The Environment Agency has reported that September rainfall totals were below the long-term average across most of England in its latest monthly water situation report.

As a result, soils got drier across much of the country and river flows decreased at almost all indicator sites. At four-fifths of indicator sites groundwater levels were classed as normal or higher for the time of year.

Total reservoir stocks for England were at 78% of capacity at the end of September (down from 83% of capacity at the end of August), just below the LTA for the time of year. At a regional scale, total reservoir stocks were close to or above the LTA in all parts of England, with the exception of south-west England where total stocks remained below average.

Reservoir stocks decreased at almost all reservoirs and reservoir groups we report on during September. The biggest decrease, as a proportion of total capacity, was at Ardingly reservoir (West Sussex) where stocks fell from 43% at the end of August to 26% at the end of September, which is classed as exceptionally low for the time of year. At over a quarter of reservoirs and reservoir groups stocks were classed as below normal or lower for the end of September.

The September rainfall total for England was 45mm, which represents 63% of the 1961 to 1990 long-term average (LTA) (64% of the 1981 to 2010 LTA). The highest monthly rainfall totals were in parts of Cumbria and Norfolk.

Monthly rainfall totals across much of central, south-west and south-east England were classed as below normal for the time of year. The Axe, Yeo and Kenn catchments in Somerset received the lowest rainfall totals, as a proportion of the LTA. These were classed as notably low, representing only 33% of LTA.

In contrast, exceptionally high September rainfall totals, representing over 200% of LTA, were recorded over parts of Norfolk. The six month cumulative rainfall totals, ending in September, highlight that over the past six months much of East and West Sussex and Kent has received notably low or exceptionally low rainfall totals.

However, the twelve month cumulative totals are classed as normal or higher in all catchments across England. At a regional scale, September rainfall totals were below the long-term average in all regions, ranging from 45% of LTA (28mm) in central England to 92% of LTA (46mm) in east England.

Forward look

Looking ahead, the EA report, which was published 3 days ago, said that a very wet start to October was expected for many parts of England, with unsettled conditions likely to continue throughout the first part of the month.

Towards the middle of the month, many parts of England could see more settled and dry weather, with the possibility of further showery conditions in the south and south-east, while the end of the month is likely to remain settled and dry across much of England.

Looking at early 2021, the Agency is flagging up the fact that more than two-thirds of the modelled sites have a greater than expected chance of cumulative river flows being below normal or lower for the time of year by the end of March 2021. By the end of March 2021, nearly half of all the modelled sites have a greater than expected chance of groundwater levels being below normal or lower for the time of year.