Risk assessment and risk management for small urban catchments

A case study exploring the effectiveness and limitations of non-structural measures (NSMs) for flood mitigation in small urban catchments.

From:
Environment Agency, Flood and Coastal Erosion Risk Management Research and Development Programme, and Department for Environment, Food & Rural Affairs
Published
18 February 2021
Category:
Understanding risks from all sources of flooding
Topics:
Communicating risk, Flood risk assessment, Flood risk governance, Health, safety and wellbeing, Investment, Natural flood management, Partnership working, Resilience planning, Resilient infrastructure, Spatial planning, Strategy and planning, Sustainable drainage systems
Project status:
Completed
Project code:
FD2603
Date of completion:
31 March 2008

Documents

Risk assessment and risk management for small urban catchments - final report (139 KB) PDF

Risk assessment and risk management for small urban catchments - technical summary (52 KB) PDF

Risk assessment and risk management for small urban catchments - figure 1 (185 KB) PDF

Risk assessment and risk management for small urban catchments - figure 2 (265 KB) PDF

Risk assessment and risk management for small urban catchments - figure 3 (244 KB) PDF

Risk assessment and risk management for small urban catchments - figure 4 (116 KB) PDF

Risk assessment and risk management for small urban catchments - appendices 1-3 (2 MB) PDF

If you use assistive technology (such as a screen reader) and need a version of this document in a more accessible format, please email: defra.helpline@defra.gov.uk. Please tell us what format you need. It will help us if you say what assistive technology you use.

Details

Objectives

This project aims to identify the efficiency of various methods of flood information in increasing risk awareness and readiness for appropriate response on the part of stakeholders in urban areas. This case study covers flood management in Heywood, Greater Manchester where storm-induced surface water flooding in 2004 and 2006 affected 200 homes. There was no previous history of flooding and the most likely causes of these flood events were:

  • urban infill
  • an ageing drainage system
  • two culverted urban streams
  • high intensity storms

This project:

  • explores the opportunities and limitations of non-structural measures (NSMs) for flood mitigation in small urban catchments
  • assesses the effectiveness of physical and ecological modifications to drainage systems (from green roofs to channel changes) in managing the risk of flooding in urban areas
  • assesses the social, economic and environmental effectiveness of NSMs in managing flood risk in developed urban areas

Outcome

This project contributes to our understanding of the causes of flooding from small, often hidden, urban rivers and streams. It improves the evidence base for selecting effective ways to manage such small urban catchments. In heavily urbanised areas, the scope for NSMs to manage flooding is potentially limited, but good urban design and increased risk awareness may offer opportunities.

This project develops a methodology for the effective application of NSMs in urban environments. The results will be of value to:

  • urban planners
  • regulators
  • water companies

This project provides regulators with a planning framework, which may influence the investment decision of local authorities and water companies with asset management responsibilities.

The findings from the case study have informed the inquiry into flooding by the House of Commons’ Environment, Food and Rural Affairs Select Committee. The outputs of the research will be integrated into the findings of the wider ERA-Net CRUE collaborative research project.

This project ran from 2006 to 2008 at a cost of £63,300.

Published 18 February 2021
Contents