تعیین حقابه زیست محیطی در مناطق خشک و نیمه خشک با استفاده از روش‌های هیدرولوژیکی

In recent decades, the rapid growth in population with its accompanying agricultural and industrial development and climate change has transformed water ecosystems and resulted in a massive loss of biodiversity. Zanjan Province is recently facing serious problems of water withdrawal due to consecutive droughts, improper distribution of precipitation, urbanization and dam construction. Despite increasing competition over diminishing water resources, environmental-flow topic receives much less attention in this region. Environmental flows describe the quantity, timing, and quality of water flows required remain healthy and sustainable. In this study, the daily streamflow data over 30 years (-) were used in order to determine the environmental flow in Sojas River using the hydrological methods. The results indicated that the good and acceptable environmental flow calculated by Tennant's method was respectively ≥ 1.57 and ≥ 1.18 in the wet season. Also, in 37.12 percent of the studied period, the condition of the river was poor and very poor in terms of providing the minimum environmental flow. While, the average environmental flows calculated by Tessman method were 1.65 and 0.6 in the wet and dry seasons, respectively. According to the results, the condition of the Sojas River is becoming critical in terms of environmental flow that could lead to political and social consequences in the region. So, it is recommended to explain practical solutions for the ecology of this river.