Now historically low water levels are disrupting shipping lanes as cities urge residents to reduce water use. READ ALSO: Inside Germany - Political tensions run high, water levels run lowNIWIS provides an overview of water levels across Germany, including; surface waters (lakes and rivers), groundwater, and precipitation. Rivers run lowThe map below, as seen in the NIWIS portal on August 7th, shows surface water levels across Germany. Blue dots signify normal levels, whereas yellow, orange and red dots signify low, very low and extremely low levels respectively. AdvertisementDrinking water use restrictionsWhile diminished surface water levels are primarily seen as an economic threat, falling ground water levels are an immediate threat to drinking water supplies in a large number of German cities.