Qattara Depression
The Qattara depression is a region that lies 60 m below sea level on average and is currently a vast, uninhabited desert. By connecting the region and the Mediterranean Sea with tunnels and/or canals, water could be let into the area. The inflowing water would then evaporate quickly because of the desert climate. This way a continuous flow of water could be created if inflow and evaporation were balanced out. With this continuously flowing water, hydroelectricity could be generated. Eventually, this would result in a hypersaline lake or a salt pan as the water evaporates and leaves the salt it contains behind. This would return the Qattara Depression to its current state but with its sabkha soils tens of meters higher.