Alison Duffy [Dundee , UK], Brian D'Arcy 1, Neil Berwick 1, Rebecca Wade 1, Roshni Jose 1
Urban Water Technology Centre, Abertay University1
Introduction The 21st Century witnessed a revolution in drainage practices in Scotland with the implementation of sustainable drainage systems (SUDS). One of the key benefits of SUDS is mimic natural drainage processes as rainfall drains from developed land. Collectively this process is known as the stormwater treatment train. The first stage is source control with stages two and three being site and regional controls. Source controls manage rainfall events as close to the source as possible. Site and regional controls are downstream structures that manage larger events and provide additional pollutant removal. The uptake from traditional drainage to SUDS happened in a relatively short timescale with Scotland being regarded as frontrunners in the UK (Duffy et al 2013). The transition is being facilitated by a stakeholder platform which has promoted their use since 1997 - the Sustainable Urban Drainage Scottish Working Party (SUDSWP). Site and regional controls are now 'business as usual', however the uptake of source control as part of a stormwater treatment train is less routine than expected. In 2009 the Scottish Government identified in the 'Future Directions for Scottish Water Consultation' that an increase in source control measures would be fundamental to solving diffuse pollution problems in urban areas to support the Water Resources (Scotland) Act 2013 and to assist in the realisation of the Hydro Nation Agenda. Scottish Water and Local Authorities (LA) have also identified that source control measures are required for delivering surface water management plans to support the Flood Risk Management (Scotland) Act 2009. Considering these ministerial and institutional aspirations and the benefits provided by source control, this study was commissioned by SUDSWP via the Centre of Expertise for Waters (CREW) to recommend the next steps to progress the SUDS journey in Scotland.
Research Undertaken The objectives of this research were threefold: Review the background to source control (history, types and options); Appraise how source control is being delivered, within the UK and Worldwide, and comment on the approach of various responsible organisations and professional groups in Scotland; Define the next steps for optimal source control implementation and further considerations and recommendations. Research Activities included:
* Literature review supported by international experience and utilising existing networks.
* Development of technical reports and case studies that highlighted traditional and emerging source control techniques, why and how they were implemented in Scotland and Worldwide. Fifteen source control techniques were identified and seven countries appraised in their delivery of the systems.
* Workshop held for the SUDSWP including representatives of key sectors.
* Online survey and semi-structured interviews with practitioners to gain anecdotal information and identify barriers and potential solutions.
Key Findings Phase one of this research established that Scotland has benefitted from a strong legislative and regulatory regime that has assisted SUDSWP in driving the agenda from traditional drainage to SUDS. However Phase three established that Scotland has weak enforcement of regulatory requirements and inspection policies. This is resulting in reluctance by practitioners to implement the systems, particularly emerging techniques such as rain gardens which are mainstream in other countries. In the past, Scotland also benefitted from research partnerships such as the Scottish Universities SUDS Monitoring Programme which validated techniques such as swales and permeable paving to increase confidence in the systems (Jefferies, 2001 and 2004). This enabled SUDSWP in collaboration with CIRIA to develop national guidance for SUDS (CIRIA, 2000). The study established that there are three key areas of opportunity for encouraging source control implementation and that the source control toolkit is expanding as new knowledge becomes available. The study also identified key barriers or disabling factors.
Key areas of opportunity:
* Multi-functional source control in open areas and margins (local streets).
* Unit plot source control.
* Areas designated for regeneration / retrofit projects.
Key barriers:
* Governance -- fragmented inter-agency collaboration and funding mechanisms.
* Guidance -- policies, technical issues, terminology.
* Responsibility -- maintenance and health and safety.
* Education -- best practice case studies, particularly emerging techniques.
* Financial -- land take / land use and construction / maintenance costs.
Conclusions and Recommendations Due to the composition and diverse backgrounds of the stakeholders in SUDSWP, the group are in a position to continue facilitation of 'common ground' as an integrated guiding function to influence change to increasing the uptake of source control. Barriers and potential solutions were defined through this research. Based on findings a transition framework was developed to focus, orientate and guide activities. Recommendations have been delivered in a stratgic directions report. There are several activities that SUDSWP may directly drive, by collectively influencing policies and practices. Activities of note:
* Strengthen links with internal members and external stakeholders and develop an integrated long-term vision that encompasses aspirations.
* Undertake a baseline assessment to gauge uptake and performance, revise existing guidance and encourage capacity building programmes.
* Encourage application in the land use opportunities and toolkit identified.
* Explore opportunities to promote and disseminate information at SUDSWP events and for public awareness raising campaigns.
* Encourage research partnerships to validate emerging techniques which meet the aspirations and needs of retrofit situations and showcase case studies.
The report also strongly recommends that the Scottish Government undertake a National SUDS project in recognition of the new flood prevention and management requirements of LAs which adds a new impetus to the provision of SUDS. A national SUDS inspection programme (SIP), including asset register databases would be a significant step forward. The SIP would provide the evidence base against which future actions and improvements can be measured to ensure cost effective, fit for purpose measures -- poor examples were cited as one of the key barriers to their uptake. Other key recommendations advised that Building Standards Division should ensure statutory duties are not ignored. Using the SIP findings, a more active role in monitoring the design and development phases by following up with sign-off / inspection programmes would increase more confidence in the systems. All public bodies with statutory remits should also be encouraged to develop and implement their own annual inspection and enforcement policies for a sample number of approved developments. 1. CIRIA. 2000. Sustainable Urban Drainage Systems – a design manual for Scotland and Northern Ireland. Report C521, CIRIA, London. 2. Duffy. A., Berwick, N., D’Arcy, B., Wade, R., Jose, R., (2013), A rapid review of the background to source control, CRWRR006 (CD 2012 27 R1). Available online at: crew.ac.uk/publications 3. Duffy. A., Berwick, N., D’Arcy, B., Wade, R., (2013), Source control SUDS delivery on a global scale and in Scotland including approach by responsible organisations and professional groups, CRWRR006 (CD 2012 27 R2). Available online at: crew.ac.uk/publications 4. Duffy. A., D’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 5. Duffy, A., Buchan, D., Winter, D. (2013). SUDS as Usual? A transition to public ownership in Scotland. IWA Water 21 Article, pp33-38, April. 6. Jefferies, C. ed. 2001. SUDS Monitoring Programme. SNIFFER Report (00)10. 11-13 Cumberland St, Edinburgh 7. Jefferies, C. ed. 2004. SUDS in Scotland – The Monitoring Programme. SNIFFER Report (02)51. 11-13 Cumberland St, Edinburgh EH3 6RT. 8. Scottish Government (2009). Implementing the Water Environment and Water Services (Scotland) Act 2003: Scotland's Water: Future Directions: A Consultation. ISBN 978 0 7559 1911 6. 9. Scottish Government. (2012). Making Scotland a world leading hydro nation. News Release 28.6.12. Accessed on 12.12.12 http://www.scotland.gov.uk/News/Releases/2012/06/scotland-water28062012