GROUNDWATER QUALITY ANALYSIS USING MULTIVARIATE STATISTICS TO IDENTIFY THE HYDROGEOLOGY SYSTEM IN KULON PROGO REGENCY, DAERAH ISTIMEWA YOGYAKARTA

• Main Author: Musyarofah, Muzaimatul
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/79271
• Institution: Institut Teknologi Bandung

Kulon Progo located in the western part of Yogyakarta Province, has an area of 586.3 km2 with elevation range of 0-754 meters above sea level. It is divided into the North Zone, Central Zone and South Zone and includes 12 sub-districts: Girimulyo, Nanggulan, Kalibawang, Samigaluh, Sentolo, Pengasih, Kokap, Temon, Wates, Panjatan, Galur, and Lendah. Kulon Progo has a population of 442,838 people with an average growth rate of 2.11% (BPS, 2021). This figure is higher than the national average growth rate of 1.22%. With an increase in population, of course, it will in line with the increase in the need for clean water. As many as 39.7% of the population of Kulon Progo still rely on well water to meet their daily drinking water needs (BPS, 2021). At several locations, it was reported that there were indications of groundwater contamination by industrial and/or household waste. Therefore, it is necessary to carry out research related to geological conditions, geomorphology, hydrogeology, and the distribution of groundwater quality in the Kab. Kulon Progo. This research tested water samples based on the major ion as the variable. The cations tested were Na+ , Ca2+, Mg2+, K+ and the anions tested were Cl- , SO4 2- , HCO3 - , NO3 - and also pH, TDS, and EC. The methods used are multivariate analysis with Principal Component Analysis Biplots (PCA Biplot), ordinary kriging interpolation, Piper diagrams, stiff diagrams, Gibbs diagrams and chemical reaction diagrams of groundwater. This research used secondary data provided by PATGTL 2022. Software used are QGIS, ArcGIS, Global Mapper, RockWorks 16, Surfer 16, Grapher, and R. Groundwater quality based on the 2022 sample shows that all samples have good pH levels. However, there are 5 samples that have TDS values above the PERMENKES RI drinking water quality standards No. 492/MENKES/PER/IV/2010. Based on a comparison of the TDS value with samples before 2022, there is a tendency for the TDS value to decrease eastward in the North Zone, the TDS value tends to increase in the Central Zone until it exceeds the permissible threshold, and the TDS value in the South Zone increases rapidly to exceed the permissible threshold. The predominance of the sample is shallow groundwater, sample SB 1 is a type of seawater and ancient groundwater, sample SB 6 is a type of deep groundwater which is affected by ion exchange, and samples SB 2 and SB 7 are mixed types of groundwater. The sample plots in the hydrogeochemical diagram show that samples SB 2, SB 6, and SB 7 store sodium carbonate residue from irrigation water which can cause foaming problems, and sample SB 1 can cause salinity problems for irrigation water and drinking water.