Lake Belau

The Bornhöved Lake District comprises six lakes, in two broadly parallel alignments due to Weichselian pleniglacial meltwater and late-glacial dead ice dynamics (cf. Section 2.2.1): Bornhöveder See, Schmalensee, Belauer See in the southeast, and Fuhlensee, Schierensee, Stolper See in the northwest (Fig. 1.1; Section 2.2.4). Hydrographically speaking, they form parts of the Schwentine system which includes a major proportion of ditches in the southern part of the drainage basin. Lake Bornhöved has two outlets, the western one feeding a stream flowing past the Fuhlensee and through the Schierensee to finally empty into Lake Stolpe, while the eastern one forms the Schwentine River connecting the adjacent Schmalensee with Lakes Belau and Stolpe.

From this comprehensive data set the trophic state indicators TOC, TDN and TDP were specifically analysed by means of biplot techniques (Fränzle and Killisch 1994) and classified on the basis of average linkage clustering procedures (Schernewski and Schulz 1999; Schulz 1996). By means of subsequent T-value analyses representative lakes were selected from each cluster, and among these Lake Belau proved to have the highest degree of hydrochemical representativeness in terms of TOC, TDN and TPD changes during the 1983-1993 period.