Seawater Intrusion Assessment in Palu Bay, Central Sulawesi, Indonesia

Abstract Palu Bay is a body of water covering the mainland of Palu City and Donggala Regency, Central Sulawesi, Indonesia. This phenomenon has made groundwater the city’s primary source of clean water supply, contributing 65.63% of total drinking water and estimated at 2.7 million m 3 . The community uses shallow or deep wells equipped with pumping systems to fulfill daily needs, but some have reported a brackish taste in the water. Therefore, this research aimed to assess the possibility of seawater intrusion in the area. It was achieved by analyzing the values of Electrical Conductivity (EC), Total Dissolved Solids (TDS), chloride ion concentration (Cl − ), plotting Cl/Br (bromide) vs Cl, Simpson ratio, sodium chloride ratio, and Base Exchange Index (BEX). The results showed that several areas around Palu Bay indicated seawater intrusion, including Mantikulore and Palu Barat Districts.