Mambo Dam is supposed to be constructed on downstream of Jajrood River for supplying Varamin plain’s consuming water, controlling flood and producing energy. In order to predict water quality and define the minimum flow on the downstream of Jajrood River, studies on water quality criteria and standards river self purification were done to assess parameters of dissolved oxygen, BOD5 and temperature.
Results indicate that prior or after dam construction, water quality changes are not sensible before discharging of Parchin complex effluent to the river. But after discharge even with considering complete treatment of Parchin effluent to standard level of surface water, river water quality changes severely.
The main reason for river water quality changes is high Parchin effluent flow comparing with river water flow at point of discharge. Mambo dam construction will increase this effect significantly.
We conclude that reaching discharge effluent standard is not enough for water quality control without considering pollution load.
It also suggests that, promulgation and enforcement of surface water discharge standard are necessary.