水壩安全性：水庫中大量的儲水量會增加地震發生的機會。人們通常把下游社區的安全規劃為次要。很多使用多年的水壩因長年缺乏良好維護而變得十分危險。
引起水質問題的因素包括：水庫中的倒木腐化、受污染的地面水流未經稀釋，以及重金屬累積在蓄水庫的沈澱物中。
蓄水庫淹沒農田、森林、濕地與河岸棲息地，又迫使使居民遷離家園。 世界上現存水壩已經迫使3到6千萬人遠離家園，並淹沒40萬平方公里的土地。大量的水因蒸發而喪失。疾病藉由蓄水庫中緩慢的水流和灌溉渠道傳播，特別是瘧疾和吸血蟲病。
主壩造成遷徙性魚類的物理性障礙。水量減少和淤泥流動為下游的農業、漁業和生態系統造成嚴重問題。
蓄水庫亦改變河流的化學組成、季節性水量與水溫的變化，對下游的魚類和其他物種形成危害。水壩下方河床的侵蝕急劇惡化，也降低了下游生物的多樣性。
版權歸屬 國際河網 環境信託基金會(金霞 譯，陳維立審校)
Dam safety: Mass of water in reservoir can increase earthquakes. Safety planning for downstream communities is often a low priority. Many older dams pose hazards from years of poor maintenance.
Water quality problems: Trees left in reservoir rot, polluted runoff is not diluted, heavy metals accumulate in sediments behind dam.
Reservoir floods farmland, forests, wetlands and riparian habitat, and displaces people. The world's dams have displaced 30-60 million people, and flooded 400,000 sq.km. of land. Enormous loss of water through evaporation. Slow waters of reservoir and irrigation canals spread disease, especially malaria and bilharzia.
Dam wall acts as physical barrier for migrating fish species. Reduced water and silt flows cause severe problems for downstream agriculture, fisheries and ecosystems.
Reservoir changes river's chemical composition, seasonal timing of flows, and temperature of water, harming fish and other species downstream. "Riverbed erosion increases dramatically downstream of dams, reducing biodiversity downstream."
