As a result of the 921 quake and heavy rains, woodlands along the banks of the Wushihkang Creek collapsed, causing a loss of more than 500 hectares of watershed.
過去的烏石坑溪由於九二一地震及豪雨影響，境內多處林班地崩塌，造成集水區的崩塌面積高達五百餘公頃。