Minimal impact restoration:  Is it worth all the effort?

Peter Worrall  (Penny Anderson Associates Ltd - peter.worrall@pennyanderson.com)

Proceedings paper from the 10th Annual River Restoration Centre Network Conference, 1st - 2nd April 2009

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Abstract

In January 2007, after a prolonged period of rainfall, several thousand tonnes of finely ground rock from a fluorspar mine tailings dam escaped into the Derbyshire countryside. Besides the damage to homes and property in the village of Stoney Middleton, the discharge of the heavily metal laden sediments entered the Stoke Brook and the River Derwent. These river systems were ecological diverse, supported an important salmonid fishery and had significant landscape and amenity values within the Peak District National Park. Once the immediate clean up of the village was complete attention focussed on how to remove the material from the river systems without causing undue damage to habitat, species and functions of the rivers. The  primary impact of the fine sediments was the blinding and armouring of the gravel spawning areas for trout, grayling and brook lamprey. In addition, the smothering of the bed and banks with a dense and often thixotrophic mass of sediment had implications for a range of wildlife groups as well as the amenity value these rivers afforded the area. With river banks riddled with water vole burrows, nearby ponds associated with great crested newt, and
a rich bird, plant and invertebrate fauna, the challenge to remediate and restore these sinuous tree lined river systems was a significant.

Achieving minimal impact restoration required a coordination of contractor input, project management and stakeholder involvement. In this paper we present the approach taken to achieving remediation of these contaminated sediments and the degree of success in restoring the rivers without undue damage to the important environmental assets they provided. The paper also appraises whether the costs and efforts that have to be invested in  achieving minimal impact restoration are, in the long-run, the most appropriate environmental option.

Keywords

cypollution; tailings; water vole; Stoke Brook; River Derwent; fisheries