Research and analysis

Lincolnshire and Northamptonshire water situation: March 2026 summary

Updated 14 April 2026

Applies to England

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

1. Summary

Following 3 consecutive months of exceptionally wet weather, and one of the wettest winters on record, March 2026 marked a transition back towards drier than normal conditions across the Lincolnshire and Northamptonshire Area (LNA). Monthly rainfall across the area was 68% of the long term average (LTA), representing a notable break in the sustained wet period experienced since late autumn.

Catchments, aquifers, and reservoirs continued to reflect the legacy of winter recharge, with river flows and groundwater levels generally remaining above normal for the time of year. The drier conditions led to a seasonal increase in soil moisture deficits, and a modest recession in river flows and groundwater levels at most sites.

Reservoir stocks across the area remained healthy, with all sites close to or above their normal operating curves.

2. Rainfall

Rainfall during March was notably lower than in preceding months, with much of the total falling during a single event on 12 March, which contributed nearly half of the monthly total. Outside of this day, conditions were predominantly dry.

Across LNA total average rainfall was 26mm (68% of the LTA), classifying the month as below normal. A clear north-south gradient persisted, with northern catchments receiving near-normal rainfall, while southern areas remained notably drier. For example, the Grimsby Ancholme Louth catchment recorded 41mm (103% LTA), whereas the Lower Welland and Nene received only 20mm (54% LTA).

Although conditions were much drier in March, longer-term accumulations continue to reflect the exceptionally wet winter period. The November to March period ranks as the wettest on record, while the 6-month period from October to March is the third wettest.

Furthermore, 12-month accumulations remain within the normal to above normal range, despite including the notably dry spring-summer period of 2025. This demonstrates the extent to which recent winter rainfall has offset earlier deficits.

3. Soil moisture deficit and recharge

Soil moisture deficits (SMDs) increased gradually throughout March in response to reduced rainfall and increasing evapotranspiration, typical of early spring. The mean SMD across the area rose from 4mm at the end of February to 18mm by the end of March.

Despite this increase, soils remained relatively wet for the time of year and within the normal range across all hydrological areas. Compared to the same period last year, soils ended March wetter than in 2025.

4. River flows

River flows across the area declined in response to reduced rainfall and the expected seasonal recession. Monthly mean flows generally fell from exceptionally high levels in February to normal to notably high levels in March. All key indicator sites recorded a short-lived increase in daily mean flow following the rainfall event on 12 March. Of the 12 indicator sites, 10 (over 80%) remained above normal, with some sites, such as the Lud at Louth, continuing to exhibit notably high flows. The remaining sites, including the Lymn at Partney and the Upper Nene at Geldharts Mill, recorded a monthly mean within the normal range.

By the end of the month, daily mean flows had generally receded to within the normal range at all sites except the Lud at Louth, which sits within the Lincolnshire Chalk.

5. Groundwater levels

Groundwater levels declined at most indicator sites; however, levels remained consistently above normal across the area. An exception to this trend was observed at Grainsby in the North Lincolnshire Chalk, where groundwater levels continued to rise, reaching the highest level on record for March.

By the end of the month, groundwater status classifications included:

• 2 sites classified as exceptionally high
• 4 sites classified as notably high
• 2 sites classified as above normal
• Grange de Lings classified as normal for the time of year

6. Reservoir stocks

Reservoir storage across the area remained very healthy, with nearly all sites operating at or above their normal operating curves. Pitsford and Hollowell reservoirs remained at 100% capacity throughout March, while Covenham showed notable recharge during the month.

7. Environmental impact

All transfer schemes remained switched off throughout March. There were 6 flood alerts and 16 flood warnings issued. No licence cessations were implemented during the month.

8. Forward look

8.1 Projections for river flows at key sites

June 2026: Model projections indicate a higher likelihood of normal flows across all forecast sites. Under below-average rainfall scenarios (60% to 80% of LTA), most sites are projected to remain within the normal flow range. Under average to wetter scenarios (100% to 120% of LTA), flows at most sites are also projected to remain within the normal flow range.

September 2026: Model projections indicate an increased probability of normal flows across the forecast sites. Under below-average to average rainfall scenarios (60% to 100% of LTA), flows at most sites are projected to fall within the normal range. Under a wetter scenario (120% of LTA), sites show a greater likelihood of normal or higher flows.

8.2 Projections for groundwater levels in key aquifers

September 2026: Model projections indicate a higher likelihood of above normal groundwater levels. Under below-average to average rainfall scenarios (60% to 100% of LTA), groundwater levels in the Chalk are projected to fall within the above normal range, while Leasingham Exploratory is projected to be lower than normal. Under a wetter scenario (120% of LTA), sites show a greater likelihood of normal or higher levels.

March 2027: Model projections are broadly in line with the expected probability for March. Under below-average to average rainfall scenarios (60% to 100% of LTA), most sites are projected to fall within the normal or lower range. At the 120% rainfall scenario, all sites show an increased probability of notably to exceptionally high levels.

Author: Pan 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

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