Natural wildlife and invasive species

Bourn Brook flows from Caxton in Cambridgeshire down to Byron’s Pool in Granchester, where it joins the River Cam.

It is a valuable habitat for wildlife, including water voles, otters and kingfishers. The Bedfordshire, Cambridgeshire and Northamptonshire Wildlife Trust maintain the brook, monitoring wildlife and keeping it clear of non-native invasive species such as Himalayan balsam and giant hogweed. You can read about this important work, including their latest (2019) report on water voles, otters and invasive plants, and find out how to volunteer at the Wildlife BCN site.

You can also find out more about Bourn brook from our local contact Ruth Hawksley at or 01954 713533.



From time to time Bourn brook is liable to flooding, most notably in 2001, though nowadays not nearly as frequently or as severely as in the past. New flood prevention systems have limited the severity of local flooding in recent years.

Bourn has a Flood Action Group, which monitors the water level and advises on action should the brook flood. The water level is monitored every few hours in the winter months and automatically reports the height via a Twitter feed.

The water level at Comberton is also monitored by the Flood information service provided by the Environment Agency.

A River Levels website that monitors river levels taken from the Environment Agency database also provides information about Bourn brook as well as flood alerts.