CHEMICAL COMPOSITION OF A COLLECTOR-DRAINAGE RUNOFF IN OPEN CANALS IN SEMIKARAKORSKY DISTRICT

The aim of the research was to study the dynamics of the chemical composition of sludge-wastewater in open collector-drainage canals in dynamics and to determine factors influencing the formation of chemical composition of the studied waters. Material and Methods: the object of the research was open collector canals in Semikarakorsky district under the jurisdiction of the Federal State Budgetary Institution “Rostovmeliovodkhoz” Management Branch. Results: the chemical composition of water in the Nizhny Don main canal and in the collector canals K-3, LS-2, MKL-7, Central discharge and BG-MS-4 were studied. It was found that the chemical composition of water in the main canal along its entire length complies with the standards for fishery water bodies, with the exception of sulfates, where maximum allowable concentration is exceeded by 1.5 times. The main pollutants of water in an open collector-drainage network are ions that form the ion-salt composition of water: calcium, magnesium, sodium, bicarbonates, sulfates, chlorides. In this case before the water enters the main canal, the content of the above ions and as a consequence such indicators as mineralization and hardness exceed the standard values by 2–4 times. With the beginning of the irrigation season, the concentration of ions in water decreases by almost 2 times, which is due to dilution with water passing through open collectors in transit from the main canal. Nevertheless, excess of the normative values of indicators for surface water bodies is still observed. The reason for this is the leaching of water-soluble ions from the soil by precipitation and removal with surface runoff, as well as their infiltration and removal from soil with underground runoff. Groundwater has a significant effect on the composition of water in an open collector-drainage network. An investigation of groundwater in a 5 m deep well located near the MKL-7 canal showed a mineralization value of 2471 milligrams per cubic decimeter, and a hardness of 24.4 millimoles per cubic decimeter. Conclusion: therefore, the structure of the cation-anion composition of the underground supply of collector-drainage canals determines the composition of water in canals.