Antropogeniczne zmiany odpływu rzecznego w zlewni Rudy

Abstract

Human activity represents an essential element which modifies size and regime of river runoff and also water quality in Ruda catchment, which is right-bank Odra tributary (Fig. 2). The upper part of the catchment is strongly influenced by human impact associated with hard coal mining, industrial activity and urbanisation. The results of the research concerning last several decades show that anthropogenic factors have not influenced water relations with the same intensity both in time and space. A distinct relationship is observed between development of economic processes in the catchment and intensity of water relation transformations. Anthropogenic changes of the size of river runoff were stated in urbanised and industrialised upper part of Ruda catchment. In lower part of the catchment, which is only slightly transformed by human activity, no considerable changes of river catchment caused by anthropogenic factors were observed (Tab. 22, 23; Fig. 25, 26, 27, 28, 29). The valuation of anthropogenic changes of river runoff confirms growing, with the increase of anthropogenic constituent of the runoff, disturbances in its seasonal course and natural changeability (Tab. 24). The main function of Rybnik Reservoir, which is a delivery and reception of cold storage water from Rybnik power station, causes that not all typical for water retention reservoirs changes of runoff size and regime in the profile located below the reservoir are observed. Rybnik Reservoir does not regulate the minimal discharge and also its retention influence on spring thaw high water is not visible. Moreover, some disturbances in runoff course during summer occur which result in irreclaimable wastes (in cool cold storage circulation) and wastes associated with evaporation (Tab. 25, 26, 27, 28, 29; Fig. 30, 31). A synthetic picture of water condition transformation which took place in Ruda catchment as a result of anthropopresion is a diagram of water circulation by Soczyńska and Mikulski (1984) and Jankowski (1986) supplemented by the author (Fig. 35). Basing on the introduced supplements, the water balance equation has been transformed in time function. The water balance equitation in Ruda catchment has the following form: P(i) + PW(i) + WK(t) = Q,(0 + + EVAP(i) + PWK(i) + d(INT + RPP + RPN + RSA + + RWP + RA + RZA + RKR + RG)(i) where: P — precipitation, PW — water transfer, WK — mining water, Q„ — natural constituent of runoff, Q, — antropogenic constituent of runoff, EVAP — evaporation, PWK — transfers of mining water, INT — interception, RPP — retention of permeability surface, RPN — retention of non-permeability surface, RSA — retention of aeration zone, RWP — retention of groundwater, RA — apotamic retention, RZA — retention of anthropogenic water reservoirs, RKR — retention of river bed, RG — retention of economic activity. Basing on data included in this work, an attempt was made to evaluate the elements which influenced transformation of the natural water balance equation. The estimations are as follows: PW (water transfer) — 0,85 m3 x s_1 WK (mining water) — 0,13 m3 x s_1 Q, (anthropogenic constituent of runoff) — 0,51 m3 x s_1 PWK (transfers of mining water) — 0,10 m3 x s_1 RG (retention of economic activity) — 0,15 m3 x s_1 Comparing the values of anthropogenic constituent of runoff obtained from this research with data on size of mining water transfer, lower participation of evaluated anthropogenic constituent of the runoff is observed that it would occur from the balance of the size of water transfer and disposal. This results from irreclaimable wastes of water in industry and municipal use which are difficult to define. Another element which is underestimated by the researchers and which modifies water circulation are changes of evaporation. In Ruda catchment these changes result from growing built-up areas and time-spatial changeability of water reservoirs (Rybnik Reservoir, ponds in subsidence basins, groups of fishing ponds). Another element which is very difficult to balance is water escape by intensive coal mining activity. The results of the studies have revealed also that in the catchments of complicated system of water transfer and considerably transformed water conditions (what applies to the majority of catchment in the Upper Silesian region) methods based on hydrological and statistic analysis of long-lasting measurement series are much more reliable. Additional advantage of such methods is much larger access to applied observational materials and their greater reliability. The evidence of anthropogenic changes of river runoff in Ruda catchment is poor quality of surface water (Tab. 30; Fig. 32). Ruda, Potok Boguszowicki, Nacyna and Sumina lead classless water. The following contaminations cause poor water quality: biogenic substances (nitrates and phosphates) mineral substances represented by chlorides and sulphates which come from disposed to Nacyna mining water (Tab. 18, 19, 29; Fig. 20, 21, 22), heavy metals (lead) and bacteriological contaminations. The source of water pollution of Ruda and its tributaries are numerous disposals of industrial and domestic sewage, mainly from the area of Żory, Rybnik and Kuźnia Raciborska (Tab. 31; Map 1). The activities taken up to improve water quality in the catchment (arrangement of water-sewage system, construction of sewage treatment plants) resulted in reduction of the suspension and BZT5. On the other hand, an increasing amount of biogenic substances which are disposed to water is alarming. This is especially important for proper functioning of Rybnik Reservoir which have become a waste-water tank and has undergone slowly eutrophication. This situation occurred despite the fact that part of the most polluted water was disposed to Nacyna, below the reservoir. The results of the investigation on water quality in the catchment which were not included in state monitoring show that also Rudziczka, Klokocinka and streams which drain Ruda Kozielska area, contaminate Ruda (Tab. 32; Fig. 33). Also in other areas a considerable influence of uncontrolled waste water disposal on the quality of surface water is observed. Poor quality of water in Ruda catchment induces considerations concerning possibilities of its improvement (Fig. 36). The improvement of water quality in Ruda catchment would decrease pollutant load which is disposed to Rybnik Reservoir and which is delivered to Odra river. The protection and improvement of water quality in Ruda catchment is also necessary due to establishment of Rudy Wielkie Cistercian Composition Landscape Park in this area. Ruda is an hydrographic axis of this protected area and a natural ecological passage between the Wisła and Odra drainage basins where water, side by side with woods, represents an essential value. Restoration of water values of this area would result in increase of its tourist attraction and could be a model for other areas of the Upper Silesian Region which are not totally degraded.