Question to the Department for Environment, Food and Rural Affairs:

To ask the Secretary of State for Environment, Food and Rural Affairs, if he will publish the Environment Agency’s modelling of average (a) daily and (b) monthly volumetric river flow rates for each gauging station on the Thames from Reading to Kingston for drought events that are (i) 1 in 100, (ii) 1 in 200 and (iii) 1 in 500 years.

The Environment Agency (EA) does not model flow at gauging stations using drought event return periods. The modelling of flow under a range of climate scenarios is carried out as part of planning by water companies to assess how resilient their supply systems are to droughts. This assessment is set out in their statutory Water Resources Management Plans (WRMP) and Drought Plans.

Thames Water have worked with Water Resources South East (WRSE) regional group to model flow under a range of climate scenarios as a component of regional system simulation modelling which informs their WRMP.

The EA is a statutory consultee for water company WRMPs and reviews the technical analysis undertaken by water companies showing how secure supplies are now (known as the baseline) and what actions are needed to ensure secure supplies in the future.

The EA has reviewed Thames Water’s latest draft WRMP and is satisfied with the company’s evidence provided alongside its latest draft WRMP.

I attended the National Drought Group meeting earlier this month on Wednesday 16 October 2024 where I outlined the pressure climate change is having on our water system and that we need to be prepared for all eventualities. This Government is taking decisive action to improve the resilience of our precious water supplies.

For more information on water resource system modelling completed on behalf of Thames Water see the following links:

wrse-hydrological-modelling-method-statement-november-2022.pdf

method-statement-regional-simulation-model-aug-2021.pdf.