The assessment of Groundwater Quality of Confined Aquifer Based on Hydrochemistry in the Alluvial Plain of Semarang City

Abstract

Water is one of the most important components for living things, including humans. The need for water will increase along with the increase in population in an area. It occurs in urban areas such as Semarang City which is the capital city of Central Java Province with the development of industry, trade and tourism growing rapidly. Rapid development occurred in the alluvial plains of Semarang City. Groundwater is still one of the main sources of water in Semarang City, both unconfined aquifer and confined aquifer. The unconfined aquifer is generally used by the community to meet their needs for bathing and washing via dug wells, while the confined one is developed by the industrial sector and is not least a source of drinking water via deep wells. This study aims to determine the quality of groundwater for drinking water at the study site of the confined aquifer. There are 30 groundwater samples were taken to test the chemical content of groundwater. The method used was the geospatial method and the Water Quality Index (WQI). The spatial method aims to determine the distribution of groundwater quality in the study area. WQI method was to determine the quality of groundwater for drinking water purposes. The results of the hydrochemical analysis showed that groundwater conditions are affected by weathering of silicate minerals present in the lithology of the study site. The weathering of these minerals results in ionic changes in the groundwater. WQI shows 1 sample is included in the poor classification and 2 samples are included in the very poor classification. It locates in the western and central parts of the study location.