Tuil Solutions1, Urban Water technology Centre, Abertay University2
Introduction Sustainable urban drainage systems or SUDS were introduced in Scotland over 20 years ago, following a Forth River Purification Board review of water pollution issues, which identified urban drainage as a significant source of diffuse pollution in the Forth Catchment (Forth River Purification Board, 1994). A review of progress made over the 20 year period, considers the lessons learnt and examines how legislation and key policies have played a lead role in influencing the uptake of SUDS. Engagement with practitioners and responsible bodies such as developers, consultants, architects, manufacturers, local authorities, Scottish Water and the Scottish Environment Protection Agency (SEPA) has also positively advanced the SUDS agenda. The review looked at several surveys that targeted these bodies from when the SUDS concept was in its infancy to the present day.
Methodology The surveys were conducted using various methodologies from face to face and telephone interviews to postal and online surveys. The number of participants of individual surveys varied, but a similar audience was targeted in each case, providing a useful indication of perceptions of SUDS over the years. Four key surveys document progress over the 20 year period, namely: * A MSc project carried out by Abertay University in 1996 to determine knowledge, perceptions and understanding of SUDS in Scotland (McKissock et al, 1999); * A survey carried out in 2003 by Hyder Consulting, on behalf of SEPA, to evaluate SUDS guidance in Scotland (McKissock et al, 2003); * Abertay University survey, carried out on behalf of the Sustainable Urban Drainage Scottish Working Party in February 2013, to support research that appraised how source control SUDS has been delivered, is currently being delivered, and how to further future implementation (Duffy et al, 2013); * Hydro International survey carried out in September 2013, designed to gauge how successful practitioners believe Scotland has been in delivering SUDS (Hydro International, 2013).
Results and Discussion The results from these studies suggest that attitudes to SUDS have changed over the years, with practitioners becoming more receptive to the concept, as it has progressed from 'an American idea which will never work in Scotland', to routine business (McKissock et al, 1999). However, community engagement is still very limited, with the prevailing attitude still being 'out of sight, out of mind'. Scotland has much to learn from global experience, including projects such as the Melbourne 10,000 and Puget Sound 12,000 raingarden initiatives (http://www.melbournewater.com.au/raingardens and http://www.12000raingardens.org/, where educational campaigns using terminology which the public can understand, has contributed to the success in these countries.
What is striking when reviewing the findings is that there are underlying themes in the responses to all of the surveys. Some of the issues identified in the earlier surveys have been resolved, such as the absence of guidance. This has been largely addressed though the publication of numerous CIRIA guidance manuals, Sewers for Scotland 2nd edition technical standards, SEPA publications and the SUDS for Roads manual; but the results of the survey carried out by Duffy et al (2013) suggested that further guidance may still be required. This appears to be more with uncertainty surrounding the application of the different measures and benefits provided by SUDS. There has been significant progress in terms of the numbers of SUDS implemented, with only 79 SUDS schemes being identified in 1996, which increased to over 3,900 by 2000 (Wild et al, 2002). Updated asset registers are in the process of being developed by local authorities, however it is envisaged that there are many thousands more. This is largely due to SUDS becoming law under the Water Services and Water Services Act 2006 and such measures being required under Scottish Planning. However, according to the 2013 surveys, there still seems to be a general lack of confidence in SUDS performance and a lack of good demonstration sites across Scotland.
It is widely acknowledged that SUDS implementation has come a long way, but there are still fundamental issues which were identified in the surveys carried out 20 years ago which have still to be addressed. The adoption of SUDS, or rather who is willing to take the responsibility of adopting and maintaining SUDS, is still seen as a primary deterrent to their use. There is an urgent need to clarify these issues The costs associated with SUDS are also still perceived as being an issue, which may be due to the lack of published information on capital and operating costs. 60% of those who participated in the survey carried out by Duffy et al (2013) said that they had no access to maintenance activity details or cost information.
The preferred types of SUDS over the 20 year period tend to be those which require the least land take, such as filter drains, permeable paving, and soakaways. There has also been a tendency for practitioners to employ end of pipe systems rather than source control methods, with the amenity benefit of certain measures often being overlooked.
Conclusions So what does the future hold for SUDS in Scotland? Current institutional arrangements in Scotland mean that responsibilities for managing drainage and surface water are split between different organisations and land owners. There is no one body with overall responsibility. This also means that there are fragmented funding responsibilities, which influences the ability of organisations such as local authorities and Scottish Water to adopt large numbers of SUDS. Surface water management is an area where different organisations need to work together pooling knowledge and resources, sharing costs and aligning actions. The Flood Risk Management (Scotland) Act 2009 goes some way to addressing this; encouraging authorities responsible for the management of surface water to adopt a more holistic and collaborative approach than previously was the case. The Duffy et al (2013) survey also suggested that Scotland has weak enforcement of regulatory requirements and inspection policies. This is also an area which requires addressing, as there little benefit in employing SUDS if they are designed incorrectly, they are not maintained and they are not inspected at regular intervals. Duffy. A., DÂ’Arcy, B., Berwick, N., Wade, R., Jose, N. (2013). Source control SUDS Strategic Directions Report, CRWRR006 (CD 2012 27 R3). Available online at: crew.ac.uk/publications. Forth River Purification Board (1994). Clear Future for our Waters. Video and Report, Edinburgh, 1994. Hydro International (2013). Engineering Natures Way. SUDS in Scotland- Experience and Opportunity. McKissock G, Jefferies C and DÂ’Arcy BJ (1999). An Assessment Of Drainage Best Management Practices In Scotland. Journal of the Chartered Institute of Water and Environmental Management. February, 13. McKissock, G, DÂ’Arcy, B.J., Wild, T.C., Usman, F., and Wright, P.W (2003). An Evaluation of SUDS and Urban Diffuse Pollution Guidance and Reference Material. . Diffuse Pollution Conference Dublin 2003. Wild, T.C. Jefferies, C. and DÂ’Arcy, B.J. (2002) SUDS in Scotland Â– the Scottish SUDS database. SNIFFER Final Report SR(02)09. SNIFFER, 11-13 Cumberland Street, Edinburgh, Scotland.