Specialists in flood frequency estimation at the Centre for Ecology & Hydrology (CEH) have made a major contribution to a new Environment Agency (EA) report aimed at better protecting UK residents and property from flooding.
CEH scientists joined collaborators, including those from the University of Bath and the University of Aberystwyth, to update and improve existing flood frequency estimation techniques with the addition of more local data.
This new set of enhanced methodologies is already being incorporated into guidance to practitioners and dedicated software tools to help inform decisions on the design and operation of flood defences, flood mapping and building in flood-risk areas.
The updates are intended to reduce the uncertainty associated with flood frequency estimation and as such increase the confidence of residents, government policy-makers and flood risk planners, industry, developers and insurers.
The main improvements, as outlined in the EA report 'Making better use of local data in flood frequency estimation', include the addition of local data to take account of:
- Short records of river flow
- River level measurements
- Information on flood seasonality or hydrograph widths
- Historical flood and palaeoflood data
- Information on river channel dimensions
Lisa Stewart, a Senior Hydrologist at the Centre for Ecology & Hydrology who collaborated on the EA report, said, "The outcome of the research is a set of updated procedures that will improve confidence in flood estimates and in particular will allow practitioners to make use of the wealth of historical evidence of extreme floods available in the UK".
The EA report also presents a proposal for a new system to improve access to local data to be integrated with the National River Flow Archive as well as a pilot study to develop high-resolution catchment descriptors – with the possibility of creating new ones to be used within the Flood Estimation Handbook methods.
"The outcome of the research is a set of updated procedures that will improve confidence in flood estimates and in particular will allow practitioners to make use of the wealth of historical evidence of extreme floods available in the UK." Lisa Stewart, Centre for Ecology & Hydrology
Among the conclusions drawn from the EA report are the challenges for the flood management sector to put into practice these updates and improvements to produce better estimates of design flows. The research is expected to have many benefits, including the reduction of uncertainty, flood frequency estimates that are more robust to challenge, and the enhancement of public credibility.
The 224-page EA report, as well as a 2-page summary, which was commissioned and funded by the joint Flood and Coastal Erosion Risk Management Research and Development Programme, can be accessed online.