Important lakes of natural, glacial origin in the Black Forest include the Titisee, the Mummelsee and the Feldsee. Especially in the Northern Black Forest are a number of other, smaller tarns. Numerous reservoirs like the - formerly natural but much smaller - Schluchsee with the other lakes of the Schluchseewerk, the Schwarzenbach Reservoir, the Kleine Kinzig Reservoir or the Nagold Reservoir are used for electricity generation, flood protection or drinking water supply.