Ali LUKMAN (1), Muhammad DEFI ARYANTO (2),
Adhi PRAMUDITO (2), Adi ANDHIKA (2), and DR. Dasapta ERWIN IRAWAN (3)
(1)
Student of Magister Geological Engineering Program, Bandung Institute of
Technology
(2)
Hydrogeologist and Geophysics of PT. Supra Indodrill
(3)
Hydrogeologist of Groundwater Engineering Departement, Bandung Institute
of Technology INDONESIA
alilukman.geologi@gmail.com and
pramuditoadhi.supra@gmail.com
ABSTRACT
North coast of Java has been grown to be
center of economic activities. Those activities must be supported by
sustainable water supply, groundwater is one of the source. However the complex
alluvium aquiver system has not been well-understood.
A geoelectric measurements were performed to
determine which rock layer has a good potential as groundwater aquifers in the
northern coast of Kaliwungu Regency,
Kendal District, Central Java province. Total of 20 vertical electrical
sounding (VES) points has been performed, using a Schlumberger configuration
with the current electrode spacing (AB/2) varies between 200 - 300 m and the
potential difference electrode spacing (MN/2) varies between 0.5 to 20 m with
depths target ranging between 150 - 200 m. Geoelectrical data processing is
done using Ip2win software which generates resistivity value, thickness and
depth of subsurface rock layers.
Based on the correlation between resistivity
value with regional geology, hydrogeology and local well data, we identify
three aquifer layers. The first layer is silty clay with resistivity values
vary between 0 - 10 ohm.m, then the second layer is tuffaceous claystone with
resistivity value between 10 - 60 ohm.m. Both layers serve as impermeable
layer. The third layer is sandy tuff with resistivity value between 60 - 100
ohm.m which serves as a confined aquifer layer located at 70 - 100 m below
surface. Its thickness is vary between 70 to 110 m. The aquifer layer is a
mixing of volcanic and alluvium sediment, which is a member of Damar Formation.
The stratification of the aquifer system may change in short distance and
depth. This natural setting prevent us to make a long continuous correlation
between layers. Aquifer discharge is estimated between 5 - 71 L/s with the
potential deep well locations lies in the west and southeast part of the study
area.
Keywords: vertical electrical sounding (VES),
Kendal, coastal aquifer system
This slide was presented in the ICES ITB July 2016. The official website of this event is http://portal.fi.itb.ac.id/ices2016/
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