Stream water quality in the western regions of Iran
AbstractStream water quality of a part of the four western mountainous regions of Iran: Lorastan, Kordestan, Hamadan and Kearmanshah, with a total area of 101.102´103 km2 was investigated. The chemistry of
major elements such as Ca, K, Na, Mg, Cl, HCO3, SO4 and alkalinity from hydrological basins of the regions was examined based upon samples from the relatively important basins. The difference in
these chemical elements of streams was verified on a region-by-region basis. Temporal changes of water quality in the stream water were examined using a seasonal classification of data. The results
showed that the dissolved load of about 70% of all water samples (at all basins during all seasons) was less than 500 mg/l. The same result can be concluded for seasonal variability of EC for the entire area. It
was less than 0.550 ds/m for 68% of samples. The pH variation was from 5.5 to 9 with an average of 8.2. The highest and lowest values are from autumn and summer samples, respectively. In summer, the
sodium adsorption ratio (SAR) value was maximal, and the agricultural activities cause an increasing on its normal (average annual) rate in the rivers. The results also indicated a very good relationship between the total anions and total cations, during all of seasons. There were no significant relationships between the area of the basin and the chemical element concentrations. These results have been used for the water resources management of the mountainous regions of Iran and the
modelling of water quality predication.