In Egypt, some of the water from Lake Nassar, the great reservoir formed by the Aswan High Dam on the Nile, is being pumped 320 kilometres northwest out of the Nile Valley into natural geological depressions in the Great Desert. There the water forms new lakes. The new lake system is endorheic, that is, the waters can never flow on to the sea. The Nile-sourced water creates the lakes and helps to recharge the underlying aquifer; but desert temperatures cause very high levels of evaporation. Although the new lakes already contain an impressive amount of fish, these high evaporation levels will make the waters become increasingly saline over time, reducing fish stocks and harming the newly-established flora and fauna.