A GIS-based analysis of groundwater manganese and nitrate concentration for sustainable water supply

Abstract Groundwater is the main source of water supply in Sleman Regency. Although the water quantity is not an issue, the quality of groundwater should be understood to ensure the sustainability of the water supply. A previous study shows an increase in manganese (Mn) and nitrate (NO 3 ) concentration in groundwater, yet the concentration distribution is unknown. Therefore, this study aims to develop a map of the spatial distribution pattern and to analyze the potential source of manganese and nitrate in groundwater in Sleman Regency in Yogyakarta Province. The method used is mapping groundwater quality using the ArcGIS application, analyzing groundwater pollution with water quality standards in the Indonesian Ministry of Health regulation number 492/Menkes/per/IV/2010 regarding drinking water quality requirements, and identifying the potential source of high pollution. Data processing uses the ArcGIS 10.8 application by performing the IDW (Inverse Distance Weighting) Interpolation technique. The result of this study has obtained a map of the distribution of groundwater quality for manganese and nitrate from 2017-2019. Manganese contamination may come from industrial and/or agricultural waste, while higher nitrate concentration might be a result of a septic tank leak and/or pesticide/fertilizer residue in paddy fields.