Impacts of Urban and Industrial Development on Groundwater, Bandung, West Java, Indonesia^*)

by : Soetrisno S.^**)

 

Lowering of Piezometric Heads

Due to excessive abstraction by industries, piezometric head of groundwater in the basin during the actual state lies far below the initial state. In the early 1900’s piezometric head in the areas which are now occupied by industrial area, was between 20 and 25 m above surface, while now it lies generally more than 50 m below surface.

In the area where many textile industries are concentrated, cone of depression are occured. As recorded by 48 observation wells, which are spread out in the basin, piezometric head has been declining continuosly almost in the entire of the basin, with rate of lowering is between 2 - 4 m/year (Fig. 3).

During initial state in early 1900, piezometric head in Western Bandung (Cimahi - Leuwigajah, at present is industrial area) was 20 to 25 m above surface, while in 1995 the deepest piezometric was recorded between 58 and 86 m below surface with rate of lowering of 2.5 to more than 4 m/year between 1990 - 1995. Here, wells tapped the Cibeureum aquifer.

In the Dayeuhkolot, south of Bandung, where many textile industries are located, in 1960 piezometric head was 3 m above surface. At present it is lying between 20 to 80 m below surface. Continous lowering of piezometric head is recorded between 2 to 2.4 m/year during five years of observation. Most of wells in this area tapped both Cibeureum and Kosambi aquifers.

The similar condition of groundwater has also been faced in another textile industrial center in central and east of the Greater Bandung. During the initial state in 1950, piezometric head lied 1.0 m above surface, while in 1995 it was recorded between 11.0 and 35 m below surface. Rate of lowering is observed 0.6 to 2.4 m/year during the last six year observation. Most of wells here, tapped the Kosambi and the Cikapundung aquifers.

This situation has changed the flow of groundwater system because the piezometric head is generally below the phreatic head nearly every where in the Greater Bandung (Fig. 4). Downward recharge from the upper system to the deep system, therefore, is occured and making the deep aquifer system is vulnerable to pollution. However, up to now there is no evident of pollution to deep system has been recorded.