detail of turbines at fronhas dam and with alva river, arganil portugal

detail turbines fronhas dam alva river arganil portugal concrete perspective turbines detail reserve countryside source production hydraulic turbine construction engineering forest mountain hill cliff viewpoint aerial view resource electric hydropower flow energy nature wall hydroelectric station reservoir industrial industry ecological electricity power water architecture environment outdoor landscape valley concrete structure dam pombeiro beira sao martinho cortiça fronhas coimbra arganil alva river portuguese portugal europe