Charakterystyka jakości wody cieków zasilających projektowany zbiornik Racibórz

Water reservoirs, such as Racibórz, perform many functions and can be used for various purposes. Very often, however, the potential use of water stored in the reservoir depends on its quality. Contamination of even quite clean reservoirs, as well as those which are currently built or planned, is a very important issue nowadays. Components significantly influencing quality of water in a reservoir are phosphorus and nitrogen compounds, especially their inorganic, soluble forms, they cause eutrophication of accumulated water. Problem of eutrophication of waters stored in reservoirs should already be considered on stage of study works and while projecting water reservoirs, so after building the reservoir, unfavourable biochemical processes causing eutrophication did not take place. In this study water quality characteristics of watercourses feeding the Racibórz reservoir was presented. Tributary rivers are the Odra River and its left tributary - Psina. The water quality of the Odra and Psina rivers and their tributaries, particularly the Młynówka River, is poor due to heavy contamination. The greatest problems are caused by biogenic substances: nitrogen and phosphorus. Therefore, also in the reservoir poor water quality can be expected. Water quality sampling points are located within the bowl of the planned reservoir. Therefore, it should be assumed that the quality of water in the sampling points will determine the quality of water in the reservoir. Water quality tests carried out in the Psina, Młynówka and Odra rivers showed that water in the rivers are contaminated. The highest values (V surface water quality class) in the Psina River were observed (sampling point no 1) in the total suspended solids (37 mgźdm-3), nitrites (3.682 mg NO2 -źdm-3) and phosphates (1.935 mg PO4 3-źdm-3). The Młynówka River (sampling point no 2) was classified to the V class of surface water quality due to ammonia (4.541 mg NH4 -źdm-3), nitrites (4.671 mg NO2 -źdm-3) and phosphates (2.388 mg PO4 3-źdm-3). The least favourable concentrations in the Odra River (V water quality class) were noted in the case of nitrites (1.602 mg NO2 -źdm-3) and phosphates (1.224 mg PO4 3-źdm-3). Proper agricultural economy and wastewater management in the reservoir catchment has an impact on the water quality in the bowl of the planned reservoir. Water quality analyses initiated in the planned reservoir and its catchment should be continued as in the future they will contribute to a detailed assessment of the water quality in the reservoir.