Qualitative Evaluation of Surface Water Resources Using Iran Water Quality Index (IRWQSC) and National Sanitation Foundation Water Quality Index (Case Study: Kardeh Dam, Mashhad, Iran)

The quality of water resources is one of the main subjects in ensuring public health. Therefore, monitoring water resources, especially surface waters, is one of the leading water operational management systems’ requirements. Since the quality of surface waters is affected by natural factors and pollutants from human activity, monitoring water resources’ quality leads to collecting and extracting valuable data, which needs a suitable method for interpretation and analysis. Therefore, this research assessing the annual quality of Kardeh Dam (One of the surface water sources of Mashhad) based on IRWQISC and NSFWQI qualitative index. The results showed that the Kardeh Dam quality index in spring, summer, autumn, and winter is 55.43, 49.25, 57.61, and 60.9, respectively, indicating relatively good, average, relatively good, and relatively good quality conditions, respectively. Also, according to NSFWQI analysis, the quality index was calculated for spring, summer, autumn, and winter, respectively equal to 86.4 (good), 81.28 (good), 84.48 (good), and 96.64 (excellent). Comparisons showed that IRWQISC was more rigorous than NSFWQI in judging the water quality of the Kardeh Dam. Comparisons indicate that the dam’s water quality judgment with the IRWQISC model is far more stringent than the NSFWQI model.


Introduction
Today, the water crisis is one of the major challenges in developed and especially developing countries [1]. Although water is one of the most abundant compounds in nature, only a small part of water resources, including surface and groundwater, can be exploited by humans [2][3][4][5]. FAO 1 forecasts show; by 2025, about 1.9 billion people worldwide will face severe water shortages, and two-thirds of the world›s population will be under water stress [6]. In recent decades, population growth, urbanization, and industrial development have polluted water resources [7,8]. Decreased urban water quality leads to epidemics of many diseases and has many acute (short-term) and chronic (long-term) effects. Therefore, due to the urgent need to use available water resources, it is necessary to pay attention to their protection against pollution [9,10]. Protection and optimal use of water resources are among the principles of sustainable development in any country [11].
Therefore, it is important to study surface and groundwater quality to provide water with appropriate quality for various Citation: Shahsavar  uses [12]. One effi cient method without complex mathematical and statistical equations to determine water quality is water quality indicators presented on a numerical scale. In this method, the calculated number is categorized with a relative scale that indicates water quality from very bad to excellent [13][14][15]. IRWQI SC 2 quality index is one of the most widely used indigenous criteria for surface water quality zoning. Due to the simplicity and availability of the required quality characteristics, it is a very useful and effi cient tool for researchers. This index is determined based on fecal coliform parameters, BOD 5 [25]. In another study by Hao, et al. (2016) heavy metal pollution in rivers in Bangladesh was examined.
In this study, the concentrations of heavy metals chromium, nickel, lead, arsenic, and cadmium in the river and its sediments were measured and studied [26]. Smithy, et al. (2016) studied the quality of surface water resources using multivariate statistical analysis. In this study, samples were taken from Yliki Lake over fi ve years and analyzed to measure 16 physical and chemical parameters [27].
The present study intends to investigate the water quality of Kardeh Dam using IRWQI SC and NSFWQI indices with the help of laboratory measurements and the calculation of quality parameters of Kardeh Dam. In addition to analyzing the quality conditions of Kardeh Dam in all four seasons of the year, the dam's water quality was compared in terms of Iranian standards (IRWQI SC ) and the United States (NSFWQI).

Site description
This study was carried out on the water of Kardeh Dam, located 40 km northeast of Mashhad (36°38 ' N, 59°40 ' E). Mashhad water treatment plant number one feeds from this dam and, after performing the necessary treatment, water is injected into the water supply network and provides to the subscribers ( Figure 1). It is worth noting that the Kardeh dam is not supplied by urban or industrial treated wastewater. The mentioned dam is nearby the mountain and it fed by pure precipitated water fl ow.

IRWQI SC quality index
For determining surface water quality according to IRWQI SC and NSFWQI standards, fecal coliform parameters, BOD 5 , nitrate, dissolved oxygen, electrical conductivity, COD, ammonium, phosphate, turbidity, temperature, total solids, total hardness, and pH were measured according to standard methods in time intervals which were on the 15th of May, August, November, and February (the middle day of each season) in 2015 from the diversion section of Kardeh Dam.   However, each of these parameters has different weights in IRWQI SC , shown in Table 1. [28].
Weighing and mathematical analysis of water quality status of Kardeh Dam was performed based on the scoring-weighting indicators in the IRWQI SC model according to Equation 1.
In the above relation, the parameters W i , n, and I i express the i-th parameter›s weight, the number of parameters, and the index value for the i-th parameter of the ranking curve, respectively. It should be noted that fi nally, the guide in Table   2. is used to describe the quality of the weights determined using the IRWQI SC model.

NSFWQI quality index
The NSFWQI Index was introduced in 1970 by the American Institutes of Health to monitor water resources quality. This index has nine main parameters, including fecal coliforms, BOD 5 , nitrate, dissolved oxygen, electrical conductivity, water temperature, phosphate, turbidity, total solids (TS), and pH.
In this standard, each of the mentioned factors has a unique degree of importance, summarized in Table 3 [16].
Then, the value of NSFWQI for each chapter was calculated according to Equation 2, and the related quality was evaluated based on the classifi cation in Table 4.
In the above relation, the Q i and W i parameters represent the equivalence value of the i-th parameter in the NSFWQI standard and the weight ratio of the i-th parameter, respectively.

Methods of measuring parameters
In this study, to determine BOD 5 of Kardeh Dam water, a water sample was aerated in 300 ml BOD glass bottles at 20 ° C. Immediately dissolved oxygen in one of the glass containers measured, and Other containers were incubated for fi ve days.
Finally, Equation 3 was used to calculate the BOD 5 value. In this regard, D 1 is the initial dissolved oxygen, D 2 is the fi nal dissolved oxygen, and P is the ratio of sample volume to total combined volume [29].
On the other hand, a potent oxidizing agent (potassium dichromate) and DR39000 spectrophotometer system were used to measure the COD parameter [30]. Also, fecal coliforms were determined by the Multiple-tube fermentation (possible MPN method) [31]. In this study, the spectrophotometric method was used to measure nitrate, phosphate, and ammonia [32].
UV-Visible DR39000 spectrophotometer was used to measure nitrate, and Agilent8453 was used to determine phosphate.

Results and discussion
The experiments performed on Kardeh Dam's water for spring, summer, autumn, and winter seasons are shown in Figures 2 to 6. The severity of BOD 5 , Nitrate, COD, and Ammonium contamination is highest in summer and lowest in winter ( Table 5). The high levels of BOD 5 and COD in summer can be attributed to increased microbial activity and organic load from natural organic compounds in summer [33]. It is also worth mentioning about nitrate and ammonium; In summer, the temperature and consequently microbial activity increase, and this leads to successive processes of ammonifi cation (production of ammonium nitrogen from the protein of organic compounds) and nitrifi cation (production of nitrate from the protein of organic compounds and ammonium) [34].
However, the intensity of Phosphate contamination reached its maximum concentration in autumn and has the lowest value in spring. On the other hand, the total hardness reaches its maximum in spring, while autumn has the minimum total hardness. Similarly, Figure 3 shows   The values of the dam's average quality parameters and the required water standards for agricultural and recreational purposes are given in Table 6. According to Table 6, the geometric average of the number of fecal coliforms in the dam       water resources, it is necessary to carry out global monitoring at different time intervals to obtain coherent models of the qualitative behavior of different surface water resources. In this study, the water quality behavior of Kardeh Dam was investigated using IRWQI SC and NSFWQI evaluation models. A sampling of dam water was done on the 15th of May, August, November, and February 2015. The results of quality tests showed that water quality conditions, according to IRWQI SC standards in different seasons of winter, autumn, summer, and spring, have relatively good, relatively good, relatively good, and average quality conditions, respectively. IRWQI SC quality weight index in winter, which is equal to 60.9, was estimated to be 5.39, 8.97, and 19.13 % more than weight indices of autumn, spring, and summer seasons, respectively. Moreover, NSFWQI index analyzes evoked excellent, good, good, and good quality conditions in winter, autumn, summer, and spring, respectively. In this model, the winter quality index was calculated as 12.58, 10.59, and 15.89% higher than the weight index of the samples related to autumn, spring, and summer, respectively. This difference in water quality›s desirability can indicate a difference in many factors such as temperature and ecosystem conditions in different months and seasons of the year.