Thames water situation report: October 2024 summary
Updated 13 November 2024
Applies to England
© Crown copyright 2024
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1. Summary
Thames area received 80mm of rainfall in October which was 123% of the long term average (LTA). Soil moisture deficits (SMDs) at the end of the month was 5mm with an effective rainfall of 53mm. Monthly mean flows increased at majority of our indicator sites and more than half of the sites measured their highest ever October flows since site records began. Groundwater levels continued to increase at majority of our indicator sites with almost all the indicator sites recording exceptionally high groundwater levels. There were 26 flood alerts issued on rivers during October.
2. Rainfall
In October, Thames area received a total rainfall of 80mm which was 123% of the LTA. The rainfall amount across the area was consistent with no particular spatial trends and all the areal units were classed as normal for the time of the year. Total accumulated rainfall over the past 12 months remains exceptionally high across the entire area and it was the wettest 12 months since records began in 1871.
3. Soil moisture deficit and recharge
Despite a normal rainfall in October, the soils remain saturated due to exceptionally high rainfall in September. As a result, SMDs at the end of the month was 5mm which was below the LTA of 64mm. This allowed an effective rainfall of 53mm for the month of October, which was higher than 400% of the LTA (12mm).
4. River flows
Monthly mean river flows increased at the majority (87%) of our indicator sites in October. Exceptionally high river flows were recorded at all our indicator sites with the exception of 3; Swallowfield (River Blackwater), Weybridge (River Wey) and Tilford (River Wey) which were notably high for the time of year. More than half of our indicator sites recorded their highest flow since record began.
5. Groundwater levels
Groundwater levels increased at the majority of our sites due to recharge from heavy rainfall received over the past couple of months which was expected for the start of the winter period. These resulted in all the sites recording exceptionally high groundwater levels with the exception of 2 (Ampney Crucis in the Great Oolites and Frith Cottage in the Lower Greensand) which recorded a notably high levels for the time of the year.
6. Reservoir stocks
Reservoir stocks in the Farmoor reservoir increased to 98.8% at the end of October, which is above average for the time of year. Stocks in Lower Thames were 79.2% at the end of October, a slight decreased from 79.8% at the end of September and remains above the LTA for the time of year.
7. Environmental impact
During October, there were 26 flood alerts and no flood warnings issued on rivers in Thames area. At the end of the month no abstraction licences were being constrained in the area to protect water resources and the environment.
Author: Thames Area Groundwater Resources and Hydrology, enquiriesWT@environment-agency.gov.uk
Contact Details: 030708 506 506
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.