Extract of a Schmettau map from 1767/1787 with a part of the today’s District Oder-Spree, Brandenburg, Germany. The map shows among others a part of the Scharmützelsee, the whole course of the Blabbergraben (stream) and the five lakes flown by the Blabbegraben as well as the estuary of the stream to the river Spree. Today, the first part of the Blabbergraben towards the Herzberger lake exists still in a rudimentary form.