Forbach equalising basin, reservoir in Forbach, Baden-Württemberg, Germany

The Forbach equalising basin is a 19-metre-high weir on the Murg in Forbach in the Black Forest, counted as a large dam. Built by the Badenwerk Karlsruhe between 1914 and 1918 and now run by EnBW, it holds water released from the Schwarzenbach reservoir through the Rudolf-Fettweis plant and passes it on to the river in regulated amounts.

The Badenwerk Karlsruhe built the weir and basin between 1914 and 1918; operator today is its successor EnBW. The 19 m high Schützenwehr dam holds back the Murg, making the basin count as a large dam. It balances water from the Schwarzenbach pumped-storage plant and the Murgwerk run-of-river plant.

The basin's name comes from its function: it equalises the surge of water released from the Schwarzenbach reservoir through the Rudolf-Fettweis-Werk turbines before it reaches the Murg. Its level rises and falls between 3.5 and 10 m with pumping and generating cycles, so the weir and shoreline look different from one hour to the next.

The basin lies on the Murg in Forbach, in the Black Forest of Baden-Württemberg. Its weir stands 19 m high above its foundation, and the impounded water level varies between 3.5 and 10 m because of pumped-storage operation, so the bank line shifts through the day. The site belongs to the Rudolf-Fettweis-Werk and is run by EnBW.

The basin's weir is 19 m high above its foundation, which is why the lake counts as a large dam. Its level swings between 3.5 and 10 m of usable head because of pumped-storage operation; a low-pressure plant with two Kaplan bulb turbines and two generators turns that range into up to 2.5 MW at a design flow of 29 m³/s.