waste load allocation for sub-basins of amir kabir dam reservoir using qual2k model

amir kabir dam was built in varian strait, at 23 km north of karaj in 1961. the dam is multipurpose and its maim aims are the spring floods control, supplying potable water for tehran city, producing electricity and providing irrigation water. different pollutants which discharge to the river finally enter to the dam reservoir. determining the pollution loads of the dam sub-catchments can help to prepare an effective pollution control plan. this study focuses on determining the discharged pollution loads of the sub-catchments which enter the dam reservoir, and their ranking. it can facilitate the decision process which constrains by financial and time issues. firstly, the pollution load of the sub-catchments for different parameters such as tds, cbod, ammonium, nitrate and phosphate were determined and then the discharged load to the dam reservoir was simulated by using qual2k model. finally, the sub-catchments loads ranked to five classes include very low, low, moderate, high and very high and the pollution zoning maps was prepared by gis. the results showed the loads of the river tributaries are more than the main stream, especially sub-catchments of velayatroud, shahrestanak, and siera which take accounted of more than one-third of the discharged loads to the reservoir and should have high priority in pollution prevention and control plans.