Research and analysis

Water situation: June 2023 summary

Updated 11 January 2024

Applies to England

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

June was another dry month with almost all catchments across England receiving below average rainfall. Soil moisture deficits increased with soils drier than would be expected for the time of year. River flows remained normal at half of the reported sites, although flows decreased at all sites. By the end of June groundwater levels had decreased at three-quarters of reported indicator sites compared to the end of May. Almost all end of month groundwater levels were classed as normal or higher for the time of year. Reservoir stocks decreased but just over half of reported sites remain classed as normal or higher for the end of June.

1. Rainfall

The June rainfall total for England was 41mm which represents 67% of the 1961 to 1990 long term average (LTA) for the time of year (68% of the 1991 to 2020 LTA). With the exception of 3 catchments in central and north-west England, all catchments received below average rainfall during June. The wettest hydrological area relative to its LTA was the Douglas catchment in north-west England which received 114% of LTA rainfall. The driest hydrological area was the Avon Dart and Erme catchment in south-west England which received 36% of the LTA rainfall for the time of year.

June rainfall totals were classed as normal for the time of year in over half of the catchments across England. Most of the remaining catchments were classed as below normal with just 3 classed as notably low and one classed as exceptionally low for the time of year. At the regional scale, south-east, central, north-west and north-east England all received normal rainfall during June. South-west and east England both received below normal rainfall for the time of year. June rainfall across England as a whole was normal for the time of year.

The 3 month cumulative rainfall totals show a much drier situation than the position last month, particularly for the north of England. Nearly all catchments in central and southern England have 3 month rainfall totals classed as normal while in northern England nearly all catchments are classed as below normal. Both the Upper Dee and the Dee catchments near the Welsh border recorded 3 month totals that were in the top ten driest on record for the end of June (records go back to 1891). The 6 month cumulative rainfall totals show below normal totals in north-east England in contrast to above normal totals in southern England. Twelve month cumulative rainfall totals were normal for most catchments in England apart from the south coast where many catchments were above normal or higher. Four catchments in Sussex have 12 month totals that fall within the top ten wettest on record.

2. Soil moisture deficit

Soil moisture deficits (SMD) had increased by the end of June following the below average rainfall and higher temperatures across the country. The rainfall in the middle of the month allowed some respite for northern England. By the end of the month SMDs for central and southern England had increased beyond where they were before the mid-month rain.

June SMD values across all of England were larger than average for the time of year, meaning soils were drier than would be expected. In parts of the south, south-west and west SMDs were more than 50mm larger than average.

At a regional scale, the end of June SMDs were larger than average for the time of year. This was particularly so in parts of south-west England where soils were close to their historic maximum dryness for June and drier than this point in both 2018 and 2022.

3. River flows

June monthly mean river flows decreased at all indicator sites we report on. Half of sites were normal for the time of year, while the remaining sites were fairly evenly split between higher than normal, below normal, notably low and exceptionally low. All the exceptionally low river flows were recorded in northern England. The River Swale at Crakehill Topcliffe was the lowest flow on record for the month (records go back to 1980).

Monthly mean river flows reduced at all regional index sites during June. June monthly mean flows at Offord on the Bedford Ouse, Horton on the Great Stour, Kingston on the Thames and Thorverton on the Exe were classed as normal. These sites are in east, south-east, south-east and south-west England respectively. Flows on the River Dove in central England were below normal. The River Lune in north-west England was notably low. Flows on the South Tyne in north-east England were classed as exceptionally low for the time of year.

4. Groundwater levels

By the end of June groundwater levels had decreased at three-quarters of reported indicator sites compared to the end of May. Almost all end of month groundwater levels were classed as normal or higher for the time of year. One site was below normal for the time of year.

The major aquifer index sites reflected a varied picture at the end of June, ranging from normal to exceptionally high levels. Normal groundwater levels for the time of year were reported at Dalton Estate Well in the Hull and East Riding Chalk, at Skirwith in the Carlisle Basin and Eden Valley Sandstone, at Jackaments Bottom in the Burford Jurassic Limestone, at Stonor Park in the South West Chilterns Chalk and at Weir Farm in the Bridgnorth Sandstone. Little Bucket in the East Kent Stour Chalk and Redlands Hall in the Cam and Ely Ouse Chalk were both above normal for the time of year. Chilgrove in the Chichester Chalk remains exceptionally high at the end of June after groundwater levels increased rapidly in spring.

5. Reservoir storage

Reservoir storage during June either decreased or remained similar throughout the country. The largest storage changes occurred at the Elan Valley reservoirs (near the Welsh border but supplying central England) as well as the Haweswater and Thirlmere Group (north-west England) with storage at both locations reducing by 17%. The Lower Thames Group (south-east England) was the only location to show an increase, with volumes rising by 1%. The decrease in storage throughout the month resulted in nearly half of reported reservoirs being classed as lower than normal for the time of year. Only 3 locations: the Lower Thames Group, Chew Valley and Stithians located in the south-east and south-west England continue to maintain above normal storage volumes.

At a regional scale, total reservoir storage reduced during June, with regional storage ranging from 76% in south-west England to 93% in south-east England. By the end of June the total storage for England was at 81%.

6. Forward look

The mid-July period is likely to experience unsettled conditions, with scattered showers throughout England. At times rainfall may be heavy with thunderstorms but interspersed with some clear and sunny spells. Rainfall for England is projected to be slightly above average during this period with temperatures expected to be close to normal for the time of year. The final weeks of July are likely to be drier and warmer than the first weeks, with forecasts of average to below average rainfall, alongside an increase in temperature.

For the 3 month period from July to September there is an increased chance of England experiencing heatwaves. However, near average temperatures and rainfall remain the most likely outcomes, punctuated by localised thundery downpours.

7. Projections for river flows at key sites

From now until the end of September 2023, rivers throughout England have a greater likelihood than might be expected of experiencing normal flows, with some increased likelihood of below normal flows observed in the east and west of the country. A similar trend can be observed in the projection through to March 2024; where 90% of rivers are more likely to maintain normal flows, with the remaining 10% experiencing an increased chance of below normal flows.

8. Projections for groundwater levels in key aquifers

By the end of September 2023 groundwater in the south of England has a greater likelihood than might be expected of levels classed as normal to above normal, with levels in Sussex more likely to be classed as exceptionally high. The remainder of England will likely experience normal groundwater levels with the exception of the Midlands, where above normal levels are more likely, and both Yorkshire and East Anglia where below normal levels are likely. By the end of March 2024, it is likely that groundwater levels throughout the country will remain at either normal or above normal, with the highest levels observed in south-east England and on the southern coast.

Author: National Water Resources Hydrology Team, [email protected].

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.