Evaluation of the Effects of Geology and Agricultural Development State on the Quality of Surface Water Resources Affected by Constructing Reservoir Dams (Case Study: Marun - Jarahi Basin)

Document Type : Research Paper


Department of Hydrology and Water Resources, Faculty of Water Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran


The statistical tests such as T-test and Kruskall-Wallis test were used to study and analyze the difference between the quantitative parameters before and after constructing dams and the effect of different factors on water quality. The results of statistical tests showed that the values of the investigated water quality parameters (except EC value) before constructing (pre) dams were significantly different from the values after constructing dams in reservoir downstream stations. Sulfate (SO2-4) concentration in downstream stations of Marun Dam (Behbahan and Cham Nezam) reduced by 30 and 23 percent, respectively, and Cl- concentration increased 21 and 12 percent, respectively. Similarly, the difference between the values before and after constructing Jarreh dam at Mashin station was a 106% reduction in the concentration of sulfate ion (SO2-4) and a 78% increase in the concentration of chlorine ion (Cl-). The reason for this increase is probably due to the effect of river flows on the Formation and the relationship between the reservoir and the Formations where water has a long residence time and then reduced due to the exposure to the Geological Formations as well as the existence of agricultural activities downstream and before quality monitoring stations could be another reason for this claim. In addition, in the reservoir system, the concentration of soluble salt may be diluted by runoff from winter snowmelt and spring rains. Therefore, it can be concluded that water quality characteristics of Marun and Roudzard rivers in the studied basin has been affected by the constructed reservoir dams.


  1. Davis A. (1987). Chaparral conversion and streamflow: nitrate increase is balanced mainly by a decrease in bicarbonate. Water Resources Research 23: 215–224.
  2. Egborge ABM. (1979). The effect of impoundment on the water chemistry of lake Asejire. Niger. Freshwater Biology 9: 403–412.
  3. Hannan HH, Young WJ. (1974). The influence of a deep-storage reservoir on the physicochemical limnology of a central Texas river. Hydrobiologia 44: 177–204.
  4. Jenkins A, Sloan WT, Cosby BJ. (1995). Stream chemistry in the middle hills and high mountains of the Himalayas, Nepal. Journal of Hydrology 166: 61–79.
  5. Reynolds B, Hornung M, Hughes S. (1989). Chemistry of streams draining grassland and forest catchments at Plynlimon mid-Wales. Hydrological Sciences 34: 129–139.
  6. Antonopoulos, V. Z., Papamichail, D. M., & Mitsiou, K. A. (2001). Statistical and trend analysis of water quality and quantity data for the Strymon River in Greece.
  7. Edwards, A.M.C. (1973). The variation of dissolved constituents with discharge in some Norfolk rivers. Journal of Hydrology 18: 219–242.
  8. Pinol, J., Avila, A., Roda, F., (1992). The seasonal variation of streamflow chemistry in three forested Mediterranean catchments. Journal of Hydrology 140 (1–4), 119–141.
  9. Ahmad, S., Khan, I.H., Parida, B.P. (2001). Performance of stochastic approaches for forecasting river water quality. Water Research 18 : 4261–4266.
  10. Huang and Foo 2002
  11. Zarei, H., & Bilondi, M. P. (2013). Factor analysis of chemical composition in the Karoon River basin, southwest of Iran. Applied Water Science, 3(4), 753-761.
  12. Ashrafi, S. M., & Mahmoudi, M. (2019). Developing a semi-distributed decision support system for great Karun water resources system. Journal of Applied Research in Water and Wastewater, 6(1), 16-24.
  13. Bakhsipoor, I. E., Ashrafi, S. M., & Adib, A. (2019). Water Quality Effects on the Optimal Water Resources Operation in Great Karun River Basin. Pertanika, Journal of Science and Technology, 27 (4), 1881- 1900.
  14. Ashrafi, S. M. (2019). Investigating Pareto Front Extreme Policies Using Semi-distributed Simulation Model for Great Karun River Basin. Journal of Hydraulic Structures, 5(1), 75-88.
  15. Luo, Z., Shao, Q., Zuo, Q., & Cui, Y. (2020). Impact of land use and urbanization on river water quality and ecology in a dam dominated basin. Journal of Hydrology, 124655.
  16. Zarei, H., and Ajdari, A. (2006). Chemical Quality of Water Resources in Aboulfares Dam Basin and Effect of Gachsaran Formation on it, 10th Iranian Geological Society Conference, Tarbiat Modares University, Tehran.
  17. Zarei, H., Akhund Ali, AS. M., and Damough, n. A. (2006). Effects of Gachsaran Formation on Water Quality of Karun River in Khuzestan Province and Comparison with Dez River, 7th International Seminar on Ahwaz River Engineering, Shahid Chamran University of Ahvaz, Iran.
  18. Sokal and Rohlf, (1995).Biometry: the principles and practice of statistics in biological research. W. H. Freeman, Newyork, USA.