Indonesian Journal on Geoscience

8

Authors: SETIAWAN WANGSAATMAJA, ARWIN SABAR, and MARIA ANGELA NOVI PRASETIATI

Environmental problems occurring in the Bandung Basin are resulted from improper management pertaining to land and spatial planning, including landuse policy and control. Arising environmental problems are covering disturbance of watershed hydrological function, surface and groundwater quality and quantity, solid waste, and air quality. Environmental studies in the Bandung Basin have been implemented by landuse change interpretation, surface water regime measurements, water quality, solid waste management, and air quality. Landuse change has occurred where some vegetation areas, such as forests and paddy fi elds, have decreased for 54% in one hand, and developed area has increased into 223% in the other hand. Watershed degradation is indicated by run off coeffi cient increasing from 0.3 in 1950 to 0.55 in 1998. Flow regime has also changed by presence of a maximum extreme discharge increasing tendency from 217.9 m3/sec in 1951 to 285.8 m3/sec in 1998, and minimum extreme discharge decreasing tendency from 6.35 m3/sec in 1951 to 5.7 m3/sec in 1998. Groundwater productivity index continued decreasing from 0.1 million m3/unit in 1900 to 0.0188 million m3/unit in 2002. Environmental problem has also occurred in a solid waste management sector where an average level of service is only 43.7%, and air pollution by motor vehicle and industrial emission,mikrosuch as PM10, NOx, CO2, SO2, Pb, and acid rain phenomena have also occurred. Fresh water supply level of service in the Bandung Basin only covers 43% of the total needs. Watershed degradation occurring in the Basin needs a management system recovery, administrative based-management that shifted to ecological based integrated watershed management. Effort and strategy required include the policy and institutional reassembling, pollution control, land rehabilitation and conservation, and community empowerment. Keywords: land use, watershed, run off coeffi cient, environmental strategy

13

Authors: MOHAMAD SAPARI DWI HADIAN, UNDANG MARDIANA, OMAN ABDURAHMAN, dan MUNIB IKHWATUN IMAN

Geologically the Batuceper and Benda Sub-Regencies belongs to the western part of the Jakarta Basin. The area is covered by coastal alluvial and delta deposits, and volcanic product. Understanding the distribution and groundwater pattern, either in the shallow part or the deep part, are of the basic thing for a geometric model and its groundwater fl ow in identifying the groundwater conservation. The result of the aquifer distribution, either in the shallow or the depth parts, was approached by the geoelectrical and hydrogeological surveys in the fi eld and well data that has resulted in aquifer distribution, either in the shallow or the deep parts. In general, the shallow aquifer developed downward becomes semi confi ned and confi ned aquifers. Groundwater fl ow pattern indicated local cones depression of groundwater level, especially around the city. Depression of groundwater level is considered to be related to the natural shape of aquifer as lences. However, it was possible to be caused by over pumping in this zone. Keywords: Jakarta Basin, groundwater, fl ow pattern, aquifer, groundwater conservation