Die Steuerung der externen Belastung der Sächsischen Talsperren als wesentliche Strategie ihrer Wassergütebewirtschaftung The Control of the External Loading of Saxonian Reservoirs — an Important Strategy of the Water Quality Management

Abstract

AbstractThe Reservoir‐administration of Saxony continuously investigates the development of water quality in its numerous reservoirs. 25 of these reservoirs are used for drinking water supply. About 40 reservoirs have considerable importance for recreation and fishing.The following priorities of water quality management are based on the results of scientific investigations: protection against eutrophication prevention of increase of nitrate concentrations protection against polutants, especially pesticides, heavy metals, hydrocarbons, mineral oils acidification of waters The objectives of the water quality of the Saxonian reservoirs refer to EU‐guidelines, to DVGW‐guidelines, to the drinking water ordinance of FRG, to guidelines of LAWA and to the actual knowledge of limnology.The evaluation of the most important reservoirs in the period from 1991 to 1994 shows the following result:These objects can be achieved by two main strategies: the reduction of the external loading the control by means of the internal ecological mechanisms To investigate the loadings of the reservoirs and the sources of the nutrients mass balances particularly for phosphorus and nitrogen were based on periodic analyses. From these mass balances the strategies of water qualilty management were derived. An important consequence in this conection is the following:“The protection of the water is a basic requirement to the security of water quality”Therefore, the reduction of external loading is the main field of the strategy. In the case of high nutrient loaded reservoirs, par example eutrophic waters, a combination with the strategy of internal control, particularly with the biomanipulation is carried on.