First estimation of cover for reclaimed mineland erosion control

ABSTRACT:

Federal and state regulations require landscapes reclaimed after coal stripmining to have control measures that will minimize soil erosion. This North Dakota study evaluated the influence of established vegetation on reducing erosional losses from reclaimed minelands with different soil textures and slope gradients so that the amount (%) of cover necessary to meet regulatory guidelines could be estimated. Percentage vegetative cover (ranging from 0 to 100%) was measured with point frames and converted to a cover factor (fraction of bare). Simulated rainfall was applied in three separate applications over a 3 h period and soil loss was calculated from aliquot samples of the runoff and adjusted for total volume of runoff. The Revised Universal Soil Loss Equation algorithms were used to adjust soil losses for the differences between the rainfall applications for rainfall kinetic energy, soil erodibility (seasonally-variable value), and slope length/slope gradient in order to produce unitless values. Regression analysis between the adjusted soil loss and measured cover factor showed linear decreases in soil loss as the cover factor decreases (percent cover increases). Similar results were found when soil losses from the individual rainfall runs were weighted according to the frequency of expected antecedent moisture conditions, summed, and correlated to the cover factor. A good, linear relationship (r² = 0.80, n = 37) was found between the weighted soil loss and measured cover factor. Since all factors, except cover within the Revised Universal Soil Loss Equation are known, the permissible soil loss can be divided by those factors and a first estimate of the amount of cover needed can be estimated. The rapid establishment of vegetation will further reduce soil erosion and will help prevent both on-site and off-site problems caused by transported sediment.