Essex Rivers Hub

Darren Tansley, Essex Wildlife Trust’s Water for Wildlife Officer, worked with landowners in Sible Hedingham to improve a lake that was previously a carp fishing lake.

The lake is no longer fished and the carp have been removed and is now left to become a wildlife area. The quality of the water within the lake is poor due to increased nutrients from the fish and lacks habitats within the lake itself. Darren saw this as an opportunity to try out floating islands called BioHavens. These islands not only create habitats within the lake but it is hoped that they will improve water quality through their clever design. Below is a description of how they work:

'BioHaven Floating Wetland Technology is designed around the same principles as a    wetland:  utilising the natural processes of plants and microbes to improve water quality. BioHavens are man-made floating islands, the proprietary design enables plants and microbes to live in ultra-high concentrations, exponentially higher than those found in naturally occurring or constructed wetlands.

Beneath the BioHaven, a hanging network of roots, rhizomes and attached biofilm is formed. This provides a huge active surface area for biochemical processes, as well as physical processes such as filtering and entrapment. The general design objective is to maximise the contact between the root/biofilm network and the polluted water.

BioHaven® has been specifically designed to mimic a natural wetland; these habitats are extremely valuable environments and provide a broad range of ecosystem services.

BioHaven doesn’t rely on any form of external buoyancy; its deep matrix allows emergent vegetation to naturalise, establishing extensive roots that grow into the water and provides a year round enhancement.

BioHaven can accommodate gravel finishes, otter holts, artificial sand martin banks or beautiful combinations of emergent and terrestrial vegetation, tailored to specifically target habitat creation for key species.'

The BioHavens are uniquely designed for each location, with a combination of plants that suit the needs of the area they are being installed into. The company that created and installed the BioHavens is Frog Environmental and if you would like to know more please follow this link.

The photos show some of the Conservation team from Essex Wildlife Trust and the Frog Environmental Team, including Richard Haines a founding partner of the company, assembling and installing the islands in the lake in Sible Hedingham.

It will be interesting to see how the lake will improve with the introduction of the BioHavens and the lake will continue to be monitored to see what impact they have. We will keep you informed of what the results are and any similar projects that we are involved in.

Note: the photos on the right show the following: 1st photo; the BioHven/island before anything is added, 2nd photo; a layer of compost is spread across the top and fills in all the holes which will help to absorb water from the lake to keep the plants moist, 3rd photo; a mat of aquatic plants are placed on top of the soil (the plants are grown on coir matting), 4th photo; the matting is secured in place, 5th photo; shows the weights that are attached to the bottom of the island and these will sit on the bottom of the lake preventing the island moving too far from its desired position, final photo; the island being secured in place.

Wednesday 13th May 2015.

Website key stakeholders:

Environment Agency logo      Essex Wildlife Trust logo           

Design by LTD Design Consultants and build by Garganey Consulting based on an original concept by Herts and Middlesex Wildlife Trust