Saltwater Intrusion Zone Mapping on Shallow Groundwater Aquifer in Selat Baru, Bengkalis Island, Indonesia

Abstract

Saltwater intrusion becomes a common problem in coastal area. Northern coast of Bengkalis Island in Riau, Indonesia that contiguously to Malacca Strait is experiencing the problem particularly in Selat Baru area which considered as developing area and most of the people live close to the sea. Dug well is the main source of groundwater that had been used by the population in Selat Baru and as the increasing of land occupation, the demand of clean water is rising up followed by the number of dug well. A study of groundwater monitoring was conducted to identify the zone of saltwater intrusion. Field observation had done by measuring the water level and physical parameters of groundwater such as taste, pH, electrical conductivity (EC) and total dissolved solid (TDS) from 110 existing dug wells. Some conus feature had found from groundwater elevation map which indicated lower water level caused by excessive groundwater pumping. Generally, pH shows values from 6-8 that was still in range of water quality standard, but there are 20 wells (18%) that have pH below the water quality standard (slightly acidic water). Similar pattern had been observed from Electrical Conductivity (EC) and Total Dissolved Solid (TDS) map, higher value of EC and TDS was dominant in the northern part of study area and lower value in the south. Groundwater taste map also revealed the identical condition with EC and TDS map which dominated by brackish and saline water in the northern part. Therefore, the study area had been divided into two zones of groundwater saline water zone possibly caused by the saltwater intrusion in the northern part and freshwater zone from the center to the southern part.

Hydrochemical of Groundwater and the Potential of Sea Water Intrusion in Tanah Laut, South Kalimantan

“…The pH value of groundwater characterizes the degree of acidity. Groundwater is stated to be neutral if it has a pH of around 7, or a pH of 6 -8 which is the range of water quality standards (Putra et al, 2019). Groundwater with a pH of 5 -7 is said to be weakly acidic to neutral, which characterizes that dissolved carbonates are predominantly in the form of HCO3 (Adams et al, 2001, in Ako et al, 2012.…”

“…Legend: Listyani, 2016). Therefore, the EC and TDS values usually show a similar pattern (Putra et al, 2019). TDS is the amount of all dissolved minerals that are left when all the water is evaporated, or the amount of salt contained in the water (Davis & De Wiest, 1967, in Setiawan et al, 2017.…”

Respon Morfo-fisiologi Empat Genotipe Cabai Rawit (Capsicum frutescens L.) terhadap Cekaman Salinitas

“…Petani di pesisir pantai utara (Pantura), telah merasakan dampak lahan salin di Indonesia sejak tahun 2017 (Sembiring et al, 2020). Selain di Pulau Jawa, dampak lahan salin juga terjadi di Aceh (Muhni et al, 2018;Marohn et al, 2012), Riau (Putra et al, 2019), dan Makasar (Ramli et al, 2019). Luas lahan salin akan terus meningkat dan membutuhkan perhatian lebih, sehingga perlu dilakukan antisipasi terhadap hal tersebut.…”