Runoff curve numbers for loose-dumped spoil in the Cumberland Plateau of eastern Kentucky

Abstract

Excess compaction occurs through the use of traditional surface mining reclamation techniques, resulting in low infiltration rates and subsequently high peak flows and runoff volumes. The incorporation of loose-dumped spoil into the reclamation process has been shown to promote tree growth; however, designers have little information regarding the probable hydrologic consequences (PHC) associated with this spoil disposal method. To better understand the hydrologic effects of reclaiming mined lands using loose-dumped spoil, curve numbers (CN) were developed for both a steeply sloping, forested watershed in eastern Kentucky and six, 0.4 ha test cells comprised of three types of loose-dumped spoil: (1) brown, weathered sandstone, (2) grey, unweathered sandstone and (3) a mixture of both sandstones and shale. The spoil was placed in accordance with the Forestry Reclamation Approach (FRA). Results of this project indicate that the mean CN for loose-dumped spoil was equivalent to the mean CN for the forested watershed.