Event Duration Monitoring

Rivers transform the communities around them and we know that, as a water company, there is more we need to do to take a leading role in making all our rivers the healthiest they can be. Our Get River Positive commitments are underpinned by five key pledges that pave the way for the restoration and revitalisation of the region’s rivers.​

We’ve listened to you, our customers, local communities and campaign groups and have committed to five pledges that lead the charge in protecting and revitalising rivers. We want everyone in our region to hold us to account, we will publish clear measurements for success, and we will be reporting back on progress regularly. 

We’ve published our Event Duration Monitoring (EDM) data for 2024. This data is released on an annual basis and contains all the monitoring activity at storm overflows across the Severn Trent region.

As part of our Get River Positive pledges, we have committed to ensuring we are open and transparent and provide information such as this, on our website and in an easily accessible way. Our event duration monitor (EDM) data is subjected to several levels of internal and external assurance before reporting to the regulators. 

Storm overflows are vital in protecting people from flooding and are widely used across the UK and Europe. We fully understand the concern around them and the impact they can have on rivers. We use monitors on our storm overflows to understand the performance of our sites and undertake required action. This is called Event Duration Monitoring (EDM). 

Our monitors take readings of the water level either every two minutes or every 15 minutes depending on the classification of the receiving watercourse, which is jointly agreed between Severn Trent and the Environment Agency.

Every data point captured at or above the overflow level would count towards the total time that a discharge was occurring at that location. 

We’re moving faster and further to improve river quality, once again being recognised by the Environment Agency, who gave us the highest four-star rating in 2024 for our 2023 performance. 

Our performance of 25.4 activations on average in 2024 –  in a year that saw the Severn Trent region experience rainfall over the 12-months of 2024 that was reported as ‘exceptionally’ or ‘notably’ high in the Environment Agency’s December water situation report (compared to ‘normal’, and ‘normal’ or ‘lower than normal’, in 2021 and 2022)