Causes of Polytrophism of Three Lakes in the Wdzydze Landscape Park

In the lakes Cheb and Słupino, located in the Wdzydze Landscape Park the quality of waters has been deteriorating in recent years. In the hydrologic year 2009 the quality of water was examined three times. Monthly measurements on the lake inflows and outflows were carried out 12 times to determine biogenic loads. In 2010 the supplementary measurements of biogenic loads were taken in the streams five times. According to Vollenweider's criterion, the loads of nitrogen and phosphorus compounds are too big, the heaviest to Lake Cheb. The discharge from the new sewage treatment plant is directed by the inflows into this lake. A similar situation takes place in the inflow to Lake Schodno. Paradoxically, in some catchments the construction of the sewage treatment plant may result in the deterioration of lake water quality.