Classification of Zayandehrud River Basin Water Quality Regarding Agriculture, Drinking, and Industrial Usage

Mohammad Salarian ,Masumeh Najafi *

Citation: Classification of Zayandehrud River Basin Water Quality Regarding Agriculture, Drinking, and Industrial Usage, American Research Journal of Civil and Structural Engineering, vol 1, no. 1, pp. 47-57.

Copyright This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Iran is located in arid and semi-arid of the world and it has shortage of freshwater resources. So, to review the status of water use and protection of water resources against pollution, especially in the global water crisis is necessary and vital. Zayandehrud River as the largest river of the central plateau of Iran and the most important surface water flow in Isfahan province, which preserving its quality is important because of agricultureenvironmental, industry and drinking. In this regard, the assessment of the quality of the 15 stations in the Zayandehrud river basin has been done by using the analysis of physical and chemical parameters to during 5 decades from 1967-2009. Surveying the results shows thatdrinking water quality based on the diagram Schuler is good and acceptable. Regarding agriculture and irrigation, according to Wilcox diagram, except for two stations Hossein Abad and Henjin which were salty C3S1), the other stations suitable were a bit salty but suitable for agriculture (C2S1). Water quality of ten stations has been hard water; four stations fairly hard and the only Henjin station has been estimated quite hard. The type and faces of this basin water have beenchock bicarbonate at 13 stations and in two stations Hossein Abad and Henjin have been sodic sulfate and Magnesium Sulfated. Qualitative classification of stations based on both industrial and according to Langelier index is estimated to be corrosive except Hossein Abad station that has been deposited.

Keywords: Crisis - Water Quality - Zayandehrud - Wilcox - Schuler – Langelier



The surface water or rivers are the most important water resources which have a major role in supplying water required for various activities such as agriculture, industry, drinking water and electricity production. Many of the country`s water resources planning are based on the potential of surface water sources. One of the problems facing for transferring river water is the amount of pollutants that exist in river water in the form of solution or suspended solids (Najafi, Tabatabai, & Savage, 2006). Knowing the quality of water resources is one of the important requirements for the planning, development, protection and control of them (Jabari & Najmi, 2010).Given that millions of people are affected by water pollution annually and it is considered a threat to modern societies, studying addressing surface water sources such as rivers, is one of the necessities (Mossadegh, 2003). Since information about rivers regarding capacity of pollutants entrance will help a lot in controlling pollution and future planning, many studies have been done in this field in various formats. As an example, Statistical tests of Principal Components Analysis (PCA) and Cluster Analysis CA are used to determine the source of contamination in the water supply and by the evaluation of multiple parameters measured in a specific time period (Chapman, Organization, & Press, 1996), showed that pollution elements (e.g., K) must be attributed to the natural origin of geology or human origin (Pesce & Wunderlin, 2000).ForexampleVega, Pardo, Barrado, and Debán (1998), physical and chemical variables of water have been studied by using statistical analysis during 2.5 year at the three stations regarding the assessment of seasonal changes and pollutant effects on water quality of pisuerga River, a Spain. In this study, the application of PAC has been showed that the amount of mineral material, human pollution and the temperature have been decreased. Toinvestigate the spatial and temporal variations of river Sequoia River, Argentina, Alberto and colleagues (2000) by using statistical methods CA and PCA, showed that the CA method showed good results but with little detail of spatial and temporal variations in water quality. It must be also mentioned that PCA method requires 13 parameters to show 71% spatial and temporal variations. 

Another area of research that is used to infer the quality of river water can be cited direct study of plants and animals that live in it because aquatic organisms and communities can present the current situation, also changes over time and the effect of contaminant cumulative and biological indicators can also show hidden environmental impacts (Esmaili sari, 2003). For example, Azrina, Yap, Rahim Ismail, Ismail, and Tan (2006)studied the effects of human activities on the distribution and diversity of macro-benthic communities and water quality in Langat River, Malaysia that the relationship between physical, chemical conditions and benthic invertebrates in large communities were investigated through multiple stage regression analysis and the results showed the food and diversity of benthic invertebrates in large communities were mainly influenced by TSS and EC of river water. It is also necessary physical and chemical parameters are accurately simulated in the planning and estimated the possibility of neural network applications in the areas. For instance, Misaghi and Mohammadi (2004)by using the neural network showed that the neural network has good ability to simulate changes in the quality parameters in Zayandehrud basin and for qualitative data of BOD and DO. 

In addition to the above methods, it is possible to investigate chemical quality parameters of river water by using the existing software as Hydrochemistry (AquaChem, Chemistry) and output match with Piper diagrams, Shulander and so on. Since as we know the rate of water chemical parameters depends on factors such as geological formations in the basin area, ion exchange between surface water and groundwater and the river discharge regime which in this context, for example, we can mention a few samples. Sundaray, Nayak, and Bhatta (2009)in a case study conducted in India on Mahanad river investigated the river water quality to suit for agriculture for six different time periods at 31 stations and calculated water suitability for use in agriculture by using mathematical relationships and the parameters the ratio of sodium absorbance, residual sodium carbonate, water permeability in soil and the amount of magnesium which obtained results were consistent with Wilcox diagram. Based on Wilcox index, all samples from different areas of the study classified as excellent to good (low to medium salinity with low sodium) which were appropriate for all soils and also for salt-sensitive products.Mostakmeli and Tarshiziyan (2000) recognized chemical type and kind of water in Magnesium Sulfated by Piper and Stiff diagrams through studying river water quality in Shirin-Dareh Basin in North Khorasan province. Ghasemi, Zare, Shahsavar, and Yaghobi Kikileh (2010) investigate aquifer status to examine the qualitative and quantitative changes of Hamadan - Bahar plain groundwater. They determined a few changes through water level reading in each well in different months and Polygon them in a 15 year period (1992 to 2006) and concluded that groundwater level is dropped 11 m. They also categorized wells in two groups of quality in order to evaluate the qualitative changes by using Wilcox diagram. Results showed that due to aquifer proximity to residential and industrial areas, water quality das decreased from South-East to North-East of the basin. 

Considering the importance of water quality monitoring, checking water quality parameters from 15 stations of Zayandehrud catchment in order to drinking, agriculture and industry will be one of the goals of the present study. 


Zayandehrud catchment with 41500 km area, is located in the center of Iran and there is no outlet to the sea. Zayandehrud River is the largest river in this basin, which stretches from West to East and originated from Zagros Mountains and eventually goes Gavkhuni Marsh (Figure 1). The basin has semi-arid or dry climates. Annual rainfall is 130 mm on average in Isfahan city, which most of the precipitation falls in the winter; so rainfall is not significant during the summer heat season. On the other hand, temperature is high in summer and in July is about 30 degrees centigrade. Most of the precipitation falls in the cold season and temperatures is around 3 ° C. Annual potential evaporation is 1500 mm. All these figures and numbers confirm the fact that an economic farming is impossible without controlled irrigation and good management. The First and the main Supplier source of water requirement for Dashte-Isfahan is Zayandehrud River and other sources such as streams, canals and wells don’t have important role in providing needed water. Geographic characteristics and statistical periods (during 5 decades 1967-2009) for some stations under study in Zayandehrud basin are presented in Table 1.

Before the analysis of water quality data, the degree of accuracy and the accuracy of chemical data is determined by calculating ionic charge balance error (error response: RE) by using the following equation: 

If this value is greater than 5%, Data reliability will be questionable. Schuler, Wilcox Graphical indicators and also Langelier index have been used for quality classification of basin water. The following is a brief description of them 

2.1. Schuler Chart

Schuler semi-log chart is used to show the primary ions m Eq per liter and total dry residue and total hardness of water resources in a chart. Schuler chart is commonly used for the classification of "drinking" in water hydrology reports. Drinking water are classified into six groups of good, acceptable, fair, inappropriate, totally inappropriate and potable based on five chemical parameters of sodium, chloride, sulfate, dried residues (TDS) and hardness of drinking water of (Table 2).

2.2. Wilcox Diagram

One of the most important indicators for the interpretation the quality of raw water in "agriculture" is Wilcox index. Wilcox classification has been proposed by Wilcox in 1948 and has been completed three years later by Torn. The index is a very common method nowadays for classification of waters in agriculture. In this classification, two factors are considered: electrical conductivity (EC) and sodium adsorption ratio (SAR) which any of them are converted into four sections (Table 3) sections (Table 3) that the overall result is the emergence of the 16 groups (Table 4). Eventually, the quality of water is stated for various uses including irrigation. 

2.3. Langelier Index

One of the methods used for the prediction of corrosion characteristics or deposition of water is provided by Langelier (Takubangloo, 2003). He helped from developed theories governing water solutions in order to analyze water profile. Langelier suggested that difference between pH and pHs which are the acidity of the water (measured) and calculated acidity based on the results of the chemical analysis of water with assuming saturation of calcite or calcium carbonate can also be used as a numerical indicator of water specifications, respectively (Table 5). 


In order to control the quality of the data, the values of ionic charge balance error (percent error response) have been calculated according to equation 1 and is presented in Table 6. As we have seen the data has significant quality (since the percentage error is less than 5%). 

The results obtained from studying hydro chemical quality of surface waters of 15 stations in the Zayandehrud river catchment by using Schuler classification are given in Table 7. According to this table, drinking water quality is good and acceptable in this basin. Figure 2 is a representative of Schuler diagram. 

Fig2 .Schuler diagram for classification of drinking water quality

As it can be inferred from Table 8, it is observed the qualitative classification of 13 stations in the basin understudying is C2S1 (medium salinity - low sodium) based on the values of SAR and EC form from agricultural view point (irrigation), that is, slightly salty water is suitable for irrigation agricultural lands at their downstream and 2 stations Hossein Abad and Henjin have been salty C3S1 which is definitely suitable for agriculture. Figure 3 shows the Wilcox graph to classify Zayandehrud basin water quality.