applied geology research division, faculty of earth sciences and technology institut teknologi...

APPLIED GEOLOGY RESEARCH DIVISION, FACULTY OF EARTH SCIENCES AND TECHNOLOGY

INSTITUT TEKNOLOGI BANDUNG

Characterization of Tropical Volcanic Hydrogeology based on Temperature and

Electrical Conductivity Analysis: Mount Ciremai, West Java Province,

Indonesia

Irawan, DE., Puradimaja, DJ., Notosiswoyo, S., Sumintadireja, P.

Presented in 2011 European Geosciences Union General Assembly,

Vienna Austria, 3-8 April 2011



For more discussions, today I will be at:

Hall A Board #A27217.30-19.00

Introduction (Where’s Mount Ciremai)

3Applied Geology Research Division, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung

Just to give you an idea in term of size

Applied Geology Research Division, Faculty of Earth Sciences and Technology, Institut Teknologi Bandung 4

• 13,000 of islands• Nearly 350 Million of

population• 130 of volcanoes• 81.000 km of coastline

( 400.000.000 Coca Cola cans in line)



Why Mount Ciremai, among other 129 volcanoes in Indonesia ?

5 seconds of your time = nearly 40,000 L/sec of fresh high quality groundwater


12345

Introduction (Mount Ciremai’s Profile)


Large number of springs, with no systematic catchment monitoring and management.Large number of springs, with no systematic catchment monitoring and management.

The Hydrogeological Features(Geology, from Situmorang, 1995)

Consists of old and young volcanic products of pyroclastics flow and intruded lava underlied by Oligocene-Miocene clastics sediment.

Main geological structure: NW-SE fault at south from the peak E-W fault at easter slope, resulting Sangkanhurip

and Pejambon geothermal prospect.


Map and sections are on the Map and sections are on the poster locationposter location

Why are we doing this ?

To measure groundwater response: with relatively efficient and cheap method.

To explain groundwater infiltration processes: with the thickness variation of the soil and complex condition of the strato volcanic deposits.


Why are the problems ?

Thick weathered soil and fractured rock

Complex volcanic geology Outcrops of rock is hard to find Unpredictable subsurface

condition (buried faults, buried valley, etc from geophysical method)


How do we approach the conditions ?

What if we can extract something (by any chance) from: The hydrochemistry parameters The hydrodynamic parameters


Lack of long continuous time series dataLack of long continuous time series data

Methods (Field measurements) 24 hours

measurements of: Environmental

temperature (measured at the surface)

Groundwater temperature (measure at spring site)


24 hours measurements of:Environmental temperature (measured at the surface)Groundwater temperature (measure at spring site)

Daily measurements in 2006-2007 time frame of:

Rainfall: using standard rain gauge, obtained at the nearest station: The Susukan Station

(309 masl) The Mandirancan

Station (293 masl)Groundwater discharge at spring site: using channel measurement techniqueGroundwater EC and TDS: using standard portable equipments.

What do we know so far ?

Irawan (2009, doi:10.1016/j.jhydrol.2009.07.033): There are 3 groundwater systems (based on the hydrochemistry)

Herdianita et al (2010): Isotopes confirm that the recharge area is at around 1250-2500 masl (in regional scale of the volcano).

Sumintadireja et al (2011): confirm buried structures in the volcanic layers (MT and geoelectric)


The Hydrogeological Features


Extracted from 140 spring site

Result (Cibulan Spring)


•Air temp fluctuatesAND

•Water temp fluctuates

•Open aquifersystem •Interaction with surface

Temperature profile

Proportionally sketch (no scale)

Thick permeable soil (5-10 m)

Lava (unknown thickness)

350-400 L/sec

Results (Cibulan Spring)

Response: Highest discharge:

three to four months from the peak of rainy season.

Lowering discharge: two months since the dry season begins.

Lowest discharge: six months since the dry season begins.


Spring discharge hydrograph

Results (Cibulan Spring)


TDS-EC hydrograph

DissolutionDilution

Recovery

Dissolution

Results (Telaga Remis Spring)


•Water temp relatively constant

VS•Air/surface temp

fluctuates•Closed/deeper aquifer system

•No interaction with surface

Thin-permeable soil (5-10m)

Thick-fractured lava (unknown??)

Water lake (1-5 m depth)

Proportionally sketch (no scale)

200-400 L/sec

Temperature profile



Spring discharge hydrograph Response:

Highest discharge: three

to five months from the peak

of rainy season. Lowering

discharge: four months since

the dry season begins.

Lowest discharge:

seven months since the dry

season begins.



TDS-EC hydrograph

•TDS dry = 2 x TDS rainy

•EC dry = 1.7 x EC rainy

1st cycle

2nd cycle

DilutionDissolutio

n

Recovery

Dilution

Recovery

Dissolution

Conclusion

With this methode, in my point of view we can interpret the subsurface condition.

We have to have enough geology observation and geophysical data to support that.

This convey our prediction that the aquifer is a combination of porous medium aquifer from weathered soil and fracture medium from fractured lava and breccias.

In volcanic system, the boundary is beyond the topographical catchment area. It’s controlled by the lobes of lava or volcanic breccias.


Conclusion (Proposed type curve)

Model A Quick rising period in the

baseflow recession curve. Relatively have better

compliance to the dry season. Relatively long storage

period. Combination porous-fractured

medium.

Model B Slower period in the base

flow recession curve. More vulnerable to dry

season. Relatively short storage

period. Combination porous-

fractured medium.




The authors would like to thank:

1. Chevron Pacific Indonesia for funding the participation to EGU 2011

2. Mr. Wouter Buytaert (Convener) for contacting myself to fill in the free oral session

3. Ministry of National Education of Indonesia for funding the PhD research

4. Department of Water Supply Kuningan Regency for data and permission to visit spring site

5. Dr. Thom Bogaard (TU Delft) for the discussions

Contact informationEmail: [email protected] or [email protected]

Website: blog.fitb.itb.ac.id/derwinirawan Tel: +62222514990, Fax: +62222514837

Address: Faculty of Earth Sciences and TechnologyJalan Ganesa No. 10, Bandung-40132

West Java, Indonesia

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