All major Berlin streams are dammed and extremely slow-flowing, with the lake-like expansions of the Spree and Havel in which showing very great detention times.
Tab.1: Key quanta of the lake-like expansions of the Spree and Havel
Image: Umweltatlas Berlin
Unlike natural streams, dammed stream segments, like country lakes, are sensitive to nutrient immission. Due to the high nutrient presence in the Spree-Havel area, the water quality of the Berlin stream segments is characterized by the results of Eutrophication, and to a lesser extent by external immission of easily degradable organic substances. Therefore, a water-quality classification according to the saprobic system is not practicable for Berlin.