Research and analysis

Water situation: October 2023 summary

Updated 11 January 2024

Applies to England

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

It was the wettest October across England since 2000 with rainfall totals well above average across most of England, with almost all catchments receiving above average rainfall. Soil moisture deficits (SMD) reduced across England during October as soils became wetter due to the significant rainfall in many areas. River flows increased at all but one of the sites we report on and the majority of sites recorded above normal monthly mean flows. Groundwater levels increased at the majority of sites and remain classed as normal or higher at all but one site for the time of year. Reservoir stocks increased at two-thirds of the reservoirs or reservoir groups we report on, with over three-quarters of reservoirs classed as normal or above normal for the time of year.

1. Rainfall

The October rainfall total for England was 147.2mm which represents 192% of the 1961 to 1990 long term average (LTA) for the time of year (163% of the 1991 to 2020 LTA). Nearly all catchments received above average rainfall during October, while only 5 catchments receiving below average rainfall. The wettest hydrological area relative to the LTA was South Forty Foot and Hobhole catchment in east England which received 366% of LTA rainfall. The driest hydrological area was the Esk (Cumbria) in north-west England which received 86% of LTA rainfall in October.

October rainfall totals were classed as above normal or higher for the time of year in the most catchments across England. The majority of catchments were classed as notably high with nearly a third of catchments were classed as exceptionally high, predominately across central and east England. Twelve catchments recorded the wettest ever October since records began in 1871, the:

• Don
• South West Isle of Wight
• Sussex Coast
• Lower Trent
• Upper Trent
• Shropshire Plains
• Cam
• Little Ouse and Lark
• Steeping Great Eau and Long Eau
• Witham to Chapel Hill
• South Forty Foot and Hobhole
• Lower Welland and Nene

In south-west and north-west England rainfall was classed as normal in 11 hydrological areas during October. At a regional scale only north-west England received normal rainfall for October. Rainfall totals were above normal in south-west and notably high in south-east England. North-east, central and east England all recorded exceptionally high rainfall and October rainfall totals for England as whole were also exceptionally high. It’s notable that Central England recorded the second wettest October since records began in 1871 and the wettest since 1903 and north-east England recorded the fourth wettest October since 1871.  

The 3 month cumulative rainfall totals were above normal or higher at more than four-fifths of catchments across England. Over a fifth of catchments had rainfall totals classed as exceptionally high for this period. The 6 month cumulative rainfall totals show a similar picture being classed as with above normal or higher across the majority of catchments in England. The 12 month cumulative rainfall totals were exceptionally high in more than half of catchments across England. The remaining catchments were either above normal or notably high with only 2 catchments, the Tweed in north-east England and the Esk (Cumbria) in north-west England, classed as normal. The 12 month cumulative rainfall total to October was the wettest since records began in 1871 for the Isle of Wight, the West Sussex chalk, the River Test and the east Hampshire chalk catchments in south-east England.

2. Soil moisture deficit

SMD reduced across England during October as soils became wetter in many areas due to above average rainfall. SMD across south-east and east England saw a significant decrease through October.

Across all of England SMDs were below the LTA, leaving soils wetter than expected at the end of October. Soils across much of south-west, central, north-east and north-west England were near or at saturation levels with only minimal SMDs remaining in parts of south-east and east England. 

3.  River flows

October monthly mean river flows increased at all but one of indicator sites we report on. All indicator sites were normal or higher for the time of year, with the majority of sites classed as above normal. A quarter of sites, predominately in south-west England particularly Wessex, were classed as notably high. Nearly a fifth of sites, mainly in central and east England, were exceptionally high monthly mean flows for the time of year. Eleven sites across the north-west, south-east and south-west England all had monthly mean river flows classed as normal for October.

Monthly mean river flows increased at all the regional index sites in October. Flows at Marston-on-Dove in central England on the River Dove which meant flows were classed as notably high. The River Exe in south west England, the naturalised flows on the River Thames in the south-east, the Bedford Ouse in east England and Haydon Bridge on the River South Tyne were all above normal for the time of year. The River Lune in north-west England and Horton on the Great Stour in south-east England recorded normal monthly mean river flows for October.

4.    Groundwater levels   

By the end of October, groundwater levels had increased at half of the indicator sites we report on. Apart from one site, Washpit Farm in east England which was classed as below normal, all groundwater sites were classed as normal or higher at the end of October. The majority of sites were classed as notably high for the time of year. Over a third of sites were classed as normal and groundwater levels at Priors Heyes in north-west England remain exceptionally high as West Cheshire Sandstone continue to recover from the effects of historic abstraction.

End of October groundwater levels at the major aquifer index sites at Chilgrove in the Chichester Chalk, Jackaments Bottom in the Burford Jurassic Limestone and Dalton Estate in the Hull and East Riding Chalk all increased to be classed as notably high at the end of October. Above normal levels were recorded at Skirwith in the Carlisle Basin and Eden Valley Sandstone and in the East Kent Stour Chalk at Little Bottom. Redlands Hall and Stonor Park, in the Cam and Ely Ouse Chalk and South West Chilterns chalk respectively, recorded normal groundwater levels for the time of year.

5. Reservoir storage

Reservoir storage during October increased at nearly two-thirds of the reservoirs or reservoir groups we report on. At the end of October over three-quarters of reservoirs or reservoir groups are classed as either normal or above normal. Six reservoirs recorded storage increases of 10% with Blithfield and Derwent Valley in central England registering the largest increases of 36% and 21% respectively. The Teesdale group in north-east England and Vyrnmy in north Wales supplying north-west England are both classed as exceptionally high for the time of year. In contrast, 3 sites remain below normal, Colliford and Roadford in south-west England and Ardingley in south east England .The Dee System in Wales remains notably low due to ongoing reservoir maintenance.

At a regional scale, total reservoir storage in increased across all areas of England at the end of October with the exception of south east England. For England as a whole, total reservoir storage has increased to 84%.

6. Forward look

November has started wet in many parts of the England, with the east, south-east and south-west already receiving more than half of the LTA for the month. Through the rest of the month conditions are likely to remain unsettled, with western and northern areas seeing most of the rainfall, although southern areas may have some drier spells. Temperatures are likely to remain mild for the time of year, although colder nights remain possible during settled conditions, particularly in the south.

For the 3 month period for the UK from November to January there is a higher than normal likelihood of wet conditions, with spells of wet and windy weather throughout the period. The likelihood of cold conditions is higher than recent years, with impacts more likely later in the period.

7. Projections for river flows at key sites

By the end of March 2024, river flows across the whole of England have the greatest chance of being above normal or higher, except in the north-west where river flows have the greatest chance of being normal or higher. By the end of September 2024, river flows across the whole of England have the greatest chance of being above normal or higher. For scenario based projections of cumulative river flows at key sites by March 2024.

8. Projections for groundwater levels in key aquifers

By the end of March 2024 groundwater levels in east, south east, north-west and north-east England have a greater likelihood of being above normal or higher. In south-west and central England groundwater levels have a greater likelihood of being normal or higher. By the end of September 2024 groundwater levels have a greater likelihood of being above normal or higher in north-west, north-east, central and east England. In south-west and south-east England groundwater levels have a greater likelihood of being normal or higher.

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.