Picture of Pedrogao Dam

-- After the construction of Alqueva dam was finished another one was built a few miles down the river, near the town of Pedrogao, creating a very long and beautiful water mirror. This dam serves as a kind of buffer, it was built so that water can be pumped back to the other side of Alqueva dam: when electricity is on high demand (expensive), Alqueva dam produces energy and throws a lot of water to this reservoir; when electricity is on low demand (cheap), the turbines work on reverse and send water back to the main lake.