DEVELOPMENT OF SCIENTIFIC BASIS FOR WATER MANAGEMENT IN AGROLANDSCAPES

Abstract

 Quantitative and qualitative depletion of water resources in Ukraine because of the increase in climate aridity make the problem of integrated surface and ground water management more urgent. The integrated management is based on the water balance of the territories, which automatically takes into account natural and artificial features of water use.

The paper presents the results of a long term research aimed at resolving the problems of scientific support of integrated water resources management in Ukraine in the context of climate change.

The plans for integrated water management are developed according to the administrative principle allowing optimization of the structure of water consumption and the assessment of available water resources capacity to meet water demand of the required quality without environmental risk for aquatic ecosystems and population.

The surface and ground water in Ukraine have spatially homogeneous hydrochemical spectrum, which characterizes the concentration anions and cations in water and the nature of their change at different water exchange rates.

Studies of hydrochemical spectrum have shown that its basic parameters are much higher for groundwater than for surface water.

The results of the study on the spatial changes in the chemical composition of surface waters in the Dnipro river basin testify to the distinct homogeneity of their hydrochemical spectrum, which gives the reason to limit in practice observations of changes in the chemical composition of water to local points.

As the experimental data are accumulated and the geospatial analysis of hydrochemical spectrum is made, the number of such points can be reduced ten times without significant negative impact on the reliability of the final results.

It is possible to draw up a water balance with the use of correlation functions, the observance of which will guarantee the rational water resources use, based on their actual available volume and restrictions on the total water inflow, filtration losses, surface runoff (discharges).

The water balance in the graphical representation is described by a linear function, which cuts the average of the sum of expendable elements on the ordinate axis over the entire observation period. The tangent of the slope of the graph represents the coefficient of water supply.

The scope of this methodological approach's application is limited only by the availability of raw data. There are sufficient data from precipitation observations, water abstraction from all sources in volumes comparable to precipitation and more. It is also desirable to have observations of groundwater level fluctuations and air moisture deficit.

The experimental research confirmed a high positive impact on the water resources formation made by forests, shelterbelts and meadows. In the humid zone it is possible to separate natural landscapes of wetlands and floodplains (60% of the territory), in the southern part - transitional landscapes that replace artificial agrolandscapes (40% of the territory). In arid climate conditions, the types of landscapes differ in the area of irrigated lands and the density of shelterbelts.

Agrolandscapes are complex natural-technical systems. In most cases, when investigating their impact on the processes of formation and use of water, it is possible to operate a finite number of interconnected parts (subsystems). The purpose of such separation on subsystems is to obtain typical areas for which spatial structure of agricultural landscapes can be experimentally evaluated and the nature of its relationship with the factors of surface water resources formation can be determined.

According to the assessment of water balance of rural territories, their water resources potential is equal to the sum of atmospheric precipitation and the volumes of water entering the balance space due to its withdraw for economic needs from surface and ground water bodies. When drawing up water balance for a hydrological year, water resources do not include precipitation, which is almost completely converted to river flow. The available volume of water for use should include the volume of water, the removal of which from natural or artificial circulation will not lead to negative environmental impacts or increase the cost of economic activity and restoration of fresh water bodies. The volume of water available for use is also limited by its qualitative indicators, which in turn are determined by its chemical composition (spectrum).