The purpose of constructing the Lower Maidanak Reservoir Dam is to store water and control floods in the region, which ultimately stores these floods for optimal use during droughts and dry seasons. By storing and storing runoff, the irrigated agricultural lands of the region will be significantly improved and the existing gardens will be developed. In addition, the rainfed agricultural lands of the region will be converted to irrigated lands, and a significant change will be achieved in the development of agriculture and the prosperity of livestock farming. The Lower Maidanak watershed, with an area of ​​36.2 square kilometers, has geographical coordinates of 47’11’50 to 24’17’50 east longitude and 59’45’32’ to 33’49’32 north latitude. The study area is located in Fereydounshahr County, 200 kilometers southwest of Isfahan. This region has a relatively severe to moderate topography, is located in the path of humid air fronts that enter the country from the west, and has suitable altitudes, so it has adequate rainfall.