Sustainable urban drainage

SUSTAINABLE URBAN

DRAINAGEPRESENTED BY:

LINGARAJ PANDA

SEC:CV-A(1)

ROLL NO.14010080

Seminar On

SUBMITTED TO:Mr. RAJIB LOCHAN SAHOOASST. PROFFESSORGEOTECHNIAL ENGINEERINGVSSUT,BURLA

Presentation Outlines

1. Introduction2. SUDs3. Water cycle4. Environmental effects of urban

drainage5. SUDs Triangle6. Source control & Prevention

Green Roof Retention ponds Wetlands Permeable Pavements

7. Conclusions

Sustainable Drainage• A concept that focuses on the environment and people.

• Considers:

• Quantity of runoff

• Quality of runoff

• Amenity value of surface water

• Existing urban drainage systems are:

• Unsustainable in the long-term

• Damaging to the environment

Sustainable urban drainage systems (SUDS) are a natural approach to managing drainage in and

around properties and other developments. SUDS work by slowing and holding back the water

that runs off from a site, allowing natural processes to break down pollutants.

Water cycle

• Water cycle

Percolation

Why are SUDS needed?

Hydrograph:

Floods occur quicker due to reduced infiltration

Peak discharge becomes

larger

Time

Dis

charg

e

SUDS:

• Attenuate flow

• Promote infiltration & groundwater recharge

Why are SUDS needed?

Industrial

Effluent, 2.1%

Contaminated

Land, 1%

Others, 2.7%

Urban

Drainage,

11.4%

Acidification,

11.7%

Agriculture

(Diffuse

Sources)

26.2%

Sewage

Effluent, 33.9%

Agriculture

(Point Sources)

6.3%

Mine Drainage

8.9%

SUDSWP (2000)

• 11% of Scottish river length is classified as polluted due to contamination from urban drainage

• SUDS aim to protect watercourses from point/diffuse pollution by acting

as sinks for contaminants

• Cost implications for maintaining long-term performance of SUDS

Why are SUDS needed?

Amenity

• A ‘loaded term’ when used in relation to SUDS – environmental/community issues

Covers:

• Aesthetic & Ecological quality of the landscape

• Land-use

• Wildlife habitats

• Land-values

• Recreation opportunities

• Educational opportunities

• Water-resources

Other factors:

• Opportunity costs

• Perceptions of risk

• Construction impact

The Environmental impact of urban drainage

1.Water quality

2.Flooding

3.Water resources

4.Habitat

Flooding may occur for a number of

reasons, including inadequately

designed surface water drainage

Impact of urbanization on runoff quantity

SUDS ‘Triangle’

Depends upon following factors.1.Water quantity2.Water quality3.Amneity,Biodiversity

Present Legal Status

• WFD – Water Framework Directive (2000)

• Prevent deterioration in water status• Restoration of surface waters to good ecological and chemical status by2015

• Reduction of pollution from priority substances• Contributing to mitigating the effects of floods and droughts• Preventing/limiting pollution input into groundwater

• CAR – The Water Environment (Controlled Activities) (Scotland) Regulations (2005)

• Surface water-runoff in areas constructed, or construction sites operated, after1st April 2006 must now be drained by a Sustainable Urban Drainage System

• Exceptions – Single dwellings or if the discharge is to coastal water

Conventional Drainage

Precipitation: Rainfall/Snow

Rapid conveyance of water & pollutants

Local watercourse

SUDS Drainage: The ‘Treatment’ approach

• Connect SUDS together

• Individual function of local SUDS techniques beneficial – but design should be led by a holisticvision & approach

• Combined integrated function – mimics the waterflows in the natural hydrological cycle:

• Surface Flow

• Infiltration

• Storage in water-bodies

• Interflow

• Evapotranspiration

Treatment Train

1. Good Housekeeping: best practice to eliminate, or minimise, pollutants being generated and allowed into the environment.

2. Source Controls: methods of dealing with runoff at source, e.g. permeable paving, filter strips, or roadside filter trenches.

3. Site Controls: local controls that deal with generally smaller catchment areas, e.g. detention basins.

4. Regional Controls: larger components that might typically deal with larger catchments and upstream site controls, e.g. stormwater wetlands and retention ponds.

(Heal, 2004)

Figure 2. Surface water management train: addressing runoff quality at all stages of the drainage system.

A variety of techniques

Kerb design

Filter Drain

Roof drainage reuse

Swales

Drainage conveyance

Detention Basins

Retention Ponds

Falkirk Stadium Retention Pond (Undeveloped catchment)

Retention Ponds / Wetlands

Lidl Distribution Centre, Livingston - Retention Pond (Loading bay, carpark runoff)

Green roof(designed in U.K.)

Green Roof

Tackling Contaminants

• The flood-reducing benefits of SUDS are obvious...• Store water at various points in the catchment and allow water to be

re-used, infiltrated, released slowly and/or evaporated.

• These processes also allow the trapping of potential contaminants (e.g. metals, PAHs/Hydrocarbons) within the treatment train.

• Contaminants are typically adsorbed (physico-chemically bonded) to sediment particles that are entrained in flow.

• As water speed is slowed down using SUDS, particles (and therefore contaminants) settle out.

Contaminant Sources: Vehicles

• 15-fold increase in the number of car and taxi miles covered over the last 50 years!

Increase in Traffic Miles

Car and Taxis

0

50

100

150

200

250

300

1950 1960 1970 1980 1990 2001

Year

Bil

lio

n v

eh

icle

mil

es

Campbell et al. (2004)

SUSTAINABLE (?)

Design - Site Constraints

• Physical site constraints can make construction difficult or impossible, and maintenance expensive if not addressed adequately. Factors to consider include:

• topography - e.g. steep slopes

• soils and geology - e.g. erosivity, porosity, depth to bedrock or instability

• groundwater - e.g. geochemistry and water table depth

• space - limited open space, proximity to underground services. (e.g. gas, power)

• Social constraints include issues of health and safety, aesthetics and impacts on recreational facilities. Factors to consider include

• odour problems

• visual impacts

• noise

• physical injury - resulting from unauthorised access to structures;

• contamination - infection, poisoning or injury caused by trapped pollutants or algal blooms

• vermin - e.g. mosquitoes, rats.

Design – Maintenance Issues

• Not only can a poorly maintained SUDS technique function ineffectively, it can become a source of pollution or flood hazard itself.

• When designing a SUDS measure, the following points should be considered:• ease of maintenance and operation - the selected treatment should be

easy and safe to maintain and operate • extent of maintenance - ensure the maintenance requirements are within

the operator's capability • access to the treatment site - consider the ease of site access, when

reviewing the treatment's maintenance requirements • frequency of maintenance - ensure that resources are available to carry

out maintenance at the required frequency • debris and pollutant clearing - during clearing, the treatment should not

require direct human contact with debris and trapped pollutants (automated clearing options are preferred)

• disposal - consider the disposal requirements of any waste from the treatment process.

• SUDS development (c. 2000)

• Previously agricultural land

• Now a distribution hub based mid-way between Edinburgh and Glasgow

Case Study: J4M8

J4M8 Oblique Aerial Photograph

M8 Motorway

Phase 1 Retention

Pond

Reddinghill Bing

(Landscaped, but still

burning)

Aldi Distribution

Centre

Former Scottish

Courage Distribution

Centre

Some conclusions

Take the wetlands to the people

Community management

makes SuDS sustainable

SuDS – integral to solving many

issues/agendas (inc diffuse

pollution)

References

GoogleWikipediawww.geos.ed.ac.uk

THANK YOU