Created in 1929, the Ismaninger Speichersee awaits. This artificial lake gathers water from the Mittlere-Isar-Canal. This canal flows directly through the Speichersee.
The Ismaninger Speichersee lies northeast of Munich. It is near the towns of Aschheim, Kirchheim, Pliening, and Finsing. Though named after Ismaning, the lake barely touches its land. It mainly sits within Aschheim, Kirchheim, Pliening, and Finsing.
Originally, the Ismaninger Speichersee was for water regulation. It supported power plants on the Isar Canal. It also provided flood protection. An unexpected benefit emerged. The lake started naturally purifying Munich’s wastewater. Swimming is not allowed. But watching wild birds is great here. Fishing is also permitted in designated areas.
Let’s talk about the layout of the Ismaninger Speichersee. The Isar Canal splits after going under the A99 highway. One side channel feeds the ponds of the former Birkenhof estate. These ponds run alongside the canal for several kilometers to the south. Near here, some of Munich’s wastewater gets pumped from the Gut Großlappen plant. This happens via E.ON Wasserkraft’s main pumping station. It goes through a pressure pipe bridge into the fish ponds.
Between the ponds and the canal is a diversion canal. It collects water from the ponds. After three more kilometers, another canal feeds the Ismaninger Speichersee. The lake is seven kilometers long and one kilometer wide. At the diversion canal, you will find the Ismaning power plant. Another portion of wastewater is pumped into fish ponds via a pipe bridge. The observation tower you see is actually a standpipe tower. It balances pressure in the wastewater pipes.
A key feature is the Mitteldamm. This dam divides the Ismaninger Speichersee into west and east basins. The lake’s maximum depth is three meters. Its average depth is 1.9 meters. Covering 5.8 square kilometers, it holds 11.1 million cubic meters of water.
BMW’s testing grounds in Aschheim border the lake’s north shore. The main canal meets the lake’s discharge canals at the Neufinsing power plant. Water then flows toward Landshut. South of the Speichersee lies the Birkenhof estate with its 90 fish ponds. These ponds lie between the A99 to the west and the intercepting ditch to the east. Carp farming stopped in 2000 because it was not profitable.
In 1962, the Speichersee area and Birkenhof’s 80 fish ponds became a European reserve. This area is vital for birds. It is a breeding, feeding, molting, overwintering, and stopover site. In 1976, it gained recognition as a wetland of international importance under the Ramsar Convention. The Speichersee ranks among Europe’s top three molting areas for waterfowl. Part of the Natura 2000 network, the Speichersee and the Birkenhof estate earned spots on SPA and IBA lists. The Bavarian Nature Conservation Fund supports its preservation. The southern shore of the west basin is a nature reserve. Entry here is prohibited all year.
Notably, the Ismaninger Speichersee is known for very large carp. These can weigh 20 to 25 kg. Big bream also thrive here. They can reach up to eight kg. Trout are found in the faster waters. Grayling, barbel, and nase are also present. Pike and tench live in calmer spots. The Fischwaid Munich fishing club manages the lake.
In 2013, a pair of sacred ibis nested at the Speichersee for the first time in Germany.
The banks of the Ismaninger Speichersee have resting areas and walkways. A canal runs along its south side. Birds abound here. The Mitteldamm divides the lake into west and east basins. A thousand-meter-long path tops the dam. This path lets you walk through the lake. It ends abruptly requiring a return along the same route.