Investigation of Gilan index dams' water quality using multivariate methods

Nowadays, the importance of water is known more than before as a life factor and the axis of sustainable development that to protect and manage it, it needs to be controlled using laboratory tests and various water quality indexes. The purpose of this study was to investigate water quality in diversion dams in Guilan province in which the dams have been ranked using Shannon and TOPSIS entropy methods. The dams included Pasikhan, Shakhzar, Polrud and Tarik and the measured indicators included Ec, pH, TDS, Temperature, SO4, HCO3, Cl, Ca, Mg, Na, TSS, DO, BOD5 and COD. Shannon entropy results showed that among the indicators, the highest index weight is related to TSS with the amount of 0.1973 and the lowest one is related to pH with the amount of zero. Topsis tests results showed that based on the weights derived from entropy and water quality indicators, Pasikhan dam is in the first rank, Polrud dam is in the second rank, Shakhzar dam is in the third rank and Tarik dam is in the last rank. So, according to multivariate selection methods, water quality in different dams with similar conditions can be investigated.