Event Duration Monitoring

EDM data is the key component of Environment Agency’s Storm Overflow Assessment Framework or SOAF. The purpose of the SOAF is to drive improvements across the sewage network in order to protect our Rivers.
Water Companies, including Severn Trent, use the annual EDM data return to identify discharge points that may have a high number of spills and ensure that we are constantly monitoring the impact of our assets.
Once a high frequency discharge point is identified, a spill frequency investigation is triggered to identify the cause and determine what, if any, improvements are required to reduce spills.
Storm overflows are legal and have agreed regulatory permits. In 2020 we had 2288 monitored overflows, and in 2021 we had 2437 monitored overflows.
We’re on track to deliver approximately 250 Storm Overflow Assessment Framework investigations. We’ve already completed 28 investigations.
As we work through this list, we’re also learning that not all overflows require further improvement.