Aylesbury Outfall Safari

Can you help to tackle pollution in the Bear Brook and the streams of Aylesbury?

Bear Brook, taken by Ian Parsons

What is an Outfall Safari? 

A volunteer survey using a smart phone app to map and record the location and impact of polluted surface water outfalls in urban streams and rivers.  These can then be  reported to the Environment Agency and Thames Water and prioritised for action.

Interested? you can sign up to our training event at the bottom of this page…..

What’s the problem?

Waste water contains lots of nasty chemical and pollutants that harm wildlife and damage habitat. Correctly connected drains will take all waste water to either a sewage treatment works or a domestic treatment system (such as a septic tank). Here it is treated to reduce its impact on wildlife before it is discharged into a watercourse.

However when household drains are not correctly connected and are plumbed into surface water drains they carry sewage, waste and nasty chemicals directly to streams and rivers where they can have devastating impacts on wildlife. These polluting outfalls are often a result of misconnected appliances in private properties (e.g. a washing machine or toilet connected to the surface water sewer instead of the foul sewer by mistake).

To find out more information on missconnections and other issues caused by household waste water please visit our advice page.

Did you know the drainage system in Aylesbury is formed of two sewers?

Surface Water Sewer

This convey rainfall from roofs, roads and other hard surfaces straight into the nearest river or stream.

Only surface water drains should be connected to this, like road drains and household guttering.

Foul Sewer

This transports wastewater from toilets, showers, washing machines etc. to a sewage treatment works to be treated before being released into a watercourse.

Rain water drains should not be connected to this sewer as it can cause too much water to travel to treatment works, increasing their load.

Outfalls like this can hide a dirty secret

What’s involved?

We need the help of volunteers to walk lengths of stream in the Aylesbury area to locate polluting outfalls. Once located polluting outfalls are reported to Thames Water and the Environment Agency so that they can be tackled. 

  • Attend a training session to learn how to identify and map polluting outfalls.
  • Spend some time walking your local streams to help protect them from pollution.

Who can take part?

The survey requires no previous experience, but you must attend a training event (see below). If you would like to take part, but can’t make the training event date please email Tim at tim@riverthame.org


Details coming next spring. For more information please see our events page.

This work is possible thanks to the support of the Environment Agency and Thames Water.