Lake Desilting & Biodiversity Improvements at Midhurst’s South Pond

Truxor in action at Midhurst Pond

This large 800-year old pond, which has a 270-metre perimeter and two small islands, had been suffering from pollution and heavy siltation. We have been removing litter, doing weed clearance; we will be installing a stone riprap on the western bank; we have been desilting (sometimes referred to dredging) through the centre of the pond with our Truxor.

The South Downs National Park Authority has commissioned Salix to help create a wildlife haven on the South Pond, at the edge of Midhurst town centre in West Sussex.

The large 800-year old pond, which has a 270-metre perimeter and two small islands, had been suffering from pollution and heavy siltation.

Bruce Middleton, Wealdon Heath Area Manager for the South Downs National Park Authority, explains:

“Working with the South Pond Group, Chichester District Council, Midhurst Town Council, West Sussex County Council and Salix, we devised a sustainable plan to improve the biodiversity and physical environment of the South Pond, with the aim of encouraging more wildlife and making it an area that can be enjoyed by the whole community.”

Work started on the project in October and will include: litter and weed clearance; the installation of a stone riprap on the western bank; dredging through the centre of the pond using Truxor with silt removal attachment; planting new reedbeds; installing kingfisher posts; building deadwood piles for stag beetles, amphibians and reptiles; and creating interpretation boards with information about the wildlife living there.

Water from the pond’s feeder stream had caused the western bank of the island to erode, exposing tree roots. Salix has stabilised and protected the bank by installing a 10-metre long riprap – a natural stone barrier.

Midhurst soft bank protection
Midhurst soft bank protection

Some years ago, the southern edge of the pond had been stabilised with steel piles and was devoid of aquatic vegetation. Salix installed a new reedbed here, with interwoven channels and pools to allow a mosaic of reeds to thrive, providing feeding opportunities for a wide range of birds, animals and insects.

Revetments used to retain the silt in the new reedbeds have been made out of brushwood and wooden stakes, sourced by South Pond Group volunteers from local woodland.

Salix edged the silt bed on the north side of the pond with Coir Rolls planted with a mixture of native wetland plants, creating soft bank protection.

The pond had become heavily silted over time and required desilting. To encourage better water flow through the pond, Salix dredged a channel through its centre and the dredged material was used to build up the pond’s banks.

Pete Barlow, Construction Director for Salix, says:

“This exciting community-led project will make a massive difference to the biodiversity of this historic pond.

By dredging a channel through the centre of the pond, water and silt will flow through the pond more easily, significantly improving water quality. We used our Truxor amphibious vehicle to remove silt from the pond using a dredge pump.

Analysis has shown the dredged material will be non hazardous so we plan to re-use the sediment on site to build up some of the bank areas.

The banks will then be planted with a diverse range of native plants, grasses and wildflowers, including purple loosestrife, marsh marigold, sweet flag, flag iris, water mint, gypsywort and water forget-me-not.

The new riprap will dissipate the energy of stream water as it enters the pond, creating new hydraulic effects, oxygenating the water and benefiting invertebrates and fish.

And the new reedbed will provide feeding opportunities for a range of birds, including reed warblers, reed bunting, bearded tits and little egret, as well as bats, damselflies, dragonflies and butterflies.”

Revetments at Midhurst
Revetments at Midhurst