Improving Probable Maximum Precipitation (PMP) and Probable Maximum Flood (PMF) estimation for reservoir safety

We’re assessing the suitability of existing methods for estimating PMP and PMF. We're developing new methods and guidelines to understand risks posed to reservoirs from extreme flood events.

From:
Environment Agency and Flood and Coastal Erosion Risk Management Research and Development Programme
Published
2 September 2021
Category:
Understanding risks from all sources of flooding
Topics:
Big data, Meteorology, Modelling, Reservoirs
Project status:
Ongoing
Project code:
FRS19222
Date of start:
12 October 2020

Documents

Documents will be published when the project is complete. Expected publication of phase one outputs is Winter 23/24.

Details

Design guidance at high risk reservoir spillways require the spillway to discharge the flood arising from a Probable Maximum Flood (PMF) event. The PMF is generated from the Probable Maximum Precipitation (PMP), both of which are intended to be near the limit of the credible worst case. Current methods for estimating PMP and PMF date back to the 1970s and require updating.

The first phase of the project will:

  • create and populate a catalogue of extreme historical rainfall and flood events
  • review alternative, updated methods for estimating PMP and PMF
  • develop options for updating current methods for estimating PMP and PMF
  • provide a science report and summary of the findings

Phase 2 will update the methods and associated data gathered from phase one of the project.

Published 2 September 2021

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