Determination of ecologically admissible volumes of take-off of water from small rivers

Abstract

The purpose. To determine ecologically admissible volumes of take-off of water from small rivers. Methods. Research is lead according to regular supervision over small rivers of Prypiat Polissia of Ukraine. At assessment of ecologically admissible volumes of take-off of water from the rivers the basic condition is preservation of ecologically safe condition of water eco-system at which changes of its structurally-functional organization do not harm to ability of natural complexes to self-control, to autopurification and self-restoration. Results. Ecologically admissible volume is determined of take-off of water that enables to carry out take-off of water from rivers for various economic needs without damage of water eco-system. It is established that under the influence of anthropogenic load water eco-systems for last years have undergone essential changes. In particular significant transformations of water-intaking area and big regulation of drain are observed. Ecologically admissible volumes are determined of water take-off from rivers for the long-term period in years with different security (50, 75, 95 %), and assessment of ecologically admissible volume of take-off of drain under condition of preservation river eco-system is carried out. Calculations have shown that in very shallow year (P=95 %) water resources do not provide volumes of ecological drain, and in shallow year (P=75 %) its water resources slightly exceed ecological drain. The volume of ecological drain almost at half of researched rivers reaches 40%, and in others — 50–60% of norm of drain. Conclusions. It is established that in Prypiat Polissia of Ukraine in very shallow years for water-economic needs is necessary to use stocks of other water resources. The further calculations of ecologically admissible minimal volumes of water should be complex and consider as much as possible criteria of condition of river that will enable to reveal such criteria which worst of all influence its condition.