Kuhgrabensee is a lake entirely in the southeast of the Bremen district of Blockland .

In 1998 to 1999 it was extended in the context of environmental compensation measure an approximately 4 acre flat water surface.

The lake is entered in the EU as a European bird sanctuary.

The lake offers habitat to many pioneer plants, dragonflies and amphibians.

The Kuhgrabensee is the breeding ground of many birds, such as the great crested grebe.