Qarah Aghaj river is one of the most important rivers in the Fars province of Iran with a length of 700 km and its water is currently used for drinking and agricultural purposes. Salman Farsi Dam is located on the river between Jahrom, Simkan (Dozeh) and Qir and Karzin districts. This river is formed by joining the springs of Kan Zard, Chehel Cheshmeh Koohmareh and Sarkhark in Khan Zanian and after leaving the Arjan section of Shiraz, it enters Kavar city and after passing through the agricultural lands of Kavar, Khafr, Simakan, Qiro and Karzin through Mand river enters the Persian Gulf.