TO ANTICIPATE IMPACTS OF RECLAMATION OF JAKARTA BAY

- A groundwater conservation’s perspective - ^*)

by : Soetrisno S., Satriyo H., and Haryadi T. ^**)

A b s t r a c t

The existing land and population of Greater Jakarta are highly relied on groundwater for providing their water supply. In the year 1995, deep groundwater abstraction was calculated 54 million m³ year^-1 which was about 50% higher than that of registered wells (32.2 million m³ year^-1). Only 20% of the Jakarta’s population is served by municipal water supply.

The highly dependent on groundwater has led to the degradation of both its quantity and quality, primarily in the northern part of Jakarta, such as lowering of groundwater head, about 2 - 4.6 m year^-1, salt water intrusion, and land subsidence which is highest recorded of 34 cm year^-1 between 1979 - 1991 years of observation.

The addition of 2700 ha of land which will be claimed from reclamation certainly will give impacts to groundwater setting, such as changing in fresh-salt water interface, recharge - discharge pattern, water balance, and total of water supply.

From groundwater conservation’s perspective, water supply for any activities and population on reclaimed land, therefore, must not rely on groundwater resources and efforts to restore the groundwater condition should be integrated part of reclamation activities. Empowering municipal water supply and using surface water might be the best solution for providing water in reclaimed land.

Creating retarding basins and extraction barrier along the shore line, based on result of simulation model, will give positive impacts to groundwater conservation program in North Jakarta.

___________________________

*) Paper presented at Workshop on Coastal and Nearshore Geological/ Oceanographical Assessment of Jakarta Bay: A Basis for Coastal Zone Management and Development, Jakarta, June 25 - 28, 1997.

**) Directorate of Environmental Geology, Jln. Diponegoro 57, Bandung 40122, Indonesia, Telp. +62 22 772603, Fax. +62 22 706167, E-mail: geoling@dgtl. dpe.go.id URL: http://www.dgtl.dpe.go.id.