Groundwater quality analysis using water quality index in Wonosari basin, Gunungkidul regency-Indonesia

Wonosari Basin is a physiographical unit in Gunungkidul Regency, Indonesia, that has enormous groundwater potential. Limestone inside the basin and dense population can harm the environment. The research aimed to analyze the groundwater quality in the Wonosari Basin based on the applicable quality standards, determine the water condition using the Water Quality Index (WQI), and determine the spatial pattern of the WQI grade. The total sample used in this research is 21 samples. Total Dissolved Solid (TDS), pH, Iron (Fe), Manganese (Mn), Sulfate (SO4), Nitrate (NO3), Hardness (CaCO3), and Total Coliform values of the groundwater samples were inputted to the weighted arithmetic WQI using Microsoft Excell to analyze the water quality. The spatial analysis was carried out using the cross-tabulation method with Microsoft Excell. The water quality standard used in this research is Regulation of the Minister of Health of the Republic of Indonesia number 23 of 2017. The research result showed that total coliform is the only parameter that exceeds its maximum acceptable presence, WQI values indicate that most of the groundwater samples have good quality, and the spatial pattern of water quality follows the population density.