Improving Probable Maximum Precipitation (PMP) and Probable Maximum Flood (PMF) estimation for reservoir safety
This project reviewed approaches for estimating probable maximum precipitation (PMP) and probable maximum flood (PMF) to recommend a way to improve the safety of our highest risk reservoirs.
Documents
Details
The probable maximum flood (PMF) is the greatest fluvial discharge that is realistically possible under contemporary climatic conditions for a catchment. It is estimated from the probable maximum precipitation (PMP). The PMP is the greatest depth of precipitation for a given duration that is meteorologically possible under contemporary climatic conditions for a catchment at a particular time of year.
The PMF is used to check the safety of the highest risk dams in the UK, where a breach of the dam could put lives in downstream communities at risk. It can also be used for assessing the safety of other very high risk infrastructure.
Most methods and data used to estimate the PMP and PMF have not been updated since the Flood Studies Report was published in 1975. This report describes the first phase of a project that aims to assess the suitability of methods for estimating PMP and PMF, and develop new methods to improve the safety of our highest risk reservoirs. The aim of Phase 1 is to review options for alternative approaches to estimating PMP and PMF. It also provides recommendations for future research developments which will take several years to carry out.
Accompanying the report are:
- a spreadsheet tool that uses the current method for estimating PMF, including calculating snowmelt
- the catalogue of extreme events used in the project
Project information
Project managers: Dr Sean Longfield, Dr Sarah Twohig.
This project was commissioned by the Environment Agency’s FCRM Directorate, as part of the joint Flood and Coastal Erosion Risk Management Research and Development Programme.
Updates to this page
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Project outputs published
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First published.