Research and analysis

Lincolnshire and Northamptonshire water situation: August 2026 summary

Updated 14 September 2026

Applies to England

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

1. Summary

August 2026 averaged 65mm of rain across Lincolnshire and Northamptonshire (LNA), 105% of the long term average (LTA) and normal for the time of year. Much of this rainfall fell in the last two weeks of the month and there was a strong response in the soil moisture deficit (SMD) which decreased by 33.2mm through August. Despite the rainfall, river flows remain low and 9 of the 12 key indicator sites had monthly mean flows below normal or lower. Groundwater levels also continue to decline. Reservoir stocks reduced by an average of 7.8% and all five sites remain below their respective target operating curves as demand remains high.

2. Rainfall

65mm of rain fell across LNA through August 2026, 105% of the LTA. All 6 hydrological areas recorded normal rainfall for August, between 81% LTA in Upper Welland and Nene and 121% LTA in Louth Grimsby and Ancholme. August 2026 contrasts with the previous few months in which rainfall totals have been below normal, or worse, and it is the first month in which most hydrological areas received greater than 100% LTA rainfall since February. 

When looking across the last 3 months, the incredibly dry July means rainfall totals in 5 of the 6 hydrological areas are below normal, and notably low in Upper Welland and Nene. Between June and August 114mm of rain fell across LNA, just 63% of the LTA. Observing the data over the past 6 months further demonstrates the dry conditions; 2026 experienced the sixth driest March to August since records began in 1871. Four of the 6 hydrological areas experienced exceptionally low rainfall over that period, with the Upper Welland and Nene having the fourth driest March to August and Lower Welland and Nene the fifth driest. LNA received just 57% of the LTA from March to August, with rainfall totals across the six hydrological areas ranging from 52% to 65% of the LTA.

Despite the dry 6 months, 107% of the LTA rainfall was recorded in LNA from September 2025 to August 2026. Four of the 6 hydrological areas recorded normal rainfall, while Louth Grimsby and Ancholme and Witham to Chapel Hill had above normal rainfall during this period. The contrast in rainfall across the area during the last 6 months and 12 months highlights the very wet winter that has been balanced out by a very dry spring and summer.

3. Soil moisture deficit and recharge

The SMD significantly reduced in response to the rainfall towards the end of August and averaged 100.8mm across LNA by 1 September, normal for the time of year. The SMD had reduced by 33.2mm compared to the deficit at the end of July, when it had been classified as exceptionally high, and all 6 hydrological areas saw a sharp reduction in their respective SMD. There is clear east-west divide in SMD, with the 3 hydrological areas to the west having an SMD between 88mm and 95mm, while the 3 to the east have an SMD between 113mm and 129mm by the end of the month. 

All 6 hydrological areas ended July with an SMD between 26mm and 50mm greater than the LTA. However, by the end of August, 3 of the areas had an SMD within 5mm of the LTA and the Louth Grimsby and Ancholme had an SMD between 6mm and 25mm less than the LTA. The Steeping Great Eau and Long Eau and South Forty Foot and Hobhole ended August with and SMD between 6mm and 25mm greater than the LTA.

4. River flows

River flow at the key indicator sites through August had been continuing July’s downward trend before a strong response to the heavy rainfall at the end of the month. However, despite the rain, 9 of the 12 sites ended August with a monthly mean flow below normal or less, with Wansford on the Nene recording exceptionally low flows. The River Lud at Louth recorded normal flows for the time of year, while the Rase at Rase Bishopbridge and the Welland at Ashley recorded above normal river flow. Monthly mean flows ranged from 22% of the LTA on the Welland at Barrowden/Tixover to 185% of the LTA at Rase Bishopbridge on the Rase.

5. Groundwater levels   

Groundwater levels across LNA continue to trend down despite a healthier volume of rain in August. Despite the trends, five of the key groundwater sites with data for this month still ended August with levels normal or above, with Barton, Horkstow Road recording above normal levels for the time of year. The three chalk sites in the north, in particular, are holding levels well. Both Leasingham Exploratory and Grange Farm are below normal and Grange de Lings is notably low for the time of year. There was no data available in August at Castlethorpe Bridge or Dunholme Road.

6. Reservoir stocks

Reservoirs stocks at the end of August 2026 were down by 7.8%, on average, from the beginning of the month as demand remained high. All 5 reservoirs are below their respective target curves. Stock levels vary from 86% full at Covenham, down 6% through August, to just 61% full at Hollowell, down 10% over the month. Rutland is now below Level 1 and Covenham and Pitsford levels are just above their Level 1 lines, however all sites remain about drought permit trigger 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