The nature is formed by some rivers , which flow from the south to the Danube , which runs in the north of the district : Biber ( Danube ) , GÃ 1\/4 nz , Kammel , Mindel and Zusam ; The Nau flows from the north to the Danube . The Danube runs through the northernmost parts of the district , passing the cities of GÃ 1\/4 nzburg and Leipheim . There are several affluents coming from the south , for example Biber , GÃ 1\/4 nz and Mindel .