Coy Pond Gardens – Design, bank reinstatement and erosion control

Improvements to the banks of the island to help preserve this historic site,

As an English Heritage Grade II Registered Park and Garden covering over 9 ha, Coy Pond Gardens is one of Poole’s most treasured open spaces. The site is particularly enjoyed for its pond and island with its population of koi carp and wildfowl.  Cain Bio-Engineering were approached by Borough of Poole (via competitive tender process) to assist with improvements to the banks of the island to help preserve this historic site, benefit wildlife and add to the public’s enjoyment.

a 40 metre section of bank on one end of the island with rotting log edging required urgent attention to repair erosion caused by wildfowl and wave action.  This work was identified as part of the coy pond project.

Island east side 1 coy pond

Before:  Eroded bank line around Coy Pond Island

Cain Bio-Engineering offered a soft engineering design and build solution, to provide long-term protection to the riverbank, incorporating bio-engineering techniques.  The post and geotextile technique used allows for vegetation growth to create a stable vegetated bank sensitive to the local ecology.

Restricted site access required the bulk of the work to be undertaken by hand, whilst using a boat and pontoon to deliver materials to the island.  Chestnut posts were driven into the bed along the line of the original bank with geotextiles installed behind.  Back fill behind the revetment with gravel provides protection against burrowing animals such as the invasive North American signal crayfish, wildfowl and wave erosion. The final revetment has a good structural integrity and native planting by our site operatives will promote vegetation growth into the future further binding the bank together and providing a natural appearance.


During Construction: Infill behind the new post and geotextile revetment.

IMAG0352 coy pond planted

After Construction:  Completed bank protection with native plant species to establish vegetation.