Establishment of the Iskar Reservoir Minimum Sanitary Storage Capacity

Bulgaria has suffered from considerable economic damages in the past and today, because of frequent droughts and floods. Throughout 1982-1994 one of the drought periods was observed. The runoff diminished and this led to dangerous decline of water levels in reservoirs, and was a major reason for a limited supply of drinking water. Particularly dangerous for drinking water quality were the cases of reaching the water minimum in the reservoirs. This phenomenon was also due to some faults in water management related to water allocation. In many drinking water treatment plants appropriate anti-turbidity and oxidation reagents, reagents for manganese, iron and phytoplankton removal were not used, because of inadequate water treatment technologies applied. A case study for establishing the Iskar Reservoir Minimum Sanitary Storage Capacity (MSSC) according to the water treatment technologies was carried out. The specific chemical and biological water quality state indicators coherent to the water supply function were specified and investigated during one-year period, and the obtained results are given and discussed. In conclusion recommendations that could improve drinking water supply management are made and an attempt for environmental indicators classification for the Iskar Reservoir is made, which could assist policy- and decision-makers in taking useful advanced actions.

Keywords: Iskar Reservoir, water quality, sanitary storage capacity, environmental indicators