Outfall Safari


Approximately half of all properties in Britain are serviced by two separate drainage systems. One collects rainwater and flows directly into our rivers, and the other takes foul wastewater to sewage treatment works to be cleaned before being released into a river.

Misconnections between the two drainage systems results in pollution pouring directly into our rivers via drains known as outfalls.

The Outfall Safari is a Citizen Science method devised to systematically survey outfalls in urban rivers in order to identify pollution and notify the relevant authorities. It was created by the Citizen Crane project team in partnership with staff from Thames Water and the Environment Agency, and is regarded by the Environment Agency as best practice.


Visit the ConnectRight page View the CaBA Outfall Safari guide and resource page

Project Host

Zoological Society of London


Friends of the River Crane Environment, Frog Environmental, Crane Valley Partnership, Thames Water, Environment Agency, The Rivers Trust


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