted above in section 4.1, we estimate that the average per capita consumption for metered

households in the base year was 124 l/h/d compared with 160 l/h/d for non-metered households.

At present around 31% of our households are metered. Our demand forecasts assume that this

proportion will continue to rise in line with current trends, which would increase meter penetration to

70% by 2035. This is a significant continuing rate of uptake and we will monitor it closely through

annual reviews and our water resource planning process. During our current investment programme

(2010-15) we will be spending around £30 Million on metering (about 50% on installing meters for

new meter optants and 50% on maintenance of the total meter stock – currently around 370,000

household meters).

We have considered the policy option of “metering upon change of occupancy” as a potential means

to address supply demand deficits but this is not demonstrated to be cost-effective when compared

against other options.

4.7.6 Tariffs

Although we believe that some households reduce their consumption at the point when they switch

from the unmeasured to a measured tariff, the evidence suggests that on average measured

household demand in Wales is fairly unresponsive to changes in marginal price signals once a

customer is metered. Several years of optant demand data has shown us that post-switching optant

demand moves in line with other customer demand. In other words, demand appears to be fairly

price inelastic, once a customer is metered. Accordingly, we concentrate our demand management

efforts on seeking to influence behaviours through our water efficiency promotion activities, and at

present we do not regard alternative measured tariff structures as a potent tool to achieve supply

demand objectives. We continue to review evidence as it emerges, however, and retain an open mind

towards the possibility of applying different tariff structures in the future. Meanwhile, to maintain a

strong price signal we continue to ensure the volumetric rate for our metered tariffs is greater than our

actual variable costs.

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Chapter 5. Target Headroom

“Headroom” is the difference between supply and demand: “Target Headroom” is one of the most

important features of water resource planning and is defined as the minimum planning margin or

buffer that a water company should allow between supply and demand to cater for specified

uncertainties35

in the overall supply demand balance (UKWIR, 2002).

These uncertainties include political, social, environmental and technical factors outside of a water

company‟s control that could significantly influence components of the supply demand balance.

Examples include changes to legislation, revisions to government political priorities, promotion of

economic development in specific areas, changes in planning methodologies, and so forth.

5.1 Calculating Target Headroom

We have assessed Target Headroom in accordance with the approach recommended by the

Environment Agency Guideline, as set out in “A Re-Evaluation of the Methodology for Assessing

Headroom” (UKWIR, 2002). Target Headroom is calculated by looking at the probability of uncertain

events in a similar way to the analysis of allowances for Outage. While the evaluation of Outage

entails examination of potential disruptions of short duration, the assessment of Target Headroom

involves consideration of events and uncertainties of potentially longer duration.

In line wiith the UKWIR methodology, Target Headroom is analysed in terms of nine supply

components and four demand components, viz:

S1 Vulnerable surface water licences

S2 Vulnerable groundwater licences

S3 Time-limited licences

S4 Bulk imports

S5 Gradual pollution causing a reduction in abstraction

S6 Accuracy of supply-side data

S8 Uncertainty of impact of climate change on source yield

S9 Uncertain output from new resource developments

D1 Accuracy of sub-component data

D2 Demand forecast variation

D3 Uncertainty of impact of climate change on demand

D4 Uncertain outcome from demand management measures

35

Except for those relating to Outages, which are treated as part of Deployable Output, as set out in chapter 3 above.

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Of the above categories, the uncertainty surrounding the effects of climate change on supply/demand

forecasting is especially significant in the preparation of this Plan, and is analysed in detail in Chapter

7 below.

5.2 Risk Profile

The Environment Agency Guideline recommends that an appropriate risk profile is applied to the

assessment of Target Headroom, and we have carefully considered how we should approach this for

the purposes of planning. On the one hand it would not be appropriate to allow for all possible

uncertainties in Target Headroom, because this would be overly cautious (and very expensive). On

the other hand, it could be argued that it would not be correct to look only at the probability-weighted

expected value of the uncertainties, i.e the “50 percentile” or “central projection”, because there is an

asymmetry between the value of having too much water and too little water. We have therefore

examined uncertainty from more than one perspective on risk. Further details are set out in chapter

7. After due consideration and analysis, we have chosen to adopt a fixed Risk Profile across the

planning period at the 95% confidence level.

Target Headroom has been calculated for all 24 WRZs at zonal level36

for both the Annual Average

and the Critical Period scenarios.

5.3 Baseline and Final Planning

The calculation of Target Headroom is part of the process of iteration that characterises the planning

process. Initially, “Baseline” Target Headroom Is calculated for each WRZ and applied to the

derivation of the baseline supply demand balance. If a WRZ is identified as having a supply deficit

options are selected to resolve the deficit. Since implementation of these solutions will also bring

uncertainties Target Headroom is then re-calculated and the process repeated until supply demand

balance is achieved. Thus, “Final Planning” Target Headroom is included as part of the Final

Planning supply demand balance, in which the supply deficit is fully resolved.

5.4 Work carried out since the 2008 Draft Plan

Following the 2008 Draft Plan, in preparation for the submission to Ofwat of Welsh Water‟s Final

Business Plan for 2010-2015, we undertook a detailed review of our headroom assessments. The

main areas of this work were:

a full review of the headroom allowances used in the Tywyn Aberdyfi WRZ;

a complete review of climate change uncertainty, including a full audit of our work and the

results of our analysis, a comparison of different methodologies for taking climate change into

account including an assessment of all of the approaches put forward by the Environment

Agency (see chapter 7 below);

a review of inflow uncertainty. This has resulted in a change in one zone, Tywyn Aberdyfi,

where we had allowed for uncertainty of inflows on both the Afon Fathew and the Nant Braich

36

Headroom Analysis (Entec, 2010); 2010 Review of Consents Assessment in SEWCUS Water Resources Zone, Final Report

(Entec, March 2011); 2010 Review of Consents Assessment in Pembrokeshire Water Resources Zone, Final Report (Entec, January 2011); Revised Target Headroom Modelling for NEYM (Entec, December 2010); Revised Target Headroom Modelling for Brecon – Portis Water Resources Zone (Entec, March 2011), NEYM DO summary (Welsh Water, 2010).

Page | 55


y Rhiw, whereas in fact they operate under an aggregated licence which means that if inflows

are lower in one, abstraction from the other can be increased.;

a complete re-assessment of the headroom uncertainty on demand; and

Final Planning Target Headroom was derived through a process of iteration for the three

zones presented as being in deficit in the Final Business Plan – Tywyn Aberdyfi, South

Meirionnydd and Vowchurch.

Full details of this work can be found in the associated report.37

For this Plan, baseline Target Headroom has been updated for all WRZs to account for the updated

demand forecast and the inclusion of the impacts of the UK climate change forecasts published in

2009 (UKCP09) and the outcomes of the Environment Agency‟s review of our licences. Full details

are set out in the associated reports.38

37 “Further Headroom Analysis – Summary of Headroom Components post dWRMP”: Entec 2008.

38 “2010 Review of Consent Supply Assessments in SEWCUS Water Resources Zone, Final Report” Entec, Jan 2011. “2010

Review of Consent Supply Assessments in Pembrokeshire Water Resources Zone, Final Report”: Entec, Jan 2011. Headroom Analysis (Entec, 2010); 2010 Review of Consents Assessment in SEWCUS Water Resources Zone, Final Report (Entec, March 2011); 2010 Review of Consents Assessment in Pembrokeshire Water Resources Zone, Final Report (Entec, January 2011); Revised Target Headroom Modelling for NEYM (Entec, December 2010); Revised Target Headroom Modelling for Brecon – Portis Water Resources Zone (Entec, March 2011), NEYM DO summary (Welsh Water, 2010).

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Chapter 6. The Habitats Directive and the Impact on Water Abstractions

The European Habitats Directive will have a significant influence on our water resource management

plans for the next 25 years. This chapter describes the Directive, how it operates through the Review

of Consents process, and the practical implications that this has for our long term strategy for meeting

our water supply obligations.

6.1 The Habitats Directive

The Directive was brought into Welsh law through regulations39

that

provide for the designation of “European sites” (Natura 2000 sites);

afford protection of “European protected species”;

provide for the adaptation of planning and other controls for the protection of such sites; and

impose a statutory requirement to deliver improvement schemes.

Under the Regulations, “competent authorities” i.e. any Minister, government department, statutory

authority, public body, or person holding public office, have a general duty, in the exercise of any of

their functions, to have regard to the EU Habitats Directive.

As the designated “competent authority” for England and Wales the Environment Agency is required

to ensure that its “permissions” – i.e abstraction licences and discharge consents – and its operations

have no adverse effect on the “integrity” of the Special Areas of Conservation (SAC) and Special

Protection Areas (SPA) that form part of the pan-European network of Natura 2000 sites. As a

competent authority ourselves, we must have regard to the requirements of the Habitats Directive so

far as they may be affected by the exercise of our functions..

6.2 Review of Consents (and Restoring Sustainable Abstraction programme)

The Review of Consents process is the mechanism by which the Environment Agency reviews of all

the existing and proposed permissions it has issued that could impact upon EU designated Natura

2000 sites. The process falls under the umbrella of the Environment Agency‟s Restoring Sustainable

Abstraction programme. This programme was set up by the Environment Agency in 1999 to identify

sites that may be adversely impacted by the effects of abstraction, and is ongoing. It has proved

complex in Wales because of the nature of the environment in which we operate; there are, for

example, over 90 European Special Areas of Conservation and more than 1,000 Sites of Special

Scientific Interest (SSSI).

Sustainability reductions is the term given to amendments made by the Environment Agency to

existing permissions in order that it can be demonstrated that the permission does not have an

adverse impact on a Habitats Directive site.

39 The EEC Directive 92/43/EEC (21st May 1992) on the conservation of natural habitats, wild fauna and flora was incorporated

into the UK regulatory system under the Conservation (Natural Habitats, &c.) Regulations 1994. These regulations came into

force on 30 October 1994 and were subsequently amended in 1997 and (in England only) 2000. They have since been

amended by the Habitats Regulations 2010.

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The abstractions affected are shown on Figures 6.1, 6.2 and 6.3: further detail is presented in Annex

3.

Figure 6.1 - Welsh Water’s abstractions in South East Wales subject to the review of consents

process

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Figure 6.2 - Welsh Water’s abstractions in South West Wales subject to the review of consents process

Figure 6.3 - Welsh Water’s abstractions in North Wales subject to the review of consents process

In general terms Habitats Regulations oblige the Environment Agency to review all of its

environmental permissions, in this case abstraction licences, to ensure that they have no adverse

impact on Special Areas of Conservation. The process is undertaken in four stages:

Stage Assessment

1 This stage identifies all relevant (Environment Agency) permissions that could impact upon

the Special Area of Conservation

2

Permissions are then subject to a generic assessment to determine if a likely significant

impact exists upon the integrity of the designated site, either alone or in combination with

other permissions. If deemed likely, or the Environment Agency are unsure, they move on

to Stage 3.

3

A more detailed assessment of each permission is carried forward from Stage 2 to

determine whether it can be shown to have no adverse effect upon the integrity of the site

in question, either on its own or in combination with other permissions.

4

If at Stage 3 a permission has been assessed as having no adverse affect then it will be

affirmed at Stage 4 and no modifications to it will be required. If, however, a conclusion of

no adverse affect could not be reached, then the permission will be subject to “options

appraisal” to determine the best way to resolve the issues.

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The consents review process for water resources has been ongoing in Wales since 2004. During this

period we have worked closely with the Environment Agency to try and understand the issues at each

site and how they can best be resolved. Stages 3 and 4, as they relate to our abstractions, are

described in greater detail below.

6.2.1 Stage 3

The assessment has been based upon the Resource Assessment Methodology used in the

Environment Agency‟s Catchment Abstraction Management Strategy process. Under this

methodology a generic environmental river flow objective is applied at key sites along the river that

allows for small deviations from the estimated natural flow, taking into account the effects of all the

permissions.

For the rivers under investigation that have been designated as Special Areas of Conservation under

the Habitats Directive, flows are generally only allowed to deviate below natural flows by a maximum

of 10% from Q1 to Q9540

and only 5% thereafter. This process is referred to in the methodology as

the Habitats Directive Environmental River Flow objective.41

This means, for example, that if the

natural flow at Q95 is 10 Ml/d the permitted deviation is only 5% of 10 Ml/d i.e. 0.5 Ml/d and so the

Environmental River Flow objective, i.e. the flow to be preserved at all times, would be 9.5 Ml/d.

Where more localised information on the flow requirements of designated species has been available,

for example on the River Usk Special Area of Conservation, the Habitats Directive Environmental

River Flow has been adjusted accordingly.

This process is illustrated in Figure 6.4, which shows that:

the Environment Agencydetermine the “Benchmark Flow” i.e. the natural flow of the river –

this is the red line on the diagram;

the Environment Agencyand the Countryside Council for Wales determine the Benchmark

Habitats Directive Ecological River Flow objective as the protective flow requirement for

Special Area of Conservation rivers – this is typically 10% below the benchmark flow – the

yellow line;

the Environment Agency then assesses the fully licensed scenario – licences operating at

100% - and this is shown as the dark blue line labelled “Max licensed scenario flows”; and

the dark blue line lies below the yellow line from about the 65%ile of river flow onwards

towards the lower flows. As a consequence, the abstractions from this point would have to be

reduced to move the dark blue line above the yellow line.

The Stage 3 appropriate assessments have focused on two licensing scenarios for each of the

Special Areas of Conservation – a “recent actual” scenario that reflects how we have actually been

operating our abstractions over the past 35 years (1970 – 2005) and a “full licence utilisation”

40 The term Q95 is often used to mean the 95 percentile flow statistic. This is the flow that is equalled or exceeded for 95% of

the time, based on the length of the record used to calculate the statistic. It is typically calculated from daily mean flow values. In hydrology/ water resources it is a well understood and used low flow measure as, on average, only 5% of flows are lower in value. Conversely, Q1 represents a high flow value as 99% of flows are lower in value, or alternatively, only 1% of flows are higher in value. 41 Habitats Directive Ecological River Flow Duration Curve (HD ERF) is the flow regime suggested for Special Areas of Conservation rivers based on the findings of an Environment Agency Research and Development Report “An Appraisal of the Value of the EW System for assessing impacts on HD Interest Features”.

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scenario which represents an extreme worst case scenario under which the maximum licensed

volumes are abstracted all year round.

Figure 6.4 Application of the Review of Consents process

Lake Special Areas of Conservation

As with the riverine Special Areas of Conservation, the Environment Agency has assessed our

operations in relation to Lake Special Areas of Conservation under both “maximum licensed” and

“recent actual” scenarios. The impact upon lake levels of our abstraction under these two scenarios

has been calculated, but unlike in the case of the riverine Special Areas of Conservation, no Habitats

Directive limit of deviation has been set. The assessment has instead focused on the extent to which

there is an increase in the marginal area exposed as a consequence of abstraction drawing down the

levels in the lake.

Where it has been shown that the drawdown rates cause a significant increase in the area of marginal

habitat exposed, which could negatively impact upon the designated species, the conclusion has

been drawn that “no adverse impact” cannot be demonstrated and so the relevant abstraction

licences have progressed to Stage 4.

There are some specific features of the Review of Consents process that are worth noting:

1. The Habitats Directive does not require it to be demonstrated that abstractions are actually

having a detrimental impact for a permission to be curtailed or modified. Rather, it requires a

demonstration that there is no impact for the permission to be unchanged. Thus, if “no

Page | 61


impact” cannot be proven, the “precautionary principle” applies,42

and the permission may be

modified.

2. The process focuses upon a hypothetical scenario where all abstraction licences are being

operated at their theoretical maximum, a position which has never been achieved in practice.

3. Review of Consents looks at risk of adverse impact, as well as actual impact.

Table 6.1 presents the results for 20 sites of the Environment Agency‟s Stage 3 assessments as to

whether there is either an actual (current) impact, or a perceived modelled (future) risk were we to

abstract at the maximum licensed rates. As noted above, the simulation of the “maximum abstraction”

scenario is entirely theoretical as we have never needed to abstract 100% of our daily licensed limit at

all the sites along these rivers, and it is very unlikely that we would ever need to in the future. This is

borne out by the results presented in the table, which shows that at all sites, the only impacts from our

abstractions are in the “modelled risk” category. In other words, under the recent actual scenarios no

perceived risk of adverse impact has been identified.

42

Under the precautionary principle, if there are reasonable grounds for suspecting that environmental harm may occur, protection measures should not be delayed pending scientific proof.

Page | 62


Site Name

Adverse

effect on

site integrity

can be

shown

No adverse

effect on

site integrity

cannot be

shown

Impact (I) or a Risk (R) if cannot conclude there is no impact

Impact type: Actual (A) Modelled (M) Or Suspected (S)

Alo

ne

In

Co

mb

inatio

n

Alo

ne

In

Co

mb

inatio

n

Wye at Broomy Hill R M

Wye at Monmouth (Mayhill) R M

Wye at Monmouth (Wye

Transfer) R M

Lugg at Byton R M

Pilleth boreholes R M

Dunfield boreholes R M

Midsummer Meadow well R M

Usk at Llantrisant R M

Usk at Rhadyr (Prioress Mill) R M

Usk at Brecon/Brecon

boreholes R M

Tywi at Manorafan R M

Tywi at Nantgaredig R M

Llyn Brianne reservoir R M

Teifi at Llechryd R M

Eastern Cleddau at Pont

Hywel R M

Eastern Cleddau at

Canaston R M

Western Cleddau at Crowhill R M

Llyn Eiddew Mawr R M

Llyn Morwynion R M

Llwyn Isaf borehole R M

Table 6.1 – Outcome of Stage 3 Assessments

6.2.2 Stage 4

At Stage 4 of the consents review process the Environment Agency then specifies a series of

“Environmental Outcomes” as illustrated in Table 6.2 below.

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Environmental

Outcome Objective

Env1 To ensure adequate flow throughout the Special Area of Conservation

Env2 To ensure flow variability (which can be achieved, for example, by removing diurnal

pumping practices)

Env3 To ensure frequency and magnitude of spate flows. The Environment Agency has

assumed that if Env1 is achieved then by default so will Env3

Env4 To prevent entrainment and impingement

Table 6.2 – Specified Environmental Outcomes at Stage 4

There is also an assessment of other potential impacts, such as those that relate to entrainment,

temperature, fish passage, water level and variability of flow, some of which are described later in this section, which go together to produce an overall picture of the potential impacts of our activities upon the Special Areas of Conservation. The outcomes are shown in Table 6.3. In general terms, the major impact upon existing abstraction licences is a reduction in volumes that

can be abstracted during periods of low flow so as to retain a (theoretical) “naturalised flow” within the

river (Environmental Outcome 1).

The impact of Environmental Outcome 2 - The removal of diurnal pumping (taking water at night to

save on pumping costs) - has a small impact upon the volume of water we can take, but mostly

impacts on operating costs.

The prevention of entrainment and impingement has no direct impact on water resources, but does

impact upon the utility of our abstraction assets. This is described further below.

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Licence Flow, Env 1 Variability, Env 2 Spate, Env 3 Entrainment, Env 4 Temperature Level Barrier

River Wye at Broomy Hill

River Wye at Monmouth (Wye Transfer)

River Wye at Monmouth (Mayhill)

River Wye at Builth Wells

River Wye at Llyswen

Vowchurch boreholes

Alton Court boreholes

Buckholt spring

Rogerstone Grange borehole

River Lugg at Byton

Pilleth Boreholes

Dunfield Boreholes

Midsummer Meadow

River Usk at Llantrisant

River Usk at Brecon

Brecon Boreholes

River Usk at Rhadyr (Prioress Mill)

River Lugg at Byton

Pilleth Boreholes

Eastern Cleddau at Pont Hywel

Western Cleddau at Crowhill

Eastern Cleddau at Canaston

Afon Teifi at Llechryd

Afon Tywi at Nantgaredig

Afon Tywi at Manorafon

Llyn Brianne

Llyn Cwellyn

Afon Gwyrfai at Nant Mills

Llyn Eiddew Mawr

Llyn Morwynion

Llwyn Isaf borehole

Table 6.3 – Environmental Outcomes

Page | 65


6.3 The impact of Review of Consents upon Resources

Following the completion of Stage 4 of the consents review process, we have modelled the

Environment Agency‟s proposed licence amendments to assess the impacts upon Deployable Output.

Overall, the reductions amount to an approximate Deployable Output loss of 116 Ml/d across South

Wales. However, by changing the way we operate our licences in the Pembrokeshire WRZ this

impact is reduced to 92 Ml/d. Across North Wales we are not forecasting any loss of Deployable

Output in the affected WRZs as a result of the Environment Agency‟s proposed licence changes.

6.3.1 The South East Wales Conjunctive Use System (SEWCUS) WRZ

Since 2007, we have worked with the Environment Agency to develop a series of licence amendment

options for the Rivers Wye and Usk to achieve the desired environmental outcomes. This Plan is

based on the latest options set out in the technical notes issued by the Environment Agency in

September 2010 – Wye Option W38243

and Usk Option U588.44

We have prepared a report45

that provides full details of the modelling work we have carried out to

assess the impacts upon Deployable Output of the final outcomes of the Agency‟s review of our

related consents.

Within the SEWCUS WRZ, the baseline Dry Year Deployable Output is 476 Ml/d. Implementation of

the licence amendments reduces our Dry Year Deployable Output to 401 Ml/d, a loss of 75 Ml/d. This

drop in supply capacity is driven by the significant reductions in our Wye and Usk licences, as well as

the increase in releases we have to make from the Elan Valley reservoirs to augment flows in the

Wye so as to enable abstraction at Monmouth to be maintained. As a consequence of these

changes, our overall supply/demand position in SEWCUS is projected to move from a healthy excess

of supply capacity over demand to a much smaller surplus.

Further, it should be noted that we have assumed, for the purposes of this Plan, that the licence

amendments are not formally put in place until 2020, although in fact the sustainability reductions

would not put the zone into deficit straight away, but leave a small planning surplus for the time being

according to current modelling. The size of the reductions is so dramatic that we consider that it

would be prudent to carry out further detailed work on the way that the zone is operated in order to

ensure that it is fully robust to such radical changes. Our over-riding priority is to safeguard the

security of public water supplies, and the complexity of the zone is such that more extensive analysis

is required before we can be fully confident that the major changes envisaged can be accommodated

in all circumstances. In particular, whilst SEWCUS is regarded as one zone for planning purposes, it

is not fully integrated in the sense that not every customer can theoretically be served by each source.

As such, the presence of effective bottlenecks raise the question of whether it should be modelled as

two (or more) inter-connected zones, rather than one. We intend to explore this issue carefully, and if

there is a valid alternative way of analysing the zone we will wish to ensure that what appears to be a

small planning surplus overall does not conceal the fact that there would be local areas that would be

in deficit.

6.3.2 Brecon-Portis WRZ

The impact of the consent review process on Deployable Output in our Brecon-Portis WRZ has been

calculated as a reduction of approximately 2.5 Ml/d.

43

Technical Note: Wye Option W382, EAW, September 2010.

44 Technical Note: Usk Option U588 & U591b, EAW, November 2010.

45 “2010 Review of Consent Supply Assessments in SEWCUS Water Resources Zone, Final Report” Entec, Jan 2011.

Page | 66


6.3.3 Pembrokeshire WRZ

Since 2008 we have undertaken modelling of our Pembrokeshire WRZ to understand fully the impacts

of the Environment Agency modifications to our abstraction licences on the Eastern and Western

Cleddau Rivers. The Environment Agency has not modelled the impacts themselves but have fully

audited our model and have indicated that they are satisfied with the results.

The current baseline Dry Year Deployable Output for Pembrokeshire is 79.10 Ml/d and 100.50 Ml/d

for the Critical Period. We have prepared a report46

that details our modelling work and the impact of

the consent review process on Deployable Output in Pembrokeshire.

The impact of the Environment Agency‟s proposed changes to licences in Pembrokeshire is a net

reduction in annual average Deployable Output from 79.1 Ml/d to 64.8 Ml/d and in critical period

Deployable Output from 100.5 Ml/d to 81.9 Ml/d. Note that these results are after we have mitigated

the effect of the impacts of the consent review by changing the way we operate the zone: these

changes, which are described in the supporting report, have not hitherto been implemented because,

but for the effects of the consent review process, it would not have made economic sense to do so.

The consequence of the proposed licence amendments at our Pont Hywel intake on the Eastern

Cleddau is that our abstraction would be restricted to less than 1 Ml/d, on average, during the summer

months, compared with the present situation in which we can abstract an average of 10 Ml/d. This

means that Preseli reservoir storage could not be sustained through the summer, which in turn means

that Preseli Water Treatment Works could not be operated at normal levels throughout the summer,

and so the Deployable Output of the Pembrokeshire WRZ would be greatly reduced, albeit that this

would then be partially mitigated by greater use of the Llysyfran to Preseli Water Treatment Works

transfer.

Note that, as for the South East Wales Conjunctive Use System zone, we have assumed that the

proposed abstraction licence reductions are not implemented before 2020. This is because of the

considerable lead time necessary to implement the solutions (see chapter 9 below).

46 “2010 Review of Consent Supply Assessments in Pembrokeshire Water Resources Zone, Final Report”: Entec, Jan 2011.

Page | 67


Chapter 7. Uncertainty Regarding the Effects of Climate Change

Climate change is expected to have a significant impact on both water supply and demand in the

future. Our plan incorporates the latest climate scenarios, UK Climate Projections 2009 (UKCP09),47

and looks at the potential impact of these scenarios on supply and demand. Overall we are projecting

a reduction in Deployable Output in a number of WRZs as a consequence of climate change,

increasing the likelihood of water supply deficits. We also show the dramatic effect that the

incorporation of the full range of UKCP09 projections into Target Headroom has in certain zones.

7.1 How we approach climate change

In June 2009 the United Kingdom Climate Impacts Programme (“UKCIP”) published new climate

change scenarios, known as “UKCP09”, which replaced the UKCIP‟s 2002 projections that we had

used in our 2008 plan.

It is generally accepted that there are major uncertainties in the modelling of climate change,

particularly as regards:

the severity of the changes we might see;

the timescale for changes; and

the probability of any particular scenario occurring.

For the purposes of preparing this Plan, we have used the “medium” climate change scenarios rather

than either the upper or lower scenarios.

Compared with the UKCIP 2002 projections, the main differences that these new scenarios bring to

the planning process are:

1. the variability in seasonal changes in rainfall is much greater than previously projected; and

2. this is particularly pronounced for summer rainfall, which can vary from +20% to -40%. Most

importantly, the probability of both drier winters and wetter winters is considered to be greater,

which may significantly affect water resources.

When we analyse the effects of climate change we make an assessment of the effects on the

availability of water. We have not considered any potential changes to our licences that could be

made in response to climate change.

The treatment of uncertainty involves rigorous analysis and careful judgement. Figure 7.1 shows how

the probability distribution around the effects of Target Headroom on water availability “fans out” as

we move progressively into the future. (The overwhelming bulk of this uncertainty is related to the

effects of climate change, the so-called “S8” component of Target Headroom, with only some 10%

being driven by other components.) This means that the implications for supply demand deficits and

the range of investment and other options that might have to be considered varies enormously

depending on how much risk the company is willing to bear. For example, in the case depicted in

Figure 7.1, which relates to our largest zone, the South East Wales Conjunctive Use System zone

(SEWCUS), if the company is willing to accept a 50% risk that the allowance in Target Headroom will

be inadequate by 2034 (e.g. on the basis that it considers that there is adequate lead time to deal with

shortfalls as at that date as better and less uncertain information becomes available) it would build 44

Ml/d into Target Headroom in this zone. If, on the other hand, it took a more cautious approach and

47 “UK Climate Change Impacts Programme (UKCIP)”: Murphy et al 2009.

Page | 68


wanted to be 95% sure that sufficient margin had been built into Target Headroom to allow for the

effects of climate change by 2034, it would allow 130 Ml/d, a very dramatic difference.

Figure 7.1 – Target Headroom for SEWCUS at different levels of risk

As described below, having analysed the implications of the UKCP09 climate scenarios in detail, we have treated the uncertainty around them as follows:

we have reflected the UKCP09 50 percentile impacts in our projections of Deployable Output,

as appropriate. This is in line with Environment Agency Guidelines; and

we have quantified the additional effect of the full range of UKCP09 climatic impacts in our

evaluation of Target Headroom, but have not used these sensitivities for the purposes of the

main supply demand assessment and option appraisal in chapters 8 and 9. We have,

however, presented what the outcomes would be if we had used the full range of UKCP09

impact (see below for further discussion).

It is worth noting, in this context, that the choices we have considered revolve around the “central” or

“neutral” projections (50 percentile) and the “cautious” or “pessimistic” scenarios (95 percentile). We

are not concerned with the 5 or 10 percentile projections, which could be termed “optimistic” and

indeed which, as figure 7.1 illustrates, actually imply negative target headroom.

7.2 The impact on supply

Following the publication of UKCP09 climate change scenarios we analysed its impact upon

Deployable Output in 17 of our 24 WRZs.48

The impacts on the North Eyri Ynys Mon, SEWCUS and

Pembrokeshire WRZs were assessed further as part of the work we carried out on these zones

following changes to the baseline models in 2010. The impacts are summarised in Table 7.1 below.

48

“N177i4 Assessment of the Impact of Climate Change on Deployable Output using UKCP09 Scenarios”: Entec March 2010.

Page | 69


The impact of climate change in the remaining 7 WRZs under the UKCP09 scenarios remains the

same as under the UKWIR06 approach.49

This assumes that water availability is essentially

unaffected because the relevant constraints on Deployable Output are the abstraction licence

conditions. Currently, therefore, the effect of climate change is considered to be zero.

49

As presented in “Effects of Climate Change on River Flows and Groundwater Recharge: Guidelines for Resource Assessment and UKWIR06 scenarios” (UKWIR 2007).

Page | 70


Zone Median (50%ile)

impact on DO from UKCP09 in 2035

Zone Median (50%ile)

impact on DO from UKCP09 in 2035

North Eyri Ynys Mon -18% Hereford 0%

Clwyd Coastal -1% Llyswen 0%

Alwen Dee 0% Monmouth 0%

Bala 0% Pilleth 0%

Tywyn Aberdyfi -1% Brecon Portis 0%

Blaenau Ffestiniog -3% Vowchurch -3%

Barmouth -1% Whitbourne -2%

Lleyn Harlech -1% SEWCUS 0%

Dyffryn Conwy 0% Tywi Gower 0%

South Meirionydd 0% Mid & South Ceredigion50 +3%

Ross On Wye 0% North Ceredigion -6%

Elan Builth 0% Pembrokeshire -16%

Table 7.1 Summary of median impact of UKCP09 climate change scenarios on baseline Deployable Output

The zone where UKCP09 has the biggest negative impact on Deployable Output is North Eyri Ynys

Mon with an 18% reduction in Annual Average Deployable Output, followed by Pembrokeshire with

16%. The impact on the other zones is less than 10%, including 4 zones where climate change is

expected to have no effect, either because Deployable Output is already constrained by licence

conditions or because it is bounded by the availability of storage.

The impact of the scenarios is generally greatest in west Wales, particularly in those zones that rely

on river abstractions where licence conditions may limit what we can abstract at times of low river

flows. This explains, for example, the magnitude of the impacts in Pembrokeshire and Tywyn

Aberdyfi.

7.3 The Impact on Target Headroom - Supply

Although the Environment Agency‟s Water Resources Planning Guideline requires companies to build

the effects of UKCP09 climate change projections into their water resources planning, there is

currently no guidance as to precisely how this should be done. Further, in its latest (April 2011)

update of the Guideline the Environment Agency acknowledges the uncertainty around the question

of how UKCP09 scenarios should be applied to produce robust figures for the “S8” component of

Target Headroom.51

We have therefore used our judgement in deciding how our forecasts and

assumptions should be modified to reflect the UKCP09 scenarios, drawing extensively on the

principles contained in relevant UK Water Industry Research, where appropriate.

50

For this zone, the median UKCP09 scenario has a slight positive impact on DO.

51 In section 8.4 the Guideline states: “We are currently working with the water industry to research suitable methodologies to

enable these new scenarios to be used for water resources management plan assessments. Once these methodologies have been developed we will issue updated guidelines on climate change assessment for water resource planning.”

Page | 71


We have examined how the incorporation of the full UKCP09 range of climatic scenarios into Target

Headroom would affect the supply demand position in each zone. The following presents the net

position in 2035 for each of our 24 zones:

on a “preliminary” view, before the effects of the Environment Agency‟s consent review

process and climate change are taken into account;

after allowance is made for the impact of the Environment Agency‟s consent review process,

as described in chapter 6;

incorporating both the effects of the Environment Agency‟s consent review and the 50

percentile (median) UKCP09 scenarios in Deployable Output; and

after allowing both the Environment Agency‟s consent review and the more cautious full range

of UKCP09 scenarios (5 percentile to 95 percentile) projections on Deployable Output and

Target Headroom.

Page | 72


Supply Demand Position in 2035 (Ml/d)

Baseline

(wholly

excluding the

effects of the

Environment

Agency’s

consent

review and

UKCP09)

Including the

Environment

Agency’s

consent

review

Including the

Environment

Agency’s

consent

review and

the effects of

the median

UKCP09

scenario on

Deployable

Output

Including the

Environment

Agency’s

consent

review and

the full range

of UKCP09 in

Target

Headroom

8001, North Eyri Ynys Mon +11.3 +11.3 +2.9 -4.3

8012, Clwyd Coastal +2.5 +2.5 +2.2 +1.7

8014, Alwen – Dee +7.8 +7.8 +7.8 +7.5

8020, Bala +0.1 +0.1 +0.1 +0.1

8021, Tywyn – Aberdyfi +0.1 +0.1 +0.1 +0.1

8026, Blaenau Ffestiniog +0.5 +0.5 +0.5 +0.4

8033, Barmouth 0 0 0 0

8034, Lleyn – Harlech +5.0 +5.0 +5.0 +4.8

8035, Dyffryn – Conwy +3.4 +3.4 +3.4 +3.4

8036, South Meirionnydd 0 0 0 0

8101, Ross on Wye +1.7 +1.7 +1.7 +1.7

8102, Elan – Builth +2.6 +2.6 +2.6 +2.6

8103, Hereford Conjunctive

Use System

+11.5 +11.5 +11.5 +11.5

8105, Llyswen +1.3 +1.3 +1.3 +1.3

8106, Monmouth +1.7 +1.7 +1.7 +1.7

8107, Pilleth +0.9 +0.9 +0.9 +0.9

8108, Brecon – Portis +1.9 -0.7 -0.7 -0.7

8110, Vowchurch +0.9 +0.9 +0.8 +0.8

8111, Whitbourne +1.6 +1.6 +1.5 +1.5

8121, SEWCUS +74.6 -2.7 -12.4 -104.2

8201, Tywi Conjunctive Use

System

+22.1 +22.1 +22.1 +22.1

8202, Mid & South Ceredigion +4.1 +4.1 +4.8 +4.4

8203, North Ceredigion +0.9 +0.9 +0.3 +0.0

8206, Pembrokeshire +5.2 -8.3 -12.7 -18.2

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Table 7.2 – Effect of the Environment Agency’s Review of Consents (RoC) and Climate Change on Supply Demand Deficits in 2035

The following chart illustrates how the position changes for each of the four sets of projections for the

the South East Wales Conjunctive Use System (SEWCUS) zone, where the full range of UKCP09

scenarios has the greatest impact.

Figure 7.2 – Illustration of the effect of UKCP09 climate predictions on the supply demand

balance - SEWCUS

As the chart shows, before the effects of the Agency‟s Review of Consents and UKCP09 are taken

into account, SEWCUS is projected to remain in healthy surplus throughout the Plan period. The

effect of Review of Consents, by itself, is to wipe out the 75 Ml/d surplus shown in the top line for

2034, and to produce a small overall deficit of -3 Ml/d. The incorporation of the median UKCP09

scenario into Deployable Output moves the zone further into deficit, with the 2034 position

deteriorating to a shortfall of 12 Ml/d.

When the full UKCP09 scenarios relating to the impacts of climate change are incorporated in Target

Headroom, however, a massive 104 Ml/d deficit is reached by the end of the Plan period. To put this

further into context, the following table shows how this deficit is made up.

-150

-100

-50

0

50

100

150

2009 2014 2019 2024 2029 2034

Ml/

d

Supply Demand Balance SEWCUS

Baseline (wholly excluding impacts of climate change)RoC (wholly excluding impacts of climate change)RoC (only UKCP09 50%ile directly on Deployable Output)RoC (full range of UKCP09 accounted for within Target Headroom also)

Page | 74


SEWCUS in 2034 (Ml/d)

Water available for use 378

Demand 363

Target Headroom 119

Supply demand balance -104

Table 7.3 Primary components of supply demand balance in 2034 - SEWCUS

For the purposes of this Plan we gave careful consideration to whether we should base our strategy

for planning investment and other options for achieving supply demand balance on the basis of

projections that included or excluded the “S8” component of Target Headroom. On the one hand, we

acknowledge that climate change is a major source of uncertainty, especially in relation to its

interaction with the effects of the Agency‟s consents review. On the other hand, we note that this is a

developing area, and that best practice is not yet established: as noted above, the Environment

Agency has acknowledged that there is some uncertainty as to how UKCP09 should be reflected in

methodologies for determining Target Headroom, and plans to issue guidance in time for the 2013

draft WRMPs. There is also a question mark over how relevant an exercise it would be at this stage

to prepare options for meeting a projected 104 Ml/d deficit in SEWCUS, an addition to capacity that is

greater than the total water supplied by some other water undertakers.

On balance, we have taken the pragmatic decision to opt for the latter approach. We consider that

the uncertainty around how the full UKCP09 climatic scenarios should best be incorporated in water

resource management planning, and Target Headroom in particular, is too wide to be relied upon at

the present time for reliable projections of future water resource needs. We are confident that there is

adequate lead time between now and the point at which we would have to commit to a programme of

investment to address a deficit of the magnitude presented in Table 7.3, and will be in a position to

take a more positive and less speculative view when we prepare the next draft Water Resources

Management Plan, due for publication in 2013.

In effect, therefore, for the purposes of the supply demand balances shown in the following section

and the options for addressing supply demand deficits presented in chapter 9, we have incorporated

the median UKCP09 scenarios in our projections of Deployable Output, but have not included an

allowance for the uncertainty around the projections in our calculations of Target Headroom. It should

be noted, however, that we have presented for information the options that we would select if we had

included that allowance, i.e. addressed the full deficits shown in the final column in Table 7.2 above

(see section 9.7 for details).

7.4 The Impact on Target Headroom – Demand

We have, though, included the effect of climate change on demand in Target Headroom. Many of the

components of the demand for water are influenced by weather conditions. For example, garden

watering increases significantly in hot and dry weather. Research by Oxford University for the

Department for Environment, Food and Rural Affairs52

provides the best available estimates of the

impact of climate change on future demands for water, as reflected in the UKCIP02 scenarios. The

study presented indicative predictions, for a variety of scenarios, of the potential impact of climate

change on key components of household and non-household water demands, based upon historical

52 “CCDeW: Climate Change and the Demand for Water”: Defra, 2003.

Page | 75


analysis of trends. Although we would welcome an industry update to this study to account for the

changes in climate change projections, we consider that it provides a reasonable basis for the

estimation of the effects of climate change on demand for the purposes of this Plan, and have

reflected it in our forecasts of the supply demand balance for each zone, as presented in the following

Chapter.

Page | 76


Chapter 8. The Supply Demand balance

This purpose of this chapter is to present the supply demand position for Wales over the Plan period.

We do so on the basis of the (“central”) approach we have taken to climate change uncertainty, as

described in chapter 7, and also present equivalent results on the basis of the incorporation of the

(more “cautious” or “pessimistic”) full range of UKCP09 scenarios in the “S8” component of Target

Headroom. We have not prepared projections on the basis of an “optimistic” view of the effect of

climate change on Target Headroom.

8.1 Calculating the Supply Demand Balance

The basic question in water resources planning is whether or not the supply of water, or “Water

Available for Use”, is expected to be sufficient to meet the demand for water (defined as Demand plus

Target Headroom), and therefore whether a zone is expected to be in surplus or in deficit (see figure

8.1).

Figure 8.1 – Calculating Supply Demand balance

The supply demand balance is evaluated from two perspectives: the “Annual Average” and “Critical

Period” (periods of peak demand).

8.2 The projected Supply Demand balance

Once the effects of climate change and the Habitats Review of Consents are taken into account in the

way described in chapter 7, deficits at some point in the next 25 years are forecast for three WRZs, as

depicted in the following map.

Page | 77


Figure 8.1 Surplus and deficit zones

The three zones53

that are forecast to fall into deficit at some point over the next 25 years are Brecon

– Portis, Pembrokeshire, and SEWCUS. When the full range of UKCP09 climate change scenarios

are incorporated in the “S8” component of Target Headroom, a fourth zone is projected to be in deficit

over the same period, namely North Eryri Ynys Mon.

53

South Meirionnydd zone (Dry Year scenario) is shown to be marginally in deficit from 2029-30 onwards, to a maximum deficit

value in 2034-35 of 0.08 Ml/d (80 m3/d). Given the marginal nature of this deficit late in the planning period and that significant

revisions to the water resources planning process are to be undertaken over the next 12 months by Welsh Water (e.g. demand forecast update, review and update of inflows) it is not considered necessary or appropriate to subject South Meirionnydd to a full options appraisal at this time to mitigate against this deficit. Naturally, following the WRMP updates over the next 12 months, should South Meirionnydd be in deficit, then a full options appraisal will be completed for the March 2013 Draft Plan.

Page | 78


Table 8.1 below summarises the position for these three zones:

Zone Reduction in

DO (Ml/d) Enters Deficit

Deficit by 2035 (Ml/d)

Primary reason

Brecon-Portis 3 2020 1 Habitats Directive

Pembrokeshire 19 2017 13 Climate Change and Habitats Directive

SEWCUS 85 2028 12

Climate Change and Habitats Directive

Table 8.1 – Supply Demand Deficits

Table 8.2 summarises the position for the four zones that are projected to go into deficit when the full

range of UKCP09 climate change scenarios is incorporated into the S8 component of Target

Headroom.

Zone Reduction in

DO (Ml/d) Enters Deficit

Deficit by 2035 (Ml/d)

Primary reason

Brecon-Portis 3 2020 1 Habitats Directive

Pembrokeshire 19 2015 19 Climate Change and Habitats Directive

SEWCUS 85 2020 104

Climate Change and Habitats Directive

North Eryri Ynys Mon

9 2019 5 Climate Change

Table 8.2 – Supply Demand Deficits with the full range of UKCP09 climate change scenarios

incorporated into the S8 component of Target Headroom

8.3 Brecon Portis

The projected deficit in this zone is driven wholly by the incorporation into our forecasts of the

abstraction licence reductions required by the Environment Agency in the light of the Habitats

Directive. As a result of these changes the volume of water we can abstract from the Brecon

boreholes is reduced under low flow conditions in the River Usk. This means that during dry periods,

when generally we see higher demands, our abstractions would be curtailed and we would be unable

to meet demand.

Page | 79


Figure 8.2 – Brecon / Portis Supply Demand

As noted in chapter 7 above, the supply demand deficit in this zone is unaffected if the full effects of

UKCP09 climate change projections on Target Headroom are taken into account.

8.4 Pembrokeshire

The calculated deficit in this zone is also driven primarily by the incorporation into our forecasts of the

abstraction licence reductions required by the Environment Agency in the light of the Habitats

Directive. As a result of these measures the volume of water we can abstract from our intakes on the

Eastern and Western Cleddau rivers is severely reduced, particularly at Pont Hywel which would be

rendered virtually unusable as a result of the licence changes proposed by the Environment Agency

Wales during periods characterised by low flows and high demand. As a result, we would be unable

to maintain storage levels in Preseli reservoir and could not, therefore, meet the demands placed on

Preseli Water Treatment Works.

We have also modelled the impacts of the UKCP09 climate change projections. As with the Usk and

the Wye, lower rainfall leads to lower river flows which means that the thresholds at which we have to

reduce our abstractions from the Eastern and Western Cleddau rivers are reached sooner and more

frequently thus exacerbating further the reductions in the availability of water. Inflows to our

reservoirs are also reduced and so storage levels are lower.

Page | 80


Figure 8.3 – Pembrokeshire Supply Demand

As noted in chapter 7 above, if the full range of UKCP09 climate change scenarios is taken into

account in Target Headroom, the calculated deficit in this zone increases from 12.7 Ml/d to 18.2 Ml/d

by 2035. This is illustrated in Figure 8.4 below. Section 9.7 below presents broad details of how this

would affect our strategy for achieving supply demand balance in this zone.

Figure 8.4 – Pembrokeshire Supply Demand incorporating the full effects of UKCP09 climate

change scenarios

Page | 81


8.5 South East Wales Conjunctive Use System (SEWCUS)

The deficit in this zone is primarily calculated on the basis of the Environment Agency‟s review of our

relevant licences, but the effect of UKCP09 climate change scenarios on Deployable Output further

exacerbates the position, and by 2035 there is a projected deficit of some 12 Ml/d.

Figure 8.5 – SEWCUS Supply Demand

As noted in chapter 7 above, if the full range of UKCP09 climate scenarios is taken into account in

Target Headroom, the deficit in this zone increases from 12.4 Ml/d to 104.2 Ml/d by 2035. This is

illustrated in Figure 8.6 below. Section 9.7 below presents broad details of how this would affect our

strategy for achieving supply demand balance in this zone.

Figure 8.6 – SEWCUS Supply Demand incorporating the full effects of UKCP09 scenarios

Page | 82


8.6 North Eyri Ynys Mon

Under our preferred approach to the treatment of climate change uncertainty, this zone remains in

surplus throughout the Plan period. However, if the full range of UKCP09 climate scenarios is taken

into account in Target Headroom, the projected surplus of 2.9 Ml/d in 2035 becomes a deficit of 4.3

Ml/d. This is illustrated in Figure 8.7 below. Section 9.7 below presents broad details of how we

would expect to address this.

Figure 8.7 – North Eryri Ynys Mon Supply Demand incorporating the full effects of UKCP09

climate change scenarios

Page | 83


Chapter 9. Option Appraisal

In Chapter 8 we presented details of the three zones where we are projecting that at some point

during the next 25 years demand will exceed the available water supply and the zone will enter deficit.

This chapter explains how we evaluate the options available to address those deficits. We also

provide in section 9.7 an overview of how we would address the bigger deficits in Pembrokeshire and

South East Wales Conjunctive Use System zones on the basis of more “pessimistic” projections that

take into account the full range of UKCP09 climate scenarios, together with details of the options for

address the deficit that would emerge on this basis in North Eyri Ynys Mon. We have not appraised

the options for meeting supply demand deficits on the basis of an “optimistic” view of the effect of

climate change on Target Headroom.

To maintain our relevant Level of Service, both at a company level and in each of the two WRZs, we

either need to increase supply or reduce demand (or a combination of the two). Without such

intervention these zones may experience a frequency of water restrictions such as hosepipe bans in

excess of what we have established as the minimum level of service.

9.1 Our approach to appraising the options

9.1.1 Overall methodology

Our option appraisal approach follows national best practice and is consistent with the requirements

of the Environment Agency‟s Guideline.

The most important reference document on option appraisal is “The Economics of Balancing Supply

and Demand” (EBSD) (UKWIR/EA 2002). The EBSD report sets out how water companies should

identify, assess and compare alternative options for addressing supply demand deficits. In

accordance with the Environment Agency‟s Guideline we have also used:

Assessment of Benefits for Water Quality and Water Resources Schemes in the PR04

Environment Programme (EA, 2002), commonly referred to as the Benefits Assessment

Guidance (BAG). This methodology provides non-prescriptive guidance on how to assess the

environmental and social costs of options; and

Providing Best Practice Guidance on the Inclusion of Externalities in the Economic Level of

Leakage Calculation (Ofwat, 2007). This report provides guidance on how to assess the

environmental and social costs of leakage reduction schemes.

9.1.2 Environmental Appraisal

Following the adoption of the Environmental Assessment Directive54

in 2004, it is now a statutory

requirement to undertake a Strategic Environmental Assessment of the measures contained within

the Plan. The purpose of such an Assessment is to identify the environmental, economic and social

effects of each option. Our Strategic Environmental Assessment is presented in Chapter 10.

In addition, to ensure that the options we propose have “no adverse effect” upon European

designated Natura 2000 sites, we have also completed a Habitats Regulations Assessment.55

We

54

Directive 2001/42/EC.

55 Schedule 1 of the Conservation (Natural Habitats, &c) Regulations 1994 (as amended) (the „Habitats Regulations‟) requires

that competent authorities assess the potential impacts of land use plans on the Natura 2000 network of European protected sites.

Page | 84


have elected to undertake this assessment in order to demonstrate that, when implemented, the Final

Plan will not have adverse effects on any designated sites. Full details of the Habitats Regulations

Assessment can be found in Chapter 10.

9.1.3 The unconstrained list of options

For each WRZ where a deficit has been predicted we have prepared an “Unconstrained” list of

options. This represents an exhaustive list of all technically feasible options that could potentially

redress the supply demand balance deficit. The Economics of Balancing Supply and Demand report

sets out the range of options that should be considered and summarises them into four main

categories:

Distribution Management - options which reduce consumption from the point of input into

the network to the customer property (leakage options and mains replacement);

Customer-side Management - options which reduce customers‟ consumption (water

efficiency and tariffs);

Production Management - options which reduce/modify usage from where it is abstracted to

where it enters the network; and

Resource Management - options that vary yield.

We have undertaken a full up-to-date appraisal of options across these four categories. This ensures

that every type of option has been duly considered. The range of sub-options within the above four

categories is described in the report on the Economics of Balancing Supply and Demand56

9.2 Identifying the feasible options

A Multi-Criteria Analysis57

was applied using 10 criteria grouped into the broad categories of

Technical, Potential and Achievability, to refine the unconstrained list into a shorter “Feasible” list of

options.

The Multi-Criteria Analysis was undertaken on every Customer-side, Resource, and Production

Management option to review how each compared against a number of key environmental,

engineering and technical criteria, as specified under the Economics of Balancing Supply and

Demand report approach. Additional environmental categories for the Resource and Production

Management options were added to this analysis to improve our understanding of how each option

could impact the environment. One of these categories is the inclusion of the results of the

assessments the Environment Agency undertook for their Catchment Abstraction Management

Strategy into what water, if any, is available for abstraction across the surface and groundwater

catchments of Wales. Full details of this work are set out in our supporting Engineering Report.

56

“.

57 Multi Criteria Analysis is a common and accepted technique for making a comparative assessment of options, taking account

of several criteria simultaneously. It is mainly used to assess impacts that cannot be readily quantified in monetary terms.

Page | 85


9.3 Feasible List

9.3.1 Resource and Production Management

From the Multi-Criteria Analysis process described above a total of 19 Resource and Production

Management options across the three zones were assessed as “Feasible” and carried forward for

more detailed analysis. For each we have determined:

Capital expenditure (CAPEX);

Design, planning and construction time (the lead time);

Operational expenditure (OPEX);

Gain in zonal Deployable Output or the savings in demand;

Environmental and social costs and benefits (including carbon impact); and

Average Incremental Social Costs.58

9.3.2 Customer-side and Distribution Management

From the Multi-Criteria Analysis process a total of 18 Customer-side Management options across the

three zones were assessed as Feasible and carried forward. These consisted of five “water

efficiency” options and one “tariff” option. Water savings and costs were calculated for each measure,

the effect of which was then quantified for each zone using relevant figures for the number of

properties and population.

For the water efficiency measures, we have assumed that implementation takes place over a ten year

programme, and that water savings are effective for 10 years, in line with manufacturers‟

recommendations of an average 10 year lifespan for water efficiency products. Therefore, the

measures were designed so that maximum penetration of each measure would be achieved at the

end of the 10-year programme.

In addition we have also included, for the Pembrokeshire and South East Wales Conjunctive Use

System (SEWCUS) WRZs, three Distribution Management (leakage) options. These successively

more intensive leakage control strategies essentially reduce leakage levels below the short run

Economic Level of Leakage, and can be characterised as follows:

1. Reductions in detected leak run times – this option essentially increases the amount of

leakage detection resource available;

2. Location, operation and sounding of all fittings - this option targets previously undetected

leakage from all fittings, not just those that are visible without excavation; and

3. Installation of permanent correlator noise loggers – this option helps leakage teams to

detect leaks quicker and to identify those leaks not usually detected through conventional

means.

These leakage options would ideally, but not necessarily, be implemented in sequence i.e. option 1

followed by 2 then 3, as each option involves progressively intensive actions and manpower. The

58

Average Incremental Social Cost is a measure of the overall financial, environmental and social cost of an option. It is

usually expressed in terms of pence per cubic metre of water (p/ m3).

Page | 86


costs and savings for each option have been estimated based on the manpower and capital

requirements.

59

Tables 9.160

, 9.2 and 9.3 present the feasible options and their respective total environmental, social

and financial costs, for the three zones. They also show the potential water volume benefit for each

option, enabling Average Incremental Social Costs to be calculated and the cost-effectiveness of

each option to be compared. For example, the raising of the Llys Y Fran dam option for the

Pembrokeshire WRZ has a comparatively high Average Incremental Social Costs value of 606p/m3

and is the most expensive Resource and Production Management option for this zone.

The primary feasible option shown for the Brecon – Portis WRZ is “River regulation from Usk

reservoir”. We have considered water efficiency options, but as a result of the small size of this zone

these would not yield sufficient volumes to meet the deficit. The “River regulation from Usk reservoir”

option has been discussed with and has the approval of the Environment Agency.

The Average Incremental Social Costs values indicate the relative unit costs of each option but the

overall least cost solution depends on the optimal schedule of interventions over time that best

addresses the profile of the supply-demand deficits. Consequently, the most economic plan may not

directly reflect the Average Incremental Social Costs (AISC) ranking.

Option reference and name DO benefit

(Ml/d) AIC (p/m3)

Env and social

cost (p/m3)

AISC

(p/m3)

8206.1, Re-instate Milton source for

industrial 14.0 278 40 318

8206.3, Dam raising of Llys y Fran 14.4 606 26 632

8206.5, Increased groundwater abstraction

at Pendine 12.4 236 42 278

8206.6, Upgrade Middle Mill Water

Treatment Works 9.8 179 49 229

8206.7, Re-instate Parc springs 10.3 221 61 282

8206.9, Desalination Pembrokeshire WRZ 19.1 526 120 646

8206.10, Abstraction from the Afon Taf 19.1 391 67 458

8206.11, Transfer water from Bolton Hill

Water Treatment Works to Preseli Water

Treatment Works

8.9 132 32 164

8206.6 Ef, Tariff Option – Metering 0.01 78,013 - 78,013

8206.1 Ef, Household - Home Visit

Package 0.01 112,177 31,130 143,307

8206.2 Ef, Household - Water Butts 0.04 2951 7 2,958

8206.3 Ef, Non Household Visit Package 17.0 826 176 1,002

59

“

60 Options 8206.1 to 8206.10 also require the employment of option 8206.11 to realise the full potential increase in deployable

output. Therefore, for these options, the Deployable Output Benefit, capital expenditure, operating expenditure (and hence Average Incremental Costs and Average Incremental Social Costs values) contain option 8206.11, although not specifically stated in Table 9.1.

Page | 87



(Ml/d) AIC (p/m3)

Env and social

cost (p/m3)

AISC

(p/m3)

8206.4 Ef, Non Households Audits 33.0 2,567 45 2,612

8206.7 Lk, Leakage Option 1 0.5 1,412 10 1,422

8206.8 Lk, Leakage Option 2 0.8 944 58 1,002


Table 9.1 - Feasible options, Pembrokeshire WRZ


(Ml/d) AIC (p/m

3)

Env and social

cost (p/m3)

AISC (p/m3)

8108.4, River regulation from Usk reservoir 1.0 26 33 59

Table 9.2 - Feasible options, Brecon - Portis WRZ

Page | 88



(Ml/d) AIC (p/m

3)

Env and social

cost (p/m3)

AISC

(p/m3)

8121.1, Increase zonal transfer from Tywi

Gower in combination with Schwyll option 22 426 748 1,174

8121.5b, New abstraction, S.E.Wales

groundwater resource, new Water

Treatment Works

35.3 427 56 482

8121.7, Dam raising at Craig Goch 200 121 4 125

8121.11, Re-instate Grwyne reservoir with

new Water Treatment Works 5.9 319 6 325

8121.12, Utilisation of Grwynne as Usk

compensating reservoir 3.9 9 -26 -17

8121.13, Re-instate Wentwood reservoir

with new Water Treatment Works 7.8 309 27 336

8121.14, Reinstate treatment for Ynys y Fro

and Pant yr Eos reservoirs 10 284 848 1,132

8121.15, Reinstate the Bwllfa Graig Water

Treatment Works 5.5 363 715 1,078

8121.20, Desalination SEWCUS WRZ 10 650 222 872

8121.21, Reinstate Clydach reservoir and

Perthcelyn Water Treatment Works 5 365 2,205 2,570

8121.6 Ef, Tariff Option - Metering 0.3 34,935 - 34,935

8121.1 Ef, Household - Home Visit

Package 22.1 450 165 615

8121.2 Ef, Household - Water Butts 0.04 18 0.04 18

8121.3 Ef, Non Household Visit Package 11.2 335 71 407

8121.4 Ef, Non Households Audits 21.5 799 14 813


8121.8 Lk, Leakage Option 2 12.9 852 52 904


Table 9.3 - Feasible options, South East Wales Conjunctive Use System (SEWCUS) WRZ

Page | 89


9.4 Environmental and Social costing

As noted above, the environmental and social costs of each option are taken into account in deriving

the optimal strategy for addressing supply demand deficits, in accordance with the Environment

Agency‟s guidance.61

We divide environmental and social impacts into those that are water-related

(primarily changes in river flows) and those that are non-water related, such as the effects of

construction works and use of energy.

Full details of the Environmental and Social costing can be found in our supporting Engineering

Report.62

We have also made a separate assessment of carbon emissions. This is a new element of Water

Resources Management Plans.63

In carrying out this analysis we have distinguished between

embedded carbon emissions resulting from construction activities such as the processing of raw

materials, transport, waste removal etc, and operational carbon emissions that arise both directly and

indirectly from our own activities.

The graph below shows an example of the output of this analysis. Full details of the carbon

accounting process can be found in the technical supporting document.64

Figure 9.1 – Carbon Costing in Pembrokeshire

We have also assessed the operational carbon impact of the preferred options on the estimated

Company operational carbon footprint for water services. This is shown in Figure 9.2. Actual (out-

turn) data is shown in blue along with forecasted data (in red), based on our year on year reduction

61

Benefits Assessment Guidance: EA, 2002. 62

“Water Resource Options Assessment, Revised Draft”: Welsh Water, April 2011. 63 The requirement to undertake carbon accounting is set out in the joint Defra / Welsh Government Water Resources

Management Plan Direction 2007. 64 Carbon accounting of the Water Resources Management Plan (Halcrow 2009).

Page | 90


target of 3% per year. The actual and the forecast data has been „uplifted‟ to represent Dry Year

scenario outputs as the original forecast was based on a „normal‟ year. This was undertaken to allow

direct comparison with, and inclusion of, the preferred options which emerge under the Dry Year

scenario.

The forecast data also takes into account that from 2020-21 onwards our operations will be

significantly influenced by the changes to our existing licences under the Habitats related consents

review. The forecast data has been adjusted accordingly. The implementation of the preferred

options are shown cumulatively on top of the forecast data.

Figure 9.2 Operational carbon impact of the Preferred options over and above the Company

total footprint

Page | 91


9.5 Selecting the preferred option

To select the preferred option(s) for each zone we added the financial costs to the environmental and

social costs to arrive at an overall Average Incremental Social Costs estimate. Using a bespoke

mathematical least cost planning model65

we then derived the least cost combination of options that

would meet the deficits under both the Annual Average and Critical Period planning scenarios. This is

explained further in section 9.6 below. Annex 4 provides details of the ranking of options for the three

deficit zones.

9.6 Optimisation model

The optimisation model calculates the supply demand balances, from the individual components, for

each WRZ then evaluates the least cost combination of options, from the range of options and cost

data, which could be implemented to meet the forecast deficits. The model:

determines the Average Incremental Cost & Average Incremental Social Cost for each option;

identifies the least-cost combination/ mix of options that best meets the supply demand deficit

for each WRZ; and

derives the Preferred set of options that meets the supply demand balance deficit, for each

WRZ, at the least long-run marginal cost.

The model has been developed to allow changes in the various components of the supply demand

balance to be rapidly incorporated to take account of, for example, potential climate change scenarios

and sustainability reductions.

The model allows for the identification of options links and dependencies. For example, the model will

only select one option, if programmed to do so, where multiple source options have been identified to

supply one Water Treatment Works, or, where there are transfers from one source to multiple WRZ‟s.

The model also includes a Geographic Information System (“GIS”) interface that allows the options to

be visualised and their relationship, for example, with existing Welsh Water infrastructure and their

proximity to environmentally sensitive areas.

As the Preferred option set will likely form the basis of the Plan submission, the model also produces

the optimisation run results in the required format for Tables WRP2 and WRP3, as required by the

Agency‟s Guideline.

To reiterate, the Average Incremental Social Cost values indicate the relative unit costs of the options

but the least-cost solution depends on the optimal schedule of options over time that best satisfies the

supply-demand deficit profile. Consequently, the most economic plan may not necessarily directly

reflect the Average Incremental Social Costs ranking, as shown in Tables 9.1, 9.2, 9.3 and 9.13,

which show the Average Incremental Social Costs based on the maximum capacity of the options and

not the Utilised capacity of the option (to meet the specific zonal deficit).

65

“Lot 5 – Least Cost Water Resources Planning Model – Functional Description” (Jacobs 2008a), and “Lot 5 – Least Cost

Water Resources Planning Model – User Guide” (Jacobs 2008b).

Page | 92


9.7 Preferred Options for Addressing Supply Demand Deficits (Without Incorporating the Full Range of UKCP09 Climate Scenarios in Target Headroom)

9.7.1 Pembrokeshire

The options that have been selected on a least cost basis for this zone, which meet the deficits under

both the Annual Average and Critical Period scenarios, are presented in Table 9.4. Further detail of

what these options entail is contained in Table 9.5.

Option No.

and Name

Implementation

date

/Deployable

Output benefit

Capital

Expenditure

(£M)

Annual

Operating

Expenditure

(£M)

Net Present

Value of

Capital

Expenditure

and

Operating

Expenditure

(£M)

Net

Present

Value of

Env and

Social

costs

(£M)

Total

Net

Present

Value

(£M)

8206.1,

Reinstate

Milton

source for

industrial

use &

8206.11,

Transfer

water from

Bolton Hill

Water

Treatment

Works to

Preseli

Water

Treatment

Works

(implement

ed as an

aggregated

solution)

2017

14.0 Ml/d 12.3 0.5 15.1 1.4 16.5

Table 9.4 Preferred solution (on least cost basis) for Pembrokeshire WRZ

Page | 93


8206.1, Reinstate Milton

source for industrial use

Milton Borehole, located 3km from Carew, is an emergency source that is

only made operational to supplement the potable supply from Bolton Hill

Water Treatment Works during periods of high demand.

Water would be abstracted and softened in a new 8Ml/d Water Treatment

Works and blended with existing supplies.

The water would be used to deliver water to the industrial supplies in the

area thereby releasing water currently abstracted from the Eastern Cleddau

for distribution in the wider WRZ.

8206.11, Transfer water

from Bolton Hill Water

Treatment Works to

Preseli Water Treatment

Works

Bolton Hill Water Treatment Works near Haverfordwest is currently

supplied with water from the Eastern and Western Cleddau; Preseli Water

Treatment Works is mainly supplied from Preseli Reservoir supplemented

from an abstraction at Llysyfran.

This option involves upsizing and re-commissioning 10km of mains in and

around Haverfordwest to enable water to be transferred between the two

Water Treatment Works, and building a new water pumping station to allow

water to be moved from the south west of the WRZ to the north east.

Table 9.5 – Pembrokeshire Options

Figure 9.3 shows how these options address the deficit over time.

Figure 9.3 - Preferred solution (least cost) for Pembrokeshire WRZ, Utilised Water Available for Use (Annual Average Dry Year)

9.7.2 Brecon – Portis WRZ

The option that has been selected for this zone is Option No. 8108.4 – “River regulation from Usk

reservoir”, details of which are presented in Table 9.6.

Page | 94


Option No. and

Name

Implementation

date/

Deployable

Output benefit

Capital

Expenditur

e (£M)

Annual

Operating

Expenditure

(£M)

Net Present

Value of

Capital

Expenditure

and

Operating

Expenditure

(£M)

Net

Present

Value of

Env and

Social

costs

(£M)

Total

Net

Present

Value

(£M)

8108.4, River

regulation from

Usk reservoir

2020

1.0 Ml/d 0.3 0 0.2 0.4 0.6

Table 9.6 - Preferred solution (on least cost basis) for Brecon - Portis WRZ

This option involves making additional releases from Usk Reservoir in order to augment river flows

and thereby enable abstraction at Brecon to be maintained at required levels.

9.7.3 SEWCUS WRZ

The options that have been selected on a least cost basis for this zone are presented in Table 9.7.

Further detail of what these options entail is contained in Table 9.8.

Page | 95


Option No.

and Name

Imple-

mentation

date/DO

benefit

Capital

Expenditure

(£M)

Annual

Operating

Expenditure

(£M)

Net Present

Value of

Capital

Expenditure

and Opex

(£M)

Net

Present

Value of

Env and

Social

costs

(£M)

Total

Net

Present

Value

(£M)

8121.11,

Reinstate

Grwyne

reservoir

with new

Water

Treatment

Works

2028

5.9 Ml/d 10.2 0.2 6.3 0.1 6.4

8121.13,

Reinstate

Wentwood

reservoir

with new

Water

Treatment

Works

2032

7.8 Ml/d 12.9 0.2 6.4 0.1 6.5

Table 9.7 Preferred solution (on least cost basis) for SEWCUS WRZ

8121.11, Reinstate

Grwyne reservoir with new

Water Treatment Works

Grwyne Reservoir previously supplied water to the Abertillery area, over 40

km to the south. The reservoir is now mothballed.

This option would construct a wholly new Water Treatment Works to treat

the raw water from the reservoir. Potable water mains have recently been

re-laid so no new mains would be required. This option would provide up

to 6 Ml/d.

8121.13, Reinstate

Wentwood reservoir with

new Water Treatment

Works

Wentwood Reservoir, that previously supplied the south east Gwent

distribution zone, has some algal problems. It is now used for recreation

and fishing.

This option would reinstate Wentwood Reservoir and provide improved

treatment facilities. This option would provide up to 8 Ml/d.

Table 9.8 – SEWCUS Options

Figure 9.4 shows how these options address the deficit over time.

9.7.4 Demand Management and Leakage options

As stated in section 9.6, the options are selected on a least cost basis, in parallel with the

environmental appraisal conducted through the Strategic Environmental Assessment and Habitats

Regulations Assessment (section 10.2 and section 10.3). Although many of the demand

management and leakage options have been appraised as potentially contributing positively to the

environment, in conjunction with the least cost modelling process they have not been selected as the

Preferred options as the demand savings of the options are either not sufficient to meet the deficits –

either because the option demand savings are wholly too low to meet the deficits, or, in the case of

Page | 96


the water efficiency options, the ramping up (10 year period) and ramping down (10 year period) of

the demand savings cannot meet the deficits across the full planning period (see section 9.3). Where

demand management and leakage options do have sufficient „yields‟ to meet the deficits, then their

implementation is not cost effective.

Figure 9.4 - Preferred solution (least cost) for SEWCUS WRZ, Utilised WAFU (Annual Average

Dry Year)

Page | 97


9.8 Preferred Options for Addressing Supply Demand Deficits, Incorporating the Full Range of UKCP09 Scenarios in Target Headroom

Our preferred options for addressing the deficits that arise when the full effects of UKCP09 scenarios

in Target Headroom are taken into account (see Table 8.2 above) are presented below. The options

for Pembrokeshire and North Eyri Ynys Mon meet the deficits under both the Annual Average and

Critical Period scenarios.

9.8.1 Pembrokeshire

For Pembrokeshire the supply demand deficit that we would have had to address on this basis would

have been somewhat greater, rising to 18.2 Ml/d by 2035 instead of 12.7 Ml/d. Our indicative

preferred options for meeting this shortfall are set out in table 9.9, and further details of the schemes

are set out in table 9.10.

Option No. and

Name

Imple-

mentation

date/DO

benefit

Capital

Expenditure

(£M)

Annual

Operating

Expenditure

(£M)

Net Present

Value of

Capital

Expenditure

and Opex

(£M)

Net

Present

Value of

Env and

Social

costs

(£M)

Total

Net

Present

Value

(£M)

8206.3 Ef, Non

Household -

Non Household

Visit Package

2015

17.0 Ml/d 23.2 0.5 19.0 4.1 23.1

8206.10,

Abstraction from

the Afon Taf &

8206.11,

Transfer water

from Bolton Hill

Water

Treatment

Works to Preseli

Water

Treatment

Works

(implemented

as an

aggregated

solution)

2020

19.1 Ml/d 27.0 0.5 22.6 1.9 24.5

Table 9.9 Preferred solution (on least cost basis) for Pembrokeshire WRZ

8206.3 Ef, Non Household

- Non Household Visit

Package

This water efficiency option targets small businesses, advising on the

efficient use of water and providing water efficient devices, such as, low

water use taps. This option would save up to 17 Ml/d.

8206.10, Abstraction from

the Afon Taf

The Afon Taf originates on the western fringe of the Preseli Hills and flows

southwards, before flowing into Carmarthen Bay, south west of

Carmarthen.

This option would abstract water from the lower reaches of the Afon Taf. A

Page | 98


new Water Treatment Works and associated pipeline/ network changes would be required. The option yield is 10 Ml/d.

8206.11, Transfer water

from Bolton Hill Water

Treatment Works to

Preseli Water Treatment

Works

Bolton Hill Water Treatment Works near Haverfordwest is currently

supplied with water from the Eastern and Western Cleddau; Preseli Water

Treatment Works is mainly supplied from Preseli Reservoir supplemented

from an abstraction at Llysyfran.

This option involves upsizing and re-commissioning 10km of mains in and

around Haverfordwest to enable water to be transferred between the two

Water Treatment Works, and building a new water pumping station to allow

water to be moved from the south west of the WRZ to the north east.

Table 9.10 – Pembrokeshire Options

9.8.2 Brecon – Portis WRZ

As explained in section 8.3 above, DO in this zone is considered to be constrained by licence

conditions, so the use of the full range of UKCP09 scenarios in Target Headroom has no incremental

impact. The preferred option is therefore the same as shown in Table 9.6 above.

9.8.3 SEWCUS WRZ

For SEWCUS the supply demand deficit that we would have to address would have been

considerably greater as a result of the use of the full range of UKCP09 scenarios in Target Headroom,

rising to 104.2 Ml/d by 2035 instead of just 12.4 Ml/d. Our indicative preferred options for meeting this

shortfall are set out in table 9.11, and further details of the schemes are set out in table 9.12.

Page | 99


Option No.

and Name

Imple-

mentation

date/DO

benefit

Capital

Expenditure

(£M)

Annual

Operating

Expenditure

(£M)

Net Present

Value of

Capital

Expenditure

and Opex

(£M)

Net

Present

Value of

Env and

Social

costs

(£M)

Total

Net

Present

Value

(£M)

Options

implemented

as a group:

8121.11,

Reinstate

Grwyne

reservoir with

new Water

Treatment

Works

8121.13,

Reinstate

Wentwood

reservoir with

new Water

Treatment

Works

8121.5, New

abstraction,

S.E. Wales

including new

Water

Treatment

Works

8121.15,

Reinstate the

Bwllfa Graig

Water

Treatment

Works

8121.14,

Reinstate

treatment for

Ynys y Fro

and Pant yr

Eos reservoirs

2020

50.8 Ml/d 92.3 6.0 114.0 45.8 159.8

Page | 100


8121.8 Locate,

Operate and

Sound All

Fittings

(leakage

option)

2022

12.9 Ml/d 43.8 2.0 36.9 1.5 38.4

8121.3 Ef,

Non

Household -

Non

Household

Visit Package

2026

11.2 Ml/d 14.2 0.3 7.3 1.5 8.8

8121.20,

Desalination

plant

SEWCUS

WRZ

2027

10.0 Ml/d 24.6 1.8 16.7 3.1 19.8

8121.4 Ef,

Non

Household -

Non

Households

Audits

2032

21.5 Ml/d 22.1 1.2 9.2 0.2 9.4

Table 9.11 Preferred solution (on least cost basis) for SEWCUS WRZ

Page | 101


Options implemented as a

group:

8121.11, Reinstate

Grwyne reservoir with new


8121.13, Reinstate

Wentwood reservoir with

new Water Treatment

Works

8121.5, New abstraction,

S.E. Wales gw resource,

new Water Treatment

Works

8121.15, Reinstate the

Bwllfa Graig Water

Treatment Works

8121.14, Reinstate

treatment for Ynys y Fro

and Pant yr Eos reservoirs

Grwyne Reservoir previously supplied water to the Abertillery area, over 40

km to the south. The reservoir is now mothballed. This option would

construct a wholly new Water Treatment Works to treat the raw water from

the reservoir. Potable water mains have recently been re-laid so no new

mains would be required. This option would provide up to 6 Ml/d.

Wentwood Reservoir, that previously supplied the south east Gwent

distribution zone, has some algal problems. It is now used for recreation

and fishing. This option would reinstate Wentwood Reservoir and provide

improved treatment facilities. This option would provide up to 8 Ml/d.

Investigations have shown that there is a significant amount of groundwater

available from the carboniferous limestone block of south east Wales and

so we plan to utilise this by building a new Water Treatment Works to treat

the abstracted water and deliver the water into the Cardiff/ Newport area.

This option would provide up to 33 Ml/d.

The reservoir at Bwllfa Graig has been out of operation for a number of

years and the associated Water Treatment Works has been de-

commissioned. This option would reinstate the Water Treatment Works

and deliver the water into the supply network. This option would provide up

to 5 Ml/d.

The reservoirs at Ynys y Fro and Pant yr Eos have been out of operation

for a number of years and their associated Water Treatment Works have

been de-commissioned. This option would reinstate the Water Treatment

Works and deliver the water into the supply network. This option would

provide up to 10 Ml/d.

8121.8 Lk, Locate,

Operate and Sound All

Fittings (leakage option)

This leakage option targets previously undetected leakage from all fittings,

not just those that are visible, by increasing the available resources. This

option would save up to 13 Ml/d.


- Non Household Visit

Package

This water efficiency option targets small businesses, advising on the

efficient use of water and providing water efficient devices, such as, low

water use taps. This option would save up to 11 Ml/d.

8121.20, Desalination

SEWCUS WRZ

This option would construct a seawater desalination plant. Treated water

would be transferred to an existing Water Treatment Works or service

reservoir for blending with alternative supplies. This option would save up

to 10 Ml/d.


- Non Households Audits

This water efficiency option targets large businesses advising on the

efficient use of water, specifically related to their processes, and

recommending alternative water efficient engineering solutions. This option

would save up to 22 Ml/d.

Table 9.12 – SEWCUS Options

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9.8.4 North Eyri Ynys Mon WRZ

For North Eyri Ynys Mon, the surplus that we had been forecasting turns to a deficit of 4.3 Ml/d by

2035. Table 9.13 presents the Feasible options and their respective total environmental, social and

financial costs for this zone.

Option reference and name DO

benefit (Ml/d)

AIC (p/m3)

Env and social cost (p/m

3)

AISC (p/m

3)

8001.3, Connect Afon Rhythallt to Cwellyn Water Treatment Works

10.93 60.67 2.04 62.71

8001.4, New Crug Water Treatment Works and utilisation of existing Afon Rhythallt source

11.90 98.53 53.21 151.74

8001.5, New abstraction at Llyn Cowlyd and upgrade Mynydd Llandygai Water Treatment Works

9.15 136.93 8.50 145.43

8001.6, New abstraction at Llyn Cowlyd - new Water Treatment Works

8.49 266.75 68.97 335.72

8001.7, Licence Variation at Llyn Cwellyn and Cwellyn Water Treatment Works upgrade

7.06 109.76 0.48 110.24

8001.8, Utilisation of abstraction from Afon Seiont - upgrade Mynydd Llandygai Water Treatment Works

9.15 143.43 11.42 154.85

8001.10, Dam Raising Ffynnon Llugwy 10.01 170.16 1.98 172.14

8001.11, Desalination North Eryri/Ynys Mon WRZ

10.58 289.3 92.67 381.97

8001.6 Ef, Tariff Option - Metering 0.02 51,301.16 - 51,301.16

8001.1 Ef, Household - Home Visit Package

2.22 110.92 31.97 142.89

8001.2 Ef, Household - Water Butts 0.04 8.64 0.02 8.66

8001.3 Ef, Non Household Visit Package 3.23 104.9 22.82 127.72

8001.4 Ef, Non Households Audits 6.33 338.84 6.05 344.89

8001.7 Lk, Leakage Option 1 0.38 1274.92 8.87 1,283.79

8001.8 Lk, Leakage Option 2 1.94 1586.63 100.19 1,686.82

Table 9.13 Feasible options, North Eyri Ynys Mon

Our indicative preferred options for meeting this shortfall are set out in table 9.14, and further details

of the schemes are set out in table 9.15.

Page | 103


Option

No. and

Name

Imple-

mentation

date/DO

benefit

Capital

Expenditure

(£M)

Annual

Operating

Expenditure

(£M)

Net Present

Value of

Capital

Expenditure

and Opex

(£M)

Net

Present

Value of

Env and

Social

costs

(£M)

Total

Net

Present

Value

(£M)

8001.3,

Connect

Afon

Rhythallt

to Llyn

Cwellyn

2019

10.9 Ml/d 4.1 0 3.3 0.2 3.5

Table 9.14 Preferred solution (on least cost basis) for North Eyri Ynys Mon WRZ

8001.3, Connect Afon

Rhythallt to Llyn Cwellyn

Afon Rhythallt drains the Padarn and Peris lakes at Llanberis. An existing

intake at Crawia weir near Llanrug previously abstracted water to Crug

Water Treatment Works, near Caernarfon. Crug Water Treatment Works is

now abandoned.

This option would abstract water from Afon Rhythallt and transfer the water

to Cwellyn Water Treatment Works, which has been upgraded as part of

Welsh Water‟s AMP 5 Quality Programme and would enable the increased

flows to be managed. This option has a yield of 3.4 Ml/d.

Table 9.15 – North Eyri Ynys Mon Options

The above Preferred option for North Eyri Ynys Mon has been selected by our least cost model in line

with the comments in section 9.8.4.

In summary, the options we have identified to address the deficits in these four zones on this basis

would cost some £200m in Net Present Value terms, and would add approximately £20 per annum to

the average household bill for water supply in our area.

9.9 Sensitivity

Our Plan is based on detailed studies, calculations and expert opinion about future outcomes. It is

critical to consider the sensitivity of the Plan to any changes to demonstrate the robustness and

flexibility of the Plan. We have examined:

sensitivity of the supply-demand balances to changes in data; and

sensitivity of the strategy to changes in the options.

9.9.1 Changes in data

Target Headroom (see Chapter 5) enables the quantification of a wide range of potential uncertainties

and includes some allowance for them in the supply-demand balance calculations. This is generally

particularly critical for the potential impact of climate change on source yields and uncertainty in future

demand (although we have detailed our approach regarding climate change earlier in the Plan).

Page | 104


Actual demand for water is likely to vary from forecast levels due to uncertainties about future

conditions outside of Welsh Water‟s control, such as population changes and economic trends.

To some degree the water resources management plan process is able to accommodate these risks,

as the Plan is updated every five years. For example, within that five year period, demand forecasts,

climate change impacts, changes in source yields, are all revised and updated. This ensures in

theory, that the Plan at any given point in time is robust, flexible and up to date.

Page | 105


9.9.2 Changes in Levels of Service

For the three deficit zones of SEWCUS, North Eyri Ynys Mon and Pembrokeshire we have also

undertaken an analysis of varying the Level of Service of the baseline models to ascertain the impact

of Deployable Output. The results are shown in Table 9.16.

WRZ Deployable

Output (Ml/d)

LoS

(years)

Hosepipe

Bans (no.)

Demand

shortfalls Other comments

SEWCUS

401.75 1 in 33 0 0 Llandegfedd

reservoir at 20%


reservoir at 15%


reservoir at 7%


reservoir at 1%

NEYM

50.86 1 in 24 2 0 -

51.52 1 in 15 3 2 -

52.88 1 in 15 3 14 -

Pembrokeshire

64.76 1 in 36 1 0 -

65.03 1 in 18 2 0 -

65.31 1 in 12 3 0 -

Table 9.16 Deployable output sensitivity to LoS (SEWCUS, NEYM and Pembrokeshire WRZ)

The baseline Deployable Output value for SEWCUS is 401.75 Ml/d, under which no Hosepipe Bans

occur and Landegfedd reservoir storage continues to comply with Emergency Storage requirements.

The Deployable Output in the zone can be increased, still with no Hosepipe Bans, to 421.38 Ml/d (5%

increase), but storage levels in Landegfedd reservoir fall to 7% which does not comply with

Emergency Storage requirements. The Deployable Output in the zone can be increased further still

to 429 Ml/d (7% increase) on the basis that 4 Hosepipe Bans will occur in a 33 year period (resulting

in a LoS for the zone of 1 in 8 years) but with Landegfedd reservoir storage falling to 1% in the critical

year.

For the North Eyri Ynys Mon Water Resource Zone, the Deployable Output can only be increased to

52.88 Ml/d (increase of 4%) by lowering the Level of Service to 1 in 15 years and incurring a number

of demand failures. For the Pembrokeshire Water Resource Zone the Deployable Output can only be

increased to 65.31 Ml/d (increase of <1%) by lowering the LoS to 1 in 12 years.

In summary, for the small gains in Deployable Output in each zone and the considerable risk to

security of supply, we do not consider that varying the zonal Level of Service and potentially imposing

restrictions on our customers on a more frequent basis is justified.

9.9.3 Changes in the options

This Plan has identified preferred solutions which are likely to form part of the overall strategy. For

each option we have allowed sufficient investigation time and costs. Therefore, we are not

anticipating that the list of resource options will change.

Page | 106


However, during the investigation phase should, for example, an environmental issue arise that would

rule out that option, then we assessed what other options would be selected as part of the Preferred

solution. In preparing the Plan, this was a major concern for the Countryside Council for Wales and

Natural England who, rightly, required us to demonstrate that should an option at detailed project

stage prove to have a likely adverse impact on protected environmental sites or species, that we

could implement alternative options to maintain the supply demand balance. This is detailed in the

Strategic Environmental Assessment and the Habitats Regulations Assessment reports.

For the deficit zones of SEWCUS and Pembrokeshire, should at least one of the options need to be

excluded, then we have itemised, in Table 9.17 the next alternative preferred solutions.

SEWCUS Pembrokeshire

Preferred

option

excluded

8121.11, Reinstate Grwyne reservoir with new Water

Treatment Works

8206.1, Reinstate Milton

source for industrial use

Alternative

options

selected

8121.13, Reinstate Wentwood reservoir with new


8121.15, Reinstate the Bwllfa Graig Water Treatment

Works

8206.10, Abstraction

from the Afon Taf

Table 9.17 Alternative Preferred options

Due to the geography of Wales, some of the preferred options naturally have high Operating

Expenditure due to increased pumping requirements. We have undertaken sensitivity on the choice

of preferred solutions for each deficit zone, should the Operating Expenditure estimates of the

feasible list of options prove to be different from that currently estimated. If we increase the Operating

Expenditure costs of all the feasible options by 20%, then the same preferred options are still

selected.

Through the Revised Draft Plan consultation we are anticipating that consultees will suggest

alternative options that we not have considered fully. For these reasons there may be changes to the

scope, cost or feasibility of some of the options in our Final Plan. However, we expect the final

solutions to be broadly similar in nature. This is due to the size of the deficits and the low cost

effectiveness of some of the demand management measures.

Naturally if we do change or include further options between now and the Final Plan, the changes will

be fully documented in the Final Plan.

Page | 107


Chapter 10. Environmental Appraisal

10.1 Introduction

This chapter presents the work we have undertaken to identify and assess the potential effects of our

Plan on the environment. It describes how we have undertaken this assessment, the results of that

assessment, and any further work that we need to carry out.

Overall, the environmental appraisal shows that our Plan, and specifically the Preferred Options, are

not expected, at this stage, to have any significant environmental impacts. However, in the event that

any of our preferred options are found to have significant environmental impacts once we reach the

stage of detailed investigations and scheme design, we have identified a number of alternative

options that could be implemented instead.

10.1.1 Strategic Environmental Appraisal

Under the Plan we have identified the most economic (least cost) combinations of options to meet the

predicted supply shortfalls over the next 25 years. In doing so we included, within the costing

process, the potential environmental and social costs of each option.

In addition to this, we have prepared a Strategic Environmental Assessment. This Assessment is a

statutory process66

that identifies and assesses potentially significant environmental effects of the

Plan, and, where appropriate, how negative impacts might be mitigated and positive impacts

enhanced.

10.1.2 Habitats Regulations Assessment

In addition to carrying out a Strategic Environmental Assessment, we have also assessed the

potential impacts of this Plan against the conservation objectives for designated European sites.67

This is known as a Habitats Regulations Assessment 68

and is driven by the Habitats Directive.69

The Habitats Regulations Assessment determines whether there will be any “likely significant effects”

on any European site as a result of the implementation of the Plan (either on its own or “in

combination” with other plans or projects) and, if so, whether these will adversely affect the integrity of

the site.

The Habitats Regulations Assessment, like the Strategic Environmental Assessment, has been an

integral part of the development of the options from the outset and hence this Revised Draft Plan. In

essence, the Strategic Environmental Assessment and Habitats Regulations Assessment process

proceed alongside one another (and alongside the WRMP process) with the outcomes of the Habitats

Regulations Assessment being incorporated into the Strategic Environmental Assessment

66

The Water Industry, through UK Water Industry Research Ltd (UKWIR) recognises that WRMPs may be subject to a SEA

under the requirements of the European Directive 2001/42/EC (the SEA Directive). The SEA Directive has been transposed into UK legislation as Regulations. 67

HRA is required by law for all European Sites (Regulation 48). A European Site is any classified SPA and any Special Area

of Conservation from the point where the Commission and the Government agree the site as a Site of Community Importance. HRA is also required, as a matter of Government policy, for potential SPAs, candidate Special Areas of Conservation and listed Ramsar Sites for the purpose of considering development proposals affecting them (PPG9 paras. 13 and C7). As such, pSPAs, cSpecial Areas of Conservation and Ramsar Sites must also be considered by any HRA. Within this report „European site‟ is used as a generic term for all of the above designated sites 68

Appropriate Assessment‟ has been historically used as an umbrella term to describe the process of assessment as a whole.

The whole process is now more accurately termed „Habitats Regulations Assessment‟ (HRA), and „Appropriate Assessment‟ is used to indicate a specific stage of a HRA. 69

Council Directive 92/43/EEC on the conservation of natural habitats and of wild fauna and flora.

Page | 108


Environmental Report. The approach we took to carrying out the Habitats Regulations Assessment is

described in Section 10.3.

10.1.3 Consultation

We have worked closely with the Countryside Council for Wales and Natural England in preparing

both the Strategic Environmental Assessment and the Habitats Regulations Assessment, and have

discussed with them our approach to undertaking the environmental appraisal, the evaluation of the

preferred options, and the format of the Strategic Environmental Assessment and Habitats

Regulations Assessment reports. We believe that through this process we have achieved a robust

and appropriate appraisal of the potential environmental impacts of the Plan.

We intend to continue working closely with both the Countryside Council for Wales and Natural

England through the consultation process on this Revised Draft Plan, and in preparing the Final Plan.

10.2 Strategic Environmental Assessment

10.2.1 Environmental Baseline

Defining the environmental baseline, relevant issues and the context is important in setting the

framework for the Strategic Environmental Assessment. It involves the following elements:

characterising the current state of the environment (including social and economic aspects);

and

identifying existing problems and opportunities to be considered in the Plan.

Based on an analysis of up-to-date relevant information, we have identified the key sustainability

issues (or Themes) in the Welsh Water region, for example, “Water” and “Air and Climate”. Within

these broad Themes we have then assessed all the Feasible Options against key Objectives (eleven

in total) to determine the potential impact that each option, individually and in combination, may have

on the environment.

Examples of the Objective questions are:

ensuring sustainable use of water resources, and

promoting the wise use of resources.

Each of the feasible options was assessed against the Objectives to identify its potential impacts.

These were assessed on the basis of the nature of the effect, its timing and geographic scale, the

sensitivity of the people or environmental receptors that could be affected, and how long it might last.

The Strategic Environmental Assessment Environmental Report fully details the Themes, Objectives

and assessments for each of the deficit WRZs.70

10.2.4 Summary of impacts

In general, the assessment found that the options involving larger programmes of work or yielding

more water tended to have the biggest impacts (both positive and negative) across the range of

70 “Strategic Environmental Assessment of Revised Draft WRMP, Revised Environmental Report”: Entec UK Limited, March

2011.

Page | 109


Objectives. This reflected, for example, the greater use of resources during construction and the

more significant effect on security of supply.

10.2.5 Using the findings of the assessment

The assessment helped to highlight the range of potential environmental and social impacts, including

those that had been quantified and those that could only be identified qualitatively. The assessment

did not highlight any major effects that we had not already considered in developing the most

economic combinations of options, although it helped to identify where there are more minor effects

and how some of the potential negative impacts can be mitigated.

10.3 Habitats Regulations Assessment

10.3.1 The Process

As stated, we have undertaken a Habitats Regulations Assessment of this Plan, which is reported

separately.71

The Habitats Regulations Assessment was undertaken as an iterative process

alongside the development of the Plan, to help to ensure that the Final Plan will not have adverse

effects on any European Sites when implemented. The Habitats Regulations Assessment is

“appropriate” to the Plan, which means that it recognises that there are inherent uncertainties both

within strategic plans and within the Feasible options: that is, at this high level of planning it is only

possible to identify effects that may occur; it is not possible meaningfully to quantify or otherwise

assess the effects at this stage.

The Habitats Regulations Assessment has identified whether any feasible options would have

unacceptable effects on a European Site. This process informed the selection of the preferred

options. Further assessment was then undertaken on the preferred options to ensure that any likely

significant effect or adverse effects were identified and appropriate measures developed to ensure

that these effects would be avoided or reliably mitigated when the Final Plan is implemented.

The Habitats Regulations Assessment must also consider the potential impact on any European Site,

whether within our geographical boundary or not, and whether impacted individually by our Plan or in

combination with other Plans. In the case of our Plan, which operates at a strategic level, the main “in

combination” effects will be associated with other strategic plans and programmes, particularly those

involving water resources (for example, our Drought Plan).

10.3.2 Review of Feasible options

The Feasible options were reviewed for their possible effects on European Sites using a preliminary

screening method. This identified those European Sites that could potentially be affected by the

implementation or operation of each feasible option, given the characteristics of the Site, the means

by which it might be affected by the option, and the distance from the option to the Site.

This stage was primarily used to identify those options that would clearly have unacceptable effects

on a European site, which then informed the selection of the preferred options.

71 “Habitats Regulations Assessment of Revised Draft WRMP”: Entec UK Limited, March 2011.

Page | 110


10.3.3 Assessment of Preferred options

Following from the screening of feasible options through both the Habitats Regulations Assessment

and Strategic Environmental Assessment process, the initial preferred options were re-screened and

assessed in greater detail for their likely impacts on European Sites.

Where potential effects were identified as “uncertain” (as is often the case when the examination is at

a comparatively strategic level) an assessment of likely significant effect was made and avoidance

measures or mitigation proposed to help to ensure that there would be no adverse effects. For some

options, any such effects are likely to be localised and can therefore be more appropriately assessed

at the more detailed planning stages. In this case, the assessment identified the risk of effects but

assumed that Habitats Regulations Assessment of lower level strategies or the individual options

themselves will be sufficiently rigorous to avoid significant or adverse effects.

Since the precise manner and timescale in which the various options could be implemented is

unknown, not all the possible effects can be assessed at the strategic level and some can only be

determined at a project level. This means that the Habitats Regulations Assessment must assume

that all normal controls will be applied (i.e. at a project-level Habitats Regulations Assessment) and

that likely significant effect can only be concluded where the level of development required is unlikely

to be accommodated, regardless of project-level mitigation.

For example, an option requiring construction work within a Special Area of Conservation may initially

appear certain to have likely significant effect; however, that option may involve simply refitting

existing operational structures, which can almost certainly be easily accommodated without likely

significant effect or adverse effects. The opposite is also true. This means that the strategic Habitats

Regulations Assessment must consider whether the likely level of development required for the option

can be accommodated and (if this is uncertain) whether there are other practicable options available

that will not have a likely significant effect.

10.3.4 Summary of Assessment

The Habitats Regulations Assessment concluded that most of the feasible and preferred options had

the potential for likely significant effect on at least one European Site; however, for most options it

was very clear that the potential effects were of a scale and type that could certainly be avoided at the

scheme level with standard and accepted measures.

There are two options where the available data strongly suggests that there will be no adverse

effects, but this cannot be concluded with certainty at the strategic level. These schemes are:

8108.1 Brecon-Portis: additional releases from Usk Reservoir; and

8206. 1 Pembrokeshire: re-instate Milton source for industrial use.

We believe that it is acceptable to include these schemes in the Plan for now on the basis that

Habitats Regulations Assessments and assessments at the scheme level can be expected to resolve

the uncertainties (since scheme-specific Habitats Regulations Assessment will be a legal requirement

before these schemes can be implemented), provided that potential alternatives with “no adverse

effects” are identified within the Plan. The Plan has therefore included these schemes as preferred

options, with the proviso that “alternative” options have been identified that could be employed should

the options in question prove to have adverse effects that are unavoidable. This process and the

“alternative” options are detailed fully in the Habitats Regulations Assessment report.

Page | 111


10.3.5 Conclusion

Overall the Habitats Regulations Assessment has concluded that the Revised Draft Plan will not have

any significant adverse effects on any European Site (alone or in combination with other plans and

programmes) as a result of its implementation, since the preferred options:

either will have no significant or adverse effect as they stand; or

can be implemented using established and reliable best-practice mitigation/ avoidance

measures to ensure no significant or adverse effects; or

can be replaced by options that have no likely significant effect or adverse effects from the

feasible options list, should scheme-specific investigations demonstrate that adverse effects

are certain and cannot be avoided or mitigated.

All options will, in any case, be subject to project-level Habitats Regulations Assessment, as a matter

of legal requirement, which will provide an additional safeguard.

Page | 112


Annex 1 – Resource Developments in AMP 4

This Annex outlines the changes we have made to how resources are provided during the AMP4

period 2005-2010

North Eryri - Ynys Mon

In AMP4 a £8M scheme was identified for North Eryri – Ynys Mon (NEYM). This substantial

engineering scheme enables improved utilisation of resources on Anglesey and retains resources on

the mainland for increased use during a drought. The scheme was modelled in detail using

WRAPSim and increased DO by 10 Ml/d. It was completed in March 2009.

Barmouth

We completed a scheme to link Lleyn - Harlech WRZ to Barmouth WRZ, during AMP4. This scheme

was in two parts:

we resolved the restrictions in capacity on the raw water main between Llyn Eiddew Mawr

and Rhiwgoch Water Treatment Works; and

we provided additional network distribution mains from Rhiwgoch into the Barmouth WRZ,

currently fed from Eithinfynydd Water Treatment Works. A statutory undertaking we gave to

the Drinking Water Inspectorate at Rhiwgoch Water Treatment Works reduced its design

capacity from the licenced volume of 2 Ml/d to the current maximum capacity of 1 Ml/d.

Towards the end of our 2005-2010 business plan period we embarked upon our 2010-2015 water

quality investment programme. Rhiwgoch Water Treatment Works was confirmed as a works that

would be upgraded as part of this programme, and this was completed by March 2010. As such, an

export from Lleyn - Harlech WRZ to Barmouth WRZ has now been incorporated within the supply

demand balance to resolve forecast future deficits within the Barmouth supply area. Within our 2010-

2015 water quality investment programme, these two zones will be merged and reported as a single

zone.

South Meirionydd and Blaenau Ffestiniog

We identified that benefits could be achieved in South Meirionydd (Afon Wnion to Llyn Cynwch) and

Blaenau Ffestiniog (Afon Gam to Llyn Morwynion) WRZs by carrying out changes that would allow us

to re-fill the reservoirs more effectively during the winter. These capital schemes were delivered

during 2008.

Ross-on-Wye

During 2005-2010 we completed mains refurbishment on the Hereford/Ross-on-Wye boundary. The

Ross-on-Wye WRZ is currently expanded during the summer period to supply part of the Hereford

WRZ due to water capacity constraints between Ridgehill and Aconbury Service Reservoirs (within

the Hereford WRZ).

Vowchurch

The 2008 Draft Plan identified a peak week supply deficit within the Vowchurch WRZ. To remove this

a new 4.5km, 180mm diameter main from Vowchurch was connected to the Aconbury Service

Reservoir in the Hereford WRZ in 2008.

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Whitbourne

We duplicated 3.3km of main between Hope under Dinmore and Bodenham, south of Leominster,

during 2006. We also undertook mains cleansing in the Leysters Service Reservoir zone, which the

Risbury pumping station can supply, to complete the work to allow transfers of water from the

Hereford area.

The exceptional rainfall and flooding during the summer of 2007, which resulted in the temporary loss

of Whitbourne Water Treatment Works, meant that this transfer could be used to restore customer

supplies following the bad weather. The new system was therefore used effectively and the supply

demand balance has been updated showing that the previous deficit in this zone has now been

resolved. We can transfer a maximum of 0.48 Ml/d in this way.

South East Wales Conjunctive Use System (SEWCUS)

In place of the weir at Prioress Mill on the River Usk we have invested in additional infrastructure to

enable full utilisation of the abstraction licence on the River Usk at Llantrisant by allowing the

abstracted water to be transferred to Llandegfedd reservoir if required. This gave a significant

increase in baseline Deployable Output of 48 Ml/d and secured supplies within SEWCUS.

During 2010, due to the extreme dry weather conditions, we made a number of improvements to

increase the resilience of the Pontsticill High Level area and the Rhondda and Cynon area. In the

Pontsticill High Level area we have made some network improvements to allow water from Blaen-y-

Cwm reservoir to be transferred to Nantybwch Water Treatment Works. In addition, transfer licences

are currently being sought to enable the transfer of untreated water from Blaen-y-cwm to Lower Carno

reservoir for subsequent re-abstraction and transfer to Shon Sheffrey reservoir. This will increase the

resilience of the system by connecting available storage to greater treatment capacity.

In the Rhondda and Cynon area, we laid a pipeline between Penderyn reservoir, which currently

feeds Hirwaun Water Treatment Works and Llyn Fawr reservoir. The pipeline can be operated in both

directions but requires pumps to be installed at Penderyn to transfer water to Llyn Fawr.

Pembrokeshire

The deficit in North Pembrokeshire was resolved during our 2005-2010 investment programme by the

extension of the network to aggregate two WRZs, North and South Pembrokeshire, thereby reducing

the number of zones to 24. The scheme involved:

the laying of a new 7.5km 500mm trunk main from Bolton Hill Service Reservoir to the North

Bridge in Haverfordwest; and

installing new pumps and refurbishing existing ones (at Corner Piece water pumping station),

so that water from either Preseli Water Treatment Works or Bolton Hill Water Treatment

Works can be pumped to Plumbstone Service Reservoir and onto St Davids.

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Annex 2 – Water Efficiency Activity

Cistern displacement devices

We offer free hippo bags to all our customers and promote this through the literature which

accompanies customer bills, as well as leaflets, podcasts, website material and general customer

engagement. The popularity of the Hippo Bag has continued to grow. In 2008-09 we provided

16,290 hippo bags to customers and in 2009-10 we provided 20,865, of which 3,403 were requested

by household customers and 612 requested by schools. The remainder were distributed at events

held by Welsh Water. In total we estimate that these displacement devices saved 0.29 Ml/d

(assuming a 2.8 litre saving per device, per flush).

Performance and attitudes towards these devices have been covered as part of the household water

audits that have recently been completed. These identified valuable savings where the devices had

been correctly installed. However, the installation rate at 59% was lower than the Ofwat quoted value

of 65%. In addition, a significant proportion had been fitted in dual flush, low flush and ultra low flush

cisterns and had either been subsequently removed or required repeat flushing.

In an attempt to address this problem improved information has been placed on our website and is

included with the material we send with the device. It remains to be seen if this helps customers

correctly to identify cisterns where it is appropriate to install Hippos. Using information from 2008

water audits, the estimated total daily saving from the Hippos distributed in 2008–09 was around 0.32

Ml/d. For total household demand this is a negligible saving in the context of the baseline demand

forecasts. However, as part of our options for water efficiency we have included a “Home Visit

Package” option. This includes the installation of Hippo bags as one of a suite of devices/ measures.

Household water audits

We have historically provided water audit visits to domestic customers to advise them on water

savings. These provided an excellent mechanism to educate customers on water efficiency issues

and the good practice use of water throughout the home; we also provided customers with low cost

devices to help them save water (including Hippo Bags). However, in 2008-09 we only completed 21

water audits in customers‟ homes (at the request of customers). Therefore, due to the small water

savings and the high staff cost rate involved, we no longer offer this service. Instead, we choose to

promote household water efficiency via our comprehensive self-audit pack that is promoted in

company literature and on our website, and which is available to customers on request. We consider

that this is a much more cost effective and less intrusive method of promoting water efficiency in the

home.

In 2008-09 we distributed 7,197 water audit packs to homes with a total estimated water saving of

0.85 Ml/d. This represents a fourfold increase on the previous year.

Household water audits continue to be included as intervention options as part of the “Home Visit

Package” option for all deficit zones

Commercial water audits

As with the household water audits, we no longer believe that offering on-site water audits is the most

effective method of promoting water efficiency in commercial premises. In 2008-09 we only

completed 11 such audits. We continue to advertise on our website and through customer

engagement the “using water wisely, DIY water audits for homes, business and schools” advice

leaflets; overall, we consider this to be the best method to promote water efficiency.

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We are carrying out pilot audits in a number of commercial/ non-household properties to develop

further our water audit experience and gain improved data on the realistic potential savings. This

approach has been concentrated initially in the North Eyri Ynys Mon WRZ and has since been

expanded into the Vowchurch WRZ (identified as a deficit zone in AMP4). In June 2009 we

commenced our water efficiency activities in Vowchurch sending letters and self–audit packs to all

non-domestic customers using over 2m3 of water per day. We had replies from 6 farms in the area

and undertook detailed on-site audits before making recommendations on improving their water

efficiency. All of these farms also had flow loggers installed to monitor their levels of consumption.

In 2009-10, we distributed water efficiency self-audits to all schools (Primary and Secondary) in the

Vowchurch WRZ followed up by a water audit at four of the schools. During 2010-11 we expect

further savings when water efficiency devices are fitted as recommended following the audits.

The audits are combined with a “Capacity Buy Back” option.72

Capacity Buy Back is included as an

intervention option for all deficit zones

Customer education/awareness

We have placed particular emphasis on our development of educational initiatives as these provide

future populations with an understanding of the issues and challenges associated with water use.

This is a core message in delivering the objectives of our Education Strategy “Living and Learning

with Water” which promotes the understanding of “the value of water and the vital role it plays in our

everyday lives”. Our educational initiatives are summarised below.

We have 4 Education Centres. These are located in the Elan Valley, Cilfynydd (near Pontypridd,

South Wales), Cog Moors (near Cardiff) and Alwen, where every one of the 14,000 visitors each year

receives water conservation messages. To date over 124,000 visitors have visited one of our 4

centres. To enhance the messages delivered at the centres, a water efficiency lesson has been

developed to inform pupils about the responsible use of water in both schools and in the home. This

lesson was developed by teachers and is linked to the National Curriculum to support sustainability

and Global Citizenship within schools.

We have developed a water efficiency pack to help schools use water more efficiently. The bilingual

pack called “Water is Cool – Respect it” is distributed to schools achieving Silver-level accreditation

through the Eco-Schools programme in Wales. To date almost 1,000 schools have received the

pack. The pack illustrates how important water is to each of us and helps children to understand its

value and the vital role it plays in our everyday lives. It contains interesting facts on how to use water

wisely and schools can use the pack as part of the Eco-Schools programme, or as part of an

independent water conservation project.

As one of the main partners in the re-launch of the Welsh Eco-Schools project we have contributed to

the water section of the Eco-schools Handbook. Schools have to complete and be assessed on 9

elements of the programme to become a Green Flag school. Water efficiency is one of these

elements. There are over 1,300 schools registered with Eco-Schools in Wales.

In March 2007 we launched our „Be Waterwise‟ campaign to encourage customers to „use what they

need, but not to waste it‟. The launch took place at Cilfynydd Education Centre with representatives

from Keep Wales Tidy, the Consumer Council for Water and from schools staff and pupils.

72

Capacity Buy Back provides an incentive through bill rebates. The scheme works by providing companies with a reimbursement on their

water bill based upon the water savings made through the implementation of a water efficiency measure. The bill rebate incentive saving is £0.40 per litre per day (£400,000 per Ml/d) up to a maximum of 50% of the cost of the water efficiency measure.

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We have supported the development of a number of educational resources. These include

“Waterworld Explorers” an interactive multimedia resource aimed at Key Stage II (7-11 year olds)

which has a module entitled “How is water used?” which demonstrates how water is used in the home

and garden and explains the measures that can be taken to reduce water usage. Waterworld

Explorers has been well-received by children and teachers alike and has been distributed to over

1,600 primary and secondary schools.

We continue to work in partnership with Techniquest, the science discovery centre based in Cardiff,

which receives over 200,000 visitors each year. We have developed an exciting display promoting

water efficiency. This uses jets of recycled water, which children can direct and fire, to show the

relationship between efficient and wasteful practices, for example, sprinkler and hosepipe use.

In partnership with the UK Education forum, representatives from 13 UK water companies have

contributed to the development of 2 water efficiency websites called The Water School and The Water

Family. The sites were developed by Crystal presentations and are aimed at encouraging pupils and

families to be more sustainable with water both in school and at home. Both sites were trialled by

teachers and linked to the National Curriculum. During the last academic year the following statistics

were recorded at each site:

Water in the School Website – 31,394 hits

The Water Family Website – 198,558 hits

To coincide with World Water Day we will be launching a new resource to promote water efficiency in

schools. The pack has been endorsed by Keep Wales Tidy and it will assist us in achieving high

accreditation via the UK Water Industry Research guidelines from Ofwat. Schools will be encouraged

to demonstrate water efficiency good practice in school and record their evidence. The evidence will

be collated by us to show behaviour changes within the school and in the home. The pack has also

been available on-line since April 2011. This will allow schools to register with Welsh Water and

receive quarterly newsletters updating them with water efficiency tips or any other key business

messages. This will again take our level of engagement from medium to high in the UK Water

Industry Research guidelines as we will ensure ongoing contact with the customer.

Our recently re-launched company website includes several “Living and Learning” webpages which

include a large amount of child friendly material on the business as well as water efficiency tips and

challenges for pupils, including an online water efficiency calculator and home audit. The site will

enhance children‟s awareness on sustainable water usage and includes an area where children can

complete a home audit and enter into a termly competition draw. The site enable adults and children

to feed back any comments on visits to the Education centres or on resources provided by Welsh

Water.

In 2010 Ofwat confirmed that 30% of “soft” targets could be counted against our new 1.3 Ml/d target.

To date approximately 90% of the target is being achieved through education. The focus on

achieving maximum results is our main driver over the next 4 years.

To trial our Outreach Programme on water efficiency we took part in a pilot at 30 schools in Blaenau

Gwent. The pilot involved a whole school assembly focusing on water efficiency followed by

workshops in the classroom and school audit. The pupils were then tasked with a toothbrush

challenge where they recorded how many times they turned the tap off when brushing their teeth,

thereby encouraging water savings and changing behaviours. The data was returned and recorded

for the June Return. Due to the success of this pilot we have continued delivering water efficiency

outreach in targeted areas working closely with Aqualogic, our preferred suppliers on water efficiency.

To date 1,073 pupils have taken part in the challenge. Ofwat are currently considering raising the

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maximum proportion of the water efficiency target that can be met by soft measures from 30% to

40%.

It is very hard to quantify the benefits of our range of promotional and educational activities.

However, the feedback received provides strong encouragement to continue our efforts in these

areas. Successful implementation of many water efficiency measures relies on customers

understanding the issues and responding in a socially responsible way. Because of this, the

continuing development of our promotional and educational activities is considered to be an essential

component of our water efficiency strategy.

Finally, we also promote a “Don’t crack up, wrap up” campaign which provides practical advice and

information that would avoid the inconvenience and expense that a frost damaged pipe can cause.

The advice was made available through publicised literature and a podcast published on our website.

Other water efficiency initiatives

Water efficiency has considerable prominence on our company website and is continually reviewed

and updated in accordance with our water efficiency activities.

We work closely with the National Trust to deliver water efficiency messages on organised theme

days and have developed a water efficient demonstration garden within one of the National Trust sites

that provides key awareness of water efficiency issues and solutions to visitors.

Finally, we have launched a “Four minute shower campaign” which was endorsed by the then

Environment and Sustainability Minister Jane Davidson AM and which encourages customers to limit

the time spent using the shower. The campaign has its own website and has already proved popular.

Metering

Our policy is to:

provide a free meter option scheme;

meter new households and non-households compulsorily; and

have a programme to meter existing unmeasured non-households, where practical.

Water butts/ composters/ trigger hoses

We offer subsidised water butts to all our customers and help promote the efficient use of water in the

garden through customer engagement (“message” areas of bills and leaflets provided to customers

during events and press releases) and advice on our website. In 2008-09 we installed 658 water

butts in households and distributed a total of 1,116. In 2009-10 we distributed 310 water butts, with

an estimated total saving of 0.0008 Ml/d.

Water butts and trigger hoses are included as intervention options (as part of the “Home Visit

Package” option for trigger hoses) for all deficit zones.

Retrofitting – toilets, showerheads

More complex retro-fitting of water saving devices such as taps, toilets and showers were not

identified as the optimal solutions to resolve deficits during our 2005-2010 programme and therefore

no savings are attributed within the baseline demand forecast.

However, retrofitting devices continues to be included as an option for all deficit zones as part of the

“Home Visit Package” and the “Non-Household Visit” option.

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Collaborative Research and Development

The best opportunity to encourage more water efficient fittings is at the time, for example, when

existing bathrooms are being refurbished or when new houses are being built. The additional cost of

fittings providing improved water efficiency will normally be negligible in comparison to the cost of the

installation.

We are currently working with housing developers on proposals to compare the water use of standard

houses adopting improved water efficiency standards, against similar phased non-water efficient

houses. The aim is not to create expensive eco-houses, but rather to investigate what can be

achieved at minimum additional cost to enhance the performance of standard homes.

Assumptions regarding the increasing penetration of dual and low-flush cisterns and more water

efficient washing machines and dishwashers are built into the forecasts of per capita consumption in

line with the obligations now required of developers in the Code for Sustainable Homes. Additionally,

assumptions are also included for the replacement of appliances as part of home improvements in

older properties.

Supply pipe repair/ replacement

Our experience is that proactive action to tackle leakage on customers‟ supply pipes is currently the

most cost effective area of water efficiency for investment. We have applied a consistent and

proactive policy on customer leakage since 2001. Under this policy we provide free leak detection

and repair service for the first leak on a customer‟s supply pipe. In 2008-09 there were 438 supply

pipes replaced free under this policy and 1,720 repaired.

The estimated average savings from our free supply pipe repair and replacement activities in 2008-09

is 1.31 Ml/d.

Our assessment of Supply Pipe Leakage follows the Bursts and Background Estimation (approach.

Work is still progressing nationally to improve the estimation of SPL; we continue to improve the

estimated volume of Supply Pipe Leakage, together with research into ways to identify leak run times.

The initial (pre-Maximum Likelihood Estimation) estimate of regional Supply Pipe Leakage for

unmeasured properties in 2008-09 was 20.1 l/prop/d. The equivalent figure for measured properties

was 16.4 l/prop/d. Also included in our demand forecasts is an estimated 1.18Ml/d of Supply Pipe

Leakage from void properties.

In 2008-09 the total operational expenditure on the customer Supply Pipe Leakage initiative was

£760k. This results in a unit cost of £1.59 per m3. Although this is similar to the national figure quoted

by Ofwat of £1.21 per m3

for water efficiency activities, we believe that this activity has a much higher

level of confidence in the level of savings achieved than other water efficiency activities.

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Annex 3 – Sites impacted by Habitats Review of Consents

Descriptions of the individual Special Areas of Conservation and our licences subject to the the

Environment Agency‟s Review of Consents process within them are detailed below and shown in

Figures A3.2, A3.3 and A3.4; an overview map showing the relationship between Welsh Water

abstractions and the European protected sites is shown in Figure A3.1

Figure A3.1 – Special Areas of Conservation and Sites of Special Scientific Interest in our supply area and the locations of Welsh Water’s abstractions

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South East Wales

River Wye Special Area of Conservation

The River Wye has been designated a Special Area of Conservation due to the presence of the

following features58

Atlantic Salmon, Allis Shad, Twaite Shad, Brook Lamprey, River Lamprey, Sea Lamprey, Bullhead,

Otter, Atlantic Stream Crayfish, Ranunculus, Transition Mires and Quaking Bogs.

Within the River Wye Special Area of Conservation we have thirteen abstraction licences that have

been subject to the Agency‟s review of consents process:

River Wye at Builth Wells – abstracted water is treated locally at Builth Water Treatment

Works and supplies the remainder of the Elan Builth WRZ.

River Wye at Llyswen – abstracted water is treated locally at Llyswen Water Treatment Works

and supplies the entirety of the Llyswen WRZ.

River Lugg at Byton - maintained as an emergency source for use locally within the Pilleth

WRZ.

Pilleth boreholes – abstract from the gravels of the River Lugg. The water is treated at the

nearby Pilleth Water Treatment Works and supplies the entirety of the Pilleth WRZ.

Dunfield boreholes – abstract water from the gravels of the River Arrow. The water is treated

at the nearby Dunfield Water Treatment Works and supplies the immediate localised area of

the Hereford WRZ.

Midsummer Meadow well - maintained as an emergency source for use locally within the

Hereford WRZ.

River Wye at Hereford – abstracted water is pumped a short distance to Broomy Hill Water

Treatment Works and supplies the majority of the Hereford WRZ.

Vowchurch boreholes - abstract water from the gravels of the River Dore. The water is treated

at the nearby Vowchurch Water Treatment Works and supplies the entirety of the Vowchurch

WRZ.

River Wye at Mayhill – located in Monmouth, water is pumped a short distance to Mayhill

Water Treatment Works and supplies the majority of the Monmouth WRZ.

Buckholt springs – water is treated at the adjacent Buckholt Water Treatment Works and

supplies the remainder of the Monmouth WRZ.

Alton Court borehole - maintained as an emergency source for use within our Ross-on-Wye

WRZ.

Rogerstone Grange borehole - abstracted water is treated locally at Rogerstone Water

Treatment Works and supplies locally within the south western area of the SEWCUS WRZ.

River Wye at Monmouth (“Wye Transfer”) - located approximately 500m upstream of the

Mayhill intake, water is transferred out of the catchment across to Court Farm Water

Treatment Works and is used to supply parts of the SEWCUS WRZ.

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58 Site Issue Briefing (Countryside Council for Wales, 2002)

The Elan valley reservoirs have also been subject to the consents review process as they are

intrinsically linked to the operation of our Monmouth abstraction licence. Elan‟s two main functions

are to supply water to Birmingham via the Frankley Reservoirs (to Severn Trent Water) and to

regulate the River Wye to support abstraction in its lower reaches. There is a small direct supply to

Elan Water Treatment Works which supplies the majority of the Elan Builth WRZ.

Figure A3.2 - Welsh Water’s abstractions in South East Wales subject to the Review of Consents process

River Usk Special Area of Conservation

The River Usk has been designated as an Special Area of Conservation due to the presence of the


:

Atlantic Salmon, Allis Shad, Twaite Shad, Brook Lamprey, River Lamprey, Sea Lamprey, Bullhead,

Otter, Ranunculus.

Within the River Usk Special Area of Conservation we have four abstraction licences that have been

subject to the consents review process:

Brecon boreholes – this licence abstracts water from the gravels of the River Usk. The water

is treated at the nearby Brecon Water Treatment Works and supplies the majority of the

Brecon-Portis WRZ demand.

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River Usk at Brecon – this river intake is licensed for the same quantity as the boreholes

(aggregated licence). Operationally this abstraction point is not frequently used.

River Usk at Rhadyr (Prioress Mill) - water is abstracted and pumped to Llandegfedd reservoir

before being treated at Sluvad Water Treatment Works. This water is then supplied in the

SEWCUS WRZ.

River Usk at Llantrisant – the abstracted water can either be pumped to Llandegfedd reservoir

or direct to Court Farm Water Treatment Works; via both routes the water is treated and

supplied in the SEWCUS WRZ.

The operation of Usk reservoir has also been reviewed by the Environment Agency under the

consents review process due to the reservoir‟s ability to be used to regulate the River Usk.

Currently its two main functions are a small direct supply to Portis Water Treatment Works

which supplies a localised area of the Brecon-Portis WRZ and a larger export of water to

Bryngwyn Water Treatment Works, within the Tywi CUS WRZ, for localised supply within the

area.

South West Wales

Cleddau Rivers Special Area of Conservation

The Cleddau Rivers have been designated as an Special Area of Conservation due to the presence

of the following features58

Otter, Bullhead, River Lamprey, Brook Lamprey, Sea Lamprey, Ranunculus, Alluvial forests with

Alnus glutinosa and Fraxinus excelsior, Active Raised Bogs.

Within the Cleddau Rivers Special Area of Conservation we have four abstraction licences that have

been reviewed by the Agency:

Eastern Cleddau at Pont Hywel - abstracted water is transferred westwards to Preseli

reservoir (which feeds Preseli Water Treatment Works) which supplies the north of the

Pembrokeshire WRZ.

Eastern Cleddau at Canaston – abstracted water is transferred south-west to Bolton Hill

Water Treatment Works for treatment and supply but is also delivered to the large industrial

users in the Pembrokeshire WRZ.

Western Cleddau at Crowhill - abstracted water is transferred to Bolton Hill Water Treatment

Works for treatment and supply in the south of the Pembrokeshire WRZ.

Afon Syfynwy – a non-consumptive abstraction which is used to supply a fish farm – this is

currently not operational.

River Tywi Special Area of Conservation

The River Tywi has been designated as an Special Area of Conservation due to the presence of the


:

Allis Shad, Twaite Shad, Brook Lamprey, River Lamprey, Sea Lamprey, Bullhead, Otter.

Within the River Tywi Special Area of Conservation we have two abstraction licences plus the

operation of Llyn Brianne reservoir that have been reviewed by the Agency:

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River Tywi at Manorafan - the intake is generally not used due to its high operational costs but

when it is, the abstracted water is transferred to Bryngwyn Water Treatment Works for

treatment and is supplied to the central section of the Tywi Gower WRZ.

River Tywi at Nantgaredig - abstracted water is transferred eastwards to the Lliw reservoirs

which feed Felindre Water Treatment Works. The treated water supplies the conurbations of

Swansea, Neath and Llanelli and further east into Bridgend, Vale of Glamorgan and Llynfi

Valleys.

Llyn Brianne reservoir – its main function is to release water to support abstraction at

Nantgaredig.

River Teifi Special Area of Conservation

The River Teifi has been designated as a Special Area of Conservation due to the presence of the

following features:

Atlantic Salmon, Brook Lamprey, River Lamprey, Sea Lamprey, Bullhead, Otter, Luronium, Litorella,

Ranunculus.

Within the River Teifi Special Area of Conservation we have one abstraction licence that has been

subject to this consents review process:

River Teifi at Llechryd - abstracted water is transferred a short distance to Llechryd Water Treatment Works from where it is delivered to the south and west of the Mid & South Ceredigion WRZ.

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Figure A3.3 - Welsh Water’s abstractions in South West Wales subject to the Review of Consents process

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North Wales

Afon Gwyrfai a Llyn Cwellyn Special Area of Conservation

The Afon Gwyrfai and Llyn Cwellyn have been designated as a Special Area of Conservation due to

the presence of the following features:

Atlantic Salmon, Otter, Luronium, Litorella, Ranunculus.

Within the Afon Gwyrfai and Llyn Cwellyn Special Area of Conservation we have two abstraction

licences that have been reviewed by the Environment Agency as part of its review of consents

process:

River Gwyrfai at Nant Mills – this is located approximately 1km downstream of the outlet from

Llyn Cwellyn. This site is no longer operationally used.

Direct abstraction from Llyn Cwellyn where the water is transferred 2km downstream to

Cwellyn Water Treatment Works which supplies the local area in and around Caernarfon

within the North Eyri Ynys Mon WRZ.

Migneint-Arenig-Dduallt Special Area of Conservation

The Migneint-Arenig-Dduallt has been designated as a Special Area of Conservation due to the

presence of the following features:

Blanket Bog, European Dry Heaths, Northern Atlantic Wet Heaths, Natural Dystrophic Lakes

and Ponds, Lakes (Oligotrophic to mesotrophic) standing waters, Old sessile oak woods.

Within the Migneint-Arenig-Dduallt Special Area of Conservation we have one abstraction licence that

has been subject to the Review of Consents process:

Direct abstraction from Llyn Morwynion where the water is transferred 1km north-west to

Garreglwyd Water Treatment Works; the only source of water for the Blaenau Ffestiniog

WRZ.

Rhinog Special Area of Conservation

Rhinog has been designated as a Special Area of Conservation due to the presence of the following

features:

Old sessile oak woods , Blanket Bog, European Dry Heaths, Alpine and subalpine heaths ,

Depressions on peat substrates, Northern Atlantic Wet Heaths, Lakes (Oligotrophic to

mesotrophic) standing waters, Floating water-plantain (Luronium).

Within the Rhinog Special Area of Conservation we have one abstraction licence that has been

reviewed by the Environment Agency:

Direct abstraction from Llyn Eiddew Mawr - abstracted water is transferred 6km south-west to

Rhiwgoch Water Treatment Works which supplies the southern section of the Lleyn Harlech

WRZ in and around Harlech.

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Llwyn Special Area of Conservation

Llwyn has been designated as a Special Area of Conservation due to the presence of the following

features:

Alluvial forests with Alnus glutinosa and Fraxinus excelsior.

Within the Llwyn Special Area of Conservation we have one abstraction licence that has been subject

to the consents review process:

Llwyn Isaf boreholes – water is abstracted from the Clwyd sandstone aquifer and is used to

augment flows in the River Clwyd. During a drought, the abstracted water is treated locally

and put into direct supply.

Figure A3.4 - Welsh Water’s abstractions in North Wales subject to the Review of Consents process

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Annex 4 – Option Ranking

Figure A4.1 – Ranking of Feasible Options, Pembrokeshire WRZ, by average incremental social cost (p/m

3)

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Figure A4.2 - Ranking of Feasible options, Brecon - Portis WRZ, by average incremental social cost (p/m3)

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Figure A4.3 - Ranking of Feasible options, South East Wales Conjunctive Use System (SEWCUS) WRZ, by average incremental social cost (p/m3)

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Annex 5 Glossary of Terms

Abstraction The removal of water from any source, either permanently or temporarily.

Abstraction licence The authorisation granted by the Environment Agency to allow the removal of water from a source.

Annual average The total demand in a year, divided by the number of days in the year.

Available headroom The difference (in Ml/d or percent) between water available for use (including imported water) and demand at any given point in time.

Average incremental social costs

The ratio of present social costs over present net value of additional water delivered or reduced demand

Consumption monitor A sample of properties whose consumption is monitored in order to provide information on the consumption and behaviour of properties served by a company.

Demand management

The implementation of policies or measures which serve to control or influence the consumption or waste of water (this definition can be applied at any point along the chain of supply).

Deployable output

The output of a commissioned source or group of sources or of bulk supply as constrained by: • environment • Licence, if applicable • Pumping plant and/or well/aquifer properties • raw water mains and/or aquifers • treatment • water quality

Distribution input The amount of water entering the distribution system at the point of production.

Distribution losses Made up of losses on trunk mains, service reservoirs, distribution mains and communication pipes. Distribution losses are distribution input less water taken.

Drought order

An authorisation granted by the Secretary of State under drought conditions, which imposes restrictions upon the use of water and/or allows for abstraction/impoundment outside the schedule of existing licences on a temporary basis.

Drought permit An authorisation granted by the Environment Agency under drought conditions, which allows for abstraction/impoundment outside the schedule of existing licences on a temporary basis.

Economic level of leakage (ELL)

The level of leakage at which it would cost more to make further reductions than to produce the water from another source

Final planning scenario

The scenario of water available for use and final planning demand forecast which constitute the company‟s best estimate for planning purposes, and which is consistent with information provided to Ofwat for the Periodic Review.

Habitats Regulations Assessment (HRA)

An assessment, required under the EU Habitats and Species Directive, of the potential effects of a proposed plan, programme or project on one or more Natura 2000 sites.

Level of Service The frequency with which a hosepipe ban or a Drought Order/ Permit would be expected to be required in order to maintain water supplies

Meter optants Properties in which a meter is voluntarily installed at the request of its occupants.

Meter programme Properties, which are to be metered according to current company metering policy.

Net Present Value The difference between the discounted sum of all of the benefits arising from a project and the discounted sum of all the costs arising from the project.

Non-households Properties receiving potable supplies that are not occupied as domestic premises, for example, factories, offices and commercial premises.

Outage A temporary loss of deployable output.

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Point of consumption The point where the supply pipe rises above ground level within the property, usually the inside stopcock or an internal meter.

Point of delivery

The point at which water is transferred from mains or pipes, which are vested in the water supplier into, pipes which are the responsibility of the customer. In practice this is usually the outside stopcock, boundary box or external meter.

Point of production The point where treated water enters the distribution system.

Review of Consents The mechanism by which the Environment Agency undertake their review of all the existing and proposed permissions that could impact upon EU designated sites

Risk A measure of the probability and magnitude of an event and the consequences of its occurrence.

Source A named input to a resource zone. A multiple well/spring source is a named place where water is abstracted from more than one operational well/spring.

Strategic Environmental Assessment (SEA)

A process of assessing the environmental opportunities and restrictions of a project, and identifying and managing its implications.

Supply-demand balance

The difference between water available for use (including imported water) and demand at any given point in time (c.f. available headroom).

Supply pipe losses The sum of underground supply pipe losses and above ground supply pipe losses.

Sustainability reduction

Reductions in deployable output required by the Environment Agency to meet statutory and/or environmental requirements.

Target headroom The threshold of minimum acceptable headroom, which would trigger the need for water management options to increase water available for use or decrease demand.

Total leakage The sum of distribution losses arid underground supply pipe losses .

Treatment work operational use

Treatment process water i.e. net loss, which excludes water returned to source water .

Underground supply pipe losses

Losses between the point of delivery and the point of consumption.

Unrestricted demand The demand for water when there are no restrictions in place .

Water available for use (WAFU)

The value calculated by deducting allowable outages and planning allowances from deployable output in a resource zone.

Water Resource zone (WRZ)

The largest possible zone in which all resources, including external transfers, can be shared and hence the zone in which all customers experience the same risk failure from a resource shortfall of supply

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Rev_WRMP

Documents

water abstractions

water available

supplying water

water transfers

water supply capacity

operational use of water

draft plan

water resource zones