Salt water intrusion study in Jakarta aquifer system

Abstract

Saltwater intrusion in the aquifer system of Jakarta area, is a study of ground-water in conjunction with hydrostatic equilibrium between freshwater and saltwater flows in aquifer system at border of coastal. There are two main objectives of this study, namely: (i). To analyze the rate of saltwater instrusion in Jakarta aquifer system and (ii) To analyze the impact of recharge of rainwater to control the rate of saltwater intrusion in Jakarta aquifer system. To achieve that objectives, research methodology and material use are as follows: (i). Method use are descriptive, analysis and modelling; (ii) System and technique of data required use secondary and primary data which are grouped in three area of transected zones. (iii). Material use are: Salinity data (EC, Cl- and TDS) were collected over period of 1995 - 2010 with inverval per 3 km at zone transected, hydrogeology, water consumption and recharge; and (iv) Mathematic model use is SHARP model with block-centered finite-difference grid at scale 3 km x 3 km area. Conclusion of this study are: (1). The average rate of saltwater instrusion during period of 1982 – 2010 at transection zone I was 0,1 km/year, at transection zone II was 0,06 km/year and at transection zone III was 0,11km/year. (2). Based on prediction in 2025 ground water consumption amount of 8,02 m3/second will impacted saltwater intrusion at transection zone I at distance of 9 km, at transection zone II at distance of 9 km and at transection zone III at distance of 13,5 km from coastal border. (3). Based on prediction for 2025, increase of ground-water recharge with amount of 3,95 m3/second by applied 100% artificial-recharge based on requirement government regulations, will decrease the saltwater instrusion at all transection zones which are transection zone I will decrease with amount of 1,5 km, transection zone II will decrease with amount of 3 km and at transection zone III will decrease with amount of 4,5 km compare with without artificial recharge, or decrease of saltwater intrusion as of conclusion item (2) above and (4). Based on prediction for 2025, increase of ground water recharge with amount of 0,99 m3/second by applied 25% artificial recharge based on requirement of government regulations, will decrease the saltwater instrusion at 2 transection zones which are transection zone II will decrease with amount of 1,5 km and at transection zone III will decrease with amount of 1,5 km compare with without artificial recharge, or decrease of saltwater intrusion as of conclusion item (2) above.