groundwater and river water interaction on cikapundung river: revisited (icmns itb 2014)
DESCRIPTION
The interaction between groundwater and Cikapundung river water has not changed significantly in 16 years of period. This paper revisit the similar research based on 43 measurement points: 13 dug wells, 2 springs, and 24 river, distributed along the riverbank at Curug Dago to Batununggal segment. The field measurements were taken in rainy season of April to May 2014 using portable instruments. Six parameters were measured: water level, temperature, total dissolved solids (TDS), dissolved-oxygen (DO), and pH. The new model is unable to detect significant change in water flow, however it finds two local anomalies in Dago Pojok and Cikapayang area. Both locations show local drawdown circle which can induce influent stream in overal effluent environment. Moreover, water quality parameters indicate mixing processes between groundwater and river water, with erratic pattern both in effluent and influent stream. Also some DO and TDS readings exceed the permissible limit. These values suggest a lifted groundwater mineralization from organic and non-organic sources and change of chemical stability. The source of contamination is still under further examination.TRANSCRIPT
Groundwater and River Water Interaction on Cikapundung River: Revisited
Darul, A., Irawan, DE, and Trilaksono, NJ.
Faculty of Earth Sciences and TechnologyInstitut Teknologi Bandung
The 5th International Conference on Mathematics and Natural SciencesInstitut Teknologi Bandung, 2-3 November 2014 1
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Background
• Cikapundung River is a potential source for water supply. The usage has not been increasing due to the low quality.
• There are three types of groundwater and surface water interactions (Lubis, 1997):
– isolated stream at Maribaya area (upstream), – effluent stream (or gaining stream) at
Maribaya to Viaduct (Central area of Bandung) segment, and
– influent stream (or losing stream) from Viaduct to Dayeuhkolot
• The vast growth of Bandung and the landuse change have lead to the change of groundwater usage and its hydraulic connection with river.
The 5th International Conference on Mathematics and Natural Sciences Institut Teknologi Bandung, 2-3 November 2014 2
Kawasan Curug Dago
Kawasan Viaduct
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Objective
• To re-assess previous hydraulic model by Lubis (1997), with a new set of observations.
The 5th International Conference on Mathematics and Natural Sciences Institut Teknologi Bandung, 2-3 November 2014 3
Java sea
West Java
Bandung
B a n d u n g
C i t a r u m
C i k a p u n d u n g w a t e r s h e d
First draft
Methods
• The basic idea is to map the pressure level, indicated by unconfined water level in dug wells along the riverbank. We measured the wells in a distance of 75 m on left and right direction from the river stream. The dataset was composed of 43 points: 13 dug wells, 2 springs, and 24 river water measurements. In the field survey, we used handheld instruments: (1) a Solinst water level detector (WLD) for water level depth and (2) some instruments from Eutech to measure total dissolved solids (TDS), electroconductivity (EC), temperature, and dissolved oxygen (DO). All tools were calibrated before use. Figure 1b shows station locations which were taken in rainy season from April to May 2014.
• Measurements were taken in north-south direction, from Bengkok (Ciumbeuleuit area) to Batununggal (Buah Batu area). The complete traverse was: Bengkok, Curug Dago, Dago Pojok, Bukit Resik, Sangkuriang, Lebak Siliwangi, Tamansari, Cikapayang, Cikawao, Melong, and finished in Batununggal.
• A nearest neighbour algorithm using Quantum GIS (QGIS) software was applied to draw water flow direction along the riverbank. We also applied some classification based on the physical characteristics of the water. This method was succesfully used to analyse hydrogeological nature based on water quality (Irawan et al., 2014, 2012, 2009). Basic data preparation and statistical analysis was based on Bivand and Pebesma (2013).
The 5th International Conference on Mathematics and Natural Sciences Institut Teknologi Bandung, 2-3 November 2014 4
First draft
Results (1): Three types of water interaction
The 5th International Conference on Mathematics and Natural Sciences Institut Teknologi Bandung, 2-3 November 2014 5
Cikapundung
Lembang fault
Isolated Effluent Influent
Maribaya Viaduct Dayeuhkolot
0 4
km N
E
S
W
1. Isolated stream at Maribaya area (upstream),
2. effluent stream (or gaining stream) at Maribaya to Viaduct (Central area of Bandung) segment, and
3. influent stream (or losing stream) from Viaduct to Dayeuhkolot
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Results (2): Two anomalous locations
The 5th International Conference on Mathematics and Natural Sciences Institut Teknologi Bandung, 2-3 November 2014 6
Cikapundung
Lembang fault
Isolated Effluent Influent
Maribaya Viaduct Dayeuhkolot
0 4
km N
E
S
W
• Two local anomalies in: Dago Pojok and Cikapayang area.
• Both locations show local drawdown which can induce influent stream in overall effluent environment.
First draft
The 5th International Conference on Mathematics and Natural Sciences Institut Teknologi Bandung, 2-3 November 2014 7
Results (3): Water quality pattern
• Water quality parameters indicate mixing processes between groundwater and river water, with erratic pattern.
• DO and TDS readings exceed the permissible limit at some points, suggesting a lifted groundwater mineralization from organic and non-organic sources and change of chemical stability.
0
1 0 0
2 0 0
3 0 0
4 0 0
5 0 0
6 0 0
7 0 0
8 0 0
9 0 0
Bengkok Curug Dago
Dago Pojok
Bukit Resik
Sangkuriang
Lebak Siliwangi
Tamansari
Cikapayang
Cikawao-Melong
Batununggal
0
5
1 0
1 5
2 0
2 5
3 0
Bengkok Curug Dago Da
go Pojok
Bukit Resik
Sangkuriang
Lebak Siliwangi Ta
mansari
Cikapayang
Cikawao-Melong
Batununggal
0
1
2
3
4
5
6
7
8
9
Bengkok Curug Dago Da
go Pojok
Bukit Resik
Sangkuriang
Lebak Siliwangi Ta
mansari
Cikapayang
Cikawao-Melong
Batununggal
TDS (ppm)
DO (ppm)
pH
Effluent Influent
First draft
Conclusions
• The interaction between groundwater and Cikapundung river water has not changed significantly in 16 years of period.
• The new model identifies two local anomalies in Dago Pojok and Cikapayang area. Both locations show local drawdown circle which can induce influent stream in overall effluent environment.
• Moreover, water quality parameters indicate mixing processes between groundwater and river water, with erratic pattern in all stream type.
• The erratic pattern indicates many surficial influences to groundwater and river water quality.
The 5th International Conference on Mathematics and Natural Sciences Institut Teknologi Bandung, 2-3 November 2014 8
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Next step
• This work is part of my master research project.• The result from this paper will be used to set a conceptual model
for a numerical simulation.• The future model is needed to simulate the interaction between
groundwater and river water in temporal and spatial terms.
The 5th International Conference on Mathematics and Natural Sciences Institut Teknologi Bandung, 2-3 November 2014 9
First draft
Main reference: Lubis, RF., Hydrodynamic relationships between groundwater and river water in Cikapundung River (Master Program of Geology, ITB, 1997).
Groundwater and River Water Interaction on Cikapundung River: Revisited
Darul, A., Irawan, DE, and Trilaksono, NJ.
Faculty of Earth Sciences and TechnologyInstitut Teknologi Bandung
The 5th International Conference on Mathematics and Natural SciencesInstitut Teknologi Bandung, 2-3 November 2014 10
Thank you for your attention
Further questions and comments should be addressed to:
Ahmad Darul Rochman : [email protected] Dr. Dasapta Erwin Irawan : [email protected] Twitter : @dasaptaerwin
The resources from this project will be made available online by the end of this month at:•ResearchGate: https://www.researchgate.net/profile/Dasapta_Irawan
•Academic.edu: https://itb.academia.edu/dasaptaerwin
First draft