Research and analysis

Lincolnshire and Northamptonshire water situation: August 2025 summary

Updated 12 September 2025

Applies to England

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

1. Summary

After an average July August saw a return to dry weather with just an area of 17mm, just 27% of long term average (LTA). Soil moisture deficits (SMDs) remained high in Lincolnshire

and Northamptonshire (LNA). River flows and groundwater levels continued their seasonal decline. All reservoirs are below their normal operating curves.

2. Rainfall

August was a dry month across Lincs and Northants with most of the rain falling in the last 5 days of the month. The driest part was the Steeping, Great Eau and Long Eau with 14mm, 23% of LTA and the wettest was the South Forty Foot and Hobhole with 19mm, 31% of LTA. The dry August now makes it the third driest spring and summer period, March to August, since records began in 1871.

3. Soil moisture deficit and recharge

In response to the dry weather SMDs stayed high throughout LNA. The SMD on the 2 September was 131mm compared to LTA of 88mm for the end of August. In all 6 of the hydrological areas the SMD was more than 26mm of the LTA. This means that without above average rainfall a late start to the recharge period is expected.

4. River flows

In response to the low rainfall and continued decline in groundwater levels, river flows fell across LNA. Out of 12 sites reported on, 4 are classified as normal, 1 below normal, 5 notably low and 2 exceptionally low.

5. Groundwater levels 

Groundwater continued its seasonal decline during August. The Lincolnshire chalk sites are now classified as either below normal or normal. In the limestone the southern sites are classified as normal with the more northern sites being notably low, the sites in the middle are classified as below normal.

6. Reservoir stocks

Reservoir levels fell during August and all are below their normal operating curves.

7. Environmental impact 

The Trent-Witham-Ancholme transfer scheme operated throughout the majority of the month and the Slea Augmentation scheme was also in operation throughout August. The Gwash-Glen transfer scheme remained off. During August there were 28 hands off flows active across the area, with 9 resume notices issued after precipitation towards the end of the month. There were no flood alerts or warnings issued during August in LNA.

8. Forward look

8.1 Probabilistic ensemble projections for river flows at key sites

September 2025: Rivers are showing an increased probability of below normal or notably low flows this month.

December 2025: Rivers across the area are showing an increased probability of notably low flows this December. In the groundwater fed rivers in Lincolnshire, over 50% of the ensemble members are projecting notably low or exceptionally low flows.

8.2 Probabilistic ensemble projections for groundwater levels in key aquifers

September 2025: Groundwater levels are projected to be normal or below normal in the chalk and below normal or notably low in the limestone at the end of September.

March 2026: There is an increased probability of notably low levels in the limestone this March. In the chalk, over 50% of the ensemble members are projecting notably low or exceptionally low levels.

Author: Pan Hydrology Team, Hydrology-EAN-and-LNA@environment-agency.gov.uk

Contact details: 03708 506 506

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