Surface water outfalls


Pollution moves from land to rivers in a variety of different pathways. One significant pathway is via the surface water drainage network. Polluting surface water outfalls are a major contributor to poor water quality in rivers. This often occurs when household appliances are incorrectly plumbed, ‘misconnected’, into surface water drains, which flow directly into rivers. The UK MICS case study explores the role of citizen scientists in identifying pollution from surface water outfalls in two case studies in Greater London and Alfreton Brook (Derbyshire).

Nature-based solution

Once a polluting outfall has been identified, there are multiple options for remediation. The first looks at identifying and tackling the source of pollution and misconnection. Other forms of remediation involve setting back the outfalls and having a retention pond area so pollution settles out before entering rivers. The actions aim to protect and better sustainably manage pollution from surface water outfalls into rivers.  

Citizen science acitivites

Citizens in Greater London and Derbyshire are involved in ‘Outfall Safari’. Outfall Safari, is a methodology (developed by Zoological Society London and partners) where citizens use an app to score outfalls based on the appearance and flow.  Since the Outfall Safari began in 2016 over 160 citizen scientists have been involved in Outfall Safari surveying over 150 km of rivers across Greater London.

The Outfall Safari project helps to raise awareness of the issue, collect valuable data and helps water companies target efforts to reduce pollution and improve our rivers.  Citizen science activities through Outfall Safari therefore have both immediate and longer-term impacts for the environment and society. MICS aims to capture the impacts of these citizen science activities in the UK.

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 824711.


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