Research and analysis

Devon and Cornwall water situation: April 2025 summary

Updated 14 May 2025

Applies to England

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• Publication for Wales

1. Summary

Devon and Cornwall received 169% of the April long term average (LTA) rainfall, which was notably high for the time of year. Soil moisture deficit decreased overall during April, ending the month lower (wetter) than the LTA for the time of year. Monthly mean river flows were normal to notably high for the time of year across the area. Groundwater levels ended the month between normal to exceptionally high for the time of year. Total reservoir storage across Devon and Cornwall ended the month at 92%, with Wimbleball, Colliford and Roadford reservoirs at 93%, 86% and 96% respectively at the end of April.

2. Rainfall

Devon and Cornwall received 118mm of rain during April (169% of the April LTA), which is classed as notably high for the time of year. The first half of April was mostly dry, following an exceptionally dry March, with the most significant periods of rain taking place sporadically on 14 to 15 April, 17 to 18 April, and on 22 and 25 April. April was the fifth out of 7 months since the start of the water year (October) to have experienced above average rainfall.

In April, rainfall was normal to exceptionally high across Devon and Cornwall, with higher rainfall in Cornwall and west Devon and lower rainfall in east and north Devon. Cumulative rainfall was below normal to above normal in the last 3 months, and was normal across all hydrological areas in the last 6 months. In the last 12 months cumulative rainfall was normal to above normal for the time of year.

3. Soil moisture deficit

SMD increased in the first part of April reaching greater than the historic maximum deficit for the time of year, before decreasing significantly in the middle part of the month in response to the periods of heavy rainfall. The average deficit for most of Devon and Cornwall was between 11mm and 40mm, apart from west Cornwall where the average deficit was less than 10mm.

The SMD at the end of April was within 5 mm of the LTA across Devon and Cornwall for the time of year, except for east Devon where the SMD was 6mm to 25mm above (drier than) the LTA.

The SMD at the end of April was slightly lower (wetter) than the LTA for the time of year, but higher (drier) than the SMD at the end of April 2024.

4. River flows

April monthly mean river flows were normal for the time of year at most sites across the area, except for Bodmin Dunmere on the River Camel and Gwills on the River Gannel, which both recorded above normal monthly mean flows, and Truro on the River Kenwyn which recorded notably high monthly mean flows.

Following the initial period of dry weather in early April, daily mean flows increased at all sites in the middle of April in response to heavy rainfall, before falling again in the latter part of the month. On 30 April, all reporting sites in Devon recorded normal daily mean flows, whereas sites across Cornwall recorded normal to notably high daily mean flows.

Due to data accuracy concerns, Chudleigh Bridge on the River Teign has been excluded from the April report.

5. Groundwater levels       

On 30 April, groundwater levels were classed as follows:

• exceptionally high at Whitlands (monitoring the Upper Greensand)
• notably high at Winnards Perch (monitoring the Staddon Formation)
• above normal at Branscombe Lane (monitoring the Dawlish Sandstone) and Woodbury Common No2 (monitoring the Budleigh Salterton Pebble Beds)
• normal at Bussels No7A (monitoring the Dawlish Sandstone), Coleford Production (monitoring the Permian Breccias and Sandstones), and Woodleys No1 (monitoring the Otterton Sandstone Formation)

All groundwater sites were in recession by the end of April, which is normal for the time of year.

6. Reservoir stocks

Total reservoir storage was 92% at the end of April, which is an overall decrease in storage of 2% since the end of March, despite the small increase in storage in response to rainfall in the second half of the month. This is only slightly higher than total storage at the same time in 2022 (the most recent drought year), which was 89%. At the end of April, storage at Wimbleball (93%) was less than it was at the same time in 2022 (95%) and Roadford storage (96%) was similar to the same time in 2022 (95%). Colliford ended April at 86%, compared to 76% in 2022.

Author: Devon and Cornwall Hydrology, hydrology.dandc@environment-agency.gov.uk

All data are provisional and maybe subject to revision. The views expressed in this document are not necessarily the views of the Environment Agency. Its officers, servants, or agents accept no liability for loss or damage arising from the interpretation or use of the information, or reliance upon views contained in this report.