Ismaninger Speichersee, Reservoir in Bavaria, Germany

The Ismaninger Speichersee is a 7 km long, roughly 1 km wide reservoir on the north bank of the Mittlere-Isar-Kanal, northeast of Munich. A central dam divides it into a western and an eastern basin; it is at most 3 m deep and holds 11.1 million m³. Straight grass-covered embankments with rows of trees enclose the dark blue water, and a narrow parallel channel runs along the southern edge.

The reservoir was built in 1929 alongside the Mittlere-Isar-Kanal, not by damming the Isar itself. It regulates water for the canal's power plants, protects against flooding and helps naturally treat Munich's wastewater. A central dam divides it into a western and an eastern basin, 7 km long and about 1 km wide.

The reservoir lies north of the Mittlere-Isar-Kanal, between Ismaning and Neufinsing, and is reached via the surrounding embankments. The south shore of the west basin is a nature reserve where entry is forbidden all year. Swimming is prohibited throughout the lake; fishing is managed by the Fischwaid München club.

The lake is known for its diverse birdlife and serves as an important stopover for migrating birds on their journeys. Birdwatchers regularly visit to spot rare species, especially during spring and autumn months.