Portuguese Dams: How Many Exist and What They Are For

Portugal has around 260 large dams — over 15 metres high or with a reservoir capacity above 1 cubic hectometre (hm³) — used for hydroelectric power generation, drinking water supply, large-scale irrigation and flood control. Alongside these are more than 8,000 small dams and hydraulic barriers, mostly weirs and local irrigation retention structures in rural areas.

Official classification

The classification is based on height and reservoir capacity: large dams (over 15 m or ≥ 1 hm³), medium dams (5 to 15 m or 0.1 to 1 hm³) and small dams (under 5 m and under 0.1 hm³). This distinction guides safety rules, emergency plans, and investment and water-policy priorities.

• Large dams: hydropower (REN/EDP), urban water supply (e.g. EPAL), large-scale irrigation (e.g. Alqueva) and flood control
• Small and medium dams: local agricultural irrigation, livestock use, biodiversity ponds and drought reserves