Нетробчук И. М.

It is analysed the condition of water resources and the level of its usage. It is predetermined the optimization of natures use of West Bug river basin sustem on the territoru of Volun region.

Purpose. Determination of ecological stability of landscapes of the basin of the Western Bug River and its tributaries in Volyn region. Methods. Comparative-geographical, analytical, generalization, systematization, calculation of ecological stability of the landscape on the basis of the method of E. Clementova, V. Heinig. Results. The calculation of the quantitative assessment of the ecological stability of the landscapes in the basins of the Western Bug tributaries revealed that the KESL1 index of the Pischadka, Neretva and the Zolotoha River ranges from 1.3 to 1.6. That making basin landscapes conditionally stable. River Studyanka and Luga range from 0,027 to 0,026, which testifies them to the unstable structure of the landscapes of the basin with pronounced instability. It is established that in the landscapes of the basin of the Western Bug River of Volyn Region, their ecologically balanced structure is predominant at the KESL1 1.04 index. This is due to the structure of the lands of the basin, where agricultural (arable land) cause a big loading and destabilized landscapes occupies in most of the area. The largest plots of arable land occupy the sub basins of the rivers Studyanka and Luga, and the smallest ones in the sub basins of the Neretva, Zolotukha and Gapa rivers, which is due to the significant forested areas of the basin. The qualitative assessment of ecological stability of the landscape is characterized by the coefficient of ecological stability of the biotechnical elements of the entire landscape of the K ESL2. Calculations of KESL2 showed that the landscape structure of the basin of the Western Bug River in the Volyn region is slightly stable and the index is 0.48. The KESL2 coefficients of the Studyanka and Lug lakes are 0.21 and 0.23 respectively, and characterize them as unstable geosystems. The structure of the landscapes of the basins of the Peschadka and Kopayevka rivers for KESL2 - (0,95 - 0,67) is stable. Consequently, intensive settlement of land, drainage of marshes, deforestation violated the integrity of landscapes led to their denaturalization. Particularly significant changes occurred in the southern part of the basin. Conclusions. As a result of the calculations of the quantitative assessment of the ecological stability of landscapes (KESL1), the landscapes of the basin of the Western Bug River in the Volyn region are conditionally stable. And according to the indicators of qualitative assessment of ecological stability of the landscape (KESL2), they are characterized as low-static geosystems. In general, determining the stability of the landscape is important for assessing the ecological situation of the basin of the Western Bug River, since it fully reflects the overall ecological status of the river basin.

Purpose. The analysis of the surface water quality of the Stokhid river, the definition of the class and the category of water quality. Methods. Comparative geographic, analytical, generalization and systematization. Results. Inner annual dynamics of the components of the hydro chemical conditions of surface water composi-tion is closely linked with river runoff, the formation of which occurs due to loss of precipitation and nutrition of groundwater. Based on the analysis of monitoring observations, carried out by the State Environmental Inspec-torate in the Volyn region for the period from 2007 to 2017, it has been determined the multi-year time and spa-tial dynamics of the average annual values of integrated environmental indices by the average values. They are following: in the village Malinovka IE aver. = 2,2 and in Lyubeshiv village IE aver. = 2,4. The water of river Stokhid belongs to the second class of quality ("good", "pure"), to the second category ("very good", "very pure") and subcategories 2 (3) ("very good", " clean" water with a tendency to approach the category of "good", "fairly clean") respectively. Dynamics of average annual values of integral ecological indexes for the worst values in village Malinovka IE worst = 2,6 and in the village Lyubeshiv IEworst = 2,8 was characterized by water of the second class ("good", "pure"), third category ("good", "fairly clean"), subcategory 2-3 (water transitions in quality from "very good", "pure" to "good", "fairly clean") and subcategory 3 (2) ("good", "fairly clean" water with a bias to "very good", "clean"). Conclusions. In general, it should be noticed, that when calculating the values of integral ecological indexes, the value of the indexes of trophic and sapro-biological indicators are the worst. Compounds of Nitrogen was among the substances that determined the water quality as "very poor" and "very dirty". Increased levels of Nitrogen compounds in the Stokhid river is mainly due to the intake of insufficiently treated wastewater, surface runoff from agricultural land and the decomposition of non-living organic matter in the spring.