Assessment of Surface Water Quality in the Vanak-Soolegan Basin, Western Iran

Document Type : Original Article


1 PhD graduated student of irrigation and drainage Engineering

2 Assistant Professor, Department of Environmental Science and Engineering, Faculty of Natural Resources, University of Jiroft

3 Associate Professor, Water Department, Faculty of Agriculture, Shahrekord University



As monitoring and assessment of water quality are assumed as important factors in the improvement of the communities’ sanitary status the in 21st century, optimal management of freshwater resources should be taken as an integral part of d. evelopment programs worldwide. The main objective of the current study was, therefore, to assess the characteristics of surface water quality in the Vanak-Soolegan basin and to identify its long-term trend of variations, using graphical methods. To this end, the required data were collected from three hydrometric stations (Soolegan, Tagarg-ab, and Tange Zardaloo). Then, for a better understanding of water quality, the data were analyzed based on 11 different parameters including Electrical Conductivity (Ec), Total Dissolved Solids (TDS), Acidity (pH), Calcium (Ca), Magnesium (Mg), Sodium (Na), Potassium (K), Bicarbonate (Hco3), Carbonate (Co3), Chlorine (CL) and Sulphate (So4). Assessment of water quality was also performed by drawing Schoeller, Piper and Wilcox diagrams. As revealed by the Piper diagram, the dominant water type was calcium-bicarbonate. The results of the Schoeller-diagram demonstration showed that the water samples fell in potable and acceptable class and that based on the Wilcox Diagram, the majority of samples were classified into low salinity class (c2s1) which is suitable for farming. Moreover, the trend analysis of selected parameters was performed via the Mann–Kendall test on a 18-year period (from 1995 to 2012). The results indicated a positive trend in Ec, T.D.S, Ca, K, and So4 at the Soolegan and Tagarg-ab stations. In general, it seems that several factors are involved in water quality changes including the weathering of the hard rocks, lithology, drought, and increase in water consumption.


  1. Agresti, A, Categorical Data Analysis. John Wiley and Sons, Hoboken, NJ.Back W and Hanshaw B (eds). Chemical geohydrology advances in hydro science; Academic Press. 2002. (pp. 49-109).
  2. Berryman D, Bobée B, Cluis D, Haemmerli J. Nonparametric tests for trend detection in water quality time series. Journal of the American Water Resources Association. JAWRA. 1988. 24(3): 545:556.
  3. Bouza-Deano R., Ternero-Rodriguez M., Fernandez-Espinosa A.J., Trend study and assessment of surface water quality in the Ebro River (Spain). Journal of Hydrology. 2008. 361: 227: 239.
  4. Gharibi H., Mahvi A, H., Nabizadeh R., Arabalibeik H., Yunesian M., Sowlat M. H., A novel approach in water quality assessment based on fuzzy logic. Journal of Environmental Management. 2012. 112:87-95.
  5. Gilbert, R.O., Statistical Methods for Environmental Pollution Monitoring. New York, van Nostrand Reinhold. 1987.

6. Güçlü Y. S., Improved visualization for trend analysis by comparing with classical Mann-Kendall test and ITA, Journal of hydrology, 2020, 584 (124674).

  1. Kendall, M.G., Rank correlation methods, fourth ed. Charles Griffin, London, 1975.
  2. Kisi O. and Ay M. Comparison of Mann–Kendall and innovative trend method for water quality parameters of the Kizilirmak River, Turkey. Journal of Hydrology. 2014. 513(362-375).
  3. Mann, H.B., Non-parametric test against trend. Econometrica, 1945. 13:245–249.

10. Miyittah M. K., Tulashie S. K., Tsyawo F.  W.,  Sarfo J.  K., Darko A. A.,  Assessment of surface water quality status of the Aby Lagoon System in the Western Region of Ghana, Heliyon, 2020, 6(7): e04466.

  1. Mustapha M.K., Assessment of the Water Quality of Oyun Reservoir, Offa, Nigeria, Using Selected Physico-Chemical Parameters. Turkish Journal of Fisheries and Aquatic Sciences. TrJFAS. 2008. 8: 309-319.

12. Nyikadzino, B., Chitakir, M.,  Muchuru, S., Rainfall and runoff trend analysis in the Limpopo river basin using the Mann Kendall statistic. Physics and Chemistry of the Earth, Parts A/B/C, 2020, 117(102870).

  1. Parmar, K., & Parmar, V., Evaluation of water quality index for drinking purposes of river Subernarekha in Singhbhum District. International Journal of Environmental Sciences, 2010. 1:77–81.
  2. Piper M., A graphic procedure in the geochemical interpretation of water analysis. Transaction of American Geophysical Union. (Trans. AGU). 1944. 25 (6):914-928.
  3. Prasad P., chaurasia M., Shony R. A., Gupta I., Water quality analysis of surface water: a Web approach. Environmental Monitoring and Assessment. 2013. 185(7):5987-5992.
  4. Ramakrishnaiah C.R., Sadashivaiah C., Ranganna G., Assessment of Water Quality Index for the Groundwater in Tumkur Taluk, Karnataka State, Indian Journal of Chemistry.  IJC. 2009. 6(2):523-530.
  5. Sajil Kumar P.J., Interpretation of groundwater chemistry using piper and chadha´s diagrams: a comparative study from perambalur taluk. Elixir Geoscience, 2013. 54:12208-12211.
  6. UNESCO (United Nations Educational, Scientific and Cultural Organization), WHO (World Health-organization), UNEP (United Nations Environment Programme). Water Quality Assessments - A Guide to Use of Biota, Sediments and Water in Environmental Monitoring. 1996. Second Edition. Published by E&FN Spon, an imprint of Chapman & Hall.
  7. Zang b. Song X. ZhangY. Han D. Tang C. Yu Y. Ma Y. Hydrochemical characteristics and water quality assessment of surface water and groundwater in Songnen plain, Northeast China, Water research, 2012. 46: 2737-2748.