Submitted to: International Journal of Sediment Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 9, 1999
Publication Date: N/A
Interpretive Summary: Sediment-yield models are needed for surface-mine permitting and planning. However, there are few studies in which sediment data have been collected to determine the effects of mining and reclamation upon sediment delivery to the basin outlet, and to validate models of sediment yield. One model having widespread use (MUSLE) has an important factor called the runoff-energy factor, but has never been tested with surface-mine data. The runoff-energy factor represents the energy supplied by flowing water to transport sediment to a watershed outlet. Data from three experimental watersheds, that were subjected to surface mining and reclamation, were analyzed to determine the most appropriate equation to use for the factor. The study showed that the most practical equation to use was dependent upon total runoff volume and peak flow rate for individual runoff events, and that the widely-used parameters that are associated with this runoff-energy yfactor were not adequate for surface mines. Further study is needed to develop appropriate parameter values for the best model found. The study will be useful to researchers, consultants, university persons, mine operators, and surface-mine regulators.
Technical Abstract: The Modified Universal Soil Loss Equation (MUSLE) is often used for sediment-yield estimations in surface mines for design and impact evaluations. However, it is not known if the widely-used runoff-energy factor of MUSLE is appropriate, or if its parameters are the same for surface mines as for agricultural watersheds from which MUSLE was developed. Suspended-sediment data from three experimental watersheds in Ohio (approximately 10 - 20 ha), subjected to near complete disturbance due to mining and reclamation, were used to investigate five alternate runoff-energy factors in the MUSLE sediment-yield model for use in surface mines. The evaluation led to the selection of the generalized model form, a'(runoff volume x peak flow rate)**b, as the best choice among models investigated. Exponent b was greater than the widely-used value of 0.56, ranging from 0.68 to 1.10. Parameter b was dependent on whether mining- or rreclamation-related watershed activities were predominant. The original Williams (1975) model fit the data least well of the five energy factors studied.