East Anglia water situation: March 2024 summary
Updated 15 April 2024
Applies to England
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1. Summary
Following an extremely wet February, rainfall during March was normal across much of East Anglia with no areas experiencing exceptionally high rainfall as all did last month. Regional soil moisture deficit (SMD) has transitioned from exceptionally low to below normal since February, but soils remain close to field capacity. Monthly river flows were subsequently exceptionally high at several sites due to good responsiveness to the rainfall received. Furthermore, high base flow is likely contributing due to the exceptionally high groundwater levels across the majority of the region, which are still recharging at a number of locations. All reservoirs are at or above their normal levels, with most above their normal operating curves.
2. Rainfall
March 2024 rainfall was normal for most hydrological areas, with only the Lower Bedford Ouse, South Essex and Cam receiving above normal rainfall and the Upper Bedford Ouse receiving notably high rainfall. The 3, 6 and 12-month totals for the region are almost entirely dominated by exceptionally high rainfall, with no areas for any total classified as normal or below.
3. Soil moisture deficit and recharge
The East Anglia SMD for the end of March in all areas was below 10mm with a regional average of 6mm, which is below normal for the time of year. This has increased both in value and relative to the long term average (LTA) since February for the end of which the SMD was notably low at 2mm. Recharge has stopped at most monitoring boreholes for which we have data, but continues at 7 boreholes which have shown an increase in groundwater levels since February.
4. River flows
Monthly average river flows for March have remained exceptionally high for a number of sites in the North and West of the region, with many more being notably high. The only exceptions are the Bure, Yare, Waveney and Gipping in the East, which have above normal flows. Though rainfall this past month was reduced significantly, the high groundwater levels and soil moisture are maintaining these high flows through base flow and high amounts of runoff from the reduced rainfall.
5. Groundwater levels
Groundwater levels have stopped rising at all but 7 of the monitoring sites for which we have sufficient data. Despite the reduced rainfall this month, the exceptionally wet past few months have led to significant amounts of recharge which is still seeing a lagged response at these locations. Levels remain exceptionally high at all monitoring sites except for Rook Hall at above normal levels and Therfield Rectory at notably high levels. There is a fair likelihood that that these regional levels will remain above normal at many locations late into the year.
6. Reservoir stocks
Reservoir stocks remain at good levels, Grafham at a normal 85% capacity and all others above normal or higher at 90 to 98% of their capacity. Grafham and Ardleigh are slightly below their normal operating curves for the time of year.
7. Forward look
7.1 Probabilistic ensemble projections for river flows at key sites
The river flow projections indicate a very high likelihood of normal and above normal flows for June 2024, with a fair likelihood of notably high and exceptionally high flows. The likelihood of notably high and exceptionally high flows is projected to increase for September.
7.2 Probabilistic ensemble projections for groundwater levels in key aquifers
Groundwater levels are predicted to have a high likelihood of remaining exceptionally high or notably high at a number of locations by September 2024, and none are projected to fall below normal levels. By March 2025, it is predicted that there is a chance that levels at almost all sites will fall to below normal or notably low levels, but it is more likely that levels will remain normal or above.
Author: Hydrology, 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.