Tackling Storm Overflows - Saving Our Rivers?

Dr Karen Murrell is our expert in Storm Overflows

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It's #TechnicalTuesday and Dr Karen Murrell, #teamWRc Principal Consultant is discussing the issue of storm overflows, why they are needed, and what we can do to reduce their impact.

I have worked in the water industry, and at WRc, for over 30 years investigating storm overflows. Storm overflows have recently made headlines as a pressing environmental concern; however, they are not a recent phenomenon: I worked on the procedures to deal with them and their effects through the development of Urban Pollution Management in the 90s.

The water companies deal with our sewage, yours and mine, it’s not something that they manufacture and generally discard by “dumping” despite what is said in the media. The purpose of storm overflows is to prevent sewers from overflowing into our streets, homes, and public spaces during periods of heavy rainfall. When the volume of runoff entering the sewer system exceeds its capacity, excess flow is diverted through storm overflows and released into nearby waterways and the sea. Although this wastewater is diluted with rainwater, there is concern about the impact of sewage outflows on the environment. The issue has recently gained prominence due to vocal campaigners and a global pandemic which encouraged people out into nature, and saw a surge in popularity of wild swimming and recreational activities on our waterways.

Several factors have exacerbated the problem of storm overflows, which are avoidable through a change in behaviour by us, the general public. We are happy to discard items down the watery bin without a further thought: fats and oils, wet wipes, sanitary items. It’s so easy, isn’t it, to press the flush button or rinse it away? We pave over our gardens so we can park our cars, and why not? The rainwater still goes down the drain, doesn’t it? We’ve built houses without much thought to the underground infrastructure. Climate change has also led to more intense rainfall, making overflow events more common. But are we motivated enough to change our behaviour to help reduce the temperature and save our environment?

Of course, the capacity to treat sewage could always be improved, but this comes with great expense and inconvenience. Would the investment needed to eliminate all overflows be the best use of capital and operational expenditure in wastewater? Absolutely not. We must find a balance between convenience, cost, and environmental protection both at an individual and national level.

The privatisation of water companies has also been blamed, but whatever your views on private/public ownership, neither is a panacea for a guaranteed zero-spill system. Were things so much better in the good old days, pre-privatisation? Of course not. We’ve come far since then, and I for one am proud of the part that I’ve played to improve our rivers. I will continue to use sound science to balance the needs of our environment with those who live on this small, congested island.

Aside from increasing treatment capacity, there are other actions that we, the public, can take to help reduce the impact of storm overflows. For example, we must only flush the three “Ps” - pee, poo and paper - and incorporate more green areas and permeable surfaces in urban areas. Let’s also make sure that we fund our watchdogs properly, engage with the passionate campaigners and perhaps most importantly of all, invest in the continued development of professional scientists and engineers who are working to protect our environment and make it a better place for all. There is a great deal still to do regarding complex issues like improving water quality; engaging talented, enthusiastic professionals is a key piece of this complex puzzle.

Created by potrace 1.16, written by Peter Selinger 2001-2019

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Created by potrace 1.16, written by Peter Selinger 2001-2019

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Dr Karen Murrell

Principal Consultant (Catchment Management)

Karen's expertise lies in river impact assessment and integrated catchment management studies involving river hydraulic and quality modelling (both model application and development). This includes determining impacts of weather derived rural and urban pollution on receiving water quality. She also has extensive experience in consenting policy and application. Karen regularly works to apply deterministic and stochastic river quality models (such as SIMPOL ICM and SIMCAT/SAGIS) for WFD compliance, climate change impact assessment and Urban Pollution Management (UPM) studies.

2023-04-25 15:50:00