The Combined Use of Hydrological Methods and Game Theory in Determining the Environmental Flow of the Great Karun River

Introduction Due to the increase in population and the inappropriate temporal and spatial distribution of precipitation, the implementation of dam construction projects is essential. This, along with the increasing abstraction of water and discharge of wastewater and sewage, has caused the river ecosystems to be negative affected by dam construction projects. In dam construction, more attention is paid to the needs of drinking, agriculture, and industry, and less to the environmental flow of rivers. In order to maintain the ecosystem, however, it is necessary to determine the environmental requirements of the dams downstream.   Methodology There are various methods for determining the environmental flow of the river, including hydraulic, hydrological, comprehensive, etc. The use of a combination of modern sciences and other conventional methods in this field has been widely used. In this study, taking into account the environmental needs of downstream and using the new integrated hydrological method of Tennant and simulating the river BOD parameter using Qual-2k model and solving game theory (calculating the Nash function), the optimal amount of environmental flow of the Karun river was estimated under three different quantitative and qualitative scenarios.