England’s reservoir storage falls to 56.9% despite early-September rain

Rain has not repaired the national deficit

Reservoir storage in England declined to 56.9% in the week ending September 10 even though every part of the country received rain, according to an Environment Agency update published on September 11. The national level was almost 20 percentage points below the seasonal expectation, and 12 reservoirs or reservoir groups were less than half full. Ten Environment Agency areas remained officially in drought, with all remaining areas classified as experiencing prolonged dry weather.

The weekly rain ranged from 14 millimetres in eastern England to 46 millimetres in the north-west. River flows responded in many places, but numerous rivers remained below normal and groundwater continued its seasonal decline. Temporary-use restrictions stayed in force across large parts of England, covering about 30 million people. Water companies continued preparing drought permits and orders as they revised projections for autumn and winter.

Dry soil stores a longer warning

The Guardian reported very dry soil conditions across most of England and Wales. Soil moisture deficit measures how much rain would be needed to return soil to field capacity, making it more informative than raw water content across different soil types. In southern England, a typical summer deficit may be around 100 millimetres and can reach 150 millimetres or more in a dry year. Current storage deficits in the driest southern areas may require unusually high rainfall to reverse.

Persistent soil and groundwater deficits matter beyond household restrictions. Dry conditions can reduce crop resilience, limit abstraction for farmers, strain rivers and navigation, and increase subsidence risks where clay soils shrink and buildings move. Recent rain has eased some agricultural pressure because peak irrigation season has passed, and the number of abstraction restrictions fell slightly. It has not, however, changed the wider drought classification or reversed declining public-supply storage.

Winter planning becomes the next decision point

The Environment Agency asked water companies to submit updated autumn and winter projections for discussion at the National Drought Group on September 15. Those forecasts will show whether restrictions can be eased or whether utilities need further permits and conservation measures. The central risk is that an ordinary wet spell may improve rivers without rebuilding reservoirs, groundwater and soil moisture together. Sustained above-average rainfall, rather than isolated storms, will be required to reduce the accumulated deficit before next year’s higher demand.