Research and analysis

Water situation: January 2023 summary

Updated 11 January 2024

Applies to England

• Publication for Northern Ireland
• Publication for Scotland
• Publication for Wales

Monthly rainfall totals in January were above average in the majority of catchments across England. Soil moisture deficits remained low across England at the end of January as is expected at this time of year. Following another month of above average rainfall in many areas river flows increased at almost all the indicator sites and most sites were above normal or higher for the time of year. As seasonal recharge of aquifers continued groundwater levels increased at almost all indicator sites, with groundwater levels at the end of January normal or higher in many places. Reservoir stocks in January increased at three quarters of the reservoir and reservoir groups we report on, but as reservoirs continued to recover from dry conditions last year almost half remained below normal or lower for the time of year.

1. Rainfall

The January rainfall total for England was 90.5mm which represents 113% of the 1961 to 1990 long term average (LTA) for the time of year (109% of the 1991 to 2020 LTA). At the regional scale, rainfall was slightly below average in east, central and north-east England, while north-west, south-west and south-east England received above average rainfall in January. Three quarters of catchments received above average rainfall during January. The wettest hydrological area was Kent in south-east England which received 159% of LTA rainfall for January. The driest hydrological area was the Tweed in north-east England with 49% of LTA rainfall for January.

January rainfall totals were classed as normal or higher for almost all catchments across England. Only 4 were classed as below normal for the time of year, including 3 in north-east England. Tweed in the far north-east of England was the only catchment classed as notably low for the time of year. At a regional scale, January rainfall totals were normal in most regions and for England as a whole. North-west and south-west England were above normal for the time of year.

January was the fifth consecutive month of above average rainfall for England as a whole. The last 3 months were wetter than average for much of the country, with notably high and exceptionally high totals in many catchments in the south of England, and above normal total elsewhere. The 6 month cumulative rainfall totals show a similar pattern, with notably high or exceptionally high totals in the south. The 12 month cumulative rainfall totals were classed as normal for most of the country, although some in the east of England were below normal or lower and some on the south coast and in the north-west were above normal.

2. Soil moisture deficit

Soil moisture deficits (SMD) remained low across England at the end of January, with soils wet across most of the country as would be expected for the time of year.

End of January SMD values across the majority of the country were close to the LTA for the time of year. At a regional scale, the end of January SMD for most regions were typical for the time of year.

3. River flows

January monthly mean river flows increased compared to December at all except 2 indicator sites we report on. Two thirds of sites were above normal or higher for the time of year, including nine sites that were exceptionally high for the time of year. Eight of these sites were in south-west England where all sites were above normal or higher. All the remaining sites were normal for the time for the year except the River Burn at Burnham which was below normal.

Monthly mean flows for all the regional index sites were classed as normal or higher for the time of year. Flows on the River Thames at Kingston, the South Tyne at Haydon Bridge and the Bedford Ouse at Offord were normal for the time of year. The River Dove at Marston-on-Dove and the Great Stour at Horton were both above normal for the time of year, with the River Dove having moved from being below normal in December. The River Lune at Caton was notably high and the River Exe at Thorverton in south-west England was exceptionally high.

4. Groundwater levels

At the end of January, groundwater levels increased at all but 4 of the reported indicator sites as wet soils and above average rainfall in many areas helped aquifers continue their seasonal recharge. Just under half were classed as above normal or higher. A third of end of month groundwater levels were classed as normal for the time of year. Four sites were classed as being below normal for the time of year.

The major aquifer index sites showed a varied picture at the end of January, ranging from below normal to notably high levels. Stonor Park in the South West Chilterns Chalk remained at below normal levels, despite quick seasonal recharge since the end of December. In contrast Little Bucket in the East Kent Stour Chalk and Chilgrove in the Chichester Chalk were above normal and notably high respectively. Groundwater levels were also high in sandstone aquifers, with Skirwith in the Carlisle Basin and Eden Valley Sandstone and Weir Farm in the Bridgnorth Sandstone above normal and notably high respectively. Normal groundwater levels were reported at Dalton Estate Well in the Hull and East Riding Chalk, at Redlands Hall in the Cam and Ely Ouse Chalk and at Jackaments Bottom in the Burford Jurassic Limestone.

5. Reservoir storage

At the end of January reservoir stocks had increased at three-quarters of the reservoirs and reservoir groups that we report on. Three reservoirs or reservoir groups saw an increase of more than 20% in comparison to the end of December. The largest stock increases were at Stithians and Wimbleball in south-west England which increased by 30% and 31% respectively. In contrast 2 reservoirs or reservoir groups have seen no change in storage and 5 others recorded a reduction in storage at the end of January. Just under half of the reservoirs or reservoir groups were classed as below normal or lower, with Colliford in the south-west remaining at exceptionally low levels. The Dee reservoirs which supply north-west England are undergoing reservoir safety work, meaning storage is lower than would be expected for the time of year.

At the regional scale, total reservoir stocks ranged from 76% in south-west England to 92% in north-east England. Total reservoir stocks for England were at 88% of total capacity at the end of January.

6. Forward look

Early February is dominated by dry weather mixed with sunny spells. The settled conditions will continue, however wetter and windier conditions are forecast to return during towards the end of the month. Temperatures are forecast to be milder than average for February.

For the 3 month period from February to April there is an increased chance of mild conditions. There is an increased likelihood of heavy rain and strong winds during this period. There is also a slight increase in the chance that this period as a whole will be wetter than average.

7. Projections for river flows at key sites

By the end of March 2023 river flows have a greater likelihood of being above normal across most of England although central and north-west England river flows have a greater chance of being normal. By the end of September 2023 river flows have an increased chance of being above normal in all regions except in the central and north western areas where river flows are most likely to be normal.

8. Projections for groundwater levels in key aquifers

By the end of March 2023 groundwater levels have a higher than expected chance of being normal or higher in all regions except north-west England, where groundwater levels have an increased likelihood of being below normal. By the end of September 2023 groundwater levels have a higher than expected chance of being above normal in east and central England. In north-west and north-east England there is a higher than expected chance of groundwater levels being below normal. Groundwater levels in the south-west and south-east have a higher than expected chance of being normal by the end of September 2023.

Author: National Water Resources Hydrology Team, [email protected]

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.