Improving surface water flood mapping using local drainage rates

This research project has developed new guidance to estimate local drainage rates when mapping and modelling surface water flood risk.

Documents

Improving surface water flood mapping: estimating local drainage rates - summary (213KB) PDF

Gwella mapio llifogydd o ddŵr wyneb amcangyfrifo - Welsh summary (260KB) PDF

Improving surface water flood mapping: estimating local drainage rates - technical report (4.4MB) PDF

Improving surface water flood mapping: estimating local drainage rates - user guidance (2.7MB) PDF

Improving surface water flood mapping: estimating local drainage rates - appendix C (84MB) EXCEL

Improving surface water flood mapping: estimating local drainage rates - appendix D (182KB) EXCEL

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Details

This research project has developed new guidance to estimate local drainage rates when mapping and modelling surface water flood risk.

The information can be used to validate and update the national maps, called the Risk of Flooding from Surface Water, which use a national average drainage rate.

The guidance provides simple approaches for Lead Local Flood Authorities to use to check if the national maps represent surface water flood risk in their area. The approaches can also be used to see how the flood maps may change with more or less drainage, and to test scenarios like future climate change.

This project proposes and tests approaches to estimate locally specific drainage rates. This will help users estimate the impact of any changes in drainage on the extent of potential flooding – and potentially inform investment decision-making.

Updates to this page

Published 24 February 2021