From ‘Big Picture’ to Street Corner – Surface Water Quality Counts

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Report by Conference Chairman Bob Andoh, Chief Technology Officer, Hydro International

Developing best practice approaches to removing pollutants from surface water runoff is a matter of growing interest and concern to a broad community of professionals employed in the design, development and construction of drainage schemes.

If ever there was evidence of the enthusiasm and passion for the topic, it was surely the packed auditorium at the Implementing Surface Water Quality Conference.  More than 90 delegates joined a lively and sometimes controversial debate during the one-day event hosted by Hydro International, held on 17 April 2013 at the National Self Build and Renovation Centre, Swindon

There was a broad consensus that tackling diffuse pollution from surface water runoff is essential.  A panel of 11 highly respected speakers shared their learning, experiences and concerns – from a ‘big picture’ global perspective for water sensitive cities to small incremental improvements at a local street and individual property level.

Water Sensitive Cities

Keynote speaker Mark Fletcher, Director and Global Water Leader from international consultancy Arup opened the day with a fascinating presentation showcasing the consultancy’s global leadership in water sensitive cities and its holistic model for designing with water that reconnects the lives of citizens to the water cycle from source to sea.

More than 75% of people are estimated to live in cities by 2050 and climate change is likely to have a major impact during the 21st Century, he said.  The principles of Water Sensitive Urban Design (WSUD) provided a framework for a conceptual model for designing with water in mind.

Over and above functionality, such a model can create balance in the food-water-energy nexus he pointed out.  He referred to best practice in managing water quality and quantity with examples from major cities across the globe.

View Mark Fletcher’s Keynote presentation.

 

Jo Bradley, Environment and Business Advisor for the Environment Agency agreed that SuDS and WSUD could be effective in tackling surface water pollution, but she also sounded a note of caution:  The industry needs to be smart and realistic and not too evangelical in its approach.

SuDS can fix urban pollution and we must deliver what we can, where we can, she said, and we can’t always have green infrastructure.   There’s no discharge that can’t be fixed, she stressed and each outfall will need is own solution, which may require a ‘pick and mix’ approach of proprietary and/or natural SuDS.

View Jo Bradley’s Presentation

 

David Harding, Customer and Stakeholder Analyst with Thames Water Utilities outlined the challenges of implementing urban SuDS retrofit schemes.  He emphasised the importance of retrofit SuDS to future urban planning:  80% of the houses UK citizens will live in by 2050 have already been built, he pointed out.  Therefore if we are to resolve drainage issues in existing urban areas using SuDS, then we must be able to retrofit them into existing streetscapes and on individual properties.

David went on the share case studies that are developing valuable experience and learning in this area.  He highlighted some of the challenges and complexities of improving surface water drainage in the complex network of London’s sewers and watercourses, as well as highlighting retrofit SuDS schemes at a street and individual property level.

View David Harding’s presentation

 

Owen Davies, Sustainability Engineer with the London Borough of Lambeth, contributed further examples of retrofitting SuDS in the public realm, with case study examples demonstrating the effectiveness of working at a local level.

Owen’s valuable presentation shared the practical lessons learnt and successes achieved in a number of schemes across the borough using a variety of SuDS retrofit techniques.

View Owen Davies’ presentation

 

Steve Wielebski, Divisional Development Director for Miller Homes and representing the Home Builders’ Federation sounded a strong note of caution in his presentation which looked at SuDS and surface water treatment from a developers’ perspective.

Steve’s presentation entitled “Contamination Run-off – Myth or Reality?” stressed the need for robust scientific evidence of surface water treatment performance.   He also argued that current Government policy states that any newly introduced legislation should be cost neutral and that new regulation such as the Flood and Water Management Act would need to meet this criterion.

View Steve Wielebski’s presentation

 

David Schofield, Associate Director with Hydro Consultancy, referred to the evidence and experience gained in the US, where the Clean Water Act 1972 has placed a greater priority on managing surface water quality.

David highlighted some of the pioneering results of surface water treatment projects in the US, and went on to ask the question:  “How can we ensure SuDS are authentically sustainable?”  Sustainable  development, he explained, meets the needs of the present without compromising the ability of future generations to meet their own needs.  But how can we validate the 50-year surface water performance of a swale?

In a stuttering economy we need to find a middle way for developers to build sustainably with SuDS and still make money, he stressed.

View David Schofield’s presentation

 

Alastair Moseley, representing J Murphy & Sons, provided a welcome and rare viewpoint of the contractor’s perspective in SuDS design and build.  He stressed the importance of involving the contractor from the early stages of planning for SuDS to ensure they are practical to build.

To deliver Water Sensitive Urban Design would challenge the construction industry to develop a wide range of skills.  Companies like Murphy have a diverse sector experience to help to deliver an integrated urban infrastructure.   Education and training for the future was key, he added.

Alastair also championed the importance of integrated water management and the need to rethink the water infrastructure to include both local water storage and treatment.

View Alastair Moseley’s presentation

 

Paul Stewart, Associate with consulting engineers Mayer Brown provided a case study from a housing development in Berewood, Waterlooville.  Paul gave a comprehensive presentation of the history and rationale behind the design of the pioneering SuDS features at Berewood.

Paul outlined a number of challenges encountered and lessons learnt on this continuing project.  He also referred to valuable work conducted in association with the Environment Agency and the University of Portsmouth to gather water quality data for the site.

View Paul Stewart’s Presentation

 

David Morgan, PhD candidate from the School of Engineering at Trinity College, Dublin, shared his research on Characterisation of Sediments and Associated Pollutants in Urban Runoff.

David provided a scientific perspective on the day’s discussions and outlined the results of research into the sampling of sediments from different catchments captured in a gully pot and a Hydro Downstream Defender®.

View David Morgan’s presentation

 

The final presentation of the day was given by Peter Coombs, Vice President, Business Development for Micro Drainage. Peter outlined perspectives for computer modelling of surface water treatment with SuDS, including ‘hard’ and ‘soft’ SuDS features.

To end the conference, there was a lively question and answer session which raised a number of important issues for policy development and implementation of SuDS schemes.

Overall, the conference provided an excellent opportunity to share experiences and to discuss approaches to a vitally important area of environmental protection.  We will only be successful if all agencies and commercial organisations work together.  We are all stewards of the environment  and each of us has a responsibility to work through our own organisations for that common good.

Did you miss this conference?  Would you like to be advised of future events?  Email Catrin Lewis clewis@hydro-int.com to make sure you are on our mailing list.

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