Hydrogeochemical Characteristics of Spring Waters for Irrigation, Gokpinar Basin Case, Denizli, Turkey

Abstract

In this study, a detailed hydrochemical evaluation has been made to determine the chemical processes of spring waters and their suitability for irrigation. The study area consists of a drainage basin of the Gokpinar dam and has fertile soils for irrigable agriculture. During the period of August 2017 and October 2018, regular samples were collected monthly from 10 spring and 140 samples in total were subjected to hydrochemical analysis. For this purpose, 11 hydrochemical parameters such as pH, EC, TDS, TH, Na%, SAR, MR, RSC, RSBC, USSL, and Wilcox were used. GIS-based spatial mapping of the hydrogeochemical parameters has been prepared using ArcGIS. The major hydrogeochemical facies of waters are Ca2+, Mg2+, HCO3- water type. Alkaline earth metals (Ca2+, Mg2+) and weak acid (CO32-, HCO3-) dominates over the alkalies (Na+, K+) and strong acid (Cl-, SO42-) in all spring waters, respectively. Since the limit values of TDS in the samples are between 367 and 681 mgL(-1), the class of all samples is freshwater. The average Na% is between 1.29 and 9.28, and EC values are between 402 and 691 mu Scm(-1). For irrigation purposes, all spring waters fall within the category of excellent to good in the Wilcox (1955) diagram, based on the Na% and EC. Average SAR values in the range of 0.07-0.16 meqL(-1) indicate that spring water samples are excellent for irrigation purposes.