Wessex water situation: April 2024 summary
Updated 15 May 2024
Applies to England
© Crown copyright 2024
This publication is licensed under the terms of the Open Government Licence v3.0 except where otherwise stated. To view this licence, visit nationalarchives.gov.uk/doc/open-government-licence/version/3 or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email: psi@nationalarchives.gov.uk.
Where we have identified any third party copyright information you will need to obtain permission from the copyright holders concerned.
This publication is available at https://www.gov.uk/government/publications/water-situation-local-area-reports/wessex-water-situation-april-2024-summary
1. Summary
April showed a slight reprieve to the very wet weather from the previous few months. An average of 68mm of rain fell across Wessex, 128% of the long term average (LTA). While April was not a record breaking month in terms of rainfall, the last 3, 6 and 12 months have been the wettest since records began in 1871. Soil moisture deficit (SMD) mainly remained close to 0mm, with some areas in the west of Wessex ranging between 11mm to 40mm at the end of the month. Monthly mean river flows were exceptionally high, notably high or above normal across the area. All groundwater monitoring sites across Wessex recorded either exceptionally, or notably high levels at the end of April. Throughout April reservoir levels for Wessex Water remained close to 100%, with Bristol Water reservoir levels remaining consistent at around 95% capacity.
2. Rainfall
An average of 68mm of rain fell across Wessex in April (128% of the LTA), making it comparatively drier than previous months. April had a wet start with 41% of the monthly total rain falling between 1 to 4 April. A total of 91% LTA rainfall for the whole month fell at the Tollerdown rain gauge over these first 4 days.
April 2024 was the 49th wettest since records began in 1871. However, due to previously high rainfall, it has been the wettest 3 months (February to April), 6 months (November to April) and 12 months (May to April) since our records began. In April all hydrological areas recorded either normal or above normal rainfall. Most hydrological areas in the east of Wessex recorded above normal levels, with all but one area in the west of Wessex recording normal levels. Longer term, all hydrological areas across Wessex received exceptionally high rainfall for the past 3, 6 and 12 month periods.
3. Soil moisture
SMD mostly remained close to 0mm across Wessex during April, but some areas to the south and south-west of Wessex recorded a range of 11mm to 40mm. The majority of Wessex recorded a SMD of 6% to 25% lower than the LTA, with areas to the west within 5% of the LTA.
4. River flows
All sites in Wessex recorded above normal, notably high or exceptionally high monthly mean flows in April 2024. All of the sites in the Chalk catchments were exceptionally high because previous months’ heavy rainfall was still filtering through the aquifer. Sites in quicker responding catchments had above normal or notably high flows, reflecting the rainfall seen during April. Half of the sites showed reduced flows at the end of the month in comparison to March, with the other half of sites maintaining the same banding. All daily mean flows decreased from the beginning of April to the end of the month in response to the lack of rainfall, after a sustained period of wet weather previously.
5. Groundwater levels
All groundwater sites across Wessex recorded exceptionally or notably high levels at the end of April. There was an even split between the sites monitoring the Chalk with 3 reporting notably high levels and 3 reporting exceptionally high levels. In the north of Wessex Didmarton (monitoring the Inferior Oolite formation) also recorded an exceptionally high level. After a sustained period of very wet weather Kingston Russell Road (monitoring the Chalk) and Didmarton reported their highest monthly mean values since their respective records began. By the end of the month all groundwater sites showed decreasing levels.
6. Reservoir stocks
The reservoir levels remained close to 100% capacity during April for Wessex Water, reporting at approximately 99% full which is similar to the levels recorded this time last year. Bristol Water reported to have approximately 95% full storage capacity which has remained steady throughout the month, this is around 5% lower than the end of April last year.
Author: Wessex Hydrology, hydrologywessex@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.