Research and analysis

Water situation: March 2024 summary

Updated 10 April 2024

Applies to England

It has been another wet month across England with nearly all catchments receiving above average rainfall during March. Rainfall for England over the last 6 months have been the wettest on record. Soil moisture deficits (SMD) remained close to zero across England, with many parts of the country ending March with wetter than expected soils. River flows decreased at four-fifths of indicator sites however all sites were classed as normal or higher with the highest monthly mean flows for March recorded at many sites across southern England. Groundwater levels increased at over half the sites we report on and levels at more than three-quarters of sites were classed as exceptionally high for the time of year with highest levels for the end of March across multiple sites and aquifers. Groundwater flooding alerts and warnings remain active across many chalk catchments of central southern England. Reservoir storage increased at more than a third of the reservoirs we report on and the majority of reservoirs were classed as above normal or higher. 

1. Rainfall

The rainfall total for England for March was 94.3mm which represents 142% of the 1961 to 1990 long term average (LTA) for the month (196% of the 1991 to 2020 LTA). Nearly all catchments received above average rainfall during March, while only 6 catchments received below average rainfall. The wettest hydrological area relative to the LTA was the Avon Dart and Erme catchment in south-west England which received 204% of LTA rainfall. The driest hydrological area was north Norfolk in east England which received 74% of LTA rainfall in March.

March rainfall totals were classed as above normal or higher for the time of year at more than four-fifths of catchments in England. Fifteen catchments were normal for the time of year, mainly in north-east and east England. At the regional scale, rainfall totals were exceptionally high for the time of year in south-west England, with south-east and central England recording notably high rainfall totals. Rainfall totals in north-east and north-west England were classed as above normal and east England had normal rainfall totals for March. Rainfall for England as a whole was notably high for the time of year.

The 3-month cumulative totals were exceptionally high across nearly three-quarters of catchments in England with the remaining catchments classed as either notably high or above normal. The last 6 months have also seen exceptionally high cumulative totals at all but 2 catchments across country and it has been the wettest 6 month period ending in March since 1871 for 50 catchments (36% of the total). It has also been the wettest 6 month period for east and central England as well as England as a whole since 1871. The 12-month cumulative totals were exceptionally high in nearly all but 15 catchments and it has been the wettest 12 months ending in March since 1871 for 18 catchments. Since October 2022, it has been the wettest 18 month period (from October 2022 to March 2024) on record for England, with 50% of catchments also having their wettest 18 month period.

2. Soil moisture deficit

Across England soils remained saturated throughout March. SMD throughout the country have remained close to zero since October 2023.

SMD across most of north-west England were around the LTA for the time of year, however, across many parts of the north-east, central, east, south-west and south-east England soils were wetter than would be expected for the time of year.

3. River flows

Monthly mean flows decreased at four-fifths of indicator sites in March. The remaining fifth of indicator sites saw an increase in monthly mean flows compared to the previous month. Monthly mean river flows were classed as normal or higher at all sites. Six sites, predominately in north-east England, were classed as normal for the time of year. Nine sites (16% of the total) were classed as above normal for the time of year and 33% (18 sites) were classed as notably high. Twenty two sites were exceptionally high (40%). Nine sites recorded their highest monthly mean flow for March on record, the:

• Nene (since 1970) in east England
• Kennet (since 1972)
• naturalised Thames at Kingston (using data since 1951) in the south-east
• River Frome (since 1965)
• Upper River Brue (since 1964)
• Upper Avon (since 1965) in the south-west
• Mid Avon (since 1965) in the south-west
• middle Stour (since 1968) in the south-west
• River Kenwyn (since 1968) in the south-west

Most of our regional index sites saw a decrease in monthly mean flows in March, with the only exception being naturalised flows at Kingston on the River Thames. Kingston and Horton on the Great Stour, both in south-east England, were classed as exceptionally high for the time of year. The Bedford Ouse in east England, the River Dove in central England and River Exe in south-west England all recorded notably high monthly mean flows in March. Caton on the River Lune in the north-west and Haydon Bridge on the South Tyne in the north-east recorded above normal and normal monthly mean flows respectively.

4. Groundwater levels   

At the end of March, over half the groundwater indicator sites we report on had recorded an increase in levels. At more than three-quarters of the indicator sites, groundwater levels were classed as exceptionally high for the time of year. Two sites were classed as notably high and another 3 were above normal for the time of year. Only Lea Lane in north-west England in the Fylde permo-triassic sandstone aquifer was classed as normal at the end of March. Six sites recorded their highest end of March groundwater level on record including:

• Grainsby in the Northern Chalk in east England (since 1977)
• Hanthorpe in the Lincolnshire Limestone (since 1972)
• Coxmoor in the Idle Thorne Sandstone (since 1990)

Groundwater levels increased at half our aquifer index sites in March.

Groundwater levels were classed as exceptionally high for the time of year at:

• Weir Farm (Bridgnorth Sandstone)
• Little Bucket (East Kent Stour Chalk)
• Chilgrove (Chichester Chalk)
• Redlands Hall (Cam and Ely Ouse Chalk)
• Stonor Park (South West Chilterns Chalk)

Weir Farm recorded their highest end of March groundwater level on record since 1983.

Skirwith (Carlisle Basin Sandstone) and Dalton Estate (Hull and East Riding Chalk) were both classed as notably high for the time of year. Jackaments Bottom (Burford Jurassic Limestone) in the south-east was above normal at the end of March.

5. Reservoir storage

Reservoir storage increased during March at more than a third of the reservoirs and reservoir groups we report on. The largest stock increases were at Bewl in the south-east and Hanningfield in the east which increased at 17% and 10% respectively. The majority of reservoirs at the end of March were classed as above normal or higher for the time of year. Roadford in the south-west remains exceptionally high. At Farmoor in the south-east storage was classed as below normal and Grafham Water in the east notably low, as high river flows limited abstraction opportunities. The Dee system, continues to be impacted by ongoing reservoir maintenance.

At a regional scale, total reservoir storage increased in all regions except north-east England where storage decreased slightly compared to February. In east and south-east England, overall storage increased by 4% during March. For England as whole, storage increased to 95% at the end of March.

6. Forward look

April started with a continuation of the unsettled, wet conditions that have dominated over recent months. This trend is likely to continue through the middle of the month, with heavy rain and windy conditions likely further north, while southern and eastern areas have the chance of drier spells with some sunshine. Towards the end of April and into the beginning of May, things are less certain with rain and showers likely along with sunnier spells of weather as would be expected for the time of year.

For the 3 month period between April and June, there is a higher likelihood that the UK will experience warmer, wetter and slightly windier conditions than normal for the time of year.

7. Projections for river flows at key sites

By the end of September 2024, river flows are projected to be above normal or higher across England, particularly in the south-east where sites are mostly projected to be exceptionally high.

By the end of March 2025, river flows across England have the greatest chance of being above normal or higher, except in the north where river flows are projected to be normal or higher.

8. Projections for groundwater levels in key aquifers

By the end of September 2024, groundwater levels in east, south-east and north-east England have a greater likelihood of being above normal or higher, particularly sites in Chalk aquifers.

By the end of March 2025, groundwater levels have a greater likelihood of being above normal or higher in north-west, south-east and east England. In south-west and central England, groundwater levels have the greatest likelihood of being normal or lower.

Author: National Water Resources Hydrology Team, Nationalhydrology@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.