Risk Assessment and Risk Management in Small Urban Catchments
(part of the ERA-Net CRUE programme)
Project duration:
- November 2006-June 2007.
Funder:
- DEFRA. Contract Reference Number: CSA 7277.
CURE Staff:
- Ian Douglas (Chair of the PU-ECH Scientific Advisory Committee)
- Nigel Lawson
- Iain White
- Joanne Tippett
- Juliet Richards
Collaborators: (other members of the Scientific Advisory Committee)
- University of Manchester.
- Pennine Water Group, University of Sheffield.
- BRE Scotland.
- Technical University, Hamburg, Germany.
- CEREVE, École de Ponts et Chaussées, Marne-la Vallée, France.
Partners:
United Utilities, the Environment Agency and Rochdale Metropolitan Borough Council.
Urban areas greatly modify the runoff regimes of rivers, especially that of small streams which are totally within the built-up area. The catchments of these small rivers have a high proportion of paved areas that shed most of their surface water to sewers or stor, which may or may not have connections to the streams. The streams themselves may be culverted and hidden from view. Often they are part of the sewer network. Flooding commonly occurs from sewer overflows through manholes or roadside drain, but can also arise when urban stream culverts and bridges have insufficient capacity. These small urban catchments need their own flood management strategies. As, at the moment, each city or district tends to have its own mitigation strategy, some of which are highly successful, others less so. There is a strong need to exchange present good practice in flood management for these urban catchments at a European level and to identify improved ways of managing urban streams to cope.
The project is developing a methodological framework for flood management in small urban catchments. Based on case studies of urban river catchments of the cities Hamburg , Manchester, Bradford, Glasgow, Cologne, Dresden, Paris, and Lyon, the effectiveness and efficiency of non-structural measures to reduce flood damage is being analysed and evaluated with respect to
- the feasibility of assessing and mitigating flood risk from hidden watercourses and associated culverts in urban areas.
- The possibilities and ways to implement effective, non-structural solutions to minimise flooding from these sources.
- The value of “daylighting” urban streams by removing culverts and restoring open channels that include space for flood storage.
The project comprises 4 work packages:
- Legislative, planning, social, cultural and fiscal aspects of non-structural flood measures.
- Structure, effectiveness and efficiency of non-structural flood measures.
- Flood risk management strategies.
- Coordination and final reporting.
The following outcomes are expected:
- An understanding of, and thus a reduction in, the risk posed by small, often hidden, urban catchments.
- Good practice solutions for managing the risks posed by urban catchments.
- Stakeholder driven mitigation strategies to urban flooding by small catchments.
- A National and European assessment of how current planning systems both constrain, and also provide opportunities, to the sustainable and ecological management of small urban catchment.
- A prototype European framework for flood management in small urban catchments
- A transferable methodology for the effective application of non-structural solutions to flooding in urban environments.
- Input in to the goals of the European Flood Directive within the European Water Framework Directive.
The results will be of value to urban planners, regulators and the general public. They will provide regulators with a planning framework and will inform Local Authorities and water utility companies. The Greater Manchester case study area is Heywood in Rochdale Metropolitan Borough.