Projects

Local sustainable power generation

The saltmarshes at Sharpham are prime habitats. They cover an area of approximately 0.15 km2 beside the river Dart near Ashprington, 3.5km south-east of Totnes in Devon. Originally tidal mud-flats, the land here is believed to have been reclaimed around 1760 by in-filling the area and using stonewalling to protect the newly formed bank from erosion. The marshes are regularly submerged by the spring tides and a bio-diverse reed bed habitat has developed.

Impact on navigation

The saltmarshes are also important in relation to the navigation of the river. Over a number of years dredging and erosion from tidal scour have caused the wall to collapse in a number of places, exposing the saltmarsh to risk of erosion.

To protect the marshes, the gap in the river bank's retaining wall, which is approximately 40m wide and known as the Hole-in-the-Wall, needs to be stabilised. If nothing is done it is predicted that the reed beds will be lost and there will be a potential risk of rendering the main channel of the River Dart unnavigable in this area.

DEEM, Sharpham, Dart Harbour and Navigation Authority and the South Devon AONB Sustainable Development Fund are working on a joint project that aims to combat both the problem of the Hole-in-the-Wall while exploiting the tidal flow there to produce power for the Sharpham estate.

Feasibility report

The first phase of the project, a feasibility report, has just been published and can be downloaded to read.

The report examines the feasibility of installing a small-scale tidal-power electricity generation system at the site. At the site of the Hole-in-the-Wall, two identical turbines would fully harness the tidal power. Water would be allowed into the marshes on the rising tide through tidal flap gates, through two buried pipes which open into the main river channel. The pipes will be invisible to onlookers since they will be located below the minimum tide level. On the ebb the water would remain impounded until the outside river levels drops sufficiently, at which point the impounded water will be released through the turbines.