Flushing began in 1953 and ended in 1976. Today, the 272-hectare site of the former sewage pond 3, including a small remnant of the former forest, is a nature reserve.

The Salzgitter district group of the Nature and Biodiversity Conservation Union (NABU) has identified 301 bird species here in long-term population surveys; 115 of them are endangered.

These include cranes, ospreys, cormorants and sandpipers, which use the lake as a stepping stone on their way to wintering or breeding grounds.

For nature lovers, a hiking tour around the Heerter See nature reserve and European bird sanctuary is a special experience. Its salty water provides a habitat for special plant species and its shallow shores are ideal for wading birds.

Including the Heerter See, Salzgitter has 287 hectares of protected landscape.