During the last decades, world has been faced with shortage of water resources, increase of the population

and development of agricultural and industrial activities. Therefore, we should try to find reliable

water sources such as new dams. But dam reservoir will change the water quality and river downstream.

Thus, the investigation of water quality of dam reservoirs is very important. Doroudzan dam is located in

north western part of Shiraz on the Kor River, 70 km far from this city. The dam was first operated in 1351

with a capacity of 993×10

depths of Doroudzan dam and simulated using calibrated HEC-5Q and WASP7 models. Then, these models

were compared to determine suitable model. The evaluations of these models were showed that simulations

of both models were acceptable. In Farvardin, Ordibehesht, Khordad, Tir, Mordad, Shahrivar, Aban,

Azar, Dey, and Esfand months, simulation of nitrate with WASP7 model was better than HEC-5Q and in

other months, Mehr and Bahman, HEC-5Q was better than WASP7. In general, according to the mean of

measured and simulated data in dam reservoir profile, the simulation of WASP7 was better than HEC-5Q.

For orthophosphate, the simulation of WASP7 in Ordibehesht, Tir, Mordad, Aban, Azar, Dey and Bahman

months was better than HEC-5Q, and in other months, Farvardin, Shahrivar, Mehr, and Esfand, the HEC-

5Q simulations was better than WASP7. In general, according to the mean of measured and simulated data,

simulations of orthophosphate for WASP7 were better than HEC-5Q. Measured data, were showed that

mean concentrations of nitrate and orthophosphate were between 0.33-1.23 mgL

respectively.