Research and analysis

Water situation: February 2023 summary

Updated 11 January 2024

Applies to England

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

It was the driest February across England since 1993. Monthly rainfall totals in February were below average for all catchments across England. Soil moisture deficits remain low across England at the end of February but are higher than average for this time of year. River flows decreased at all but two of the indicator sites, and most sites were below normal or lower for the time of year. Groundwater levels increased at almost half of indicator sites, with groundwater levels at the end of February normal in most places. Reservoir stocks in February decreased at more than half of the reservoir and reservoir groups we report on and almost two-thirds remain either normal or below normal for the time of year.

1. Rainfall

The February rainfall total for England was 15.3mm which represents 27% of the 1961 to 1990 long term average (LTA) for the time of year (23% of the 1991 to 2020 LTA). All catchments across England received below average rainfall during February. The wettest hydrological area relative to its LTA, was the Esk (Cumb) catchment in north-west England which received 70% of LTA rainfall for February. The driest hydrological area was the River Darent catchment in south east England with 7% of LTA rainfall for February.

February rainfall totals were classed as notably or exceptionally low at more than four fifths of catchments across England. Many catchments recorded their top ten driest February on record since 1891 and it was the driest February for England since 1993. It was the driest February across 29 catchments since 1959 and driest in east Suffolk since February 1891. At the regional scale rainfall was well below average across England with almost all regions receiving notably or exceptionally low rainfall for the time of year. The exception was the north-west where rainfall was below normal for the time of year. South east England had the driest February since 1959. February rainfall across England as a whole was classed as notably low.

The 3 months cumulative rainfall totals show that over two-thirds of catchments in England are classed as normal whereas the remaining third, chiefly in central and eastern England, are below normal or lower. The 6 month cumulative rainfall totals shows a wetter pattern, with all catchments either normal or higher with a quarter of catchments notably high. The 12 month cumulative rainfall totals are classed as normal or below normal for over three quarters of catchments. Two catchments in Norfolk are classed as exceptionally low and 32 catchments are the driest since the 12 month period from March 2011 to February 2012.

2. Soil moisture deficit

Soil moisture deficits (SMD) remain low across England at the end of February. Soil deficits have increased across central and eastern England and soils remain relatively dry across most of the country for the time of year.

February SMD values across the majority of the country were close to the LTA for the time of year although difference to LTA have increased across central, eastern and south east England. At a regional scale, the end of February SMD for most regions were below average for the time of year notably so in central and eastern England.

3. River flows

February monthly mean river flows decreased at all but two indicator sites we report on since January. More than four-fifths of sites were below normal or lower for the time of year, including fifteen sites that were exceptionally low for the time of year. Five sites in total, Marston on Dove, Crakehill on the River Swale, Bathford on the Bristol Avon, Manley Hall on the River Dee and Redbrook on the River Wye, recorded their lowest mean monthly flow for February on record starting in 1965,1980,1969,1970 and 1969 respectively.

Monthly mean flows for all the regional index sites showed a mixed picture for the February. Flows on, the Great Stour at Horton, the South Tyne at Haydon Bridge and the Bedford Ouse at Offord were below normal for the time of year. As mentioned the River Dove at Marston-on-Dove was classed as exceptionally low having recorded its lowest monthly mean flow for February in a record that began in 1965. The naturalised flows on the River Thames at Kingston and the River Lune at Caton was classed as notably low and normal respectively. The River Exe at Thorverton in south west England recorded no data due to a maintenance issue at site.

4. Groundwater levels

At the end of February, groundwater levels increased at half of the reported indicator sites however below average rainfall has slowed seasonal recharge in many aquifers with groundwater levels decreasing at 12 sites. Nearly two thirds of end of month groundwater levels were classed as normal for the time of year. Five 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 February, ranging from exceptionally low to above normal levels. Levels at Jackments Bottom in the Burford Jurassic Limestone decreased to be classed as exceptionally low. Stonor Park in the South West Chilterns Chalk remained at below normal levels. In contrast Little Bucket in the East Kent Stour Chalk and Weir Farm in the Bridgnorth Sandstone were above normal for the time of year. 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 Skirwith in the Carlisle Basin and Eden Valley Sandstone. Levels at Chilgrove in the Chichester Chalk fell from above normal levels to normal levels during February.

5. Reservoir storage

Reservoir stocks at the end of February had decreased at more than half of the reservoirs and reservoir groups that we report on. Two reservoirs, Blithfield in central England and Haweswater and Thirlmere in north-west England, saw a stock decrease of 10% compared to the end of January. The largest stock increases, 8% each, were recorded at Lower Lee group in south east England and Hanningfield in eastern England. Nearly two-thirds of the reservoirs or reservoir groups were classed as normal or below normal for the time of year. Nine reservoirs across England are classed as notably low and Colliford in the south west remains at exceptionally low levels for the time of year. Reservoir safety work is ongoing at the Dee reservoirs which supply north-west England meaning storage is lower than would be expected for the time of year.

At the regional scale, total reservoir stocks ranged from 74% in south-west England to 94% in south-east England. Total reservoir stocks for England were at 87% of total capacity at the end of February.

6. Forward look

March began with ongoing dry conditions in many places, followed by wintry conditions bringing sleet and snow to much of the country. The middle of the month is expected to be dominated by unsettled conditions with periods of snow remaining possible particularly in the north. Heavy rain and strong winds are possible in the west and south, although temperatures are expected to be around average. Towards the end of March conditions are likely to be drier in the north, while strong wind and rain is likely in the south. Temperatures are expected to be around average with milder spells in the south and colder conditions in the north.

For the 3 month period for the UK from March to May there is an increased chance of warmer than expected conditions, particularly from April onwards. There is a higher than normal chance of a dry spring, but average or wet conditions remain possible.

7. Projections for river flows at key sites

By the end of March 2023 river flows have a greater likelihood of being below normal across most of England although north east and southern England river flows have a greater chance of being normal. By the end of September 2023 river flows have an increased chance of being below normal in all regions, with sites in the east having the highest chance of lower than normal flows.

8. Projections for groundwater levels in key aquifers

By the end of March 2023 groundwater levels have a greater likelihood of being lower than normal in north west, north east and east England. In south west and central England groundwater levels have a higher likelihood of being above normal. By the end of September 2023 groundwater levels have a greater likelihood of being lower than normal in the north west, north east and east England. In the rest of the country normal groundwater levels are most likely.

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.