1. Summary

Devon and Cornwall received 136% of the January long term average (LTA) rainfall, which was above normal for the time of year. Soil moisture deficit (SMD) increased slightly during the middle of January before decreasing again in the second half of the month, ending the month similar to the LTA for the time of year. Monthly mean river flows recorded normal to above normal for the time of year across the area. Groundwater levels ended the month between normal and exceptionally high for the time of year. Total reservoir storage across Devon and Cornwall ended the month at 94% net storage, with Wimbleball, Colliford and Roadford reservoirs at 96%, 85%, and 100% of net storage respectively at the end of January.

2. Rainfall

Devon and Cornwall received 189mm of rain during January (136% of the January LTA), which is classed as above normal for the time of year. Rain fell throughout the month, but the most significant periods of rain occurred between 4 to 12 January and 21 to 30 January. January was the third month since the start of the water year in October to have experienced above average rainfall.

In January, rainfall was above normal or notably high in all hydrological areas. Cumulative rainfall in the last 3 and 6 months has been normal for the time of year across most areas. In the last 12 months, all hydrological areas recorded exceptionally high cumulative rainfall, except for the Taw and North Devon Streams hydrological area, where cumulative rainfall was notably high for the time of year.

3. Soil moisture deficit

SMD increased in the first part of January, before decreasing again in the second half of the month. The average deficit for Devon and Cornwall remained below 10mm for the whole of January, meaning the average deficit was similar to the LTA for the time of year. The SMD at the end of January was similar to the SMD at the end of January 2024.

SMD was less than 10mm across the whole Devon and Cornwall area on 28 January, which is close to the LTA.

4. River flows

January monthly mean river flows were normal for the time of year at all sites across the area for the time of year, except for Whitford on the River Axe, which recorded above normal monthly mean river flows for the time of year. Most reporting stations experienced a decrease in daily mean flows over the month with some peaks in response to rainfall. On 31 January, all reporting sites recorded normal to above normal daily mean flows for the time of year.

5. Groundwater levels   

On 31 January, groundwater levels were classed as follows:

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

6. Reservoir stocks

Total reservoir storage was 94% at the end of January, which is an increase of 5% in storage since the end of December. This is higher than the total storage at the same time last year and in 2022. At the end of the month, storage at Wimbleball, Colliford and Roadford was 96%, 85% and 100% of net storage respectively, compared to 100%, 78% and 89% this time last year.

Author: Environment Agency, 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.