Precipitation Variability and Surface-Mine Reclamation in the Green, Powder and San Juan River Basins

Abstract

Federal and state legislation requires the reclamation of surface-mined lands. Reclamation usually involves landscape shaping and revegetation. In arid and semiarid regions, climate exerts considerable influence on revegetation facility. This report focuses on spatial and temporal precipitation variabilities for coal resources regions of the Green, Powder and San Juan river basin areas of the western United States. Climatological data and derivative maps show nearly a fourfold difference in annual precipitation and more than a sixfold difference in growing-season precipitation between stations in the Green River Basin. There is more than a twofold difference in annual precipitation and nearly a twofold difference in growing-season precipitation between stations in the Powder River Basin. There is nearly a fivefold difference in annual precipitation and inure than a threefold difference in growing-season precipitation between stations in the San Juan River Basin. Precipitation also varies annually, seasonally and monthly. Comparisons of means and standard deviations show the uncertainty of precipitation during these time periods. Monthly precipitation graphs reveal periods of probable drought and peaks during which there may be erosion hazards. Reclamation planning must consider these variabilities. Programs should include techniques to mitigate erosion hazards during precipitation peaks and conserve or supplement moisture during potential drought periods. Consequently, reclamation costs may vary with climatic severity in many areas.