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 the average (a) daily and (b) monthly percentage of (i) usable and (ii) deployable capacity in each of the (A) Lower Lee Group and (B) Lower Thames Group reservoirs for drought events that are (1) 1 in 100, (2) 1 in 200 and (3) 1 in 500 years.

The Environment Agency (EA) does not model how resilient water company owned supply systems are to drought. It is the responsibility of the water companies to ensure that their systems can deliver secure water supplies for customers whilst ensuring they meet their environmental obligations and legal requirements during a drought.

Every 5 years, water companies are required to evidence in their statutory Water Resources Management Plans (WRMP) how they will ensure secure supplies for the next 25 years. This includes consideration of resilience to extreme droughts, population growth, climate change and environmental water needs.

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:

Library | WRSE - Water Resource South East

method-statement-regional-simulation-model-aug-2021.pdf (wrse.org.uk)