Hydrological system of the Irelyakh River and its interaction with industrial and municipal infrastructure of the Mirny district, Republic of Sakha (Yakutia)

Open-pit mining (gold, diamonds or other ores) has a profound and multidimensional negative impact on aquatic ecosystems. The degree of anthropogenic transformation of aquatic ecosystems depends on the scale of impact assessed through water management indicators, such as the volume of water withdrawal, purpose of water use, wastewater discharge and its quality, as well as the development of recycled water supply. The paper considers the peculiarities of technogenic transformation of the hydrological system of the Irelyakh River, the only source of drinking and industrial water supply in Mirny, which also meets the technical needs of the diamond mining enterprise, as well as the possible negative impact of hydrological processes on engineering structures. A comparison of the hydrological characteristics of the Irelyakh River before and during the technological process has been made. The hydrological characteristics of the Irelyakh River before and during the anthropogenic impact have been compared, and three main anthropogenic factors of flow redistribution are considered: the Irelyakh reservoir drawdown, wastewater discharge by the sewage treatment plant in Mirny, and water intake for dredges of the Irelyakh mine by Mirny Mining and Processing Plant. Quantitative assessment of water losses for evaporation from the surface of the Irelyakh reservoir and dredge dumps in the lower reaches of the river has been given; modern maximum secured water discharge of rainfall floods has been calculated using standard methods and approaches to their forecasting in the future climate have been determined.