Three artificial lakes were built in the natural sanctuary of the Orient Forest Regional Nature Park: Temple Lake, Amance Lake, and Orient Lake. The project for this reservoir lake, the largest among them, was revived following significant floods in Paris in 1955. They serve to regulate the level of the Seine river in case of drought or rise. Orient Lake constitutes an essential biological reserve. It has been classified as a special conservation zone by the Natura 2000 network since September 1986.