11. Floating Pennywort removal, Denham

Aim: Control invasive non-native species

Water body: River Colne
Project description

Programme to remove Floating Pennywort from the Colne at Denham

Floating Pennywort is an invasive species that was first naturalised in 1990 as a result of discarded plants from garden ponds. It can grow up to 20cm per day and may quickly dominate a waterbody forming thick mats and impeding water flow and amenity use. May out-compete native species by blocking out light, causing deoxygenation, obstructing air breathing insects from reaching the water surface and reducing water temperatures.

Project lead: Environment Agency
Project end: 2013
Funding source: Environment Agency

Design by LTD Design Consultants and build by Garganey Consulting. From an original concept by the Herts and Middlesex Wildlife Trust.