The Origin and Quality of the Groundwater of the Rawadanau Basin in Serang Banten, Indonesia

Abstract

Rawadanau is a tropical mountain swamp located in Serang, Banten, Indonesia. Rawadanau groundwater is the main source of supply for the Cilegon Banten industrial area. Knowing the origin and quality of the groundwater can help preserve existing resources. This paper aims to clarify the origin of Rawadanau groundwater with new evidence of stable isotopes (18O and 2H) and hydrochemical data. Field measurements included pH, temperature, EC, HCO3ˉ, while the analyses of cations, anions and stable isotopes were carried out in the laboratory. The existing water supplies include springs, excavated wells, and river water. Cluster hierarchy analysis based on water chemistry and stable isotopes can be grouped into two clusters, cluster K (K1 and K2) and cluster L. Data δ18O and δ2H springs in Rawadanau indicate that they are of meteoric origin and that there has been evaporation from several springs. Water comes from meteoric water with a stable isotope content of δ18O between -6.39 to -4.82 ‰ and δ2H between -41.35 to -31.30 ‰, which are controlled by two main mechanisms, namely rock dissolution and evaporation dominance. Aquifers are composed of volcanic rocks with a dominant composition of porphyritic andesite, basaltic andesite, and andesite. According to the multivariate statistical analyses results other than pH and SO4 2-, all parameters (cations and anions) showed a significant correlation. There are four hydrochemical facies of groundwater, namely Ca-HCO3, Ca-Mg-HCO3, Mg-Ca-HCO3, and Na-Cl.

Multivariate Data Analysis to Assess Groundwater Hydrochemical Characterization in Rawadanau Basin, Banten Indonesia

“…In the hydrologic cycle, water can interact with the rock and the types of soil traverses to trace its origins using hydrochemical properties. Previous research has confirmed the Rawadanau Basin water potential from thermal and non-thermal sources from meteoric water (Syah et al, 2019;Hartanto et al, 2021Hartanto et al, , 2022. Meanwhile, hot springs produce various types of water, with heating sourced from beneath Mount Parakasak (Syah et al, 2019;Hartanto et al, 2021Hartanto et al, , 2022.…”

“…Previous research has confirmed the Rawadanau Basin water potential from thermal and non-thermal sources from meteoric water (Syah et al, 2019;Hartanto et al, 2021Hartanto et al, , 2022. Meanwhile, hot springs produce various types of water, with heating sourced from beneath Mount Parakasak (Syah et al, 2019;Hartanto et al, 2021Hartanto et al, , 2022. Springs with temperatures above 36.7°C and exceeding the average ambient area are called hot springs, and those below are considered cold springs (Alfaro & Wallace, 1994).…”

“…This paper will discuss and emphasize the water sources that fill the Rawadanau Basin and the temporal effects on groundwater. In addition to the development of previous research, which revealed the origin of water during the dry season and the characteristics of hot springs with heating sourced from Mount Parakasak's sub-surface (Hartanto et al, 2021(Hartanto et al, , 2022, this study aims to apply multivariate statistics to characterize groundwater and predict what components influence it using hydrochemical parameters and stable isotopes of water. Furthermore, it contributes to understanding the hydrochemical characteristics of two seasons in volcanic product areas and the hydrogeochemistry that controls the water quality.…”

Groundwater Contributing to Doline Hydrochemistry in Panggang and Wonosari-Baron Hydrogeological Subsystems, Indonesia

“…Spatial/ temporal analysis of the karst subsurface river shows that hydrochemistry of karst water, especially in total dissolved solids (TDS) and pH, was affected by precipitation during the flow process [10]. On the other hand, the quality and origin of groundwater, including the transport mechanism, can support the conservation of existing water resources, such as springs, wells, and river water [11], and protect fresh groundwater [12]. The hydrochemistry in karst doline water has not been studied specifically, so this paper aims to complement the karst research, especially Gunungsewu.…”

Hydrochemical Indicators Analysis of Seawater Intrusion in Coastal Karstic Aquifers on the Example of the Bokanjac-Poličnik Catchment Area in Zadar, Croatia

“…As groundwater moves through rocks, its chemical composition normally changes, and the longer groundwater remains in contact with aquifer rocks the greater the amount of material it will take into the solution [3]. There are many obstacles in water supply systems that use groundwater in coastal aquifers, and seawater intrusion is a major one [4][5][6][7], referring to varying degrees of mixing saltwater with groundwater.…”