| Abstract: | Through a power plant an inflow of considerably heated and very eutrophic water gets into the polymikt reservoir (volume h 15.1 · 106m3, 341 ha, MQ6 m3/s). Phosphorus is the limiting nutrient with a relatively high share from agricultural utilization. The spring maximum of phytoplankton is due to chlorophytes and diatoms, and the summer maximum is caused by cyanophyceae (up to 300 colonies/ml). It could be successfully controlled by copper sulphate. This treatment did not produce any negative effects in the free water (0.05 … 0.1 mg/l Cu2+) or in the sediment with a storage of about 1 t Cu per year. The construction of preimpoundment reservoirs, however, must be recommended for a lasting solution. |
