East Anglia water situation: March 2025 summary
Updated 14 April 2025
Applies to England
© Crown copyright 2025
This publication is licensed under the terms of the Open Government Licence v3.0 except where otherwise stated. To view this licence, visit nationalarchives.gov.uk/doc/open-government-licence/version/3 or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email: psi@nationalarchives.gov.uk.
Where we have identified any third party copyright information you will need to obtain permission from the copyright holders concerned.
This publication is available at https://www.gov.uk/government/publications/water-situation-local-area-reports/east-anglia-water-situation-march-2025-summary
1. Summary
Rainfall across East Anglia was exceptionally low for this time of year and no higher than 21% of the long term average (LTA) within any of the catchments. This loss in rainfall directly affected SMD levels, which increased significantly to between 11mm and 40mm, and river flows, which were normal to below normal of the LTA. Groundwater levels remain healthy with most catchments at normal for this time of year. Public water supply reservoirs are above, or in line with, their respective operating curves.
2. Rainfall
March 2025 was an extremely dry month across East Anglia, with all but one catchment experiencing exceptionally low rainfall totals, and no catchment receiving more than 21% of their LTA rainfall totals for the month. Upper Bedford Ouse was the only catchment above exceptionally low rainfall, but still only experienced 15% of the LTA rainfall for the catchment. The exceptionally low totals in March have meant the past 3 months of rainfall have been close the LTA in the south of East Anglia, but the northern catchments have experienced below average rainfall, and the northern-most catchments have experienced notably low rainfall totals. Over a longer timeframe, flows have been much closer to average in the past 6 months and the past 12 months has seen average rainfall across most catchments, with above normal or exceptionally high rainfall totals in the west of East Anglia.
3. Soil moisture deficit and recharge
The soil moisture deficit (SMD) has increased to between 11mm and 40mm across all East Anglia catchments, compared to less than a 10mm deficit across all catchments by the end of February 2025. The increase in the SMD in the western catchments has meant levels are 6mm to 25mm above average deficits for this time of year, while the eastern catchments have experienced a deficit 26mm to 50mm above the LTA. The SMD across East Anglia has significantly increased in the past month, a direct result in the lack of rainfall across the region, and could continue as temperatures rise and rainfall drops into the spring.
4. River flows
Despite the drop in rainfall, the majority of catchments saw a normal river flow for this time of year. One site continued above normal, the Rhee, benefitting from the high groundwater level in the area. The eastern catchments saw below average river flows in the Gipping, Waveney, Wensum and the Yare, correlating with higher SMD and exceptionally low rainfall totals. The lack of rainfall meant river flow charts trended down throughout March 2025.
5. Groundwater levels
Groundwater levels through March 2025 in East Anglia were predominately normal to above normal compared to the LTA. Biggleswade and Redlands Hall catchments had above normal groundwater levels, while Therfield levels were exceptionally high. All three of the sites above normal are in the south west of East Anglia, while the sites in the north east, Hindolveston and The Spinney Costessey, experienced below normal groundwater levels for this time of year.
6. Reservoir stocks
Storage in East Anglia public water supply reservoirs remain on, or above, the normal operating curves at their respective sites at the end of March 2025. Alton and Ardleigh levels did drop throughout the month, but remain above the normal operating curve.
7. Forward look
7.1 Probabilistic ensemble projections for river flows at key sites
River flow projections for East Anglia show a high probability of normal, or higher, river flows by the end of June 2025, despite the low rainfall and increasing soul moisture deficit. The likelihood of flows below normal are less than 10% at all sites, except the Ely Ouse which has a 46% likelihood of flows being below normal or lower. Projections to September 2025 also predict high flows, with notably high flows having a likelihood of over 15% at all sites except Ely Ouse, which has a likelihood of below normal flows of 37%.
7.2 Probabilistic ensemble projections for groundwater levels in key aquifers
Groundwater projections for September 2025 in East Anglia suggest groundwater levels should be normal or above at the majority of projected sites, with only Bury St Edmunds, 48.7%, and Bircham Newton and Newmarket, both less than 12%, having a likelihood of below normal groundwater levels. Projections for March 2026 have greater uncertainty due to the extended timeframe, however groundwater levels are likely to be normal or above. March 2026 projections also have over a 25% likelihood of groundwater levels being below normal at all projected sites.
Author: Hydrology Team, hydrology-ean-and-lna@environment-agency.gov.uk
All data are provisional and may be subject to revision. The views expressed in this document are not necessarily those of the Environment Agency. Its officers, servants or agents accept no liability for any loss or damage arising from the interpretation or use of the information, or reliance upon views contained in this report.