Water Quality Assessment in Terms of Water Quality Index (WQI): Case Study; Gorganroud River, Golestan Province, Iran

The most important aquatic ecosystems are freshwater rivers, which are considered as biodiversity and drinking water. In this regard, the quantitative and qualitative study of these resources is an important pillar of sustainable development. Gorganroud is one of the most important rivers in northeastern Iran; therefore the aim of this study was to study survey of Gorgnroud River water quality in Golestan Province using Water Quality Index (WQI). For this purpose, five sampling stations were selected along the Gorgnroud River, and samples were taken from April to August of 2015 every 45 days at sampling stations. The parameters of dissolved oxygen, nitrate, nitrite and PH were measured at each turn and the data were analyzed by WQI qualitative index. The results showed that the Water Quality Index at the first station (91/22); at the second station (85/51); at the third station (89.30); at the fourth station (87/14) and fifth station (81/11). The water quality index indicates that water quality of the Gorgnroud River was in a very good quality class during the spring and summer seasons.