Kuhsee, Reservoir in Hochzoll district, Augsburg, Germany

Kuhsee is a roughly 17-hectare artificial basin in Augsburg-Hochzoll, created by gravel extraction from the old Lech arm below the Hochablass weir. It has no direct inflow; groundwater moving south to north feeds it, and a weir on the east side of the Hochablass can lower the water level by one metre. Depths run from 1 to 5 metres.

The first plan to turn the old Lech arm into a bathing lake came in 1930 as a work-creation scheme for the unemployed, but it failed over falling visitor numbers at the city's paying pools and fears of mosquitoes. After the flood of 10 August 1970, when the Lech burst eastwards and damaged Hochzoll, the city council decided on flood dams; gravel extraction from the old arm then created today's basin.

The name Kuhsee comes from the cattle herds once driven to drink at the old Lech arm; the water body still counts legally as a side arm of the Lech, not a lake, under the Augsburg city fishers' centuries-old right to everything the river gives and takes. On sunny summer weekends around 10,000 bathers line the shores, and the Kuhsee-Fest and Kuhsee-Triathlon are held here.

Two car parks serve the site, the Nördlicher and Südlicher Parkplatz in Hochzoll, and bus lines 29 and 30 stop at "Hochzoll/Kuhsee". There are five toilet blocks, three kiosks and a restaurant on the east shore, currently closed for renovation. The water watch station is staffed at weekends during the bathing season; barbecuing is allowed only on the southern shore.

The Kuhsee is legally not a lake: it remains an old arm of the Lech, a side channel under the centuries-old right of Augsburg's city fishermen, which states that everything the Lech gives and takes belongs to them. The Kuhseeheide south of the water is dry grassland on calcareous gravel, part of the Lechtalheiden, and is protected for its rare flora and fauna, with gentians and orchids growing there.