Reza Jalilzadeh Yengejeh - Department of Environmental Engineering, Science and Research Branch, Islamic Azad University, Khouzestan, Iran.
Jafar Morshedi - Department of Geoghraphy, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran.
Razieh Yazdizadeh - Department of Environmental Sciences, Science and Research Branch, Islamic Azad University, Khouzestan, Iran.

Pollution sources into the water, the necessity of qualitative studies of water resources is one of the most important new challenges for mankind in almost every parts of the world. Dissolved oxygen (DO) and Biochemical Oxygen Demand (BOD) are among parameters of water quality indexes which are considered as water pollution indexes. In the present research, DO and BOD of Dez River basin water (in Dezful City) were studied and zoned by applying the Geographic Information System (GIS). Nine stations were considered for sampling during six months in 2013. The results indicate that the average maximum amount of DO at an average of six months is 8.47 mg/l in S1 station and the minimum amount is 1.71 mg/l in S8 station. The average maximum and minimum amounts for BOD during an average of six months are orderly 150.83 mg/l in S8 and 3.16 mg/l in S1. By a qualitative zoning, places that are prone to pollution can be recognized and measures can be taken for monitoring and preserving such areas. Decreasing the amount of water pollution and controlling the pollution sources are possible by adoption appropriate measures.

Zoning, Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD), Wastewater, Dez river