Impact of coal surface mining and reclamation on suspended sediment in three Ohio watersheds

Prior to PL95-87 little research had been conducted to determine the impact s of mining and reclamation practices on sediment concentrations and yields on a watershed scale. Furthermore, it was unknown whether sediment yield a nd other variables would return to undisturbed levels after reclamation. Th erefore, three small watersheds, with differing lithologies and soils, were monitored for runoff and suspended sediment concentrations during three ph ases of watershed disturbances: undisturbed watershed condition, mining and reclamation disturbances, and post-reclaimed condition. Profound increases in suspended-sediment concentrations, load rates, and yields due to mining and reclamation activities, and subsequent drastic decreases after reclama tion were documented. Even with increases in runoff potential, reductions i n suspended-sediment concentrations and load rates to below or near undistu rbed-watershed levels is possible by using the mulch-crimping technique and by removing diversions. Maximum concentrations and load rates occurred dur ing times of active disturbances that exposed loose soil and spoil to high- intensity rains. Sediment concentrations remained elevated compared with th e undisturbed watershed when diversions were not well maintained and overto pped, and when they were not removed for final reclamation. Diversions are useful for vegetation establishment, but should be maintained until they ar e removed for final reclamation after good vegetative cover is established.