2022 Event Duration Monitors data

31 March 2023

Today we have published our Event Duration Monitors data for 2022.

Event Duration Monitors (EDM) record the number of times and duration of time our storm overflows have operated. With monitors now on over 99.5% of our overflows, we are able to provide one of the most comprehensive reports on how our storm overflows perform. We report this information to our environmental regulators and also provide real time spill information for key bathing waters to interested bodies, including Surfers Against Sewage and Rivers Trust.

Our data for 2022 shows that we saw:

  • 12% reduction in the average number of storm releases per storm overflow compared 2021, from 43.5 to 38.3
  • 25% reduction in total spill duration in 2022, from 807512 hrs to 602987.5 hrs

While we are pleased to see the reduction, which in part is due to the investment work we are undertaking to reduce spills, the reduction has also been influenced by the weather we saw last year. The annual rainfall for the year was 10% below the long term average, we saw the driest January-August period since 1976 and drought conditions were declared across parts of Wales and England.

The total removal of combined storm overflows from our system is unaffordable and would take decades and therefore is not an option but what is in our control is the ability to target investment to CSOs which have the biggest environmental impact. That is why we are investing significantly to improve CSOs with £140m being invested between 2020-2025 and a further £420m planned from 2025 to 2030.

Our EDM data for 2022 can be viewed on our interactive map which is available on our website. Please click here.

Our investment to date in our wastewater system has delivered real improvements and helped ensure Wales has over a third of the UKs Blue Flag beaches while only having 15% of the coastline and that 40% of our rivers and waterbodies meet good ecological status compared to 16% in England. However, we recognise that with environmental legislation tightening and customer expectations changing, more needs to be done to protect bathing and river water quality. Equally as important as tackling CSO’s is tackling phosphorous pollution and we are delivering a comprehensive programme of upgrades to our wastewater treatment works that will remove 90% of our phosphorous discharges by 2030. We have just published our Manifesto for Rivers in Wales which outlines how we will be investing in our wastewater network, particularly around rivers in Special Areas of Conservation.

Our Manifesto can be viewed on our website here.