South East water situation report: June 2024 summary
Updated 12 July 2024
Applies to England
© Crown copyright 2024
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1. Summary
There was only 36% of the long term average (LTA) rainfall for June across the south-east of England. This was the first month in a year when there was significantly below average rainfall. There were also, on average, 23 dry days when there was less than 0.2mm rainfall recorded. The low rainfall led to there being little to no effective rainfall. As a consequence the soil moisture deficits (SMD) rose steadily to end above the LTA for June. River flows generally declined through the month, although there were some small responses to the rainfall in the middle of the month at many of the sites. There were no fluvial flood alerts issued during June and the last groundwater alerts were also removed. Groundwater levels have declined during the month as is expected at this time of year. However, the high rainfall over the previous months has maintained high groundwater levels for June.
2. Rainfall
There was only 36% of the LTA rainfall for June across the south-east of England. This was the first month in a year when there was significantly below average rainfall. The wettest days were 13, 14 and 15 June when on average, there was over 60% of the monthly total rainfall recorded. The highest daily total was 22.9mm recorded at Poverty Bottom (SSD) on 14 June. There were also, on average, 23 ‘dry’ days when there was less than 0.2mm rainfall recorded.
This has been the driest June since 2018 for the:
- South-east
- Thames (THM)
- Hertfordshire and North London (HNL)
- Kent and South London (KSL)
- Thames catchment (THM)
3. Soil moisture deficit and recharge
The significantly below average rainfall led to there being little to no effective rainfall. As a consequence the SMDs rose steadily to end above the LTA for June. This was the first time SMDs were above the LTA since August 2023.
4. River flows
River flows generally declined through the month, although there were some small responses to the rainfall in the middle of the month at many of the sites. Generally, the Chalk baseflow-fed rivers in HNL and SSD in particular, were at higher flows, being at notably high and exceptionally high flows for June. The Ver at Colney Street (HNL) recorded the highest June flow on record and the Mimram at Panshanger (HNL) was at the fourth highest June flow on record, since 1983. Flows from the Upper Thames catchments (THM) were normal for the time of year. The Clay rivers, primarily around the Weald across KSL and SSD recorded lower flows and were at normal to above normal flows. The exception was the Arun at Alfodean (SSD) that recorded below normal flows.
There were no fluvial flood alerts issued during June and the last groundwater alerts were also removed.
5. Groundwater levels
Groundwater levels have declined during the month as is expected at this time of year. However, the high rainfall over the previous months has maintained high groundwater levels for June. All of the key indicator sites ranged from above normal levels to exceptionally high. There was one exception at Jackaments (THM) that was normal for June, but it is a site that responds quickly to recent conditions.
Levels at Lilley Bottom (HNL) and Wolverton (KSL) were their highest for June on record. Groundwater levels at Stonor and Gibbet Cottages (both THM) were the second highest on record for June since 2001. There were also levels at their third highest, also since 2001 at:
- Ashley Green (HNL)
- Little Bucket (KSL)
- Clanville Lodge (KSL)
6. Reservoir stocks
The reservoirs remain above average for June at all of the reservoirs across the South east with just two exceptions. Both Arlington (SSD) and Powdermill (KSL) ended the month just below the monthly LTA.
Author: groundwaterhydrology@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.