Background Information
The River Hun is a chalk stream of just 6km, flowing from its source in Hunstanton Park to its mouth in Holme Dune National Nature Reserve. Aquamaintain Ltd were commissioned by Norfolk Rivers Trust to install a series of bunds, ditches, and wetland scrapes.
Scope of the Project
Wildlife is plentiful in the surrounding area, with a profusion of birdlife. Nevertheless, the river habitat has been degraded by centuries of modification and would benefit from conservation work. The stretch of the Hun on the project site was heavily modified and suffered from sedimentation originating from surrounding agricultural land and a series of land drains flowing into the channel. The adjacent farmland consisted of heavy clay soil that made agriculture challenging and resulted in poor yields. As a result, it was decided to hand the land over to conservation so that the field could be flooded. This would create habitat for the huge array of wetland birds that inhabit the area.
Our Solution
The work involved the excavation of 3 shallow wetland scrapes that were located on the site of ghost ponds. These created important habitat for amphibian populations. A ditch backwater was excavated off the existing ditch to increase the wetland area of the site. The wetlands were created by installing a new 600m long shallow ditch and bund, then diverting the existing ditch with the use of a headwall water control structure. This allowed the naturally low-lying area of land to seasonally fill with water creating important habitat for wading birds. Field drains that originally flowed into the Hun and ditch were blocked to further wet the area, while improving the water quality of the water reaching the river and reducing sedimentation. In addition, logs and woody material were placed in the main river channel to constrict flow, creating habitat for fish and inverterbrates. In just 6 weeks since work was completed, a wide variety of birds have already been spotted visiting the wetland areas including: oystercatchers, snipe, marsh harrier, spoonbill, egret, avocet, shelduck, lapwing and sparrow hawk.
