Bouldnor: Heart and Dart Eel Pass (Holbrookes Stream)

Objectives:

-          To support wildlife passage through new culverted road crossing of the Holbrookes Stream.

-          Use a retrofit tiled system to enhance existing infrastructure.

-          Target eels as a priority species but optimise structure for maximum freshwater ecological gains.

-          Make a visibly pleasing and purposeful structure visible to the public.

Collaborations:

Island Roads | Environment Agency | Arc Consulting | Isle of Wight Council

 
 

Methods of Design and Installation 

The tiles were cast from folded paper inlays with a pegged texture, a kerb for low-flow containment and bankside margins with sculpted ‘backwater’ features. The lift from the main channel to the culvert spillway was made from steel and inlaid with tiles.

 

Results and Development

The eel pass will be monitored through highways maintenance visits, EA site visits and Artecology surveys. A trail camera is to be installed to provide images and evidence over peak migration periods.

Early indications are that freshwater species are using the installation which is now abundantly populated by Gammarus shrimp and, at its ramp into deeper water, prospected by sticklebacks.

 

The project also received BBC Radio Solent coverage and has been entered into the CIRIA Biodiversity Awards 2017.