The water resources formed in the territory of Eastern Zangezur and Karabakh region freed from the occupation are of special importance for the sustainable water supply of the republic. Efficient and comprehensive use of these water resources will contribute to the connection of fertile lands located in the freed Karabakh and East Zangezur economic regions to the agricultural cycle and the population can be settled quickly. Before settlement, irrigation and water supply systems should be established using the water and hydropower potential of the rivers located in this area. It is necessary to efficiently use the water resources of these rivers, during the autumn and spring highwater period. These rivers have a huge energy potential, and by building hydrotechnical facilities of various purposes on them, it is possible to fully satisfy the electricity demand of the population living in these economic regions, as well as to create a water management system that can be controlled in a self-flowing mode, which is more economically favorable. Engineering hydrological studies were carried out on the development of a more optimal water management system, taking into account the factors of natural conditions and relief indicators of the area, and the location of fertile land suitable for cultivation outside the river basins. In the article, the design solution for the creation of two derivative-type hydroelectric power plants outside the Okhchuchay riverbed in order to obtain green energy from the seriously polluted water resources of this river, which has a large hydropower potential, is presented. In the HPPs to be built on the Okhchuchay river, 80.0 million kWh of electricity can be obtained during the year, which will allow the permanent supply of electricity to more than 120,000 people. Besides, the article proposed project solutions related to the construction of water reservoirs on the rivers Hekari, Bargushad, Gargar (Zarisli tributary), and Guruchay, regulation of their flow regimes and use in the sustainable water supply of the region. The water management system to be created will allow providing a permanent drinking water supply to more than 4.0 million people and provide irrigation water to almost 80 thousand hectares of agricultural land.