Kent and South London water situation: August 2024 summary
Updated 13 September 2024
Applies to England
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1. Summary
The whole of the Kent and South London (KSL) area received 68% of the long term average (LTA) rainfall during August. Rainfall received across catchments in the area ranged from notably low to normal. Soil moisture deficits (SMDs) increased in most catchments in August due to the reduction of the effective rainfall received. Monthly mean flows (MMFs) ranged from below normal to exceptionally high in August. Groundwater levels during August continued to fall consistently across the whole KSL area, ranging from normal to exceptionally high for this time of the year. Levels in all 5 reservoirs in KSL decreased in August.
2. Rainfall
The whole of the KSL area received 68% of the LTA rainfall during August. Rainfall received across catchments in the area ranged from notably low to normal. Normal rainfall was recorded across most catchments in the south and in the Lower Mole in the west. Below normal rainfall was recorded in all other rainfall areas except North West Grain in the north, which received notably low rainfall. The percentage of LTA rainfall received across catchments ranged from 91% across Romney Marsh rainfall area to 45% in the North West Grain rainfall area. The highest daily rainfall total of 54.6mm for August was recorded at Eden Vale sewage treatment works (STW) rain gauge in the Medway catchment on the 1 August. The next highest daily rainfall totals were on 24, 15, 23 and 30 August and ranged from 24.8mm to 8.4mm. In August, 5 dry days where less than 0.2mm of rainfall was received were registered.
3. Soil moisture deficit and recharge
At the end of August, SMDs in the north and in the east of the patch ranged between 102mm and 134mm. SMDs in rainfall areas in the south-west registered slightly lower values ranging from 93mm and 100mm. SMDs increased in most catchments in August due to the reduction of the effective rainfall received. Across the whole area, on average, effective rainfall received this month was at 59% of the LTA.
4. River flows
MMFs ranged from below normal to exceptionally high in August. Five key flow sites saw normal MMFs, one in the south, 2 in the west and 2 in the central east of the patch. Three flow sites in the centre and one in the far east of the patch saw above normal and notably high MMFs during August. Teise at Stonebridge recorded the highest percentage LTA of 180% for the month of August, in part due to planned works at Bewl Reservoir. Teise was the only flow site that was in the exceptionally high category. Ravensbourne at Catford recorded the lowest percentage LTA of 74%, being the only flow site in the below normal category.
5. Groundwater levels
Groundwater levels continued to fall consistently across the whole KSL area, ranging from normal to exceptionally high in August. The Lower Greensand aquifer at Riverhead continues to register notably high groundwater levels for this time of the year. Groundwater levels in the Chalk aquifer are also mostly notably high. An exception are the key monitoring points in the west of the patch registering levels in the Chalk at Chipstead and Sweeps Lane that are assessed as normal and above normal, respectively. This is due to the drier weather seen in that area in August.
6. Reservoir stocks
Levels in all 5 reservoirs in KSL decreased in August.
At the end of August, reservoir levels were:
- normal at Bewl at 68% and Powdermill at 62%
- notably high at Weir Wood at 96%, Darwell at 76% and Bough Beech at 70%
7. Environmental impact
Hands off flow (HoF) constraints were applied to certain licensed abstractions within the Rother catchment and Little Stour/Wingham River during August. HoF constraints continue to apply to certain licensed abstractions within the Upper Stour and Medway catchments. Seven fluvial flood alerts and one flood warning were issued in the first 2 days of August.
Author: Groundwater and Hydrology Team, ksl.gwh@environment-agency.gov.uk
Contact Details: 03708506506
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.