Multitemporal water quality analysis of an epikarst spring for agricultural irrigation in the Gunungsewu Karst Area, Indonesia

Guntur Spring provides clean domestic and agricultural irrigation water and is the only water source in Girijati Village (Gunungkidul Regency) and Sorotopo Village (Bantul Regency), Yogyakarta Indonesia. The research was designed to analyze the multitemporal suitability of an epikarst spring water in the tropics for irrigation, with Guntur Spring as an example. It employed Na analysis, Sodium Adsorption Ratio (SAR) calculation, and hydrogeochemical data plotting on the USSL and Wilcox diagrams. The observed elements were Ca2+, Na+, Mg2+, K+, and electrical conductivity. Based on the Na and SAR values, all samples of the Guntur Spring were excellent (S1). The USSL plot classified them as moderate to good (S2-C1), and the Wilcox diagram indicated excellent to good attributes. Guntur Spring has higher water suitability parameter values for irrigation (Na and SAR) than other springs in the Gunungsewu Karst Area that receive allogenic recharges. However, such a difference does not necessarily place these springs in different classes. Likewise, although extreme events like the tropical cyclone Savannah diminish the water quality, it does not lower the water suitability class for this purpose. © 2023 Author(s).