Hydroecological assessment of collector-drainage runoff from irrigation systems of the Rostov region

Abstract

The purpose of the work is to conduct a comprehensive hydroecological assessment of collector-drainage waters of irrigation systems of the Rostov region in dynamics to establish spatial and temporal patterns of changes in their quality. The objects of the study were 20 main collector channels of fi ve branches of the Federal State Budgetary Institution «Management «Rostovmeliovodkhoz». Structurally, all collectors are open channels in the earth bed. For the hydrochemical assessment, an integral indicator, the coeffi cient of maximum pollution (Cmp), was used, taking into account the priority indicators of the quality of collector-drainage waters (CDW). The dynamics of the coeffi cient of water pollution limit in the reservoirs of the Semikarakorsky branch for the period 2009-2021 showed the absence of sharp fl uctuations in the quality of drainage runoff, the value of the coeffi cient of maximum pollution ranges from 0 to 1, drainage water is characterized as moderately polluted. In the collectors of the Bagaevsky branch, the value of the Cmp fl uctuates in the range of 0…2.7, drainage water is characterized as moderately polluted, polluted. The predominant ions in the drainage runoff are sulfates and sodium. The high content of sulfates in the drainage runoff is due to the introduction of sulphate groundwater, characteristic of this region. A study of collector-drainage water in the reservoirs of the Semikarakorsky and Bagaevsky branches for the content of biogenic elements in 2021 showed a regular excess of phosphates during the entire irrigation period. A comparative analysis of the quality of natural water of the CDW water intakes in the background and collector-drainage waters showed that the hydrochemical composition of the studied waters is approximately the same, which indicates the merger of water bodies and open reservoirs in the earth channel into a single hydrographic network. In 25% of the studied collectors, lower water quality was observed than in the water intake.