Human activities in the Syr Darya river basin

Abstract

Changes in land use and water use can greatly impact the cycling of water and water-borne substances. Increased redistribution of river water to irrigated fields can cause enhanced evapotranspiration and decreased river discharge. Additionally, the water quality can be affected by the external input of fertilisers and pesticides, and by changed pollutant transport pathways in expansive irrigation canal systems. This work examines basin-scale changes in water use, land cover/use change (LLUC), water quality under conditions of intensified irrigated agriculture, development water constructions. When considering land use in the basin, it can be noted that most of the land is grassland (about 42%) and cropland (about 28%). A comparative analysis of 1992 and 2015 revealed that bare land and forestland area decreases. The percentage of the urban area during the increased to 1.0% during the study periods. The urban area expanded most rapidly mainly by encroaching into the agricultural area and grassland. Moreover, it revealed that over the long-term period the water construction was intensively taking placed in the basin. Especially since the 1960s. The construction of reservoirs and the increase in water withdrawal from rivers significantly changed their water regime, especially in the downstream. In fact, due to agricultural, industrial, and urban development’s, such as irrigation and drainage, hydraulic structure across a river, the elements of the hydrological cycle have changed in terms of quantity and quality, both in time and space. In this work, an attempt is made to analyze the effect of human activity on river runoff.