1. Sustainable Urban Drainage
Alan Jones

2. 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

3. Why are SUDS needed? Hydrograph: SUDS: Discharge
Peak discharge becomes larger
Discharge
Time
Floods occur quicker due to reduced infiltration
SUDS:
Attenuate flow
Promote infiltration & groundwater recharge

4. Why are SUDS needed?
11% of Scottish river length is classified as polluted due to contamination from urban drainage
SUDSWP (2000)
SUDS aim to protect watercourses from point/diffuse pollution by acting as sinks for contaminants
Cost implications for maintaining long-term performance of SUDS

5. 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

6. SUDS ‘Triangle’

7. Present Legal Status WFD – Water Framework Directive (2000)
Prevent deterioration in water status
Restoration of surface waters to good ecological and chemical status by 2015
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, after 1st April 2006 must now be drained by a Sustainable Urban Drainage System
Exceptions – Single dwellings or if the discharge is to coastal water

8. Conventional Drainage
Precipitation: Rainfall/Snow
Rapid conveyance of water & pollutants
Local watercourse

9. SUDS Drainage: The ‘treatment train’ approach
Connect SUDS together
Individual function of local SUDS techniques beneficial – but design should be led by a holistic vision & approach
Combined integrated function – mimics the waterflows in the natural hydrological cycle:
Surface Flow
Infiltration
Storage in water-bodies
Interflow
Evapotranspiration

10. Treatment Train
Good Housekeeping: best practice to eliminate, or minimise, pollutants being generated and allowed into the environment.
Source Controls: methods of dealing with runoff at source, e.g. permeable paving, filter strips, or roadside filter trenches.
Site Controls: local controls that deal with generally smaller catchment areas, e.g. detention basins.
Regional Controls: larger components that might typically deal with larger catchments and upstream site controls, e.g. stormwater wetlands and retention ponds.
(Heal, 2004)

11. A variety of techniques
Drainage conveyance
Kerb design
Roof drainage reuse
Detention Basins
Filter Drain
Swales

12. Falkirk Stadium Retention Pond (Undeveloped catchment)
Retention Ponds
Falkirk Stadium Retention Pond (Undeveloped catchment)

13. Retention Ponds / Wetlands
Lidl Distribution Centre, Livingston - Retention Pond (Loading bay, Carpark runoff)

14. 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.

15. Contaminant Sources: Vehicles
15-fold increase in the number of car and taxi miles covered over the last 50 years!
SUSTAINABLE (?)
Campbell et al. (2004)

16. Land-Use & Contamination
Vehicles
Pavement
Surface Debris
Brakes
Tyres
Frame & Body
Fuels & Oils
Concrete
Asphalt
De-icing Salts
Litter
Cadmium (Cd)
Chromium (Cr)
Copper (Cu)
Iron (Fe)
Lead (Pb)
Nickel (Ni)
Vanadium (V)
Zinc (Zn)
Chlorides
Organic Solids
Inorganic Solids
PAHs
Phenols
(Beasley and Kneale, 2002)

17. 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.

18. 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.

19. Case Study: J4M8 SUDS development (c. 2000)
Previously agricultural land
Now a distribution hub based mid-way between Edinburgh and Glasgow

20. J4M8 Oblique Aerial Photograph
M8 Motorway
Phase 1 Retention Pond
Reddinghill Bing (Landscaped, but still burning)
Aldi Distribution Centre
Former Scottish Courage Distribution Centre