Lake Stechlin is a a deep clear-water lake located in a nature reserve approximately 80 km north of Berlin, Germany (53°10°N, 13°02° E), at 59 m elevation.The lake basin was formed during the last continental glaciation some 12,000 years ago and today is situated at the transition between temperate/maritime and temperate-continental climates.The drainage basin is almost completely covered by forest (95%), with the exception of the area of a former nuclear power plant and a small village, which diverts its wastewater into a different drainage basin. The shoreline of Lake Stechlin is largely undeveloped with no notable infrastructure. The seepage lake is essentially fed by precipitation and groundwater, resulting in a theoretical water retention time of greater than 40 years.