The effects of short term low pH and long term acid mine drainage (AMD) stress were studied in relation to recovery and restoration of aquatic macrobenthic communities. Experimental acid additions were made to a healthy productive stream. Recovery was related to downstream drift of recolonizing organisms. A second study was made to observe drift born recolonizing organisms. Baetis sp. dominated drift collections and was most abundant in bottom fauna collections indicating a relationship between drift and section recovery. A two-year study was made on Indian Creek, Fayette Co., Pa. which received a major and several minor AMD discharges. Recovery was shown by density and diversity values similar to upstream reference stations. The addition of unpolluted tributary waters provided suitable habitat for recolonizing organisms and recovery occurred within 10 miles of the initial AMD discharges. Hydrologic and water quality models were also applied and developed. Estimated periods of high stream discharge correlated well with periods of high stream density and diversity in stream biota.