Groundwater Potential at Ciliwung River Basin

Abstract

Water is one of the human primary necessity. Development of water resources basically is the way to give an equal access to everyone to get water, so that they can live healthily and cleanly. Naturally Indonesia faces problem to fulfil water demand because of uneven distribution. Water availability is not in accordance with water demand in terms of both quality and quantity. Water are controlled and arranged for a lot of purposes, such as flood control and water supply. The research objectives were : (1) Identify characteristic of aquifer in Ciliwung river basin. (2) To analyze the ground water potential at Ciliwung river basin. In the upstream of Ciliwung river basin an aquifer was formed by sand, sand stones and sands brections In the middle Ciliwung river basin was formed by sandy-clay and sandy-brections and in the downstream was formed by sand and sandy-clay. The thickness of unconfined aquifer in the upstream was 10 – 45 m, in the middle was 10 – 41 m and in the downstream was 5 – 10 m. The confined in the upstream was 30 – 60 m, in the middle was 20 – 40 m and in the downstream was 20 – 40 m. Hydraulic gradient at upstream was between 0.0709 – 0.101, in the middle was 0.007 - 0.0709 and downstream was 0.004. Hydrauic conductivity in the upstream was 12 - 45 m/day, while in the middle and downstream was 0.08 – 12 m/day. The analysis result showed that in the unconfined aquifer groundwater potential in zone 1 (Gunung Mas – Cibinong) was 584,211.29 m3/day or 6.76 m3/sec and in zone 2 (Depok – Jakarta) was 131,208.55 m3/day or 1.52 m3/sec. Groundwater potential of the confined aquifer was in zone 1 (Gunung Mas – Cibinong) was 2,028,514.23 m3/day or 23.48 m3/sec ground water potention and in zone 2 (Depok – Jakarta) was 369,985.73 m3/day or 4.28 m3/sec.