Presentation on theme: "SUDS and Sustainability Kate Heal, University of Edinburgh Neil McLean, SEPA Brian D’Arcy, SEPA."— Presentation transcript:
SUDS and Sustainability Kate Heal, University of Edinburgh Neil McLean, SEPA Brian D’Arcy, SEPA
SUDS and Sustainability Sustainability - Neil –Economic Issues –Social Issues –Environmental Issues SUDS – Kate –Are SUDS Sustainable? –Pollutants and Ecology –Limits and Effects –Increasing the Sustainability of SUDS ?
Sustainable Development Quote from the Brundtland report - 'development which meets the needs of the present without compromising the ability of future generations to meet their own needs'. Environmental SocialEconomic The Sustainability Triangle
Economic Issues (i) River restoration/flood control schemes may face major costs due to the legacy of contamination in stream sediments & hydrological impacts. Can SUDS avoid the need for future flood control schemes if used at outset of major urbanisation projects in stream headwaters? Can SUDS reduce costs by better management of the fate of persistent pollutants?
Economic Issues (ii) There has been a progressive increase in sales of permeable surface systems in England – yet no regulatory driver: cost effectiveness drives uptake. Formpave report that a permeable surface car park is about 15% cheaper than a conventionally drained one since no gullies or oil interceptor and fewer pipes (P Hart)
Economic Issues (iii) Can cost savings be achieved for SUDS technology ? –Motorway service areas M40 & M42 (R Bray Assoc.) –Schools Projects & Stroud College (R Bray Assoc.) Savings are achievable when SUDS are an alternative, not an add-on Challenge for public bodies is to allow developers to realise potential cost-savings
The SUDS Triangle Water Quality –SEPA Water Quantity –Local Authority Habitat/Amenity –SNH Water Quality Water Quantity Habitat/Amenity
Social issues (i) Abertay studies: questionnaires, door-to-door, focus groups (Apostalaki) Community Engagement projects (e.g. DEX and SE Wedge) Just look around the DEX site: ad hoc footpaths around every pond… people like water.
Social Issues (ii) –Tree with raised kerbed plot –Stops water draining from pavement –Keeping water out of tree’s root system –Tripping hazard! Wet day in Perth with no permeable paving –Puddles to be negotiated
Environmental Issues 16 fold increase in car/taxi mileage in last 50 years 500km downgraded due to urban runoff SEPA’s “Pressures & Impacts on Scotland’s Water Environment” Report & Consultation –Over 6,000 km of waterbodies “at, or probably at, significant risk” from diffuse pollution –Urban runoff –Bathing waters SUDS can help ! Source; Campbell et al, 2004
Environmental Issues & SUDS Protect aquatic environment using the SUDS treatment train –prevent deterioration SUDS retrofits for river & bathing water quality and combined sewers –Restoration SUDS as habitats where possible Most important: need action to reduce traffic volume, & develop cleaner technology for construction & motor industries – Are the drainage systems unsustainable? It’s the inputs of persistent pollutants that are not sustainable SUDS – Lose the “S” for sustainable UDS - Unsustainable Drained Substances!!
Are SUDS sustainable? Maintenance requirement Fate of pollutants –Redistribution of pollutants –Groundwater pollution –Disposal of SUDS sediments Impoverished ecology –Exotic species, monoculture planting SUDS failures
Estimated relative mass flow (%) of copper in different urban drainage systems for Sankt Gallen, Switzerland, (75,000 inhabitants) (after Boller, 1997)
Scottish urban rivers sediment study (SEPA, 2003) –23/26 sites: at least 1 metal exceeded lowest effect level –4/26 sites: sediment classified as Special Waste Anthropogenic metal accumulation in top 5 cm soil over 8 years, Göteborg, Sweden (Lind & Karro, 1995)
Limits to SUDS SUDS designed for specific circumstances –e.g. 10-year, 60 minute storm –e.g. treat runoff from 90% annual storms Poor design, construction and maintenance Treatment facility ≠ pristine ecosystem No one correct solution: in some situations conventional drainage techniques (or mixture) is most sustainable option SUDS only one part of solution to urban drainage problems
Poor design, construction & maintenance Blocked & broken inlets Inlet to perforated pipe covered with sediment (Images: Wolfram Schluter, Ewan Associates) Inlet to trench Bypass Inlet
Groundwater inputs to Linburn Pond (Morgan, 2004) Data from UWTC, University of Abertay: –Continuous rainfall for DEX catchment –Continuous outflow for Linburn Pond Total inflow (10% impermeable surface) Max possible inflow (100% impermeable surface) Total observed outflow 5.33 x 10 7 l5.33 x 10 8 l6.36 x 10 8 l Outflow > maximum possible inflow
Increasing the sustainability of SUDS Surface water management train Improved design at all scales: –Design with development –Design for maintenance –Design detailing Community engagement from start Multi-disciplinary approach Construction swale, Waterside Gardens Swale, Waterside Gardens
Sustainable development is “a journey and not a destination” development is an opportunity… “SUDS: Sustainable urban drainage system: a sequence of management practices and control structures designed to drain surface water in a more sustainable fashion than some conventional techniques” (CIRIA C521, design manual for Scotland & Northern Ireland)