Stable Isotopes and Hydrochemistry Approach for Determining the Salinization Pattern of Shallow Groundwater in Alluvium Deposit Semarang, Central Java

Abstract

A groundwater study has been conducted in the Semarang City in August 2014, aiming to determine the source of shallow groundwater salinization using stable isotopes (18 O, 2 H) and water chemistry approach, and supported by local hydrogeological data. A number of shallow groundwater samples were taken at several locations with a depth of 0-35 m. Based on geological data, shallow groundwater of Semarang alluvium is dominated by insertion of sand-gravel and sandy-clay with average porosity of around 56.0 %. This layer is thinning towards the south and then increasingly thickening to the north and northeast of the studied area. The results of the analyses show that the characteristics of shallow groundwater, i.e. approximately 51% of groundwater, still have the original composition as meteoric water and the remaining approximately 49% obtained a shift in the isotopic composition as caused by interaction with seawater and the little influence of evaporation. The results of chemical analysis of water indicates that in dry seasons, shallow groundwater aquifers in the Semarang City is dominated by chloride (Cl-) with NaCl of water type. While the parameters of bicarbonate, chloride, and Na/Cl ratio, shallow groundwater can be classified into two groups, namely unintruded groundwater around 51% spread from the foot hills to the south towards the hills with elevations of 9-142 m above sea level and intruded groundwater around 49% spread from the coastline to the urban direction.

Groundwater Flow Model In The Center Of West Progo Dome, Kaligesing, Purworejo, Central Java And Its Surrounding Area, Based On Hydrochemical And Isotopic Characteristics

“…Whereas, the stable isotopes 18 O and 2 H are present in water in the form of 1 H 2 18 O and 1 H 2 H 16 O compounds (Satrio et al, 2017). These two isotopes are very sensitive to physical processes such as evaporation and condensation, therefore to prevent this the sampling was carried out in the following manner.…”

“…Hydroisotope method using 2 H and 18 O has been chosen because of its relatively low cost of analysis (Irawan, 2009;Alam et al, 2014). The advantage of using the stable isotopes δ 18 O and δ 2 H compared to other isotopes is that the content of these stable isotopes in rainwater shows a linear relationship in the form of a global meteoric water line (Satrio & Sidauruk, 2015).…”

Geochemistry of groundwater and saltwater intrusion in a coastal region of an island in Malacca Strait, Indonesia

“…Interaction of groundwater-seawater traced using δ 2 H and δ 2 O isotope analysis and hydrochemical methods. Both isotopes used as a marker in identifying the source of groundwater in the aquifer, the possibility could be coming from rain, deeper or shallower groundwater, seawater, fossil water, or magmatic water ( [21]; [31]). The isotope analysis in Riau province studied by [32] was the first to define the Local Meteoric Water Line (LMWL) found that the reference value for LMWL in this area is δ 2 H = 7.6 δ 18 O + 10.5 (r 2 = 0.921).…”

“…The salinity of groundwater occurred in major cities and found to intruded the groundwater wells, both shallow and deep wells [20]. It is occurred not only on the wells that closed to the shoreline [21] but also in further sites [22]. One of the major provinces in Indonesia, Riau, has also faced saltwater intrusion and upconing problems, particularly in the coastal areas and in the islands.…”

Hydrochemistry and Characteristics of Groundwater: Case Study Water Contamination at Citarum River Upstream

“…1), the findings could not reveal any geological factors that caused the groundwater contamination in the area. (Hadian et al, 2014(Hadian et al, , 2015Satrio, 2015Satrio, , 2017Barkah, 2015). …”