The heavy rainfall in Wu-She area on June 2006 caused surface settlement, cracks on anchor cells, surface subsidence, and slope failure on the right ridge of Wu-She reservoir, which had suffered a long-term creep in the past. The geological investigation showed the right ridge of Wu-She reservoir was composed of slate. Due to different weathering and different pressure release levels, parts of the slate were a hard and dense rock, but some parts were very weak. From monitoring records analysis and considering the pros and cons of the various slope stability methods, a rehabilitation project including drainage tunnels, pile wall, surface drainage, maintenance, reinforcement of tunnel spillway and river bank repair, is proposed