1. Summary

East Anglia started 2025 wet with rainfall through much of the first week. January as a whole however has been particularly average, with most catchments observing both normal volumes of rainfall and river flows. Catchments in the south and west have been wetter on average, containing some above normal rainfall totals and river flows. Groundwater levels are healthy for the time of year with almost all measuring stations reading normal or above normal levels.

2. Rainfall

Rainfall in January was close to the monthly average across East Anglia, with almost all catchments receiving normal amounts of rainfall for the time of year. The Upper Bedford Ouse and North and South Essex are the only exceptions, receiving above normal levels. Most rainfall fell within the first and final week of the month, with all catchments receiving upwards of 20mm from the 1 to 7 January and again from 23 to 31 January.  Catchments in the northeast did receive noticeably less rainfall on average, being the only ones to receive less than 100% of their respective catchments’ long-term average. The last 3 months have been close to the long-term average, with the last 6 months slightly below though still normal in most catchments. The cumulative 12 months totals remain high owing to the high rainfall volumes in both February and September.

3. Soil moisture deficit and recharge

The soil moisture deficit at the end of January was slightly below the long-term average across East Anglia. Following the heavy rainfall and sharp SMD decline of September, the very average rainfall observed this January combined with low winter evapotranspiration rates has produced a slow but steady increase in soil moisture.

4. River flows

Like rainfall, river flows were close to average across much of the region, with almost all monitoring sites reading normal flows. The only exceptions to this were clay rivers in the upper and lower Bedford Ouse, responding to the above normal rainfall in these areas with above normal flows, and the chalk-fed Rhee, fed by very high groundwater levels in its proximity.

5. Groundwater levels   

Still impacted by the last year of high rainfall, groundwater levels remain above normal levels at many sites in the western catchments, being exceptionally high at Therfield Rectory. Catchments in the North and East are relatively lower for their areas by comparison, at normal levels with the exception of Hindolveston which is below normal. This can be attributed to these catchments receiving below average rainfall for the past 6 months while those in the west and central areas receiving more.

6. Reservoir stocks

Reservoir storage in public water supply reservoirs is healthy for the time of year, with each above their respective normal operating curves.

7. Forward look

7.1 Probabilistic ensemble projections for river flows at key sites

River flow projections are predicting over 70% of normal or above flows by March 2025 for all modelled catchments, and above 30% chance of slightly above normal or higher flows. For June 2025, the it is predicted that there will be almost no likelihood of below average flows

7.2 Probabilistic ensemble projections for groundwater levels in key aquifers

Much like the current levels, groundwater projections for March predict normal or above levels for all modelled sites, with Therfield Rectory in the west projecting notably high or exceptionally high levels with almost certainty. Forecasts for September are much the same, though shifted more towards normal levels at all sites. There is also a small likelihood of below normal levels at boreholes in the central region for September.

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.