Climate Change Allowances - Peak River Flow by Management Catchment

This dataset contains peak river flow allowances showing the anticipated changes to peak flow by management catchment. It contains information generated by UK Centre for Ecology and Hydrology using UK Climate projections.

The Environment Agency uses peak river flow allowances as benchmarks for the advice it gives as a statutory consultee for flood risk assessments and strategic flood risk assessments (https://www.gov.uk/guidance/flood-risk-assessments-climate-change-allowances). The Environment Agency also uses peak river flow allowances in guidance for risk management authorities when claiming Flood & Coastal Erosion Risk Management Grant-in-Aid in support of new projects, schemes and strategies (https://www.gov.uk/guidance/flood-and-coastal-risk-projects-schemes-and-strategies-climate-change-allowances).

Allowances are included for three future time-frames - 2020's, 2050's and 2080's. The 2020's epoch is 2015 to 2039, 2050's epoch is 2040 to 2069 and the 2080's epoch is 2070 to 2125.

The range of allowances included is based on percentiles. A percentile describes the proportion of possible scenarios that fall below an allowance level. The 50th percentile is the point at which half of the possible scenarios for peak flows fall below it, and half fall above it.

The:

• central allowance is based on the 50th percentile
• higher central allowance is based on the 70th percentile
• upper end allowance is based on the 95th percentile