Research and analysis

South-east England water situation report: February 2025 summary

Updated 12 March 2025

Applies to England

• Publication for Northern Ireland
• Publication for Scotland
• Publication for Wales

1. Summary

February was a wet month with 120% of the long-term average (LTA) rainfall recorded across the south-east of England. The second half of the month accounted for nearly 70% of the monthly total. The soil moisture deficits (SMDs) rose slightly at the beginning of the month, then fell on 21 February in response to the rainfall. Most of the monthly recharge occurred after 21 February. During February, the key indicator flow sites recorded flows ranging from normal to notably high. There were 59 fluvial flood alerts, 4 flood warnings and 1 groundwater flood alert issued during the month. Across the south-east of England, the groundwater levels varied from normal to exceptionally high. The expected steady rise of groundwater levels for this time of year continued during the month.

2. Rainfall

February was a wet month with 120% of the LTA rainfall recorded across the south-east of England. The second half of the month accounted for nearly 70% of the monthly total rainfall on average. There was an average of 14 dry days during February, where the total rainfall for any day was less than 0.2mm. Notably, there was heavy rainfall on 9 February, with further significant rainfall occurring on 21 February. The most intense rainfall was recorded on 23 February, where a concentrated period of heavy rain impacted the region. The total rainfall on 9, 21, and 23 February accounted for an average of 50% of the monthly total, with 23 February alone accounting for 24%.

The top 5 daily rainfall totals were recorded in Solent and South Downs (SSD), all on 23 February. The highest daily rainfall total was 32.8mm, recorded at Princes Marsh, Western Rother Greensand, (SSD) on 23 February.

The rainfall totals for the 12 months ending February were among the highest 10 recorded for a number of areal units in the south-east, including:

• Berkshire Downs, THM, fifth wettest since 2001
• Chilterns West, THM, eighth wettest since 1961
• Thames, THM, seventh wettest since 1883
• Enbourne, THM, seventh wettest since 1961
• Test Chalk, SSD, seventh wettest since 1925

These statistics are reflected in the exceptionally high rainfall displayed for most of the THM and the far west of SSD in the rainfall map below for the last 12 months.

3. Soil moisture deficit and recharge

The SMDs rose slightly at the beginning of the month, then fell on 21 February in response to the rainfall. They remained low for the rest of the month and were generally below the end of month LTA. Most of the monthly recharge occurred after the rainfall from 21 February onwards when the SMDs had returned to zero. The recharge was on average 25% higher than what would normally be expected for February

4. River flows

During February, the key indicator flow sites experienced flows ranging from normal to notably high. Flows were notably high at 4 sites, above normal at 8 sites, and normal at 9 sites across the south-east. The Ver at Colney Street and the Mimram at Panshanger (both HNL) recorded the fourth and fifth highest February flows respectively and continued to be supported by high groundwater levels during the month. Both sites were in the notably high category. Apart from these 2 key indicator sites, all other sites recorded flows lower than those measured in February 2024. Rivers draining impermeable catchments were largely in the normal range for February, including the Lymingon River at Lymington (SSD) and the Teise at Stonebridge, Kent and South London (KSL).

There were 59 fluvial flood alerts, 4 flood warnings and 1 groundwater flood alert issued during the month.

5. Groundwater levels   

Across the south-east of England, groundwater levels varied from normal to exceptionally high. Half of the indicator sites recorded above normal or higher levels.

The expected steady rise in groundwater levels for this time of year continued during the month. Lilley Bottom (HNL) recorded the second highest February levels on record after 1991. In THM, Ampney Crucis (Cotswolds West) recorded the second highest February levels after 2020 and Stonor Estate (Chilterns West) recorded the third highest February levels after 2001 and 2014.

6. Reservoir stocks

Reservoir storage for February was above the LTA at all reservoirs across the south-east with the exception of Lower Thames (THM), Farmoor (THM) and Darwell (KSL) which is just below the LTA.

Author: groundwaterhydrology@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.