Waioeka-Otara Asset Management Plan...2018/10/06 · Waioeka-Otara Asset Management Plan Operations Publication 2007/06 The total average annual level of expenditure required to meet

Working with our communities for a better environment E mahi ngatahi e pai ake ai te taiao

Waioeka-Otara Asset Management PlanPrepared by Roger Waugh, Principal Technical Engineer

Environment Bay of PlentyOperations Publication 2007/06September 2007

5 Quay StreetP O Box 364WhakataneNEW ZEALAND

ISSN: 1176 5550

Environment Bay of Plenty i

Operations Publication 2007/06 Waioeka-Otara Asset Management Plan

Foreword

This plan is a statement by Environment Bay of Plenty, the Manager of the Waioeka–Otara Rivers Scheme, as to how it will manage the assets of that scheme. The plan represents prudent management as required by the Local Government Act 2002 including section 90 of the Act, namely the Policy on significance. The Council adopted the original plan in September 1998 following consultation, in particular, with the scheme ratepayers. This is the second edition plan.

Environment Bay of Plenty iii


Executive Summary

The purpose of this plan is to provide a document for the management of the Waioeka–Otara Rivers Scheme and in particular its infrastructural assets.

It establishes and communicates the level of funding required to maintain and meet the scheme objectives and levels of service.

The plan covers the assets of the scheme including stopbanks, a pump station, rockwork and other erosion protection measures including plantings. The current valuation at June 2007 (in terms of Local Government Act requirements) of these assets is $20.15 million.

Maintenance programmes are already in place and these have ensured that the assets are in good condition and are providing the desired levels of service.

Environment Bay of Plenty through its day to day management of the scheme receives continuous feedback about the scheme. Feedback to date indicates strongly that the ratepayers support the scheme objectives as established at the time of construction.

Service levels have therefore been defined to ensure the original scheme objectives are met and maintained.

The stopbanks will be maintained to a level to ensure the design flood can be conveyed. Settlement of up to 50% of the freeboard will be allowed before stopbank reconstruction will be undertaken. Where the design standards do not include freeboard, settlement of up to 150 mm will be allowed.

Structures will be maintained in a workable condition at all times to function to their design standards.

Rockwork will be maintained at all times to a minimum of 75% of the original design placement rate.

River edge protection will be maintained to full potential at all times while not allowing any willow growth to be older than 15 years.

Environment Bay of Plenty has a number of tools, which are utilised for the management of its assets. Information systems have been developed to assist the asset managers in general management, maintenance, operations and long term planning. The principle components are the asset register, geographic information system and the Finance One financial management system.

Environment Bay of Plenty has developed a maintenance programme strategy, which will provide for the most efficient and economic operation, to the desired service levels. A detailed assessment has been undertaken of the work requirement, to provide for the long term, sustainable management of the scheme assets.

The scheme has been separated into a number of distinct reaches or locations and the key maintenance issues have been identified for each of these areas.

iv Environment Bay of Plenty

Waioeka-Otara Asset Management Plan Operations Publication 2007/06

The total average annual level of expenditure required to meet the scheme objectives and the desired levels of service, over the 50 year time horizon of the plan, is a 10% decrease to 2007/2008 budgeted expenditure. Years 2 -10 require an average increase in expenditure of 6.7% to meet scheme objectives. Year 1 of the plan is considered to be the 2007/2008 financial year. Expenditure changes, and subsequently rate funding requirements will take effect in the 2008/2009 financial year.

Increases in expenditure in the early years of the plan are primarily brought about by:

• recommendations included in the Waioeka Otara Flood Management Strategy

• new stopbanks

• additional rock edge protection

• repayments of additional loans

• local authority protection programme (LAPP) contribution

• additional drainage maintenance areas

It is estimated that an average of $373,400 (excluding depreciation) per year will generally be required to meet the regular and ongoing maintenance necessary to keep the assets operating at the required level of service. This does not include the requirements to contribute to the flood damage reserve and Local Authority Protection Programme Disaster Fund. Nor does it include the costs that may be from time to time required to fund significant flood or disaster damage repairs beyond the levels predicted in the plan.

In addition to this there will be renewal expenditure required to upgrade or renew the asset to its full (or original) and agreed service potential. The scheme is funded by targeted scheme rates, regional general funds contribution and loans.

Independent internal and external audits will be carried out to establish a continuous improvement cycle, maintain best practices and to assess the quality of asset management.

Dollars are expressed in June 2007 values unless otherwise noted. All costs exclude GST.

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Contents

Foreword ................................................................................................................ i

Executive Summary............................................................................................ iii

Chapter 1: Introduction ......................................................................................1

1.1 Asset to be managed........................................................................................1

1.2 Rationale for ownership ....................................................................................1

Chapter 2: General Information .......................................................................3

2.1 Purpose and ownership of the plan ..................................................................3

2.2 Legislative requirements...................................................................................3

2.3 Relationship to other Environment Bay of Plenty documents ...........................4

2.4 Duration of the plan ..........................................................................................5

2.5 Principal scheme features ................................................................................5

2.6 Climate change impacts .................................................................................10

Chapter 3: Assets...............................................................................................13

3.1 Objectives of the scheme ...............................................................................13

3.2 Description of the assets ................................................................................13

3.3 Physical parameters .......................................................................................16

3.4 Asset capacity ................................................................................................22

3.5 Asset condition ...............................................................................................23

3.6 Asset value .....................................................................................................25

3.7 Asset management systems...........................................................................29

Chapter 4: Maintenance Plan .........................................................................31

4.1 Introduction.....................................................................................................31

vi Environment Bay of Plenty


4.2 Service levels ................................................................................................. 31

4.3 Maintenance history ....................................................................................... 33

4.4 Maintenance programme ............................................................................... 35

4.5 Maintenance costs ......................................................................................... 37

4.6 Expenditure.................................................................................................... 39

4.7 Funding .......................................................................................................... 40

Chapter 5: Creation/Acquisition/Disposal................................................. 49

Chapter 6: Quality Assurance ....................................................................... 51

Chapter 7: Monitoring ...................................................................................... 53

7.1 Effectiveness monitoring ................................................................................ 53

7.2 Asset Manager ............................................................................................... 54

7.3 Internal ........................................................................................................... 54

7.4 External.......................................................................................................... 55

7.5 Cost monitoring.............................................................................................. 57

Chapter 8: Asset Management Plan Improvement Plan...................... 59

8.1 Background to Asset Management Plan ........................................................ 59

8.2 Improvement tasks......................................................................................... 59

8.3 Improvement plan budget .............................................................................. 60

References ........................................................................................................... 61

Appendices .......................................................................................................... 63

Appendix 1 – Responsibilities and Roles in Asset Management ............................. 65

Appendix 2 – Asset Maintenance Requirements Waioeka-Otara Rivers Scheme Asset Maintenance Requirements ............................................................................ 67

Appendix 3 — Expenditure Tables ........................................................................... 73

Appendix 4 — Flood Damage Reserve .................................................................... 77

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Appendix 5 — Renewals Fund and Renewal Table ..................................................81

Appendix 6 — Loan Payment Schedule as at 30 June 2007 ....................................85

Appendix 7 — Drain Locations ..................................................................................99

Chapter 9: Glossary............................................................................101

1


Chapter 1: Introduction

1.1 Asset to be managed

The plan is to provide a single document intended to assist those delegated the responsibility for managing the Waioeka-Otara Rivers Scheme assets on behalf of the Bay of Plenty Regional Council (Environment Bay of Plenty). Figure 1 shows the location of the Waioeka-Otara Rivers Scheme maintenance area.

The Waioeka-Otara Rivers Scheme is a comprehensive river control scheme, providing benefits of flood protection, channel edge stability and some drainage and pumping to the township of Opotiki and surrounding land on the flood plain.

The scheme has substantial physical assets, including stopbanks, a pump station, rock work and other erosion protection measures including plantings. The current valuation of these assets (in terms of Local Government requirements) to June 2007 is $20.15 million.

1.2 Rationale for ownership

The rationale for the existing ownership is as a result of the Local Government Act provisions whereby Regional Authorities are responsible for the provision and control of the asset.

In common with all other similar river schemes throughout New Zealand the Waioeka-Otara Rivers Scheme was established under the Soil Conservation and Rivers Control Act 1941. This legislation had its genesis earlier this century and was, for its time, far reaching; Government recognised that flooding and drainage problems were best dealt with on a large scale (catchment) basis. Major catchments frequently traversed more than one existing territorial authority (at that time county and borough councils). The magnitude of the problem was such that the authorities of the day determined special purpose (ad hoc) authorities, with specialist engineering and soil conservation skills, were required to administer these functions and hence the creation of catchment boards and catchment commissions.

In 1960 the Poverty Bay Catchment Board was invited by residents to assume Catchment Board functions for the district and particularly to design a stopbank scheme for the township of Opotiki. Stopbanks protecting the town to a nominal “250 year” standard were completed in 1966 and followed by rural “30 year” stopbanks in 1970. The two schemes were joined together about 1980.

2 Environment Bay of Plenty


Under the Local Government reforms of 1989, Environment Bay of Plenty took over the assets and management of the scheme from the East Cape Catchment Board (who had previously succeeded the Poverty Bay Catchment Board). River schemes were set up under a tripartite arrangement involving the Government, the Catchment Authority as the designated manager of the schemes, and local ratepayers. Briefly, the principle was that the Government provided the majority of the funds for capital works (in this case generally 75% of capital works was funded by the Government), with the local ratepayers providing the balance. In return Government required ratepayers of the scheme to commit to funding its maintenance in perpetuity. Additionally, until 1987 Government provided assistance with maintenance to the extent of about 25%. Nowadays however, the costs of the scheme, including capital works and maintenance of the assets are borne largely by the scheme ratepayers, identified under a separate rating area known as the Waioeka-Otara Rivers Scheme. Environment Bay of Plenty currently subsidises the scheme rate income by 20% from regional general rate funds in recognition of the wider regional benefits provided by the scheme. Environment Bay of Plenty introduced a new differential catchment wide rating system to fund the scheme on 1 July 2002

Today the continuing management of the Scheme by Environment Bay of Plenty is consistent with s10 of the Local Government Act 2002:

10. Purpose of local government

(b) to promote the social, economic, environmental, and cultural wellbeing of communities, in the present and for the future.

The management is also consistent with the Community Outcomes for the Region, developed following consultation with the community, in particular the following Outcomes

• Quality, Affordable Infrastructure: Our infrastructure - serves business and the community well, contributes to quality of life in the region, and is sensitive to the natural environment.

• A Prosperous and Sustainable Economy: Our productive, diverse regional economy provides long-term sustainable growth and prosperity.

Furthermore, by virtue of its previous experience, Environment Bay of Plenty has extensive knowledge of the Scheme assets and management issues. It also possesses the engineering expertise required to manage the Scheme.

3


Chapter 2: General Information

2.1 Purpose and ownership of the plan

The purpose of this plan is to provide, within one document, the means and mechanisms to enable the manager of the asset, to plan for the most efficient and economic ways to provide for sustainable ongoing management of the Waioeka-Otara Rivers Scheme.

These assets need to be managed, to ensure they continue to effectively deliver scheme benefits on a long term, sustainable basis. Management requires provision for monitoring, maintenance and in some instances eventual replacement of these assets.

This plan defines the objectives and performance standards for the scheme and the level of maintenance needed to ensure these are met at all times.

The plan also provides a base against which Environment Bay of Plenty’s performance in maintaining these infrastructural assets can be measured.

This asset management plan will provide a framework for technical, economic and financial inputs relating to the assets and their impact on long term financial planning.

The ownership of the plan, after consultation with the ratepayers, rests with the policy makers namely Environment Bay of Plenty which is the body responsible for managing the asset (the Asset Manager). It is essential that there is continuing client (principally scheme ratepayer) input throughout the duration of the plan.

The plan relies on inputs from data collected by Environment Bay of Plenty and from Council resolutions pertaining to policy matters, as well as from those who implement the works and contracts to maintain and provide the service.

Appendix 1 contains a diagram illustrating how the responsibilities for the plan and assets are defined.

2.2 Legislative requirements

The principle regulatory requirements affecting the management of infrastructure assets result from:

• Local Government Act 2002

• Local Government (Rating) Act 2002



• Resource Management Act 1991

• Soil Conservation and Rivers Control Act 1941

• New Zealand Society of Accountants “New Zealand Accounting Standards”; generally accepted accounting practices (GAAP) as defined in particular by New Zealand Equivalent to International Accounting Standard 16 Property, Plant and Equipment (NZ IAS 16).

• National Asset Management Steering Group (NAMS) guidelines on best practice, most recently as outlined in the International Infrastructure Management Manual (IIMM)

• National Asset Management Steering Group (NAMS), New Zealand Infrastructure Asset Valuation and Depreciation Guidelines.

The Local Government Act 2002 provides councils with a framework of powers to carry out democratic decision-making and action for and on behalf of its community. It also imposes accountability for prudent management and stewardship of community assets in the present and into the future. The Act requires councils to identify community outcomes and develop a comprehensive long-term council community plan (LTCCP) including the identification of assets and how those assets are to be managed. It is intended that this asset management plan will be a vehicle for developing and recording community outcomes in relation to the river and drainage schemes management, and will be a ‘feeder plan’ supporting LTCCP functions and forecasts and asset information.

Asset management should also be consistent with the objectives of the Resource Management Act, which requires:

• Sustainable management of physical and natural resources.

• Consideration of alternatives and assessment of benefits and costs.

• Determination of best practicable options.

2.3 Relationship to other Environment Bay of Plenty documents

The Asset Management Plan is but one of a number of documents that Environment Bay of Plenty uses to guide the management of the Waioeka-Otara Rivers Scheme, consistent with the Community Outcomes for the region. All of these documents should complement one another and be consistent with each other. As well as the Asset Management Plan, the documents include:

• Regional Policy Statement.

• Proposed Regional Water and Land Plan. This Plan aims to integrate the management of land and water resources in the Region. The plan has not yet been adopted by Council, however, the bulk of this plan is now considered operative under RMA section 19.

• Floodplain Management Strategies. These are non-statutory documents that aim to appropriately manage the flood risk on the region’s floodplains. They include advisory, educational and advocacy measures, in addition to referencing statutory measures (e.g. planning controls) and physical works

Environment Bay of Plenty 5


measures (e.g. new flood control assets). The Waioeka-Otara Floodplain Management Strategy was completed in 2001 and further updated in June 2007.

• Bay of Plenty Regional Council Floodway and Drainage Bylaw 2002. These were adopted in 2003 giving powers to control various activities that may impact upon the level of service provided by scheme assets.

2.4 Duration of the plan

This plan has been prepared with a 50 year time horizon. However, long term predictions of such factors as maintenance requirements, costs and interest rates are difficult to make with certainty.

The plan will be reviewed, usually five yearly, and updated to ensure that the requirements of the customers are met, and that the systems are maintained at their most effective levels of service.

The information prepared under Chapter 4 of this plan will be incorporated into the long term council community plan as well as the annual plan for each financial year.

2.5 Principal scheme features

2.5.1 Background

The scheme comprises two main branches, the Waioeka and Otara Rivers (Figure 1). The Waioeka catchment covers 825 km2 extending 60 km, while the Otara covers 350 km2 and extends 30 km. Both catchments are relatively steep with extensive bush cover. The lower reaches of both rivers meander across flood plains before joining at Opotiki and flowing out to sea. Intensive rainstorms occur in both catchments with associated flooding and gravel movement being difficult to control.

A full analysis of the hydrology of both rivers concluded that, from continuous river flow records, the one hundred year flow for the Waioeka River as measured at the Cableway recorder, is 1850 cumecs (cubic metres per second). Similarly, the one hundred year flow for the Otara River at the Browns Bridge recorder is 930 cumecs. Mean flows for the Cableway and Browns Bridge sites are 32 and 12 cumecs respectively.

2.5.2 Overview

The Waioeka–Otara Rivers Scheme includes substantial stopbanking of both the urban and rural sections of both rivers, one pump station (Duke Street) and considerable bank edge protection works including rock riprap, rubble and plantings. The scheme also includes flood protection to the land adjoining Mill Stream and minor drainage works.

The original scheme completed in 1960 was in fact two stopbanking schemes; each financed by separate rating areas. The “urban scheme” protected 770 ha, including Opotiki, to a nominal 250 year protection standard. The “rural scheme” protected 1230 ha of farmland in the valleys of the two rivers to a 30 year protection standard.

Because of limited local finance the rural scheme was designed to the lower standard with emphasis on cleared fairways with berm planting to reduce flood velocities near the stopbanks.



Although the schemes were effective in relieving flooding, it was at the cost of continual repairs as no river training works had been allowed for in the original scheme. In 1974 an economic report on the rural scheme was undertaken to support an application for Government funding of a ten year river training program. A second ten year program of river training was proposed in 1984 and a subsidy for the works secured from the Government. It was clear that until the rivers in the rural area were trained into suitable channel alignments the integrity of the stopbanks would always be at risk.

In 1986 the National Water and Soil Conservation Authority (NWASCA) requested a comprehensive scheme study be carried out (in accordance with its unified flood loss reduction policy) as a prerequisite for further funding of the Waioeka-Otara schemes.

The NWASCA requested study was completed in July 1989. The study investigated four major options for the scheme. Comparisons of the major options with respect to all the relevant factors concluded that the most preferred option from the Board’s perspective was the “continue” option, in both the “urban” and “rural” areas.

The “continue” option was for the continued maintenance of the urban banks at their present level, but it did not preclude the possibility of raising the banks at a later date to allow for the effects of berm aggradation and sea level rise. Constructing a new urban stopbank in the Te Rere Pa area was included as part of this “continue” option. In the rural area, maintaining the present banks and continuing with the river training works was the most preferred option.

Following the report, a grant of $660,000 was approved by the Ministry of Environment to be matched by a local share of $440,000.

Following Environment Bay of Plenty’s inheritance of the Waioeka–Otara Rivers Scheme during 1989, the design was further reviewed before construction works began (Titchmarsh 1990). The review revealed the following problems:

• Design flows for the Waioeka–Otara Rivers Scheme were now rated approximately 20% to 30% higher than the original 1966 design flows.

• There was reason for concern at the rapid rate of aggradation of town berms, particularly for the Otara River. Control of berm vegetation needed urgent attention otherwise the level of flood protection would continue to diminish with time.

• Maintenance of the stopbanks and berms had been neglected.

• While the condition of the mainly indigenous catchment cover was considered good at that time, there was reason to believe that wild animal numbers had increased rapidly in the last few years and, unless future control measures were implemented, would continue to rise.

The review also made the following recommendations:

(i) That the works to upgrade the stopbanks in the scheme to the following standards be implemented:-

Otara rural left bank 30 year + 300 mm freeboard

Waioeka rural right bank 30 year without freeboard



(a) Otara urban left bank 100 year + 450 mm freeboard

(b) Otara urban right bank 100 year without freeboard

(c) Waioeka urban right bank 100 year + 450 mm freeboard

(d) Waioeka urban left bank 100 year + 450mm freeboard

(ii) That the works to relocate the stopbanks on the Otara right bank between cross-sections 15.945 and 13.500 and on the Otara left bank between cross-sections 15.470 and 14.220 be implemented.

(iii) That the works to relocate and extend the Otara left bank across Gaults Road be implemented.

(iv) That the Council instigate regular monitoring of the stopbanks to ensure that design standards are maintained. Special attention should be given to locations where roads cross the stopbanks and making sure that good grazing management practices are followed.

(v) Where roads crossed the stopbanks that they be sealed as part of the scheme works and then be maintained by the Opotiki District Council.

(vi) The Council in conjunction with Opotiki District Council control the growth on berm areas, either with a mowing and/or spraying programme.

(vii) River training works continue as part of the annual maintenance programme.

The stopbank works recommended were all constructed over the 1990–91 period.

A subsequent review of the rural stopbanks was undertaken in 2002 following floods in 1998 and 1999 which highlighted that the actual standard of protection was shown to be less than designed. With data collected from the 1998 event a computational hydraulic model was built of the rivers and floodplain. The model was used to identify and recommend design standards and works required to meet these standards. Following liaison with the scheme, the design standards were reviewed and much of the recommended works were completed between 2002 and 2005.

The design standards proposed during this review included a number of sections of bank that required higher design flood flow standards and a number of existing banks where their existing built levels were defined to carry a higher probability flood (lower standard). The adoption of this plan will formalise the new standards of protection for the rural stopbanks.

Figure 1 identifies the new standards throughout the scheme.



Figure 1 Proposed Stopbanks Standards



Three sections of stopbanks reconstruction works still exist to complete all the recommendations of the review. Petersons ringbank and Snells Road stopbank have been programmed to be completed in 2007/2008 and the realignment of Waioeka stopbank around 1 1/4L has been programmed for 2008/2009. These works have been included in this asset management plan review for expenditure and funding purposes. Following consultation with the scheme, a request has been made to allow funding for a project to investigate better drainage in the Te Rere Pa Road area. No allowance has been made for a new pump station should the investigation recommend that.

Maintenance, renewal and capital expenditure on the scheme is funded by way of a differential rating system (under the Rating Powers Act & Local Government Act), struck over the whole of catchment and which lies within the Bay of Plenty Regional Council region. The part of the catchment that lies within the Gisborne District Council region is not rated because Environment Bay of Plenty do not have powers to rate those lands and Gisborne District Council have declined to collect the rate on Environment Bay of Plenty’s behalf.

A “differential analysis report” establishes the relative benefits received by the lands within the scheme and lands where exacerbatory effects occur. Rates for any property are calculated on the basis of this classification. Environment Bay of Plenty currently contributes to the annual scheme rate requirements by 20% from regional general rate funds in recognition of the wider regional benefits provided by the scheme.

2.5.3 Summary of assets

Today, the Waioeka-Otara Rivers Scheme includes:

• stopbanking including urban and rural stopbanks (67.37km)

• concrete walls (400m)

• riverbank edge protection comprising

plantings (32.19km)

trenched willows (18.07km)

fencing (45.09km)

rockwork (6.31km)

rubble (860 m)

• buffer zone protection (18.63km)

• Duke Street pump station

• drains (19.9km)



2.6 Climate change impacts

Environment Bay of Plenty is presently undertaking a study to determine its policy for the provision of climate change in the region’s river and drainage schemes.

Climate change has the potential to increase the magnitude, level and frequency of flooding and so the capacity of existing flood protection assets must be reviewed periodically when new flood data and climate change forecasts are available.

2.6.1 Sea level rise

The Intergovernmental Panel on Climate Change (IPCC) issues projections on the impact of climate change on sea levels at five yearly intervals. In 2000 the IPCC predicted increases between 0.15m – 0.2m by 2050 and 0.43m by 2100.

Whilst there is some scepticism by a minority of scientists on the quantity and local variations, it is fact that in New Zealand sea levels have risen by an average of 1.2mm per year since 1900.

Council has adopted the IPCC estimates for the purpose of the Bay of Plenty Regional Coastal Environment Plan.

Currently, some provision for sea level rise is included in some of the schemes. The impacts of this are limited to the lower reaches of the river and are small compared to the magnitude of storm surges. This policy will be reviewed on completion of the study.

2.6.2 Increased frequency and magnitude of flooding

A second, but less quantified adverse effect of climate change is that the frequency and magnitude of high intensity rainfalls are expected to increase.

Dr Andy Resinger, from the Ministry of the Environment, in his visit to Environment Bay of Plenty in 2002 advised that the frequency of floods of a particular size are estimated to increase between zero and four-fold by the year 2070. A four-fold increase would mean that he estimated 400-year flood magnitude would then become the 100-year flood.

In response to an enquiry, whether adopting a doubling in frequency was prudent, Dr Resinger indicated that would be a reasonable approach.

A doubling in flood frequency by the year 2070 would mean that the currently estimated 200-year flood magnitude would become the 100-year flood.

Currently no policy or provision exists for increasing frequency and magnitude of flooding. It is important that when key structures and those that are difficult to retrofit (e.g. flood walls) come up for construction or renewal that they are designed for likely intensification of flows during their lifetime. However, at this point there is little information on the required provision, and any provision should be critically examined. This aspect will be reviewed on completion of the study.



2.6.3 Impact of the Interdecadal Pacific Oscillation

The Interdecadal Pacific Oscillation (IPO) is a climate cycle affecting the majority of the Pacific. This cycle has more immediate impact on flood frequency than climate change and is to be considered in any future review of flood protection assets.

The IPO cycle is strongly correlated to heavy rainfall and floods in the Bay of Plenty resulting in successive “benign” and “active”: phases. These phases persist for 20 to 30 years. The cycle shifted to a “benign” phase in the mid-1970’s and subsequently to an “active” phase around 1997-98.

The influence on the larger floods is more pronounced (as demonstrated in a report by Dr A I McKercher, NIWA in Tephra) and a full report on this matter will be prepared in the near future.

The impact is that we can expect a series of floods with above average magnitude over the next 20 years.

13


Chapter 3: Assets

3.1 Objectives of the scheme

The Waioeka–Otara Rivers Scheme consists of a number of component infrastructural assets to provide the following:

• Security from floods up to the 1% Annual Exceedance Probability (AEP) level to the township of Opotiki. By definition, the 1% AEP flood has a 1% probability of occurring in any one year. This is more commonly known as the 1 in 100 year flood.

• Security from floods up to the 5% AEP (20 year) level to most rural areas adjoining the Waioeka River.

• Security from floods up to around the 10% AEP (10 year) level to most rural areas adjoining the Otara River.

• The maintenance of the Waioeka and Otara Rivers to a stable alignment in terms of width and meander pattern.

• Reduced erosion of river banks.

• Minor drainage and pumping.

3.2 Description of the assets

3.2.1 Stopbanks

Stopbanks (also known as flood banks) are compacted earth structures, which provide protection to urban and rural properties from floodwaters. The asset ‘stopbanks’ includes an allowance for the minor culverts and fences that normally surround or are part of the stopbanks.

3.2.2 Structures

(a) Floodgates

Floodgates are structures constructed of reinforced concrete and timber that may be opened or closed to admit or exclude flood and tidal waters. There are no major floodgates on this scheme. However, there are a large number (around 100) of small floodgates at stormwater outlets.



(b) Pump Stations

Mechanical and electrical equipment with associated reinforced concrete structure that raises water to a position where it is able to flow away under gravity. Currently there is only one pump station, located at Duke Street.

3.2.3 Concrete walls

Concrete walls are constructed of reinforced concrete and are an integral part of the stopbank system. These are generally constructed where there is insufficient width to construct an earth embankment.

3.2.4 Edge protection

(a) Rock

Mechanically placed rock riprap provides protection to the riverbanks particularly in the lower reaches of the river system where willow trees will not grow. Willows do not grow in these reaches due to the tidal influence and the regular inundation with saline water. Rock also provides a much higher degree of erosion protection than willows — but at substantially greater cost.

(b) Rubble

Similar to rock, mechanically placed rubble provides protection to the riverbanks particularly in the lower reaches. Rubble provides less erosion protection than rock because it has a lower density, poor shape characteristics (it can be ‘plucked’ off the riverbank by the river flow) and is generally less durable. It requires more monitoring than rock and is aesthetically inferior. However it is a cost effective method for some applications.

(c) Live protection

Vegetation (generally willows) that is planted and “layered” onto the river bank and/or willows that are trenched into the river bank to provide a low growth habit down or near the water level in the river to provide protection against riverbank erosion. (Refers to Edge Protection and Trenched Willows in Table 6).



Figure 2 Typical River Cross Section



3.2.5 Buffer zone

Area adjacent to the river which is fenced and planted with both willows and native shrubs to provide back up material for edge protection; to filter, collect and sort debris during large flood events and give some flexibility in the migration of the meander pattern in the river system.

In most instances the live protection and buffer zone will be fenced off to exclude stock. Fencing is an integral part of the live protection and buffer zone assets. Fences are installed and maintained by the scheme on rivers and streams (drains excluded) in these protection zones within the maintenance boundary of the scheme.

3.2.6 Drains

Excavated channels designed to convey water to the Waioeka and Otara Rivers, tributary streams and the Duke Street pump station. The locations of the scheme drains are shown in Appendix 7.

3.3 Physical parameters

The following tables 1 to 6 provide a summary of the physical parameters of the assets.

More detailed information is contained in Environment Bay of Plenty’s asset register, file 0360-04. Asset information is also stored on the following computer directory; V:TS_RD\assets\valuatio\waioeka\valuation 2007\ *.*

The methods of valuation are described in section 3.6.

Note: The river reference points have long-established distances in terms of miles.



Table 1 Infrastructural Assets Stopbank Quantities 2007

Loca

tion

Batte

rsTo

p W

idth

S/B

Heig

htLe

ngth

Volu

me

Basi

c Co

stLi

near

Cos

tTo

tal C

ost

Top

ofDe

sign

Free

boar

dDe

sign

Retu

rnEq

uivi

lent

Age

Depr

ecia

tion

Net V

alue

Curre

nt V

alue

mm

mm

3$

$Ba

nk R

.L.

Floo

d Le

vel

Flow

Perio

das

at

DRC

2007

2007

(at d

/s X

S)(a

t d/s

XS)

(m)

m3 /s

(yea

rs)

2007

Wai

oeka

LB

Floo

dway

22

1.6

3,20

026

,624

$341

,852

$141

,920

$483

,772

65,

805

477,

967

$483

,772

Wai

oeka

LB

Alan

Row

es3

31.

81,

020

15,4

22$1

98,0

24$4

5,23

7$2

43,2

616

2,91

924

0,34

1$2

43,2

61W

aioe

ka R

B W

harf

to B

ridge

33

1.8

1,50

022

,680

$291

,211

$66,

525

$357

,736

64,

293

353,

443

$357

,736

Wai

oeka

RB

Brid

ge to

2.5

33

1.2

565

4,47

5$5

7,45

6$2

5,05

8$8

2,51

46

990

81,5

24$8

2,51

4W

aioe

ka R

B3

33.

550

023

,625

$303

,345

$22,

175

$325

,520

63,

906

321,

614

$325

,520

Wai

oeka

LB

Woo

dlan

ds R

d Ur

ban

33

1.5

181

2,03

6$2

6,14

5$8

,027

$34,

173

00

34,1

73$3

4,17

3To

tal R

each

1

6,96

694

,862

$1,2

18,0

34$3

08,9

42$1

,526

,976

$1

7,91

4$1

,509

,062

$1,5

26,9

76An

nual

Dis

p3,

054

Wai

oeka

RB

2.5

to 3

(MS)

33

3.5

1,13

053

,393

$685

,560

$50,

116

$735

,675

68,

828

726,

847

$735

,675

3

33.

275

030

,240

$388

,282

$33,

263

$421

,544

65,

059

416,

486

$421

,544

33

2.5

950

24,9

38$3

20,1

98$4

2,13

3$3

62,3

306

4,34

835

7,98

2$3

62,3

30M

ill St

ream

22

2.5

3,35

058

,625

$752

,745

$148

,573

$901

,318

610

,816

890,

502

$901

,318

Wai

oeka

Rur

al2

22

18,9

0022

6,80

0$2

,912

,112

$838

,215

$3,7

50,3

276

45,0

043,

705,

323

$3,7

50,3

27To

tal R

each

225

,080

393,

995

$5,0

58,8

96$1

,112

,298

$6,1

71,1

94$7

4,05

4$6

,097

,139

$6,1

71,1

94An

nual

Dis

p12

,342

Ota

ra R

B .

75 to

2.2

52.

52

22,

160

30,2

40$3

88,2

82$9

5,79

6$4

84,0

783

2,90

448

1,17

3$4

84,0

78O

tara

RB

2.2

5 to

2.7

53

32.

585

522

,444

$288

,178

$37,

919

$326

,097

31,

957

324,

140

$326

,097

Ota

ra R

B 2

.75

to 3

.53

32

1,00

018

,000

$231

,120

$44,

350

$275

,470

31,

653

273,

817

$275

,470

Ota

ra R

B 3

.5 to

4.0

2.5

22.

595

019

,594

$251

,584

$42,

133

$293

,716

31,

762

291,

954

$293

,716

Ota

ra R

B 4

.0 to

5.0

33

2.4

1,09

026

,683

$342

,612

$48,

342

$390

,954

32,

346

388,

608

$390

,954

Ota

ra R

B 5

.0 to

5.2

52.

52

230

04,

200

$53,

928

$13,

305

$67,

233

340

366

,830

$67,

233

Ota

ra L

B W

harf

to 2

.75

33

1.8

2,13

232

,236

$413

,908

$94,

554

$508

,462

33,

051

505,

412

$508

,462

Ota

ra L

B 2

.75

to C

W3

31.

552

05,

850

$75,

114

$23,

062

$98,

176

358

997

,587

$98,

176

Ota

ra L

B 3

.25

to 5

.25

33

2.5

3,29

086

,363

$1,1

08,8

95$1

45,9

12$1

,254

,806

37,

529

1,24

7,27

7$1

,254

,806

Ota

ra L

B 5

.5 to

5.7

52.

52.

52.

540

08,

750

$112

,350

$17,

740

$130

,090

378

112

9,30

9$1

30,0

90O

tara

LB

5.7

5 to

GR

33

2.2

1,20

025

,344

$325

,417

$53,

220

$378

,637

32,

272

376,

365

$378

,637

Tota

l Rea

ch 3

13,8

9727

9,70

3$3

,591

,387

$616

,332

$4,2

07,7

19$2

5,24

6$4

,182

,473

$4,2

07,7

19An

nual

Dis

p8,

415

Ota

ra L

B 6

.5 to

7.5

2.5

2.5

22,

750

41,2

50$5

29,6

50$1

21,9

63$6

51,6

1313

16,9

4263

4,67

1$6

51,6

13O

tara

LB

7.5

to 8

.53

31.

71,

230

16,9

37$2

17,4

72$5

4,55

1$2

72,0

233

1,63

227

0,39

1$2

72,0

23O

tara

LB

8.5

to 9

.52.

52.

52.

51,

620

35,4

38$4

55,0

18$7

1,84

7$5

26,8

653

3,16

152

3,70

3$5

26,8

65O

tara

LB

9.7

5 G

aults

Rin

g3

32.

225

05,

280

$67,

795

$11,

088

$78,

883

347

378

,409

$78,

883

Ota

ra L

B 9

.75

to 1

1.0

2.5

2.2

1.7

1,98

021

,711

$278

,765

$87,

813

$366

,578

32,

199

364,

379

$366

,578

Ota

ra L

B 1

1.0

2.5

2.2

1.2

700

4,36

8$5

6,08

5$3

1,04

5$8

7,13

03

523

86,6

07$8

7,13

0O

tara

Rur

al2

22

12,9

0015

4,80

0$1

,987

,632

$572

,115

$2,5

59,7

473

15,3

582,

544,

389

$2,5

59,7

47To

tal R

each

421

,430

279,

783

$3,5

92,4

18$9

50,4

21$4

,542

,838

$40,

289

$4,5

02,5

49$4

,542

,838

Annu

al D

isp

9,08

6

Tota

l Wai

oeka

Ota

ra67

,373

1,04

8,34

4$1

3,46

0,73

4$2

,987

,993

$16,

448,

727

$1

57,5

04$1

6,29

1,22

3$1

6,44

8,72

7To

tal A

nnua

l Dis

p$3

2,89

7

Reac

h 4:

Ota

ra R

ural

6.2

5 to

11.

8 m

iles

Reac

h 1:

Wai

oeka

Tow

n 1

to 2

.5 m

iles

Reac

h 2:

Wai

oeka

Rur

al 2

.5 to

7.5

mile

s

Reac

h 3:

Ota

ra T

own

0 to

6.2

5 m

iles



Table 2 Infrastructural Assets - Structures

Location Contract Plan No Structure Contents n Year Built Replacement CGPI Year Replacement Age Depreciation Net Value Net Value Replacement Life DepreciationNo. Valuation Valuation i Valued CCI Cost CCI S2DD Built Cost Structure YTD 30.6.07 Structure Jun 07 Contents Jun 07 Cost Contents Remain Annually

Waioeka OtaraDuke Street-Structures 84,800 3700 5143 not fixed 84 117,872 23 54,221 63,651 0 27 2,357Duke Street - Contents 67,500 3700 5143 not fixed 84 9 21,111 72,714 93,825 31 2,346Duke Street - telemetry 7,670 4,760 5143 not fixed 2004/05 3 2,486 5,801 8,287 7 829Total Waioeka Otara 84,800 67,500 117,872 63,651 72,714 102,112 5,532

Table 3 Infrastructure Assets Concrete Wall Stopbanks 2007

Location River Length Volume Replacement Age Top of Design Design Return DepreciatedDistance m Height m3/m Value as at Wall R.L. Flood Level Freeboard Flow Period Depreciation Replacement Cost

2007 (at d/s XS) (at d/s XS) (m) m3/s (years)Reach 3: Otara Town 0 to 6.25 miles

LB Otara 3 313 0.6 0.375 120,309 14 33,687 86,623LB Otara Wharf 87 1.8 1.3375 119,272 5 11,927 107,344

Total Waioeka Otara 400 $239,581 $33,687 $193,967Annual Depreciation $4,792



Table 4 Infrastructure Assets - Rockwork

Loca

tion

Riv

erR

efer

ence

Leng

thVo

lum

eTo

nne

Dat

eVa

lue

From

To

mm

3Pl

aced

or R

eple

nish

ed20

07

Rea

ch 1

: Wai

oeka

Tow

n 0

to 2

.5 m

iles

R

B W

aioe

kaU

nion

Stre

et2.

0km

5028

044

824

640

RB

Wai

oeka

Uni

on S

treet

500

1620

1900

1045

00LB

Wai

oeka

Har

ford

s2.

25km

120

670

1072

5896

0R

B W

aioe

kaIs

land

3.2k

m3.

39km

190

798

2007

4389

0LB

Wai

oeka

Wel

lingt

on S

treet

3.5k

m3.

65km

150

630

2007

3465

0

Tota

l Rea

ch 1

1010

2570

4848

$266

,640

Rea

ch 2

: Wai

oeka

Tow

n 2.

5 to

7.5

mile

sR

B W

aioe

kaR

iver

loch

farm

s; s

tub

groy

nes

9.5k

m12

040

6.25

650

2003

$35,

750

RB

Wai

oeka

A R

owes

4.1k

m4.

3km

200

840

2007

$46,

200

RB

Wai

oeka

Riv

erlo

ch fa

rms

9.5k

m15

040

6.25

650

2005

$35,

750

Tota

l Rea

ch 2

470

812.

521

40$1

17,7

00

Rea

ch 3

: Ota

ra T

own

0 to

6.2

5 m

iles

LB

Ota

ra2.

0km

110

620

992

5456

0LB

Ota

ra2.

5km

400

2240

3584

1971

20LB

Ota

ra3.

0km

580

3250

5200

2860

00LB

Ota

ra3.

5km

7040

064

035

200

LB O

tara

3.75

km4.

0km

125

700

1120

6160

0LB

Ota

raW

gtn-

Brid

ge S

t10

3262

510

0055

000

LB O

tara

Fish

ing

Clu

b19

0418

12.5

2900

1595

00LB

Ota

raM

emor

ial P

ark

990

625

1000

5500

0R

B O

tara

Thor

nton

Orc

hard

2.2k

m60

125

200

2004

$11,

000

Tota

l Rea

ch 3

5271

7210

1663

6$9

14,9

80

Rea

ch 4

: Ota

ra R

ural

6.2

5 to

11.

8 m

iles

LB O

tara

11.8

km95

530

848

$46,

640

LB O

tara

Loch

eads

Cor

ner

10.9

km20

060

020

04$3

3,00

0LB

Ota

raLo

chea

d/B

row

n10

.9km

200

600

2005

$33,

000

RB

Ota

raC

arte

rs13

km20

060

020

05$3

3,00

0R

B O

tara

Gow

Roa

d7.

1km

3010

020

04$5

,500

LB O

tara

Aero

drom

e C

orne

r8.

6km

3010

020

04$5

,500

RB

Ota

raG

ow R

oad

7.0k

m7.

0220

5020

07$2

,750

Tota

l Rea

ch 4

9553

028

98$1

59,3

90

Tota

l Wai

oeka

Ota

ra68

4611

122.

526

522

$1,3

41,4

80

Riv

er D

ista

nce



Table 5 Infrastructural Assets - Rubble Lo

catio

nRiv

erRe

feren

ceLe

ngth

Volum

eTo

nne

Date

Place

dVa

lueDis

tance

From

Tom

m3or

Reple

nishe

d20

07

Reac

h 1: W

aioek

a Tow

n 1 to

2.5 m

iles

LB W

aioek

aCo

nners

1.25k

m1.3

712

0pre

1996

$9,34

2LB

Waio

eka

Conn

ers2.2

km2.2

770

450

2007

$5,45

0LB

Waio

eka

Peter

sons

0.9km

1.02

120

520

2006

$9,34

2

Total

Reac

h 112

0$2

4,134

Reac

h 3: O

tara T

own 0

to 6.

25 m

iles

LB

Otar

a 0.25

-0.5

0.25

0.519

0pre

1996

$14,7

92LB

Otar

a 1-1.

25

Wharf

1.00

1.25

250

pre 19

96$1

9,463

LB O

tara 1

.25

1.25

220

pre 19

96$1

7,127

LB O

tara 2

2.0

040

pre 19

96$3

,114

RB O

tara

Thorn

ton O

rchard

2.00

4020

03$3

,114

Total

Reac

h 374

0$5

7,609

Reac

h 4: O

tara

6.25 t

o 11.8

mile

s

RB O

tara

Edwa

rdson

s15

.7km

15.82

120

590

2007

$9,34

2To

tal Re

ach 4

120

$9,34

2

Total

Waio

eka O

tara

980

$91,0

85

River

Distan

ce



Lo

cati

on

Pla

n N

oE

dg

eT

ren

ch

ed

F

en

cin

gB

uff

er

Co

st

Co

st

To

tal C

ost

Co

st

Co

st

Pla

nti

ng

Willo

ws

Zo

ne

Ed

ge P

lan

tin

gT

ren

ch

ed

Willo

ws

Ed

ge P

rote

cti

on

Fen

cin

gB

uff

er

Zo

ne

S

hee

t 4

75

011

04

70

312

7.5

76

45

$1

0,7

73

0$4

,58

3 S

hee

t 5

95

05

10

3,9

62

03

,96

20

4,9

73

Du

ke

Str

ee

t -

Opo

tiki W

harf

C2

001

08

48

40

00

2,7

10

0

To

tal R

ea

ch

11,7

00

11

048

49

80

7,0

89

$7

,64

5$1

4,7

34

$2

,71

0$9

,55

5

Sh

ee

t 6

1,5

10

96

01

64

018

90

$6

,29

7$

66

,72

0$7

3,0

17

$9

,18

4$

18

,42

8 S

hee

t 7

1,6

00

70

01

84

014

50

$6

,67

2$

48

,65

0$5

5,3

22

$1

0,3

04

$14

,13

8 S

hee

t 8

59

023

057

05

80

$2

,46

0$

15

,98

5$1

8,4

45

$3

,19

2$5

,65

5 S

hee

t 9

99

078

01

13

015

30

$4

,12

8$

54

,21

0$5

8,3

38

$6

,32

8$

14

,91

8 S

hee

t 10

78

078

01

15

015

60

$3

,25

3$

54

,21

0$5

7,4

63

$6

,44

0$

15

,21

0 S

hee

t 11

1,2

00

93

01

39

016

20

$5

,00

4$

64

,63

5$6

9,6

39

$7

,78

4$

15

,79

5 S

hee

t 12

1,6

40

1,1

90

123

06

90

$6

,83

9$

82

,70

5$8

9,5

44

$6

,88

8$6

,72

8 S

hee

t 13

1,2

90

1,2

90

137

010

80

$5

,37

9$

89

,65

5$9

5,0

34

$7

,67

2$

10

,53

0 S

hee

t 14

37

012

540

0$1

,54

3$8

,68

8$1

0,2

30

$2

,24

0$

0$

0$

0$0

$0

$0

To

tal R

ea

ch

29,9

70

6,9

85

10

,72

01

0,4

00

$4

1,5

75

$4

85

,45

8$

52

7,0

32

$6

0,0

32

$1

01

,40

0

T

ota

l W

aio

eka

11,6

70

7,0

95

11

,20

41

1,3

80

$4

8,6

64

49

3,1

03

541

,76

662

,742

11

0,9

55

S

hee

t 1

41

0$1

,71

0$

0$

1,7

10

$0

$0

Sh

ee

t 2

71

038

0$2

,96

1$

26

,41

0$2

9,3

71

$0

$0

Sh

ee

t 3

1,1

90

96

030

0$4

,96

2$

66

,72

0$7

1,6

82

$1

,68

0$

0 S

hee

t 4

1,5

60

1,4

60

175

0$6

,50

5$

101

,47

0$

10

7,9

75

$9

,80

0$

0 S

hee

t 5

1,5

50

1,0

30

136

0$6

,46

4$

71

,58

5$7

8,0

49

$7

,61

6$

0 S

hee

t 6

60

060

096

0$2

,50

2$

41

,70

0$4

4,2

02

$5

,37

6$

0D

uke S

tre

et -

Opotiki W

harf

(C

ontr

act 20

0108)

221

3$

0$

0$0

$1

2,3

93

$0

Ota

ra L

B (

Op

otiki W

harf

to D

uke S

t, C

20

0109)

11

48

5$

0$

0$0

$6

4,3

16

$0

To

tal R

ea

ch

36,0

20

4,4

30

18

,06

80

$25

,10

3$

307

,88

5$

33

2,9

88

$10

1,1

81

$0

Sh

ee

t 6

1,6

00

17

00

$6

,67

2$

11

,81

5$1

8,4

87

$0

$0

Sh

ee

t 7

2,3

20

59

02

56

04

10

$9

,67

4$

41

,00

5$5

0,6

79

$1

4,3

36

$3

,99

8 S

hee

t 8

1,9

00

1,1

90

227

010

40

$7

,92

3$

82

,70

5$9

0,6

28

$1

2,7

12

$10

,14

0 S

hee

t 9

2,3

80

1,5

40

138

021

20

$9

,92

5$

107

,03

0$

11

6,9

55

$7

,72

8$

20

,67

0 S

hee

t 10

68

068

029

08

70

$2

,83

6$

47

,26

0$5

0,0

96

$1

,62

4$8

,48

3 S

hee

t 11

2,3

00

1,1

10

231

011

10

$9

,59

1$

77

,14

5$8

6,7

36

$1

2,9

36

$10

,82

3 S

hee

t 12

1,1

90

98

01

07

012

15

$4

,96

2$

68

,11

0$7

3,0

72

$5

,99

2$

11

,84

6 S

hee

t 13

1,8

20

28

051

0$7

,58

9$

19

,46

0$2

7,0

49

$2

,85

6$

0 S

hee

t 14

31

04

80

$1

,29

3$

0$

1,2

93

$0

$4

,68

0T

e R

ere

Pa to G

ault R

d, C

20

0110

)

542

3$

0$

0$0

$3

0,3

69

$0

To

tal R

ea

ch

41

4,5

00

6,5

40

15

,81

37,2

45

$60

,46

5$

454

,53

0$

51

4,9

95

$8

8,5

53

$70

,63

9

To

tal O

tara

20,5

20

10

,97

033

,88

17,2

45

$85

,56

8$

762

,41

5$

84

7,9

83

$18

9,7

34

$70

,63

9

To

tal S

ch

em

e3

2,1

90

18

,06

545

,08

51

8,6

25

$1

34

,23

2$1

,255

,51

8$

1,3

89,7

50

$25

2,4

76

$1

81

,59

4

15 %

En

gin

ee

rin

g e

tc$

20

,13

5$

188

,32

8$

20

8,4

62

$3

7,8

71

$27

,23

9

To

tal W

aio

eka

/Ota

ra$

154

,36

7$1

,443

,84

5$

1,5

98,2

12

$29

0,3

47

$2

08

,83

3

Re

ac

h 3

: O

tara

To

wn

0 t

o 6

.25 m

iles

Re

ac

h 4

: O

tara

Ru

ral 6

.25

to

11

.8 m

iles

Re

ac

h 1

: W

aio

eka

To

wn

1 t

o 2

.5 m

ile

s

Re

ac

h 2

: W

aio

eka

Ru

ral 2

.5 t

o 7

.5 m

iles

Table 6 Infrastructure Assets Edge Protection 2007



3.4 Asset capacity

3.4.1 Stopbanks

Stopbanks are built to a level and grade where they will not be overtopped by the design flood. They are also constructed to appropriate batters and top width to ensure their structural integrity.

The capacity of stopbanks is reviewed regularly by Environment Bay of Plenty. Reviews have resulted in physical works to return the stopbanks to a level that meets the scheme design objectives. The programme of works between 1990 and 1994 and again between 2002 and 2005 brought the stopbanks up to the design standards stated in the table below. The next capacity review for the Waioeka-Otara Scheme is scheduled for 2009-10.

Location Design Level

Waioeka Urban Right Bank 1% (100 yr) plus 450 mm freeboard

Waioeka Rural Right Bank 5% (20 yr) plus 300 mm freeboard

Waioeka Urban Left Bank 1% (100 yr) plus 450 mm freeboard

Waioeka Rural Left Bank 5% (20 yr) plus 300 mm freeboard

Waioeka Rural Coastal Left Bank 50% (2 yr) plus 300 mm freeboard 1

Otara Urban Left Bank 1% (100 yr) plus 450 mm freeboard

Otara Rural Lower Right Bank 5% (20 yr) plus 300 mm freeboard

Otara Rural Coastal Right Bank 50% (2 yr) plus 300mm freeboard 1

Otara Rural Left Bank 10% (10 yr) plus 300 mm freeboard

Otara Rural Right Bank 10% (10 yr) plus 300 mm freeboard

Gault Ring Bank 2% (50 yr) plus 400 mm freeboard

1 These banks also provide some spillway function during flood events

Design levels of the Waioeka-Otara stopbanks were reviewed in 2002 (Wallace).

3.4.2 Structures

(a) Pump Stations

Pump stations are designed to discharge drainage and flood flows to a particular design standard. Pump stations operate when the gravity outlet is closed or inhibited.

The only pump station on this scheme is the Duke Street pump station constructed in 1984. This is primarily a flood pump and is sized for a 10 year 24 hour storm (160 mm). It is also used for drainage when required.



(b) Concrete Walls

Concrete Walls provide the same function as the stopbanks.

Location Design Level Otara Urban Left Bank 100 year plus 450 mm freeboard


Rock work and live protection are erosion control works that are designed to protect the stopbanks and/or natural channel banks from erosion and consequential flood overflows, to maintain channel stability and to reduce the deposition of sediment in the lower reaches of the river system.

3.4.4 Buffer zone

The buffer zone has no definitive design standard and the width allowed is a matter of considered judgement on a site by site basis. For consistency a minimum width of vegetation is maintained in most circumstances. The standard selected for the buffer zone ideally would be the width of the minor meander (30 metres). However, in some cases there is insufficient space to achieve this and an average width of 15 metres has been adopted.

3.5 Asset condition

3.5.1 Stopbanks

Asset condition is monitored by visual inspections, physical surveys and scheme reviews including detailed computer analysis.

Stock damage can arise from variable grass cover and poor grazing management e.g. use of the stopbank as a race for cattle or heavy grazing during wet weather. It is important that scheme monitoring continues to prevent future damage.

Problems exist with the alignment from the inherited situation where the stopbanks are too close to the river channel leaving little or no berm area. This increases the risk of stopbank failure in some places due to undermining by a smaller flood rather than being overtopped by the design event. This is a particular problem through part of the Opotiki township reaches of both rivers. It is also a problem in some rural reaches. In some cases there simply is not enough room to create a protected berm in front of the stopbanks. In most cases additional edge protection works and the maintenance of the existing edge protection works and buffer zones has improved this situation.

The rural stopbanks are also narrower than the ideal minimum in many locations. This puts the banks in greater risk of breach, both before and after a bank is overtopped, and makes maintenance more difficult.



3.5.2 Structures

A regular programme of maintenance is carried out on the Duke Street pump station. In particular, any working parts that wear out or that are showing signs of age are replaced. The pump station is also linked to Opotiki District Council’s telemetry system for day to day pump monitoring. Asset condition is monitored by regular inspection (see Appendix 2). Structural concrete is inspected periodically. Minor movement in the pump house structure is monitored periodically.


The concrete walls are in good condition and are inspected on a regular basis (see appendix 2). The walls are surveyed regularly and monitored against their design height. Any structural defects are repaired promptly.


(a) Live edge protection

The condition of the live edge protection in the scheme varies depending on its age and its previous maintenance.

Most of the vegetation protection present in the scheme are matsudana hybrids with some crack willow (Salix fragilis). Whilst the crack willow does have some desirable characteristics, such as a large root mass and some resistance to animal grazing, it is rather brittle, and being largely female it tends to seed and spread uncontrolled. Thus it is not an ideal species to use. In general, S. matusdana x alba hybrids tend to be more suitable, in particular male hybrids such as Hiwinui or Moutere.

It is anticipated that as other species and clones are planted in the future, much of the existing crack willow will be displaced. Having a mix of species and clones reduces the vulnerability of edge protection to a disease or insect infestation — as different species have different resistance to particular diseases or insect. Leaf rust, sawfly, silverleaf and Armillaria are examples of common problems that could strike willows. Willow sawfly exists and has caused the death of willow trees in the scheme, at this stage only in sporadic locations. In other areas of the country willow sawfly has wiped out entire scheme protection plantings that have had to be replaced with expensive alternative edge protection methods. The Armillaria fungus has also been detected in some willows on both the Otara and Waioeka Rivers. Field inspections monitor both situations on a regular basis.

Trials of various hybrid species of willows, in particular golden willow hybrids (matsudana x alba vitelina) are being assessed, and findings from crown research institutes are being obtained to further help identify suitable species to use as a bank protection.

In order to create more native edge protection plantings and to reduce the risk of sawfly damage to willows, Environment Bay of Plenty is carrying out field trials of native edge protection plantings. Whilst early results of these trials are showing potential at present they take years to establish and evaluate therefore a cautious transition from willows to natives is prudent.

The four major river schemes in the Bay of Plenty each contribute towards national funding for research into willow species for river control purposes.



A regular layering programme is already in place and this will intensify as new areas of edge protection age and thus require layering.

(b) Rock protection

Where rockwork exists, a maintenance programme is included in this plan to replenish areas where levels have fallen below 75% of the original design placement rate.

A rock replenishment programme between 1999 and 2005 has addressed areas where rock was insufficient to meet the design standard.

3.5.5 Buffer zone

Similar to the live edge protection, much of the buffer zone is in good condition. Regular inspections are carried out followed by maintenance fencing and planting to ensure the buffer zone is maintained.

3.6 Asset value

The Council complies with Generally Accepted Accounting Practices (GAAP) for capitalisation, depreciation, and valuation of assets as promulgated by the Institute of Chartered Accountants of New Zealand.

The principle Reporting Standard is the New Zealand equivalent to International Accounting Standard 16 Property, Plant and Equipment (NZ IAS 16).

NZ IAS 16 requires that where a revaluation takes place, they are to be revalued to a fair value, and in the case of specialised infrastructural assets, fair value is the depreciated replacement cost.

Usually the asset has been added to over a period of time, and has been upgraded and maintained to a high level of serviceability in order to continue providing the required level of service to its customers and users.

Council completed the revaluation of the Waioeka-Otara assets to June 2007 as part of this plan preparation. Revaluations were peered reviewed and then checked and approved by Audit New Zealand.

3.6.1 Stopbanks

All schemes in the Bay of Plenty region have either had upgrading work undertaken, or had new works built, within the last ten years. This gives Environment Bay of Plenty data to establish the value of the stopbank assets.

It is noted that if the stopbanks were to be rebuilt now, the methods of construction and available borrow could be completely different from when the banks were originally constructed. For example, in some cases stopbanks were built from borrow won from the river; this material may no longer be available or suitable and borrow would have to be sourced in from off site, thus potentially increasing the costs. With berm aggradation occurring on the Waioeka and Otara Rivers it is highly unlikely that material would be required from outside the scheme therefore the basis for valuation is based on the same method of construction as originally carried out, that is onsite borrow to fill construction. On-site material has been available and used in all recent capital and renewal works.



The stopbanks will be maintained to convey their design floods but settlement of up to 50% of the freeboard will be allowed before stopbank reconstruction will be undertaken. Therefore, the stopbanks value will depreciate to some extent. At this stage the best estimate is that an average reconstruction will be required every twenty years. A depreciation rate of 0.2% has been used, i.e. after twenty years the stopbanks will have lost 4% of their value. Therefore, the valuation of stopbanks is by “depreciated replacement cost” (DRC).

The latest estimate of unit rate is used as the replacement cost for valuation purposes with an adjustment made for depreciation. The depreciation is calculated based on the time elapsed since the bank was built, actual height measured and age assessed or the last reconstruction works undertaken. Following reconstruction works the age of the stopbank is returned to zero, ie the stopbank is in as new condition and is performing to its design standard, including freeboard and the value adjusted accordingly.

DRC = construction costs (latest unit rate values) x (1–0.002 x age)

Figure 3 illustrates the depreciation — only a portion of the stopbank needs to be replaced every 20 years; the remainder is retained.

Figure 3 Depreciation of Stopbank

(i) Compensation Costs

These relate to lands purchased or when land was utilised during construction works. The average cost of compensation paid to landowners for more recent stopbank reconstruction, per metre length of stopbank, has been included for valuation purposes. This has been included in the ancillary costs identified below.

Volume replaced to restore service potential Design bank level ∇

Ground level ∇

Original Stopbank Stopbank settlement and reconstruction

Volume lost due to settlement

Volume lost = Volume replaced



(ii) Valuation Summary

The valuation has two components, a direct cost per m3 and ancillary costs per lineal metre.

Direct costs include: earthworks contract staff salaries to prepare, supervise and administer contract. vehicle costs

Ancillary costs include: fencing, grassing. culverts compensation

On a “depreciated replacement cost” basis, the valuations are:

June 2007 Value $16,448,727

Depreciation $157,504

Stopbanks June 2007 Valuation $16,291,223

3.6.2 Structures

The current replacement cost of the structure and contents of the Duke Street pump station has been revalued for the purposes of this plan review.

The structure and associated floodgates of the pump station have an estimated useful life of 50 years and knowledge of the age of each structure enables the “depreciated replacement cost” (DRC) costs to be calculated.

For the contents of the pump station there is regular and ongoing annual expenditure necessary to keep the asset operating at the required level of service. There are also other less frequent maintenance works (Table 7) which periodically returns the asset to close to the original service potential. Nevertheless an initial decline in value after construction does occur since at any one time the pump station contents will consist of components of mixed age.

As at June 2007 valuations for the Duke Street Pump Station are:

Structure Contents

Replacement Cost June 2007 $117,872 $102,112

Depreciation $54,221 $23,597

Depreciated replacement cost June 2007 $63,651 $72,714


The method of valuation used for the concrete walls is “depreciated replacement cost”.

Environment Bay of Plenty has carried out concrete wall construction works in recent years. Similar site and working conditions exist for all the concrete walls so the latest work provides an indicative cost for concrete wall construction. This cost has been used to determine the current replacement cost of the works.



Replacement cost – June 2007 $1025/m3 $239,581

Depreciation $33,687

Depreciated replacement cost – June 2007 $193,967


The method of valuation used for edge protection is the “replacement cost”. These assets will be maintained in perpetuity, an allowance is made annually to clear, burn and replant live vegetation and to replenish rock and rubble. These assets are not depreciated.

Replacement costs for these assets have been taken from the costs of current works for rock and rubble, and for live protection cost of current works plus engineering of generally 15%:

rockwork 6,846 lineal metres $1,341,480

rubble 980 lineal metres $91,085

Live protection: edge planting 32,190 m $154,367

trenched willows 18,065 m $1,443,845

fencing 45,085 m $290,347

3.6.5 Buffer zone

The method of valuation used for buffer zone is the “replacement cost” plus engineering of 15%.

NB: The buffer zone does not include fencing costs.

Buffer zone 18,625 m $208,833

3.6.6 Summary of valuations

In summary, the valuations including allowance for depreciation (depreciated replacement cost values) as described previously, to June 2007 are:

Stopbanks $16,291,223 Structures $63,651 Structures — contents $72,714 Concrete walls $193,967 Edge protection: rockwork $1,341,480 rubble $91,085 edge planting $154,367 trenched willows $1,443,845 fencing $290,347 Buffer zone $208,833

TOTAL $20,151,512



3.7 Asset management systems

Environment Bay of Plenty has a number of tools that are utilised for the management of its assets.

Information systems including GIS (geographical information systems), spreadsheets, and financial accounting systems assist the asset managers in general management, maintenance, operations and long term planning.

The system comprises:

3.7.1 Asset register

The asset register constitutes the heart of the asset management system. It provides a definition of assets (description, location), details of physical dimensions and capacity. It also details age and replacement costs. At present the register is in two formats. The initial gathering of information on all Environment Bay of Plenty assets has been incorporated into one initial document, Bay of Plenty Regional Council Asset Register 1993, which is stored in file 0360 04.

The information has then been updated and summarised (in Excel spreadsheet files) before being used for valuation purposes. The files are stored in the following folder in their appropriate asset type.

V:\ts_rd\assets\valuatio\waioeka\valuation 2007\*.*

The assets are also shown on hard copy and aerial photographs, and ideally this information should be included in a GIS for ease of access and analysis. This is currently being undertaken with some of the assets now included as a GIS layer.

3.7.2 Accounting

Environment Bay of Plenty operates the “Finance One” Financial Management System.

Maintenance costs and capital expenditure are captured against each asset component within this system. In the financial system a series of job codes has been set up so that information as to the nature, location, extent and cost of servicing and operating the assets can be identified.

This data can be analysed to assess the real cost of maintenance, optimise maintenance procedures, identify future workloads, prepare future budgets and record the maintenance history for each asset.

Other data, not of a statistical nature, will also be collected and used by the manager of the asset in the development of strategies for the economic and efficient operation of the scheme.

Future development of the Asset Management System will focus on developing work-scheduling functionality and fine-tuning of the physical maintenance data collected for each asset. It is envisaged that links to Environment Bay of Plenty’s Geographic Information System will be developed so asset managers are able to access financial and physical data associated with each asset in a spatial environment. Direct links from the database to the spreadsheets, to ensure both are kept up to date, may also be created, although eventually the spreadsheets will become redundant.

31


Chapter 4: Maintenance Plan

4.1 Introduction

Maintenance refers to the work necessary to retain the operating standard or service capacity of the scheme and to keep the asset operational. Because a natural river system is involved, the work needed is not always able to be accurately forecast in time but experience gives a very good guide as to the type and general level of work necessary to meet scheme requirements in periods of ‘normal’ river flow, i.e. the base level of maintenance.

Maintenance can include works to maintain a structural element e.g. a stopbank or a length of edge protection; an operating cost e.g. fairway/channel weed spray or electricity; replacement of elements of the system such as culverts or floodgates.

The maintenance plan will set out the programmes and costs required to maintain the desired level of service.

4.2 Service levels

4.2.1 General

Environment Bay of Plenty in preparing this plan has had to ascertain the scheme ratepayers’ views and requirements in particular whether the original scheme objectives (section 3.1) are relevant for this review period. For example if lower scheme standards were requested/agreed (eg protection from the 5% AEP rather than the 1% AEP) then this plan could allow for deterioration of assets (eg stopbank height) by setting service levels which require less maintenance. Audit New Zealand has indicated that such change of standards is acceptable provided it is done following consultation with ratepayers.

Environment Bay of Plenty, through its day to day management of the scheme, has a great deal of ratepayer contact, and receives continuous feedback about the scheme. This feedback indicates strongly that ratepayers support the scheme objectives; and service levels have been set accordingly.

Consultation between stakeholders and Environment Bay of Plenty also occurs during the development and revision of other strategies and documents that are developed on behalf of the scheme. The Waioeka Otara Flood Management Strategy aims to address many of the issues to manage the risks around of human settlement, farming and horticulture within the floodplain. The flood protection and river control scheme is one measure to modify this risk.



The hydraulic capacity provided by river control works can be determined with reasonable consistency and accuracy. The greater problem is in determining the security of the primary defences — stopbanks, floodgates, natural terraces - against erosion.

The greater part of expenditure on maintenance of a river control system is on erosion protection works. River control works are constructed in highly mobile high energy locations and are built to withstand that energy.

Nevertheless flows much less than the design level can cause substantial damage to edge protection works and threaten the integrity of the stopbank system.

Minor damage to the river control system at a critical location can result in a failure of the primary stopbanks leading to inundation of a large part of the floodplain i.e. the Scheme’s value could be retained almost 100% but its operating standard completely compromised.

Further, in many instances major damage to the river control system can occur even though all floodwater is contained within the system.

Service levels are defined to cover these aspects.

4.2.2 Stopbanks

Environment Bay of Plenty will maintain the stopbanks to a level to ensure the design flood can be conveyed. For design standards see section 3.4.

An ideal stopbank would have 3 m top width and 2:1 batters as a minimum. However, some existing stopbanks are narrower than this. Most of the town banks are 3 m top width, with width dropping to 2 m in many rural reaches.

Where practicable access is to be available along the top of all stopbanks except where there are concrete walls.

Settlement of up to 50% of the freeboard will be allowed before stopbank reconstruction will be undertaken. Where the design standard does not include freeboard, settlement of up to 150 mm will be allowed before stopbank reconstruction.

4.2.3 Structures

Environment Bay of Plenty will maintain all structures in a workable condition at all times to function to their design standards.


Environment Bay of Plenty will maintain the concrete walls to ensure their structural integrity is retained so the design flood can be conveyed.

4.2.5 Edge protection — rockwork

Rockwork is to be maintained at all times to 75% of the original design placement rate.



4.2.6 Edge protection — live protection

Environment Bay of Plenty will maintain stable river edge and buffer zone protection. Willow growth will be layered and otherwise managed so as not to allow any willow growth older than 15 years. In the future Environment Bay of Plenty intends planting more natives in the buffer zone.

4.3 Maintenance history

Environment Bay of Plenty holds service (maintenance) costs for the assets. The Financial Management System provides the ongoing service record and from there, the service history can be developed for the economic and efficient management of the assets.

4.3.1 Past maintenance practices

Past maintenance in the rural reaches has consisted of construction of permeable groynes, diversion works, vegetative planting of hard points, mass planting of old (and undesired) areas of dry river bed and extraction of metal where contractors could be encouraged to do so.

In the early 1990’s, programming of these works was reduced as government subsidy money became unavailable. Thus while the scheme was kept in a reasonable state, to a degree works became reactive and only carried out if funds were available. However capital injections into the scheme as recently as the 2002 - 2005 works mean that much of the edge protection is young willows whose maintenance is not lagging at this time.

The location of edge protection works has been determined by river alignments based on the “flow dominant” width for both rivers. This stratagem has worked fairly well, however in places the associated buffer zones are minimal (averaging 15 m width) due to space restrictions. This has meant that gravel extraction has been essential to maintain bank edge security — particularly adjacent to some of the rural stopbanks.

In the lower river rockworks were placed on the river banks during the major stopbank construction works to protect against bank erosion. These works were placed in isolated lengths on the outside of bends. Limitations on finance meant that application rates (tonnage/m) were not high and some considerable loss of rock has occurred in some places. A recent programme of works over the last three years has addressed the critical areas. Rubble has also been used in lower velocity areas as an acceptable solution.

4.3.2 Berm and river aggradation

A difficulty experienced in the lower reaches, more particularly in the reach of tidal fluctuation, is the build up of silt islands and beaches. Build up of silt on the Otara River is particularly pronounced. Apart from periodic clearing of large vegetation, so that the silt can be transported during floods and the borrowing of fill material for stopbank works, no work has been carried out to remove the accumulation of silt.

The rate of aggradation of the channel and berms and the erosion of the catchment headwaters has had an effect on the flood protection level.



In the medium term there is reason for concern at the rate of aggradation of the town berms, particularly for the Otara River. The town berms of the Otara River have aggraded an average of 350 mm over the past 20 years and this is reflected by an almost equal increase there in flood levels in 1986 as compared to levels of a flood of the same discharge in 1966.

On the Waioeka River town (right) berms downstream of the State Highway Bridge, the aggradation has been particularly heavy (800 to 1100 mm over the past 20 years), however the increase in flood levels for the floods of the same discharge over the same 20 year period is only 100 to 250 mm.

In the upper catchment there are three main factors which lead to very high natural suspended sediment and bedload which has historically built up the Waioeka-Otara floodplain. Firstly, there is the steepness of the upper catchment, three quarters of which has steep to very steep slopes (greater than 26 degrees), secondly, is the relatively soft fractured nature of the underlying greywacke rock; and thirdly, is the exposure to very high intensity rainfall. These three factors will ensure that despite any human intervention there will always be large amounts of material being conveyed by the two rivers, and being continually deposited and eroded in the floodplain area.

A fourth factor, the control of wild animals, is also beginning to have an effect on the sediment load. The recent apparent increase in the feral pest animal numbers must be kept in check otherwise the loss of bush cover from deer, goat and possum browsing will certainly increase erosion in the steeper hill country and accordingly a higher suspended sediment and bedload in the rivers.

Environment Bay of Plenty carries out regular and ongoing catchment condition surveys. This will indicate whether erosion rates are static or changing and any possible implications regarding feral animal control, monitoring of specific erosion sites and possible erosion control techniques. These surveys are planned to be repeated five yearly.

Another major contribution to town berm build up is poor grazing or no grazing of these areas. This has led to establishment of weeds and rough grasses that collect sediment during flood events. It is beneficial for berms to have a regular grazing rotation which Opotiki District Council presently administers as landowners. In the future should gazing not be the preferred method of maintenance, any costs associated with other methods of grass and weed control will be required to be funded by the scheme.

An existing programme in conjunction with the Opotiki District Council arranges mowing part of the berm areas and a large proportion of the town stopbanks. It has been highlighted that this could be extended to cover a larger area of the lower reach berms. Environment Bay of Plenty hopes to have a cost share arrangement with Opotiki District Council in place in the future, no funding has been allowed in this revision of the plan.

4.3.3 Gravel extraction

Extraction of shingle from the riverbed has been, and will continue to be, an integral part of the maintenance of the Waioeka–Otara Rivers Scheme.

The main aim of gravel extraction is to lower beach levels, to reduce pressure on edge protection work located on the opposite bank, and to maintain flood carrying capacity within the flood channel.



The sources of gravel are many and varied and the impact of any one source is generally a function of the climatic cycle.

During stormy periods mass movement on hill slopes is the major supplier of gravel while during settled climatic cycles the major source of bedload is from storage in the bed and bank erosion.

At present only small quantities of gravel are being extracted from the Otara River due to the poor quality in the lower reaches. Over recent years demand for gravel in the Opotiki area has declined and contractors are also making more use of quarry sourced material

Gravel extraction is subject to the resource consent process and Environment Bay of Plenty has instigated an extensive cross-section monitoring programme. This along with the extraction returns from the consent holders provides a valuable tool for assessing gravel extraction requirements.

Environment Bay of Plenty’s Rivers and Drainage department hold resource consent for the extraction of gravel from both rivers and has offered to pay the management fee on behalf of contractors to encourage extraction from the Otara River.

Gravel extraction has, and will always form a vital part of the maintenance of the Waioeka–Otara Rivers Scheme system. Supply of the system over the last few years has exceeded demand, and extractors have directed their material sourcing elsewhere. If extraction cannot be encouraged, or marketed in some other way, in the short to medium term there will be a significant impact and increase on the expenditure required to maintain the scheme. These possible costs are not included in this plan.

4.4 Maintenance programme

The Council has developed a maintenance programme strategy, which will minimise the risks of failures to the system, and thereby provide for the most efficient and economic operation, to the service standards determined previously. A detailed assessment has been undertaken of the work requirement, to provide for the long term sustainable management of the scheme assets.

The key work components of this are summarised in Table 7, along with a general description of the activity and its estimated required frequency. Frequencies given are for the range of conditions anticipated throughout the scheme.

The scheme has been separated into a number of distinct reaches or locations and the key maintenance requirements have been identified for each of these areas (Appendix 3).

Table 7 General Asset Management Activities and Assumptions

Item/Activity Description Estimated Frequency

Fairway/Channel General overview Oversight and general inspection of reach 1 year Cross-section survey Resurvey for main rivers and streams 5 years Berm Maintenance Miscellaneous/weed spray 1 year Beach Shaping Managing gravel build-ups on beaches 5 years Stopbank



Item/Activity Description Estimated Frequency

Minor Floodgates Regular operational check Monthly Annual inspection Oversight and inspection 1 year Survey Stopbank long section and representative sections 5 years Misc. maintenance Miscellaneous minor repairs to stopbanks/culverts/fences/

trees/gorse/weeds 1 year

Stopbank reconstruction Reconstruction for settlement and miscellaneous damage 10–25 years Pump Stations (submersible pumps)

Normal inspection Regular operational check, clean screens and floodgates, replace fuses, light bulbs, minor electrical components, etc as required.

2 weeks

6 monthly inspection Full pump station check (refer pump station check sheet) 6 months

2½ year maintenance Change oil and check for contamination, test windings, check/replace sacrificial anodes.

2½ years

5 year maintenance Replace bearings and mechanical seals. Sandblast and repaint with anticorrosive paint.

5 years

Pump Recondition Fully dismantle, re-varnish windings; replace wear ring, impellor and castings as required. Replace/refurbish weed screens, upgrade switchboard as needed.

20 years

Pump station replacement

Full replacement of structure and pumps 50 years

Riverbanks Normal inspection Oversight and general inspection of reach 6 months Layering Lopping of willows 6 years

Tree clearing Trimming, removal and burning 15 years Rock Provision for new and maintenance of existing rip rap as

required 15 years

Rubble As for rock 10 years Fence maintenance Inspection and repair 10 years Buffer Zone Normal Inspection Oversight and inspection, particularly fencing and

vegetation 6 months

Clearing/Burning Cleaning and burning of over-grown willows, plantings and vegetation

15 years

In general the priority order for maintenance work in the river scheme will be:

• Retaining the integrity of the stopbanks.

• Retaining the strength and integrity of erosion control works.

• Keeping the channel clear of obstruction.

• Maintenance of ancillary works.



4.5 Maintenance costs

4.5.1 Existing

Since 1993/94 a portion of the maintenance expenditure has been used to fund a disaster reserve (see 4.7.1).

The maintenance expenditure for the Waioeka–Otara Rivers Scheme over recent years has been as follows in Table 8.

Table 8 Waioeka–Otara Rivers Scheme Maintenance Expenditure

Year Including Disaster Reserve Contribution

Excluding Disaster Reserve Contribution

1992–93 $108,797 $108,797

1993–94 $123,363 $112,963

1994–95 $170,163 $155,363

1995–96 $162,317 $147,517

1996–97 $248,885 $234,085

1997-98 $207,840 $197,940

1998-99 $439,718 $434,118

1999-00 $305,397 $299,697

2000-01 $279,053 $273,253

2001-02 $310,508 $304,308

2002-03 $336,514 $329,814

2003-04 $547,686 $541,086

2004-05 $429,894 $422,694

2005-06 $286,676 $279,276

2006–07 $491,208 $491,208

2007-08 (budgeted) $370,800 $363,200

4.5.2 Asset maintenance and renewal expenditure requirements

All expenditure on infrastructure assets will fall into two categories: capital expenditure or operating expenditure.

(a) Capital expenditure

Capital expenditure projects are those displaying one or more of the following characteristics:

• construction works which create a new asset that did not previously exist in any shape or form,



• expenditure which purchases or creates a new asset (not a replacement) or in any way improves an asset beyond its original design capacity,

• upgrade works that increase the capacity of the asset.

The scheme received a major review in 1989 and in 2002 the rural stopbanks were again reviewed, with the majority of those works recommended under those reviews completed during 1990-94 and 2002-07 respectively. Three sections of stopbank reconstruction are still outstanding from the 2002 review and have been included in this plan review.

(b) Operating expenditure

Renewal accounting treats all upgrading, reconstruction, renewal and renovation work that does not increase the capacity of assets as operating expenditure.

Operating expenditure can be further subdivided into two: normal ongoing routine maintenance works and those other more infrequent but periodic larger projects that upgrade or renew the asset to its full (or original) service potential.

(c) Routine maintenance expenditure

Routine Maintenance projects can be expected to display some of the following characteristics:

• regular and ongoing annual expenditure necessary to keep the assets operating at the required level of service, e.g. inspections; management; liaison with ratepayers etc.

• day to day and/or general upkeep works designed to keep the assets operating, e.g. insurance, power costs.

• works which provide for the normal care and attention of the asset including repairs and minor replacements,

• minor response type remedial works i.e. isolated instances where portions or sections of a unit of an asset fail and need immediate repair to make the asset operational again.

(d) Renewal expenditure

Work displaying one or more of the following attributes can be classified as renewal expenditure:

• works which do not increase the capacity of the asset, i.e. works which improve and enhance the assets restoring them to (or below) their original size, condition, capacity, etc,

• the replacement component of augmentation works which does not increase the capacity of the asset, i.e. that portion of the work which restores the assets to their original size, condition capacity, etc,

• the replacement component of a capital work which replaces the redundant element of an existing asset.



• reconstruction or rehabilitation works involving improvements, realignment and regarding.

• renewal and/or renovation of existing assets, i.e. restoring the assets to a new or fresh condition.

4.6 Expenditure

4.6.1 Repairs and maintenance and decline in service potential

Appendix 3 schedules the projected expenditure required to maintain the scheme under the criteria of this plan. All costs are in terms of June 2007. Average annual expenditure on works, including renewals is $444,343.

The average annualised cost of renewals amounts to $43,200. This figure is equivalent to the average annual cost of depreciation of the Waioeka Otara Rivers Scheme for the duration of this plan.

Note: the projected expenditure on maintenance, renewals and decline in service potential has been prepared in terms of costs applying for the 2007-2008 financial year (June $2007). The annual expenditure estimates in future years will require updating for inflation. The procedure will be to adjust the base figures in this report by the movement in CGPI S2DD for Reclamation and River Control as forecast to each June immediately proceeding the financial year.

Table 9 and Figure 4 present the works expenditure distribution. They include the following:

(a) Forecast operation and maintenance, based on the data presented in Appendix 3.

(b) Predicted renewals, also based on the data presented in Appendix 3.

(c) Predicted flood damage, based on the scenario presented in Appendix 4 (refer also to section 4.7.1(b)).

(d) Anticipated capital works.

4.6.2 Projects

An average expenditure of $20,000 per annum is required for projects and investigations. This engineering support covers several tasks including flood forecasting modelling, river hydraulic modelling, asset management, stopbank structural evaluation, consent applications and compliance. An additional extra allowance of $20,000 has been made in 2008/09 for an investigation into additional pumping in the Te Rere Pa Road area. The above investigations are aimed to optimise scheme management to the set performance standards.

4.6.3 Loan repayment

The scheme at 30 June 2007 had capital debt of $1,527,947. The schedule of estimated annual loan repayments is shown in Appendix 6.



4.7 Funding

The scheme is funded predominantly from annual rates levied over a separate rating area known as the Waioeka Otara Rivers Scheme Differential Rating Area. Environment Bay of Plenty contributes 20 % towards the annual river scheme rates requirement from its regional general funds.

Annual targeted rates predominantly fund the scheme (see Section 4.7.2). Funds are used for repairs and maintenance, decline in service potential (depreciation), and if necessary for repayment of loans. Appendix 8 shows funding and expenditure relationships associated with this scheme.

The method by which decline in service potential is recognised and funded has been discussed extensively with both the office of the Auditor General and its agent, Audit New Zealand, and their advice taken. As a result the decline in service potential will be funded annually with funds initially set aside under what is known as “renewals based” accounting system. A “rolling” estimate by year of renewal expenditure requirements has been calculated. All renewal expenditure – for example, stopbank top-ups or refurbishment of pumping station contents -restores service potential of the assets; that is there is no element of upgrading (increasing of service potential) involved. For further details of how the renewals fund will operate refer to section 4.7.1(c).

Annual rates are based on estimated expenditure. Actual expenditure will usually vary from estimated expenditure in any one year, and therefore the scheme account will at year end have a credit or debit balance which will be carried forward into the next year as at present.

Table 9 Asset Management Works Expenditure Distribution

Asset Management Works Expenditure Distribution ($ 2007) Year Operation and Predicted Projected Total

Maintenance Renewals Flood Damage excl. reserves & Capital 1 2007 / 2008 $315,700 $42,000 $0 $357,700 2 2008 / 2009 $373,400 $125,000 $0 $498,400 3 2009 / 2010 $373,400 $0 $0 $373,400 4 2010 / 2011 $373,400 $245,000 $0 $618,400 5 2011 / 2012 $373,400 $0 $150,000 $523,400 6 2012 / 2013 $373,400 $0 $0 $373,400 7 2013 / 2014 $373,400 $0 $0 $373,400 8 2014 / 2015 $373,400 $0 $0 $373,400 9 2015 / 2016 $373,400 $0 $0 $373,400

10 2016 / 2017 $373,400 $0 $75,000 $448,400 11 2017 / 2018 $373,400 $0 $0 $373,400 12 2018 / 2019 $373,400 $0 $0 $373,400 13 2019 / 2020 $373,400 $0 $0 $373,400 14 2020 / 2021 $373,400 $245,000 $0 $618,400 15 2021 / 2022 $373,400 $0 $150,000 $523,400 16 2022 / 2023 $373,400 $0 $0 $373,400 17 2023 / 2024 $373,400 $0 $0 $373,400 18 2024 / 2025 $373,400 $0 $0 $373,400 19 2025 / 2026 $373,400 $0 $0 $373,400 20 2026 / 2027 $373,400 $0 $75,000 $448,400 21 2027 / 2028 $373,400 $0 $0 $373,400 22 2028 / 2029 $373,400 $0 $0 $373,400



23 2029 / 2030 $373,400 $0 $0 $373,400 24 2030 / 2031 $373,400 $245,000 $0 $618,400 25 2031 / 2032 $373,400 $0 $150,000 $523,400 26 2032 / 2033 $373,400 $0 $0 $373,400 27 2033 / 2034 $373,400 $205,000 $0 $578,400 28 2034 / 2035 $373,400 $0 $0 $373,400 29 2035 / 2036 $373,400 $0 $0 $373,400 30 2036 / 2037 $373,400 $0 $75,000 $448,400 31 2037 / 2038 $373,400 $0 $0 $373,400 32 2038 / 2039 $373,400 $0 $0 $373,400 33 2039 / 2040 $373,400 $0 $0 $373,400 34 2040 / 2041 $373,400 $245,000 $0 $618,400 35 2041 / 2042 $373,400 $64,000 $150,000 $587,400 36 2042 / 2043 $373,400 $0 $0 $373,400 37 2043 / 2044 $373,400 $0 $0 $373,400 38 2044 / 2045 $373,400 $0 $0 $373,400 39 2045 / 2046 $373,400 $0 $0 $373,400 40 2046 / 2047 $373,400 $0 $75,000 $448,400 41 2047 / 2048 $373,400 $0 $0 $373,400 42 2048 / 2049 $373,400 $245,000 $0 $618,400 43 2049 / 2050 $373,400 $0 $0 $373,400 44 2050 / 2051 $373,400 $0 $0 $373,400 45 2051 / 2052 $373,400 $0 $150,000 $523,400 46 2052 / 2053 $373,400 $196,300 $0 $569,700 47 2053 / 2054 $373,400 $0 $0 $373,400 48 2054 / 2055 $373,400 $0 $0 $373,400 49 2055 / 2056 $373,400 $0 $0 $373,400 50 2056 / 2057 $373,400 $0 $75,000 $448,400



Waioeka Otara Rivers SchemeWorks Expenditure Distribution

$0

$100,000

$200,000

$300,000

$400,000

$500,000

$600,000

$700,000

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49

Year

Exp

endi

ture

($)

Predicted Flood DamagePredicted Renewals & CapitalOperation & Maintenance

Figure 4 Works Expenditure Distribution



4.7.1 Reserves

(a) Disaster Reserves

Under the Government’s Disaster Recovery Plan, in the event of a disaster, the Government will provide for 60% of the loss (subject to certain conditions). The remaining 40% is the responsibility of the local authority. Following consultation with river schemes Environment Bay of Plenty joined the Local Authority Protection Programme Disaster Fund (LAPP fund) on 1 July 2006 to cover the remaining 40% short fall following a major disaster. The fund is established by the New Zealand Local Government Association Incorporated.

Membership of the LAPP fund is intended as a prudent risk financing initiative that will assist with the restoration of infrastructure assets of Council following natural disasters or other emergencies. As at June 2006 Council had a total asset value of $109,629,449 declared for coverage under the LAPP fund. The expected loss in relation to these assets from an earthquake with a 1 in 1000 year return period has been estimated to be $4,032,818. The expected loss for a flood with a 1 in 500 year return period is estimated to be $11,526,867. The Waioeka Otara Rivers Scheme premium for their share of the coverage is $8900 annually.

At present the fund does not recognise some forms of river scheme assets, that being ‘live vegetation’ protection. This is presently being reconsidered by the fund administrators.

The Waioeka Otara Rivers Scheme has up until now been contributing towards a disaster reserve and in the future, should the LAPP fund still not recognise ‘live’ assets the scheme will need to continue having a fund for these types of assets. The fund maximum and contributions will be calculated following the outcome of the LAPP fund administrators’ conclusions into ‘live’ asset types and their funding. At 30 June 2007 the Waioeka Otara Rivers Scheme has $30,600 in their disaster recovery fund.

Because of the infrequency and unpredictability of disaster events no prediction has been made as to the timing or size of disaster recovery works which may result in withdrawals from any disaster reserve.

(b) Flood Damage Reserves

Presently a large percentage of the maintenance budget has been spent on repairing flood damage which results from moderate size floods. Experience has shown, even on schemes where a comprehensive channel training programme has been implemented, backed up by an annual programme of works, there is still a requirement to have funds set aside to finance damage that does occur periodically from floods.

A flood damage reserve has been established to repair damages associated with floods greater or equal to 20% AEP. The flood damage reserve is to be capped at $225,000 ($2007). Funds from this reserve will be utilised only for flood damage repairs. The effect of the reserve is a relative smoothing out of the rate requirement from year to year.

44

Waioeka-Otara Asset Management Plan

The current balance of the flood damage reserve is $59,900, payments into the reserve will initially be made at the rate of $18,800 p.a. until 2010/11 when the payments will increase to $25,000 to maintain a positive balance and build the balance up to the capped threshold. Also, if necessary, Environment Bay of Plenty will borrow to fund flood damage repairs. Appendix 4 contains a graph and table showing the manner in which the flood damage reserve might operate. Exact figures cannot be given because floods obviously occur at fairly random intervals. What is presented is a typical scenario, illustrating the accumulation of the fund and use of the fund for the medium sized flood events postulated at average 5 yearly intervals.

Note that asset damage from smaller floods and freshes (of less than five year return period, or 20% AEP) are covered by a separate flood damage allowance ($43700) in the annual maintenance requirements of the scheme.

(c) Renewals Reserves

The Office of the Auditor General has advised that the renewals fund can be used not only to fund renewals expenditure but also to assist funding of the annual principal portion of the scheme’s existing loan repayments.

Details of how the renewals fund is forecast to operate are presented in a table and graph at Appendix 5. It should be noted that in some years the fund goes into deficit or has not built up at all. This is due to the fund not having accumulated a sufficient balance to finance the renewals works forecast. At these points in time the advisability of loans will require consideration. Projections beyond about year 20 are only projections at best (the plan will be renewed every 10 years).

4.7.2 Sources of funding

The Waioeka-Otara Rivers Scheme maintenance budget is funded approximately as follows:

Separate Rates/User Pays 80%

Regional Contribution 20%

Total Funding Requirement 100%

Table 10 shows the funding requirement anticipated for the next 50 years.

This funding regime has been in existence since the withdrawal of Government assistance. The current rating system is a differential rating system, which covers the entire catchment area.

4.7.3 Analysis of funding requirements

Table 10 and Figure 5 present the total funding requirements for all activities including loan charges. They are based on data presented in Appendices 3 to 6.

The average funding requirement of $637,100 over the first 10 years, represents a 6.7% increase on the current 2007/2008 funding level of $597,400.



Waioeka Otara Rivers SchemeTotal Funding Requirements

$0

$100,000

$200,000

$300,000

$400,000

$500,000

$600,000

$700,000

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49

Year

Com

pone

nts

($) Projects & Investigations

Flood Damage ReserveDisaster ReserveDepreciation FundedNett Loan ChargesOperation & Maintenance



Table 10 Total Funding Requirements

Operation and

Maintenance

LAPP Contribution

Projects &

Invests.

Flood Damage Reserve

Depreciation Funded

Subtotal

Total Loan

Charges

Less Principal

Funded From Depreciation

Nett Loan

Charges

Total Funding

Requirement

Year (from App.3) (from App.4) (from

App.5) (from App.6) (from

App.7) (from App.6) 1 2007 / 2008 $315,700 $7,600 $25,900 $18,800 $28,700 $396,700 $229,400 $28,700 $200,700 $597,400 2 2008 / 2009 $373,400 $8,900 $40,000 $18,800 $43,200 $484,300 $216,600 $43,200 $173,400 $657,700 3 2009 / 2010 $373,400 $8,900 $20,000 $18,800 $43,200 $464,300 $219,900 $43,200 $176,700 $641,000 4 2010 / 2011 $373,400 $8,900 $20,000 $18,800 $43,200 $464,300 $221,400 $43,200 $178,200 $642,500 5 2011 / 2012 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $234,700 $43,200 $191,500 $662,000 6 2012 / 2013 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $225,400 $43,200 $182,200 $652,700 7 2013 / 2014 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $216,200 $43,200 $173,000 $643,500 8 2014 / 2015 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $206,800 $43,200 $163,600 $634,100 9 2015 / 2016 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $197,500 $43,200 $154,300 $624,800 10 2016 / 2017 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $188,200 $43,200 $145,000 $615,500 11 2017 / 2018 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $178,900 $43,200 $135,700 $606,200 12 2018 / 2019 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $169,600 $43,200 $126,400 $596,900 13 2019 / 2020 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $159,600 $43,200 $116,400 $586,900 14 2020 / 2021 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $156,100 $43,200 $112,900 $583,400 15 2021 / 2022 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $160,200 $43,200 $117,000 $587,500 16 2022 / 2023 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $107,800 $43,200 $64,600 $535,100 17 2023 / 2024 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $99,000 $43,200 $55,800 $526,300 18 2024 / 2025 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $83,500 $43,200 $40,300 $510,800 19 2025 / 2026 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $63,500 $40,200 $23,300 $493,800 20 2026 / 2027 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $58,200 $38,000 $20,200 $490,700 21 2027 / 2028 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $50,300 $33,000 $17,300 $487,800 22 2028 / 2029 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $45,700 $30,900 $14,800 $485,300 23 2029 / 2030 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $37,200 $24,600 $12,600 $483,100 24 2030 / 2031 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $45,100 $24,600 $20,500 $491,000 25 2031 / 2032 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $53,000 $24,600 $28,400 $498,900 26 2032 / 2033 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $51,000 $24,600 $26,400 $496,900 27 2033 / 2034 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $57,200 $24,600 $32,600 $503,100 28 2034 / 2035 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $73,400 $34,900 $38,500 $509,000



29 2035 / 2036 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $70,600 $34,900 $35,700 $506,200 30 2036 / 2037 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $67,800 $34,900 $32,900 $503,400 31 2037 / 2038 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $64,900 $34,900 $30,000 $500,500 32 2038 / 2039 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $62,200 $34,900 $27,300 $497,800 33 2039 / 2040 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $59,400 $34,900 $24,500 $495,000 34 2040 / 2041 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $66,400 $34,900 $31,500 $502,000 35 2041 / 2042 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $76,100 $34,900 $41,200 $511,700 36 2042 / 2043 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $78,900 $38,100 $40,800 $511,300 37 2043 / 2044 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $75,800 $38,100 $37,700 $508,200 38 2044 / 2045 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $72,800 $38,100 $34,700 $505,200 39 2045 / 2046 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $69,800 $38,100 $31,700 $502,200 40 2046 / 2047 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $66,700 $38,100 $28,600 $499,100 41 2047 / 2048 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $63,700 $38,100 $25,600 $496,100 42 2048 / 2049 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $70,400 $38,100 $32,300 $502,800 43 2049 / 2050 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $89,000 $43,200 $45,800 $516,300 44 2050 / 2051 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $84,900 $43,200 $41,700 $512,200 45 2051 / 2052 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $69,200 $38,100 $31,100 $501,600 46 2052 / 2053 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $74,000 $38,100 $35,900 $506,400 47 2053 / 2054 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $88,200 $43,200 $45,000 $515,500 48 2054 / 2055 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $74,500 $37,600 $36,900 $507,400 49 2055 / 2056 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $71,500 $37,600 $33,900 $504,400 50 2056 / 2057 $373,400 $8,900 $20,000 $25,000 $43,200 $470,500 $68,500 $37,600 $30,900 $501,400

49


Chapter 5: Creation/Acquisition/Disposal Capital works represent the creation of assets that did not previously exist. Capital works may are defined as assets that improve the level of service and may be created as a result of flood damage sustained and the subsequent works undertaken to reduce the threat posed to the community or other assets (particularly stopbanks).

At the completion of capital works, the project is valued at the appropriate unit valuation and capitalised into the asset register and financial accounting system. In practice this usually occurs at the end of each financial year.

Disposal of assets does not normally occur in management of river schemes. Assets are usually fixed to the ground and design standards are not generally lowered. No disposal of assets has been envisaged in the development of this plan. Where an asset is damaged by a flood event, a loss of service potential will occur until the asset is replaced. Replacement of damaged assets are, in the majority of cases, completed in the same year the loss occurs. Should the asset not be replaced in the same year, the loss is recorded in the asset register by removing it (a write down) and its associated value from the asset register. The value is recorded as a cost in the statement of Financial Performance in the period on which it occurs.

51


Chapter 6: Quality Assurance Environment Bay of Plenty has a number of policies and procedures that deal with quality of systems and information that are included in this plan.

This plan is prepared using the International Infrastructure Management Manual as a guideline. Valuations are prepared under the New Zealand Infrastructure Asset Valuation and Depreciation Guidelines. Other internal documents that deal with internal processes are also integrated into operational requirements as a result of this plan. Such documents are:

• Contracts Manual

• Funding Policy

• Decision Making Policy

• Health and Safety Policy and Manual

• Information Technology Policy

Finally, review of the procedures will also be appropriate at various times, to ensure that current best practices are maintained.

53


Chapter 7: Monitoring Monitoring demonstrates that Council is doing what it said it would to provide the agreed level of service, and that maintenance is being provided that ensures assets are maintained in perpetuity.

Two forms of monitoring are considered below — effectiveness and cost/financial monitoring. Monitoring results are collated and summarised in an annual asset management report to the Operations Committee.

7.1 Effectiveness monitoring

Traditional performance monitoring techniques are not easily applied to management of river schemes. Outcomes depend on the occurrence of unpredictable flood events, and the nature of fluvial hydraulics is complex and subject to random phenomena. However, it is still possible to apply the general principles of monitoring. Indeed, performance monitoring is required in order to adequately manage the assets. Review of the asset management plan will also depend on findings of performance monitoring.

The goal of the river scheme management is to maintain the risk of flood damage at acceptable levels (as determined by a floodplain management process), by maintaining the desired levels of flood protection and erosion control. (Note that the risk of flood damage rather than actual flood damage is referred to). More specific objectives against which to monitor performance have been identified in section 3.1 of this plan. In summary these are

• provide security from floods of up to the 1% AEP to the township of Opotiki;

• provide security from floods to most of the rural areas adjoining the Waioeka and Otara Rivers; the level of security varies as detailed in section 3.4

• maintain the Waioeka and Otara Rivers in the scheme area to a stable alignment;

• reduce erosion of riverbanks;

• minor drainage.

Other outcomes will be relevant, such as environmental enhancements. These will be described in various regional plans. Scheme management needs to be compatible with these.



Performance indicators, with which to measure the achievement of the goal and objectives, or progress towards them, are difficult to establish. Using indicators based on actual events, such as actual length of riverbank eroded or actual damages, are not ideal given that the causes and results may be beyond the reasonable expectations of the asset management.

The 5-yearly riverbed cross-section and stopbank surveys are one of the most important monitoring programmes for management of the scheme. The cross-section surveys can be used to help identify volumetric changes to the river bed and banks, and possibly local points of erosion or deposition. Using the cross-section information, the design flood levels can be reassessed every five years, and the stopbank surveys used to monitor the available freeboard.

It is possible to develop other quantitative measures regarding the standard of protection, based on flood modelling techniques and risk assessment methods, using indicators such as annual average damages. It is also possible to measure scheme performance regarding drainage, asset condition and operation, riverbank erosion susceptibility and ratepayer satisfaction. Trends in these aspects will need to be identified also, in order to assess the effectiveness of the scheme asset management. Further work is needed to develop a performance monitoring system (both qualitative and quantitative) and a consistent format for reporting.

The assessment is aided by the use of photographic records (and comparison of these taken over time), by regular reports on scheme operation and performance, and by feedback from scheme beneficiaries. Access to reliable information, current and historical, on the scheme performance, is required, and it is thus important that adequate data collection and information storage procedures are followed, as identified in quality assurance systems.

The monitoring will be performed at the following levels.

7.2 Asset Manager

The asset managers (River and Drainage Department) already monitor the scheme on a continual basis. Reports from the asset managers — such as monthly (or when otherwise appropriate) reports on the performance of the scheme (as well as work done, funds spent, etc) should be copied to this separate (and centrally accessible) asset management file for the scheme.

7.3 Internal

Performance monitoring will also be undertaken internally within Environment Bay of Plenty by the Manager of Engineering, and reported upon annually to the Operations Committee. The report will draw links between the performance of the scheme and the scheme management. The monitoring performed by the asset managers will also be audited and used as input into the report.

At five yearly intervals or following a 5% AEP event, a capacity review will be undertaken assess the design flood levels and stopbank freeboard.



7.4 External

It is essential that appropriate external audits be carried out to:

• assess the internal audit activities, the validity of their processes, and verify their conclusions and strategies adopted.

• judge the relative status of the organisation and its performance in asset management with respect to:

– benchmarking with other like organisations

– comparison with best practice

• Assess the relative improvement achieved since the previous external audit and compare this performance with what was capable of being achieved.

• Assist the Asset Managers and the internal audit/plan review team (Engineering Section) to improve their activities and to derive better guidelines and assessment procedures.

• Confirm the technical content in the Asset Management Plan is sound and correctly applied in developing Asset Management Plan outputs.

Suitably qualified independent persons will undertake management and technical audits every five years from the commencement of the plan.

The findings of the independent management and technical audit will be reported to Council and be included, in summary form, in the Annual Report of the year that the audit was performed.

The contents of the annual asset management plan report to the Operations Committee are summarised in Figure 6.



Figure 6 Monitoring Flow Chart

Monitoring

Maintenance Programme

Review and compare activities including renewals (annual).

Confirm budget for next

financial year

Capital Works

Review against

progress & budgets provided (annual) Confirm

priorities for next

financial year

Inspections

Summarise Rivers & Drainage

staff reports (annual)

Levels of Service &

Performance Measures

Review performance

against desired

service levels (Refer

Section 4.2)

Survey

Review results of the Riverbed cross-section

survey Stopbank long section survey

(both five-yearly) & Gravel

extractions

Asset Register

Update asset register.

Complete asset

revaluation and peer

review (five yearly)

Update AMP (five yearly)

Waioeka Otara Annual Asset Management Plan Report to

Operations Committee



7.5 Cost monitoring

7.5.1 Internal

Annual plan and annual report requirements ensure that cost or financial monitoring is already performed. A cost monitoring report shall accompany, or form an identifiable part of, the Engineering Section’s annual commentary on the scheme discussed in 7.4 above.

7.5.2 Financial audits (external)

The Local Government Act requires that independent annual financial and performance audits be undertaken on the Council, which may include all significant activities.

The Audit opinions will be included in the Annual Report.

59


Chapter 8: Asset Management Plan Improvement Plan

8.1 Background to Asset Management Plan

The Asset Management Plan for the Waioeka Otara Rivers scheme was approved by Council and published in September 1998. Asset management philosophies were reviewed to develop this updated plan thus meeting Audit NZ requirements for regular review.

8.2 Improvement tasks

Refinement of this asset management plan, as detailed below, is required to ensure the plan continues to be developed and is useful for the management of flood protection and river control assets.

8.2.1 Ongoing review of asset management plan

Regular review of the asset management plan is recommended on a five-yearly basis. The next review and update is due in 2012/13.

8.2.2 Asset register update

Updating of the asset registers are to be confirmed through the process described in Section 3.6. The process used for valuation purposes is to be peer reviewed. Another regional council or engineer familiar with river engineering assets may do this. The valuation determined will be reconciled with the asset value held in the corporate financial system. Annual updates are made to satisfy audit through the Annual Report process as well.

Future revaluations and reconciliation with corporate valuations are required five yearly but it is intended to undertake this on an annual basis in the future.

Currently Environment Bay of Plenty has a number of internal projects to improve the quality of data and link between the infrastructural asset register and the information stored in the corporate financial ledger. These projects are due for completion 30 June 2008.

8.2.3 Risk management

As discussed previously Environment Bay of Plenty are now members of the Local Authority Protection Programme Protection Fund (LAPP fund) which is seen as a prudent risk financing initiative. Recommendations from the present climate change



study should also be incorporated into next capacity review (2009/10) with outcomes included in the next asset management plan review. Environment Bay of Plenty also commits to studies related to damage from disaster, such as earthquakes, where appropriate.

8.2.4 Reports

Prepare an annual AMP monitoring report to be submitted to the Operations Committee. Refer to Section 7.1 for details.

8.3 Improvement plan budget

Assets are required to be revalued at least every five years with the asset register updated annually. This asset management plan will be reviewed, updated and published once every five years.

The budget provided for these tasks are provided in Appendix 3.

61


References Campbell G A (1989); East Cape Catchment Board and Regional Water Board “Waioeka-

Otara Catchment Management Study: Review of the River Training Scheme in the Waioeka and Otara Rivers”.

Environment B·O·P files.

Marsh and McLennan Limited (1993); “Bay of Plenty Regional Council Risks Assessment of Uninsured Infrastructural Assets”.

National Asset Management Steering Group; “International Asset Management Manual” 2006 Edition.

National Asset Management Steering Group; “New Zealand Infrastructure Asset Valuation and Depreciation Guidelines” Edition 1.2 2001 and Amendments.

Peacock D H (1988); East Cape Catchment Board and Regional Water Board “Waioeka-Otara Catchment Management Study: Part I Summary of the Waioeka and Otara River Statistics”. Engineering Technical Report 1988/1.

Peacock D H (1988); East Cape Catchment Board and Regional Water Board “Waioeka-Otara Catchment Management Study: Part I Report (Final)”. ECCB Report No. 7327.

Surman M (1997); Environment B·O·P “Natural Environment Regional Monitoring Network River and Stream Channel Monitoring Programme 1995/96”. Environment B·O·P Environment Report 97/4.

Taylor P L (1983); East Cape Catchment Board and Regional Water Board “Waioeka-Otara Flood Control Scheme: River Training Design”. ECCB Report No. 6537.

Titchmarsh B R (1990); Environment B·O·P “Waioeka–Otara Rivers Schemes III: Investigations and Design Report”. Environment B·O·P Operations Report 90/1.

Blackwood PL (1998) Waioeka Otara Rivers Scheme Asset Management Plan, Environment B·O·P Operations Report 98/02

Risk Management Partners (2006); Local Authority Protection Programme Member Authority Risk Profile for Environment Bay of Plenty.

Wallace PL (2000); Preliminary Options for Waioeka-Otara Floodplain Management. Environment B·O·P Operations Report 2000/01.

Wallace PL (2001) Urban Flood Protection Works- Opotiki, Environment B·O·P Operations Report 2001/02



Wallace PL & Pak I (Draft) Waioeka Otara Rivers Scheme Rural Stopbanks, Environment B·O·P Operations Report 2001/04

Boyes Campbell & Associates (2001) Waioeka Otara Rivers Scheme Report on Rural/Urban Rating Incidence, Campbell June 2001

Wallace PL (2007) Waioeka Otara Floodplain Management Plan – Woodlands Road Stopbank, Environment Bay of Plenty Operations Publication 2007/01

63


Appendices



Appendix 1 – Responsibilities and Roles in Asset Management

(Based on structure of Environment Bay of Plenty as at June 2007)

Principal roles

• Asset Managers: Operations Section (Environment Bay of Plenty)

Responsible for day to day management of the River Scheme. Assistance with preparing, monitoring and reviewing the Asset Management Plan.

• Asset Management Plan preparation, monitoring and revision: Engineering Section (Environment Bay of Plenty)

Responsible for providing technical advice regarding the design and management of the River Scheme. Responsible for preparing and revising the Asset Management Plan, and for monitoring the plan and the performance of the scheme.

Other sections and departments will have input into plan preparation and revision — in particular, to ensure consistency with various regional plans.

Consultation with external parties, in particular scheme ratepayers, will occur in the preparation and revision of the plan. External parties have also provided feedback about the scheme performance in the past, and the monitoring role they thus undertake is expected to continue.

The following diagram illustrates the relationships between the various parties that have roles in management of the assets.



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Appendix 2 – Asset Maintenance Requirements Waioeka-Otara Rivers Scheme Asset Maintenance

Requirements

The following outlines the asset maintenance requirements for the Waioeka Otara Rivers Scheme. Various assumptions used in developing the expenditure Table 1 in Appendix 3 are described.

The river scheme has been split into four reaches, and each reach divided into fairway/channel, riverbank, stopbank, buffer zone and structures components. In addition, a number of items are applicable to the scheme as a whole.

Details of the reaches are:

Reach Location Distance Cross-Section

1 Waioeka River Town 0 – 2.5 miles 1 – 8 2 Waioeka River Rural 2.5 – 7.5 miles 9 – 17 3 Otara River Town 0 – 6.25 miles 1 – 21 4 Otara River Rural 6.25 – 11.8 miles 22 – 37

1.1 Management

General management staff costs to allow for administration, inspection, monitoring and auditing of scheme performance identified in section 7 of this plan are summarised in Table 1, Appendix 2. Rates and costs shown in Table 1, Appendix 2 are aligned to June 2007 dollars.

1.2 General flyover inspection

Flight over whole scheme to give an overview of the fairway/channel. Followed up by staff inspection in the field and response to any queries.

1.3 Inspections of riverbanks and stopbanks

Visual inspections are carried out on the ground of riverbanks and stopbanks. Inspections might be carried out together or separately.

1.4 Environmental data services charges

This is an internal charge for environmental data collection, processing and storage.

1.5 Rates commission and remission

This is the cost Council incurs for collecting rates as well as rate write-offs.

1.6 Electricity and insurance

Power charges for pumping stations, telemetry etc. Insurance is for flood control structures.



1.7 CTS and information service charges

These are the internal costs that Rivers and Drainage Group are charged for computer support.

1.8 Asset valuation and asset management plan update

Asset valuation is required to be carried out at least five yearly and requires the input of several engineering officers. In addition this asset management plan is reviewed, updated and republished every five years.

1.9 Engineering design and investigation projects

Several matters including catchment condition surveys, flood forecasting models, river hydraulic modelling, asset management, stopbank structural investigations and floodplain management planning.

Average annual requirement $20,000

1.10 Flood damage - freshes

An annual sum is allocated to allow for clean up and repair of flood protection assets that have been damaged in flood events with a return period less then 5 years only (or 20%AEP).

1.11 Flood monitoring

Flood monitoring costs are an estimate of costs of flood duty, of inspection during the event and of monitoring of post event inspections and flood pegging, etc. Input during the event from hydrologists has not been included.

1.12 Miscellaneous

These are the various costs incurred for legal fees, scheme newsletters etc.

2 Cross – sectional survey

Resurvey of river cross-sections every 5 years provided there are no significant freshes/floods in the river.

3 Long sectional survey of stopbanks

Resurvey long section of stopbank along crest every five years. Survey includes a representative cross-section.

4 Weedspraying

Miscellaneous maintenance of berms and channel fairway. This consists predominantly of noxious weed removal. It is estimated that a 2-man gang can spray weeds at a rate of 3.5km per day.



5 Layering

Willows are cut and “layered” into the river bank when they are around 6 years old. Thinning of a willow stand should also occur at this time to allow willows to spread horizontally. This work is therefore given a work frequency of 6 years but the work is undertaken annually as there are willows of different age throughout the river system. These willows shoot out new growth, which is required to be “layered” again in a further six years. A two labourer gang will layer approx 500 m per day. Vehicle/Plant costs are additional at $0.50/km and chainsaws at $35/ day.

Note that the cost of layering trench willows has been assumed to be the same as for other planting – that is, an average cost of layering has been estimated.

6 Tree clearing

The layered willows become overgrown and reach a stage where they require trimming, removal and burning. This occurs approximately every 15 years. It is assumed 1/15 of the total edge protection requires clearing each year. A two labourer gang will layer approx 330 m per day. Vehicle/Plant costs are additional at $0.50/km and chainsaws at $35/ day.

Trench willows are assumed not to need clearing, burning and replanting.

7 Tree burning

If there is no market for the timber, the cleared trees will need to be burnt. Burning has been assumed in this plan. With a 10m wide zone, one labourer and a machine can burn 500m in a day.

8 Tree replanting

After clearing and burning, an area will need replanting. An average replanting cost is estimated at $7/m. (This is considered an average for willow planting and planting of native trees and flaxes in the buffer zone).

9 Fence maintenance

Maintenance of the edge protection fences is ongoing and it is estimated that 10% of the fence requires repair each year. Estimated costs of repairs are 50% of the $3/m replacement value.

10 Rock maintenance

At approximately once every 15 years rock riprap bank protection needs to be maintained by topping up with new rock or by retrieving and reusing existing rock.

The cost of doing this works depends on whether access is available or not. Cost of work is based on the cost of new work less 30%, as the full batter will not require replacement.

Approximately 1/15 (or 6.67%) of the work will be completed each year assuming that access is available 50% of the time.



11 Stopbanks

11.1 Minor floodgate inspection

Floodgate inspections are carried out on a monthly basis.

11.2 Miscellaneous maintenance

Various ongoing minor repairs to stopbanks, culverts, and fences with some work being undertaken every year.

11.3 Stopbank reconstruction

Stopbank reconstruction/top up to restore banks to full design height. It is difficult to ascertain what settlement will occur; the best estimation is that every 20 years, 4% by value/volume requires work.

Costs per cubic metre and lineal metre are assumed the same as for construction.

Direct cost of reconstruction June 2007 rate = $12.84/m3

Ancillary cost of reconstruction is calculated similarly = $44.35 per lineal metre.

Based on quantities taken from June 2007 asset register the total stopbank volume is 1,048,344m3 and the length is 67,373m

12 Minor outlet structures

Environment Bay of Plenty own and maintain a large number of minor gravity outlet structures that run under stopbanks. The gravity outlet structures comprise culverts and in most cases floodgates. Culvert diameters range between 150 – 1200 mm.

At present the replacement cost of minor outlet structures are included in the stopbank ancillary cost. Maintenance of minor outlet structures is included in this schedule.

12.1 Inspections

Inspect minor outlet structures; say twice a year before freshes.

12.2 Miscellaneous maintenance

Following inspection replace some bolts and replace one or two flap gates per year.

Regular mowing of some of the town stopbanks is carried out each year.



13 Pump stations

13.1 Inspections

Regular inspections are carried out on a fortnightly basis of the Duke Street pump station. Operational checks are done on the pumps, motors, floodgates and the pump screens are cleaned.

In addition a full pump station check is carried out every six months.

13.2 Pump inspection

All three pumps are lifted and inspected and oils changed based on 2.5 year cycle.

13.3 Pump servicing

All three pumps are lifted and serviced on a five year cycle. Pumps are stripped and parts replaced as required.

Pump Date of Last Servicing No. 1 2007

No. 2 2007

No. 3 2007

13.4 Major maintenance

Major refurbishment of pump stations’ machinery, electrical switchboards, structural components, pipelines, weed screens etc. Average life anticipated to be approximately 20 years.

13.5 Structure replacement

The life of a pump station structure is estimated at 50 years. The scheduled replacement date is:

Pump Station Year Built

Structure Replacement Date

Duke Street 1984 2034/35 14 Floodwalls

Inspection of the concrete walls is performed as part of the stopbank inspection.

The floodwalls are assumed to have a design life of 50 years. Hence every 50 years the walls will need to be reconstructed. The design cost is included but the costs of demolition are assumed to be insignificant compared to the overall construction cost.

This item is treated as a renewal.



15 Beach shaping

Gravel build up occurs on the inside bends of the major rivers. This requires some reshaping once every five years to move the gravel into the deeper parts of the river and reduce the pressure on the outside bend. It is assumed 20% is undertaken each year.

16 Drain maintenance

Drains are sprayed annually and on average desilted every five years. Minor drain maintenance within the scheme area to the following drains (refer to appendix 7 for a map of drain locations).

• Vanstone (3380m)

• Apanui (3340m)

• Mill Stream (5480m)

• Mill Stream tributaries (to Warrington Road) (3900m)

• Clarks Cross Road (1800)

• Duke Street (2330m)

• Aerodrome (1500m)

• Aerodrome 2 (580m)

• Te Rere Pa (1340m)

• McCallions (2750m)

• Edwards (420m)

• Total Drain Length 26,820 m



Appendix 3 — Expenditure Tables









Appendix 4 — Flood Damage Reserve



Waioeka Otara Rivers SchemeFlood Damage Reserve Fund

($50,000)

$0

$50,000

$100,000

$150,000

$200,000

$250,000

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49

Year

Fund

Bal

ance

($)



Waioeka Otara Rivers Scheme Flood Damage Reserve Fund ($ 2007)

Year Contribution Flood Damage Change to Fundto Reserve Balance Balance

1 2007 / 2008 $18,800 $0 $18,800 $02 2008 / 2009 $18,800 $0 $18,800 $18,8003 2009 / 2010 $18,800 $0 $18,800 $37,6004 2010 / 2011 $18,800 $0 $25,000 $62,6005 2011 / 2012 $25,000 $150,000 ($125,000) ($62,400)6 2012 / 2013 $25,000 $0 $25,000 ($37,400)7 2013 / 2014 $25,000 $0 $25,000 ($12,400)8 2014 / 2015 $25,000 $0 $25,000 $12,6009 2015 / 2016 $25,000 $0 $25,000 $37,60010 2016 / 2017 $25,000 $75,000 ($50,000) ($12,400)11 2017 / 2018 $25,000 $0 $25,000 $12,60012 2018 / 2019 $25,000 $0 $25,000 $37,60013 2019 / 2020 $25,000 $0 $25,000 $62,60014 2020 / 2021 $25,000 $0 $25,000 $87,60015 2021 / 2022 $25,000 $150,000 ($125,000) ($37,400)16 2022 / 2023 $25,000 $0 $25,000 ($12,400)17 2023 / 2024 $25,000 $0 $25,000 $12,60018 2024 / 2025 $25,000 $0 $25,000 $37,60019 2025 / 2026 $25,000 $0 $25,000 $62,60020 2026 / 2027 $25,000 $75,000 ($50,000) $12,60021 2027 / 2028 $25,000 $0 $25,000 $37,60022 2028 / 2029 $25,000 $0 $25,000 $62,60023 2029 / 2030 $25,000 $0 $25,000 $87,60024 2030 / 2031 $25,000 $0 $25,000 $112,60025 2031 / 2032 $25,000 $150,000 ($125,000) ($12,400)26 2032 / 2033 $25,000 $0 $25,000 $12,60027 2033 / 2034 $25,000 $0 $25,000 $37,60028 2034 / 2035 $25,000 $0 $25,000 $62,60029 2035 / 2036 $25,000 $0 $25,000 $87,60030 2036 / 2037 $25,000 $75,000 ($50,000) $37,60031 2037 / 2038 $25,000 $0 $25,000 $62,60032 2038 / 2039 $25,000 $0 $25,000 $87,60033 2039 / 2040 $25,000 $0 $25,000 $112,60034 2040 / 2041 $25,000 $0 $25,000 $137,60035 2041 / 2042 $25,000 $150,000 ($125,000) $12,60036 2042 / 2043 $25,000 $0 $25,000 $37,60037 2043 / 2044 $25,000 $0 $25,000 $62,60038 2044 / 2045 $25,000 $0 $25,000 $87,60039 2045 / 2046 $25,000 $0 $25,000 $112,60040 2046 / 2047 $25,000 $75,000 ($50,000) $62,60041 2047 / 2048 $25,000 $0 $25,000 $87,60042 2048 / 2049 $25,000 $0 $25,000 $112,60043 2049 / 2050 $25,000 $0 $25,000 $137,60044 2050 / 2051 $25,000 $0 $25,000 $162,60045 2051 / 2052 $25,000 $150,000 ($125,000) $37,60046 2052 / 2053 $25,000 $0 $25,000 $62,60047 2053 / 2054 $25,000 $0 $25,000 $87,60048 2054 / 2055 $25,000 $0 $25,000 $112,60049 2055 / 2056 $25,000 $0 $25,000 $137,60050 2056 / 2057 $25,000 $75,000 ($75,000) $62,600



Appendix 5 — Renewals Fund and Renewal Table



Waioeka Otara Rivers SchemeFlood Damage Reserve Fund

($50,000)

$0

$50,000

$100,000

$150,000

$200,000

$250,000

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49

Year

Fund

Bal

ance

($)



Renewals Table

Asset Management Renewals Fund ($ 2007) Year Depreciation

Funded Loan

Principal Nett

Depreciation Funded

Renewals Funded by

Loans

Renewals Expenditure

Fund Balance

1 2007/2008 $28,700 $95,500 $0 $42,000 42,000 $0 2 2008/2009 $43,200 $97,600 $0 $125,000 125,000 $0 3 2009/2010 $43,200 $103,900 $0 $0 0 $0 4 2010/2011 $43,200 $103,900 $0 $245,000 245,000 $0 5 2011/2012 $43,200 $116,200 $0 $0 0 $0 6 2012/2013 $43,200 $116,200 $0 $0 0 $0 7 2013/2014 $43,200 $116,200 $0 $0 0 $0 8 2014/2015 $43,200 $116,200 $0 $0 0 $0 9 2015/2016 $43,200 $116,200 $0 $0 0 $0 10 2016/2017 $43,200 $116,200 $0 $0 0 $0 11 2017/2018 $43,200 $116,200 $0 $0 0 $0 12 2018/2019 $43,200 $116,200 $0 $0 0 $0 13 2019/2020 $43,200 $115,500 $0 $0 0 $0 14 2020/2021 $43,200 $111,300 $0 $245,000 245,000 $0 15 2021/2022 $43,200 $114,700 $0 $0 0 $0 16 2022/2023 $43,200 $69,600 $0 $0 0 $0 17 2023/2024 $43,200 $66,000 $0 $0 0 $0 18 2024/2025 $43,200 $55,500 $0 $0 0 $0 19 2025/2026 $43,200 $40,200 $3,000 $0 0 $3,000 20 2026/2027 $43,200 $38,000 $5,200 $0 0 $8,200 21 2027/2028 $43,200 $33,000 $10,200 $0 0 $18,400 22 2028/2029 $43,200 $30,900 $12,300 $0 0 $30,700 23 2029/2030 $43,200 $24,600 $18,600 $0 0 $49,300 24 2030/2031 $43,200 $24,600 $18,600 $177,100 245,000 $0 25 2031/2032 $43,200 $24,600 $18,600 $0 0 $18,600 26 2032/2033 $43,200 $24,600 $18,600 $0 0 $37,200 27 2033/2034 $43,200 $24,600 $18,600 $149,200 205,000 $0 28 2034/2035 $43,200 $34,900 $8,300 $0 0 $8,300 29 2035/2036 $43,200 $34,900 $8,300 $0 0 $16,600 30 2036/2037 $43,200 $34,900 $8,300 $0 0 $24,900 31 2037/2038 $43,200 $34,900 $8,300 $0 0 $33,200 32 2038/2039 $43,200 $34,900 $8,300 $0 0 $41,500 33 2039/2040 $43,200 $34,900 $8,300 $0 0 $49,800 34 2040/2041 $43,200 $34,900 $8,300 $186,900 245,000 $0 35 2041/2042 $43,200 $34,900 $8,300 $55,700 64,000 $0 36 2042/2043 $43,200 $38,100 $5,100 $0 0 $5,100 37 2043/2044 $43,200 $38,100 $5,100 $0 0 $10,200 38 2044/2045 $43,200 $38,100 $5,100 $0 0 $15,300 39 2045/2046 $43,200 $38,100 $5,100 $0 0 $20,400 40 2046/2047 $43,200 $38,100 $5,100 $0 $0 $25,500 41 2047/2048 $43,200 $38,100 $5,100 $0 0 $30,600 42 2048/2049 $43,200 $38,100 $5,100 $209,300 245,000 $0 43 2049/2050 $43,200 $50,400 $0 $0 0 $0 44 2050/2051 $43,200 $50,400 $0 $0 0 $0 45 2051/2052 $43,200 $38,100 $5,100 $0 0 $5,100 46 2052/2053 $43,200 $38,100 $5,100 $186,100 196,300 $0 47 2053/2054 $43,200 $47,900 $0 $0 0 $0 48 2054/2055 $43,200 $37,600 $5,600 $0 0 $5,600 49 2055/2056 $43,200 $37,600 $5,600 $0 0 $11,200 50 2056/2057 $43,200 $37,600 $5,600 $0 0 $16,800



Appendix 6 — Loan Payment Schedule as at 30 June 2007

Waioeka Otara Rivers Scheme Asset Management Loan Charges

Year Principal Interest Subtotal Less

Principal Funded from Depreciation

Nett Loan

Charges New

Loans

1 2007/08 $95,500 $120,100 $215,600 $28,700 $186,900 $42,0002 2008/09 $97,600 $119,000 $216,600 $43,200 $173,400 $125,0003 2009/10 $103,900 $116,000 $219,900 $43,200 $176,700 $04 2010/11 $103,900 $117,500 $221,400 $43,200 $178,200 $245,0005 2011/12 $116,200 $118,500 $234,700 $43,200 $191,500 $06 2012/13 $116,200 $109,200 $225,400 $43,200 $182,200 $07 2013/14 $116,200 $100,000 $216,200 $43,200 $173,000 $08 2014/15 $116,200 $90,600 $206,800 $43,200 $163,600 $09 2015/16 $116,200 $81,300 $197,500 $43,200 $154,300 $0

10 2016/17 $116,200 $72,000 $188,200 $43,200 $145,000 $011 2017/18 $116,200 $62,700 $178,900 $43,200 $135,700 $012 2018/19 $116,200 $53,400 $169,600 $43,200 $126,400 $013 2019/20 $115,500 $44,100 $159,600 $43,200 $116,400 $014 2020/21 $111,300 $44,800 $156,100 $43,200 $112,900 $245,00015 2021/22 $114,700 $45,500 $160,200 $43,200 $117,000 $016 2022/23 $69,600 $38,200 $107,800 $43,200 $64,600 $017 2023/24 $66,000 $33,000 $99,000 $43,200 $55,800 $018 2024/25 $55,500 $28,000 $83,500 $43,200 $40,300 $019 2025/26 $40,200 $23,300 $63,500 $40,200 $23,300 $020 2026/27 $38,000 $20,200 $58,200 $38,000 $20,200 $021 2027/28 $33,000 $17,300 $50,300 $33,000 $17,300 $022 2028/29 $30,900 $14,800 $45,700 $30,900 $14,800 $023 2029/30 $24,600 $12,600 $37,200 $24,600 $12,600 $024 2030/31 $24,600 $20,500 $45,100 $24,600 $20,500 $177,10025 2031/32 $24,600 $28,400 $53,000 $24,600 $28,400 $026 2032/33 $24,600 $26,400 $51,000 $24,600 $26,400 $027 2033/34 $24,600 $32,600 $57,200 $24,600 $32,600 $149,20028 2034/35 $34,900 $38,500 $73,400 $34,900 $38,500 $029 2035/36 $34,900 $35,700 $70,600 $34,900 $35,700 $030 2036/37 $34,900 $32,900 $67,800 $34,900 $32,900 $031 2037/38 $34,900 $30,000 $64,900 $34,900 $30,000 $032 2038/39 $34,900 $27,300 $62,200 $34,900 $27,300 $033 2039/40 $34,900 $24,500 $59,400 $34,900 $24,500 $034 2040/41 $34,900 $31,500 $66,400 $34,900 $31,500 $186,90035 2041/42 $34,900 $41,200 $76,100 $34,900 $41,200 $55,70036 2042/43 $38,100 $40,800 $78,900 $38,100 $40,800 $037 2043/44 $38,100 $37,700 $75,800 $38,100 $37,700 $038 2044/45 $38,100 $34,700 $72,800 $38,100 $34,700 $039 2045/46 $38,100 $31,700 $69,800 $38,100 $31,700 $040 2046/47 $38,100 $28,600 $66,700 $38,100 $28,600 $041 2047/48 $38,100 $25,600 $63,700 $38,100 $25,600 $0



Waioeka Otara Rivers Scheme Asset Management Loan Charges

Year Principal Interest Subtotal Less

Principal Funded from Depreciation

Nett Loan

Charges New

Loans

42 2048/49 $38,100 $32,300 $70,400 $38,100 $32,300 $209,30043 2049/50 $50,400 $38,600 $89,000 $43,200 $45,800 $044 2050/51 $50,400 $34,500 $84,900 $43,200 $41,700 $045 2051/52 $38,100 $31,100 $69,200 $38,100 $31,100 $046 2052/53 $38,100 $35,900 $74,000 $38,100 $35,900 $186,10047 2053/54 $47,900 $40,300 $88,200 $43,200 $45,000 $048 2054/55 $37,600 $36,900 $74,500 $37,600 $36,900 $049 2055/56 $37,600 $33,900 $71,500 $37,600 $33,900 $050 2056/57 $37,600 $30,900 $68,500 $37,600 $30,900 $0



Appendix 7 – Drain Locations

101


Glossary Accrual Accounting – Recognition of revenues as they are earned and expenses as they are incurred. Activity – An activity is the work undertaken on an asset or group of assets to achieve the desired outcome. Annual Plan – A document produced annually by local authorities to inform stakeholders of its objectives, intended activities and expenditure required for a period of one financial year. Asset – A physical facility of value which enables services to be provided and has an economic life of greater than 12 months. Asset Management (AM) – The combination of management, financial, economic, engineering and other practices applied to physical assets with the objective of providing the required level of service in the most cost effective manner. Asset Management System (AMS) – A system (usually computerised) for collecting analysing and reporting data on the utilisation, performance, life cycle management and funding of existing assets. Asset Management Plan (AMP) – A plan developed for the management of one or more infrastructural assets that combines multi-disciplinary management techniques (including technical and financial) over the life cycle of the asset in the most cost effective manner to provide a specified level of service. A significant component of the plan is a long term cash flow projection for the activities. Asset Management Strategy – A strategy for asset management covering, the development and implementation of plans and programmes for asset creation, operation, maintenance, rehabilitation/replacement, disposal and performance monitoring to ensure that the desired levels of service and other operational objectives are achieved at minimum cost. Asset Register – A record of asset information considered worthy of identification, including inventory, historical, financial, condition, construction, technical and financial information about each. Basic Asset Management – Asset management which relies primarily on the use of an asset register, maintenance management systems, job/resource management, condition assessment and defined levels of service in order to establish alternative treatment options and long term cashflow predictions. Priorities are usually established on the basis of financial return gained by carrying out the work (rather than risk analysis and optimised renewal decision making).



Capital Expenditure (CAPEX) – Expenditure used to create new assets or to increase the capacity of existing assets beyond their original design capacity or service potential. CAPEX increases the value of an asset. Cash Flow – The stream of costs and/or benefits over time resulting from a project investment or ownership of an asset. Components – Specific parts of an asset having independent physical or functional identity and having specific attributes such as different life expectancy, maintenance regimes, risk or criticality. Condition Monitoring – Continuous or periodic inspection, assessment, measurement and interpretation of resulting data, to indicate the condition of a specific component so as to determine the need for some preventive or remedial action. Corrective Maintenance – The actions performed, as a result of failure to restore an item to a specified condition. Corrective maintenance may or may not be programmed. Critical Assets – Those assets for which the financial or service level consequences of failure are sufficiently severe to justify proactive inspection and rehabilitation. Critical assets have a lower threshold for action than non critical assets. Current Assets – Those assets which are expected to be realised in cash or sold or consumed within one year of an organisation’s balance date. Current Replacement Cost – The cost of replacing the service potential of an existing asset, by reference to some measure of capacity, with an appropriate modern facility, e.g. modern equivalent asset. Decommission – Activities required to take an asset out of service. Deferred Maintenance – A shortfall in rehabilitation work required to maintain the service potential of an asset. Depreciated Replacement Cost (DRC) – The replacement cost of an existing asset after deducting an allowance for wear or consumption to reflect the remaining economic life of the existing asset. Depreciation – The wearing out, consumption or other loss of value of an asset whether arising from use, passing of time or obsolescence through technological and market changes. It is accounted for by the allocation of the historical cost (or revalued amount) of the asset less its residual value over its useful life. Design Standard (Or Service Level) – The standard of the flood mitigation methods designed to contain a flood of a certain size. Deterioration Rate – The rate at which as asset approaches failure. Discounting – A technique for converting cash flows that occur over time to equivalent amounts at a common point in time. Discount Rate – A rate used to relate present and future money values, e.g. to convert the value of all future dollars to the value of dollars at a common point in time, usually the present. Disposal – Activities necessary to dispose of decommissioned assets.



Economic Life – The period from the acquisition of the asset to the time when the asset, which physically able to provide a service, ceases to be the lowest cost alternative to satisfy a particular level of service. The economic life is at the maximum when equal to the physical life however obsolescence will often ensure that the economic life is less than the physical life. Equity – The residual interest in the assets of the entity after deduction of its liabilities. Facilities Audit – The physical audit of a facility to provide an input for life cycle costsanalysis, short term maintenance planning and long term planning purposes. Flood – A relatively high river flow that overtops the natural or artificial banks in any part of a watercourse (see cumec). Financial Statements – Balance sheets, profit and loss accounts, statements of changes in financial position, notes and other statements which collectively are intended to give a true and fair view of the state of affairs and profit or loss of an entity for a defined period. Generally Accepted Accounting Principles (GAAP) – Approved financial reporting standards (within the meaning of the Financial Reporting Act 1993) so far as those standards apply to a particular entity; or, where there are no approved standards, accounting policies that are appropriate to the entity and have authoritative support within the accounting profession in New Zealand. Geographic Information System (GIS) – Software which provides a means of spatially viewing, searching, manipulating, and analysing a database of records. Inflation Rate – A rate of increase applied to costs incurred at a future date to reflect the relative purchasing power of money in terms of a chosen time, usually the present. Infrastructural Assets – Stationary systems forming a network and serving whole communities where the system as a whole is intended to be maintained indefinitely at a specified level of service potential by the continuing replacement and refurbishment of its components. Internal Rate of Return – The discount rate for which the ‘net present value’ is zero. Land Information Memorandum (Lim)/ Project Information Memorandum (PIM) – They contain a wide range of information about a chosen parcel of land, such as the presence of natural hazards, access easements, services such as stormwater drains, or resource consents issued on the property. Including all publicly available hazard information in a LIM or a PIM is a statutory requirement under section 31 of the Building Act section 44 of the Local Government and Official Information and Meetings Acts, respectively. Guidance may be given for the way this information is interpreted and presented. Level of Service – The definition of service quality for a particular activity (i.e. roading) or service area (i.e. street lighting) against which the service performance may be measured. Service levels usually relate to quality, quantity, reliability, responsiveness, environmental acceptability and cost. Life – A measure of the anticipated life of an asset or component, such as time, number of cycles, distance intervals etc.



Life Cycle – Life cycle has two meanings: (a) The cycle of activities that an asset (or facility) goes through while it retains an identity

as a particular asset i.e. from planning and design to decommissioning or disposal. (b) The period of time between a selected date and the last year, over which the criteria

(e.g. costs) relating to a decision or alternative understudy will be assessed. Maintainability – A characteristic of design and installation usually identified by the time and effort that will be required to retain an asset as near as practical to its new or desired condition within a given period of time. Maintenance – All actions necessary for retaining an asset as near as practical to its original condition, but excluding rehabilitation or renewal. Maintenance Plan – Collated information, policies and procedures for the optimum maintenance of an item, or group of items. Maintenance Standards – The standards set for the maintenance service such as preventive maintenance schedules, operation and maintenance manuals, codes of practice, estimating criteria, statutory regulations and mandatory requirements in accordance with maintenance quality objectives. Market Value – The estimated amount at which an asset would be exchanged on the date of valuation, between a willing buyer and a willing seller, in an arms length of transaction after profit, marketing, and when the parties have each acted knowledgeably, prudently and without compulsion. Modern Equivalent Assets – Assets that replicate what is in existence with the most cost efficient asset performing the same level of service. Non-Structural Measures – Non-structural measures mainly deal with the residual risk of flooding. These measures keep people away from floodwaters and help the community cope when flooding occurs. Land-use measures influence the way land is used and buildings are constructed. They include regulatory methods (policies and rules in district plans) and voluntary actions (information and advice to help people to make their own decisions). Emergency management measures seek to improve the community's preparedness and response to flooding. Non-structural measures are the most cost-effective flood mitigation approach. Operation – The active process of utilising an asset which will consume resources such as manpower, energy, chemicals and materials. Operation costs are part of the life cycle costs of an asset. Performance Monitoring – Continuous or periodic quantitative and qualitative assessments of the actual performance compared with specific objectives, targets or standards. Planned Maintenance (i) Periodic - necessary to ensure the reliability or sustain the design life of an asset. (ii) Predictive - condition monitoring activities used to predict failure. (iii) Preventive - maintenance that can be initiated without routine or continuous checking

(e.g. using information contained in maintenance manuals or manufacturers’ recommendations) and is not condition-based.

Recoverable Amount – Is the greater of the amount recoverable from an assets further use and ultimate disposal, and its current net realisable value.



Rehabilitation – Works to rebuild or replace parts or components of an asset, to restore it to a required functional condition and extend its life, which may incorporate some modification. Generally involves repairing the asset to deliver its original level of service (i.e. heavy patching of roads, slip lining of sewer mains, etc) without resorting to significant upgrading or renewal using available techniques and standards. Renewal – Works to upgrade refurbish or replace existing facilities with facilities of equivalent capacity or performance capability. Renewal Accounting – A method of infrastructure asset accounting which recognises that infrastructure assets are maintained at an agreed service level through regular planned maintenance, rehabilitation and renewal programmes as set out in the asset management plan. The relevant rehabilitation and renewal costs are treated as capital expenditure and any loss in service potential is recognised as depreciation. Repair – Action to restore an item to its previous condition after failure or damage. Replacement – Complete replacement of an asset that has reached the end of its life, so as to provide a similar or agreed alternative level of service. Replacement Cost – The cost of replacing an existing asset with a substantially identical new asset. Risk Management – The application of a formal process to the range of possible values of key factors in order to determine the resultant ranges of outcomes and their probability of occurrence. Routine Corrective Maintenance – Corrective maintenance, excluding emergency corrective and programmed corrective maintenance. Routine Maintenance – Day to day operational activities to keep the asset operating (replacement of light bulbs, cleaning of drains, repairing leaks, etc) and which form part of the annual operating budget, including preventative maintenance. Service – As in utility service, is a system and its network infrastructure that supply a community need. Service Maintenance – Service undertaken seasonally or annually to enable the required level of service to be delivered. Service Potential – At any point in the life of an asset, its ability to provide a service over and above a minimum acceptable standard. Statement of standard accounting practice (SSAP) – Methods of accounting approved by the Council of the NZ Society of Accountants for application to all financial statements. Statement of Financial Performance – A report on the net surplus/deficit, and its components, arising from activities or events during a given period, that are significant for the assessment of both past and future financial performance. Statement of Financial Position – Disclosure of all assets and liabilities of the entity, appropriately classified including resources, financing structure and contingencies. Statement of Objectives – A formal expression of the mission and overall objectives of the reporting entity.



Statement of Resources – A description in physical terms of the major resources held by the reporting entity. Statement of Service Performance – A report for each significant activity undertaken by the reporting entity, on the degree of success achieved in meeting agreed targets, in qualitative and quantitative terms. Stopbanks – Banks aligned beside the river to prevent floodwaters flowing into floodplain areas. They are also known as flood defences. Structural Measures – Structural measures are structures or other physical works designed to keep floodwaters away from existing development. Stopbanks and floodwalls are obvious examples of structural works. Channel works include bank edge works and channel management. Rock linings, vegetation buffers and groynes are bank edge works, which protect flood defences like stopbanks and maintain the channel's position. Other active channel management methods include bed and beach re-contouring and gravel extraction. They are used occasionally to reduce the opportunity for the river to erode its banks and damage structural works. Unplanned Maintenance – Corrective work required in the short term to restore an asset to working condition so it can continue to deliver the required service or to maintain its level of security and integrity. Useful Life – May be expressed as either: (a) The period over which a depreciable asset is expected to be used, or (b) The number of production or similar units (i.e. intervals, cycles) that is expected to be

obtained from the asset. Valuation – Estimated asset value which may depend on the purpose for which the valuation is required, i.e. replacement value for determining maintenance levels or market value for life cycle costing. Value Management – An evaluation process which addresses the technical and functional dimensions at the early stages of a project (i.e. establishment of project objectives, preparation of project brief and consideration of concept/design options) to ensure a fully integrated approach has been taken, the project is consistent with strategic goals and non-build solutions (including demand management) have been properly assessed.

Waioeka-Otara Asset Management Plan...2018/10/06 · Waioeka-Otara Asset Management Plan Operations Publication 2007/06 The total average annual level of expenditure required to meet

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