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Outfall Safari

Measuring the impact of Outfall Safari

The MICS team are working with citizen scientists, project managers and other stakeholders of Outfall Safari to measure the impacts of the project. You can read more about the activities within the Outfall Safari case study by clicking on the images below.


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). 

In the UK, the scale of misconnections is believed to be worst in the South East of England, specifically London, with an estimated 10% of properties in the Thames region being wrongly connected. Within the Greater London Authority boundary, only one waterbody is at ‘good’ ecological potential under the Water Framework Directive (WFD). 

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 acitivities

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 Outfall Safari began in 2016 over 221 citizen scientists have been involved in Outfall Safari surveying over 249km of rivers across Greater London (as of 2021) 

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. 

Outfall Safari has also been adopted in other urban areas in the UK:  

To get involved or to find out more, get in touch with the Outfall Safari coordinators here -  This email address is being protected from spambots. You need JavaScript enabled to view it.