Research and analysis

Yorkshire water situation: August 2026 summary

Updated 14 September 2026

Applies to England

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

1. Summary

Monthly rainfall was close to or above average in most catchments but remained below normal in the northern Dales catchments. Monthly mean river flows remained very low but rainfall produced increased flows and less dry soils in the second half of the month. Reservoir levels continued to decline. Groundwater levels declined in most aquifers 

2. Rainfall 

There was a significant increase in rainfall when compared with the previous month. According to the Met Office Had-UK data set of catchment averaged rainfall, monthly totals for August ranged between 63% and 144% of the long term average (LTA) and were more typical for the time of the year. Rainfall in the Upper Pennine catchments was categorised as below normal, in the Rye, Derwent, Esk, Ouse, Aire and Calder as normal and in the Don and Hull and Humber as above normal. It was the third consecutive month of below average rainfall for Yorkshire as a whole, with only May recording above average rainfall in the past 6 months.  

For the first 15 days of the month very little rain fell across Yorkshire., Between days 16 to 31 wetter days occurred, particularly on days 19, 27 and 30. Higher rainfall totals were observed in the most southern and eastern catchments of the Don, Rother and Hull.  

On day 19, rain was widespread and at many locations reached between 10% and 35% of the monthly LTA. On day 27, a rain gauge in the Don catchment recorded 63mm of rainfall, 98% of the monthly LTA. A further wet period occurred between day 30 and 31 which again affected most of Yorkshire and on average recorded 15% of the monthly LTA rainfall, with slightly higher totals in the Ouse, Rye and Hull.  

3. Soil moisture deficit and recharge  

Soil moisture deficit (SMD) reduced overall through the second part of the month. For the first 2 weeks of August all soils were very dry. In the third week SMD decreased in the Lower Aire, Calder and Don catchments and soils there were classified as dry. During the fourth week of August soils across the catchments of the western Pennines, North Yorkshire Moors and Don similarly changed from very dry to dry. As a result of rain in the last few days of August, the Derwent and areas bordering the Humber estuary also changed from very dry to dry while SMD in the upper Hull and much of the East Yorkshire coast reduced into normal. 

4. River flows 

Monthly mean flows were notably low for all the western Pennine catchments (19% to 42% of LTA), Ouse (24%) and Hull and Humber (58%). The lower Wharfe, Swale, Derwent and Esk remained exceptionally low, between 23% and42% of LTA. Monthly mean flows in the Don and Rother increased to normal range, 95% of LTA, however this was mainly due to a single high flow episode between days 27 to 31, in response to heavy rainfall.  

Catchment response in August showed a contrast between the first and second halves of the month. As a result of the low rainfall across Yorkshire, daily mean flows remained in the notably to exceptionally low range for the first 16 days for most catchments. The only exception was in the Lower Nidd and Upper Wharfe where flows were below normal until day 8 and then fluctuated between below normal and notably low until day 18.  

Then with increased rainfall, flows across Yorkshire began to rise. First in the Don and Rother from day 17 where they increased to normal range, followed by the remaining Pennine catchments, Esk and Rye by day 19 or 20. The recovery in flows was not sustained and rivers soon receded below the normal range for approximately a week. Flows increased again in response to rain during the last few days of the month. Particularly in the Don and Rother: heavy rainfall on day 27 increased the flows here to exceptionally high and they remained in the high range until month end.  

Flows in the River Derwent also increased following the periods of rainfall but did not reach the normal range for late August. In the West Beck in the upper Hull catchment, flows were notably low and declining for the first 18 days. They responded slightly to rainfall on days 19 and 20 before reducing again and remaining notably low to day 26. Flows then fluctuated between normal and below normal in response to rainfall from day 27 to month end but it is likely that the underlying baseflow from the chalk continued its gradual decline. 

5. Groundwater levels    

5.1 Magnesian Limestone 

The groundwater level within the Magnesian Limestone decreased at Brick House Farm and was normal for the time of year. 

5.2 Millstone Grit 

The groundwater level within the Millstone Grit decreased at Hill Top Farm and was notably low for the time of year. 

5.3 Sherwood Sandstone 

The groundwater level within the Sherwood Sandstone remained stable at Great Ouseburn and was normal for the time of year. The groundwater level decreased at Riccall Approach Farm and was below normal for the time of year. 

5.4 Corallian Limestone 

The groundwater level within the Corallian Limestone slightly decreased at Sproxton and was normal for the time of year. 

5.5 Chalk 

The groundwater level within the Chalk decreased at Wetwang and was at the boundary between below normal and notably low. The groundwater level decreased at Dalton Estate Well and was below normal for the time of year. 

6. Reservoir stocks  

Reservoir stocks continued to decline. At the end of August stocks were 49% full which is 20% less than the LTA. Overall Yorkshire stocks declined weekly by an average of 3%.  

7. Environmental impact   

In late August there were 49 abstraction licences with a hands off flow condition in force, and another 39 abstraction licence holders had been given advance warning that flows were low.  

Author: Yorkshire Hydrology Team, hydrology.northeast@environment-agency.gov.uk 

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.