concrete
Concrete is a composite material composed of aggregate bound together with a fluid cement that cures to a solid over time. It is the second-most-used substance (after water), the most–widely used building material, and the most-manufactur ...
buttress dam A buttress dam or hollow dam is a dam with a solid, water-tight upstream side that is supported at intervals on the downstream side by a series of buttresses
A buttress is an architectural structure built against or projecting from a wall which ...
on the
Douro
The Douro (, , , ; ; ) is the largest river of the Iberian Peninsula by discharge. It rises near Duruelo de la Sierra in the Spanish Soria Province, province of Soria, meanders briefly south, then flows generally west through the northern par ...
, where the river forms the national border line between
Spain
Spain, or the Kingdom of Spain, is a country in Southern Europe, Southern and Western Europe with territories in North Africa. Featuring the Punta de Tarifa, southernmost point of continental Europe, it is the largest country in Southern Eur ...
and
Portugal
Portugal, officially the Portuguese Republic, is a country on the Iberian Peninsula in Southwestern Europe. Featuring Cabo da Roca, the westernmost point in continental Europe, Portugal borders Spain to its north and east, with which it share ...
. It is located in the municipality
Miranda do Douro
Miranda do Douro (), officially the City of Miranda do Douro (; , ), is a city and a municipality in the district of Bragança, northeastern Portugal. The population in 2011 was 7,482, in an area of 487.18 km2. The town proper had a populati ...
, in
Bragança District
Bragança District ( ; ) is a traditional political division of Portugal, in the northeast corner bordering on Spain (Castile and Leon and Galicia), covering 7.4% of the nation's continental landmass. the total resident population was 136,252, ...
, Portugal.
Construction of the dam began in 1955. The dam was completed in 1961. It is owned by ''Companhia Portuguesa de Produção de Electricidade'' (CPPE).
Dam
Miranda Dam is an 80-m-tall (height above foundation) and 263-m-long buttress dam with a crest altitude of 535 m. The volume of the dam is 240,000 m³. The dam contains 4 crest
spillway
A spillway is a structure used to provide the controlled release of water downstream from a dam or levee, typically into the riverbed of the dammed river itself. In the United Kingdom, they may be known as overflow channels. Spillways ensure tha ...
s (maximum discharge 11,000 m³/s) and one bottom outlet.
Reservoir
At full reservoir level of 528.05 m (maximum flood level of 533 m) the reservoir of the dam has a surface area of 1.22 km2 and its total capacity is 28.1 mio. m³ (active capacity 6.66 mio. m³).
Power plant
The power plant went operational in 1960. It is a
run-of-the-river
Run-of-river hydroelectricity (ROR) or run-of-the-river hydroelectricity is a type of hydroelectric generation plant whereby little or no water storage is provided. Run-of-the-river power plants may have no water storage at all or a limited amou ...
hydroelectric
Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...
power station. It is owned by CPPE, but operated by EDP. The plant has a
nameplate capacity
Nameplate capacity, also known as the rated capacity, nominal capacity, installed capacity, maximum effect or gross capacity, (390)MW. Its average annual generation is 897.8 (879 or 1,036.3) GWh.
Miranda I
The power station contains 3
Francis turbine
The Francis turbine is a type of water turbine. It is an inward-flow reaction turbine that combines radial and axial flow concepts. Francis turbines are the most common water turbine in use today, and can achieve over 95% efficiency.
The pro ...
-generators with 58.84 (67) MW each in an underground powerhouse. The turbine rotation is 150 rpm. The minimum
hydraulic head
Hydraulic head or piezometric head is a measurement related to liquid pressure (normalized by specific weight) and the liquid elevation above a vertical datum., 410 pages. See pp. 43–44., 650 pages. See p. 22, eq.3.2a.
It is usually meas ...
is 51 m, the maximum 66 m. Maximum flow per turbine is 128 m³/s.
Miranda II
In 1995 an additional underground powerhouse was completed and a further Francis turbine with a 193 MW capacity went online. The turbine rotation is 100 rpm. The minimum
hydraulic head
Hydraulic head or piezometric head is a measurement related to liquid pressure (normalized by specific weight) and the liquid elevation above a vertical datum., 410 pages. See pp. 43–44., 650 pages. See p. 22, eq.3.2a.
It is usually meas ...
is 40 m, the maximum 60 m. Maximum flow of the turbine is 386 m³/s.