Research and analysis

Water situation: April 2024 summary

Updated 14 May 2024

Applies to England

April was another wet month across England, with all except one catchment receiving above average rainfall. England as a whole received 154% of the long term average (LTA) for the time of year. The north-west was particularly wet, with the wettest April since records began in 1871. Soil moisture deficits (SMD) remain close to zero across most of England, although soils have begun to dry in the north-west and parts of south-west and central England. Monthly mean river flows decreased at most sites, but almost all sites were still classed as above normal or higher in response to ongoing wet spell. Groundwater levels told a similar story, with two-thirds of sites recording decreased levels at the end of April but almost all sites continue to be classed as notably high or exceptionally high. Reservoir storage decreased at just over half of the reservoirs we report on, although changes were small and storage for England as a whole remained the same as the end of March.

1. Rainfall

The rainfall total for England for April was 85.5mm which represents 154% of the 1961 to 1990 LTA for the time of year (152% of the 1991 to 2020 LTA). South Forty Foot and Hobhole in east England was the driest catchment and the only one to receive rainfall lower than the LTA for April, with just 43.4mm of rainfall which represents 95% of the LTA. In contrast, Eden in north-west England was the wettest catchment, having received 152.6mm of rainfall which is 232% of the LTA.

Rainfall totals for April were classed as normal or higher in all catchments in England, with 14% of catchments classed as normal for the time of year. Nine catchments, mainly in the north-west, were classed as exceptionally high. Just over a quarter of catchments were classed as notably high for the time of year, and the remaining half of catchments were above normal. At the regional scale, rainfall totals were above normal in south-east, central and east England. In north-east and south-west England rainfall totals were notably high. In the north-west, exceptionally high rainfall was received and it was the wettest April since records began in 1871. For England as a whole, rainfall was notably high for the time of year.

The 3-month cumulative totals were exceptionally high for almost all catchments, and 69 catchments recorded the highest 3-month total ending in April since records began in 1871. The last 6 months were also wet, with just 2 catchments receiving rainfall in a band lower than exceptionally high. For the 12-month period ending in April, 90% of catchments were classed as exceptionally high, with the remaining catchments either notably high or above normal. Over the 18-month period starting in November 2022 and ending in April 2024, England as a whole and 81 catchments (58% of the total) have been the wettest on record (since 1871).

2. Soil moisture deficit

Despite above average rainfall across England, the warmer temperatures and increased evapotranspiration associated with spring have helped soils in some parts of England begin to dry. In east England and in parts of south-west, central and north-west England SMD had begun to develop at the end of April. Across the rest of the country, soils remained saturated.

Across most of England SMD remained wetter than the LTA for the time of year. In the north-west, western central and parts of the north-east, soils were around the LTA, with some areas in north Wales and Lancashire slightly drier than expected for the time of year.

3. River flows

Monthly mean flows decreased at almost all indicator sites in April. Monthly mean river flows were classed as above normal or higher at almost all sites, with just 3 sites classed as normal for the time of year. Twelve sites (22% of the total) were classed as above normal, and 21 sites (38% of total) were notably high. The remaining 19 sites (35% of total) were classed as exceptionally high for the time of year.

Despite decreasing flows across most of the country, 10 sites recorded their highest monthly mean flows for April on record (record start given in brackets):

• in the north-east, the River Till (since 2001) and South Tyne (since 1974)
• in the north-west, the River Eamont (since 1970) and River Weaver (since 1977)
• in east England, the River Nene (since 1970)
• in the south-east, the River Kennet (since 1972)
• in the south-west, the middle River Avon (since 1965), River Frome (since 1965), River Tamar (since 1956) and River Kenwyn (since 1968)

Almost all regional indicator sites saw a decrease in monthly mean flows in April. Haydon Bridge on the South Tyne in the north-east was the only regional site to see an increase in flows, and was classed as exceptionally high. The River Lune in the north-west was also classed as exceptionally high. The River Dove in central England, and the Great Stour and the naturalised flows on the River Thames in south-east England were all classed as notably high in April. In east England, the Bedford Ouse was classed as above normal, as was the River Exe in the south-west.

4. Groundwater levels   

At the end of April, groundwater levels had decreased at two-thirds of the indicator sites we report on. Of the 7 sites (27% of the total) which recorded an increase in levels, 4 were in the north-west. Just 2 sites had groundwater levels classed as normal for the time of year, and 3 sites were classed as above normal. Just under a quarter of sites were classed as notably high, and the remaining 15 sites were classed as exceptionally high for the time of year.

Six sites recorded their highest end of April level on record (record start given in brackets):

• Aycliffe (since 1979) in Skerne Magnesian Limestone in the north-east
• Priors Heyes (since 1972) in West Cheshire Sandstone in the north-west
• Weir Farm (since 1983) in Bridgnorth Sandstone in central England
• Four Crosses (since 1990) in Staffordshire Sandstone in central England
• Coxmoor (since 1990) in Idle Torne Sandstone in central England
• Redlands Hall (since 1963) in Cam and Ely Ouse Chalk in east England

Groundwater levels decreased at most of our aquifer index sites in north-east, east and south-east England in April. Weir Farm (Bridgnorth Sandstone) recorded an increase in levels and ended April classed as exceptionally high. In the north-west, Skirwith in the Carlisle Basin Sandstone was also classed as exceptionally high as groundwater levels increased. Jackaments Bottom in the Burford Jurassic Limestone of the south-east was the only aquifer index site classed as normal for the time of year. The other 3 aquifer index sites in the south-east (Chilgrove, Little Bucket and Stonor Park) which are all in Chalk aquifers were classed as exceptionally high for the time of year. In east England, Redlands Hall (Cam and Ely Ouse Chalk) was classed as exceptionally high at the end of April. Dalton Estate in the Hull and East Riding Chalk was classed as notably high.

5. Reservoir storage

Reservoir storage decreased during April at just over half of the reservoirs and reservoir groups we report on, although these decreases were 5% or less. Of the 10 sites (32% of the total) which saw storage increase, Farmoor reservoir in the south-east recorded the largest increase of 8%. Ten reservoirs or groups were 100% full at the end of the month. At the end of April, the majority of reservoirs or reservoir groups were classed as normal or higher. Only the Dee System which has ongoing maintenance work, and Grafham Water which has been impacted by limited abstraction opportunities earlier in the year, were classed as below normal for the time of year.

At a regional scale, total reservoir storage showed little change at the end of April, with the largest increase being 3% in east England. For England as a whole, storage remained at 95% at the end of April.

6. Forward look

May started with a continuation of the unsettled, wet conditions that have dominated over recent months. Following a brief dry spell, this trend is likely to continue throughout May, particularly during the middle of the month when above average rainfall resulting in heavy, thundery, showers is expected, across most of the country. Near average temperatures are likely throughout this period. Towards the end of May temperatures are expected to rise to above average with signs that the south and east England will receive less rainfall than the north and west.

For the 3 month period between May and July, there is a higher likelihood that the UK will experience warmer and wetter conditions 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 normal or higher across England, with the greatest flows projected in south-east England, where many sites are projected to be above normal or higher.

By the end of March 2025, river flows across England have the greatest chance of being normal or higher, particularly in the south-east where there is greater likelihood of above normal or higher flows.

8. Projections for groundwater levels in key aquifers

By the end of September 2024, groundwater levels in across England have a greater likelihood of being normal or higher, with sites in chalk and sandstone aquifers likely to be above normal or higher.

By the end of March 2025, groundwater levels across most of England have a greater likelihood of being normal or higher, Skirwith in north-west England is the only site likely to be notably high or higher.

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.