8/6/2019 PDF 2007 Erwin Ciremai Bali
1/16
26th Annual Indonesian Geologist AssociationJoin Convention Bali, 2007
Full Paper Submission
Corresponding Author: Dasapta Erwin Irawan
Address:Research Division on Applied GeologyFaculty of Earth Science and TechnologyInstitut Teknologi BandungBasic Science building 3
thfloor
Jl. Ganesa no 10, Bandung - 40132
Email:[email protected],Tel/Fax: 022-251 0802
Title of paper:Outlining Hydrogeological System using Multivariate Analysis on Groundwater Quality at Mt.Ciremai, West Java, Indonesia
Author(s) and Affiliations1. D. Erwin Irawan2. Deny Juanda PuradimajaResearch Group on Applied Geology, Faculty of Earth Sciences and Technology,Institut Teknologi Bandung, Jl. Ganesha No. 10, 40132 Bandung, Indonesia (e-mail: [email protected])3. Sudarto NotosiswoyoResearch Group on Earth Resources Exploration, Faculty of Mining and Petroleum Engineering,Institut Teknologi Bandung, Jl. Ganesha No. 10, 40132 Bandung, Indonesia (e-mail:[email protected])
Abstract (no more than 200 words)
Volcanic slopes are important sources of water. Groundwater observation in east slope of Ciremai wasconducted in period of dry season of May until June 2006 on 119 springs. Fourteen variables wasmeasured: elevation, spring discharge, TDS, EC, pH, T water, T air, calcium, magnesium, chloride,sodium, sulphate, potassium, bicarbonate.
Cluster analysis has successfully extracted 3 clusters: cluster 1 (112 obs), cluster 2 (5 obs), cluster 3(2 obs). The hydrogeological schematization has been constructed based on interpretations of 3clusters. There are 3 hydrogeological systems: 1) Hydrogeological system 1 is characterized by:cluster 1, heterogeneous data, normal water temperature, TDS, EC, and major elementsconcentrations, and many chemical influences. 2) Hydrogeological system 2 is characterized by:cluster 2, homogeneous data, high water temperature, TDS, EC, the result of interaction betweennormal meteoric water and hot water of volcanic origin. 3) Hydrogeological system 3 is characterizedby: cluster 3, high water temperature, TDS, and EC with homogeneous characters, deep flow system,
and interaction with sedimentary layers of Fm. Kaliwungu.
Key words:1 Stratovolcanoes2 HydrogeologicalTracer3 Multivariate analysis
mailto:[email protected]:[email protected]:[email protected]:[email protected]8/6/2019 PDF 2007 Erwin Ciremai Bali
2/16
Outlining Hydrogeological System using Multivariate Analysis on Groundwater Quality
at Mt. Ciremai, West Java, Indonesia
D. Erwin Irawan1, Deny Juanda Puradimaja1, Sudarto Notosiswoyo2
1Research Group on Applied Geology, Faculty of Earth Sciences and Technology,
Institut Teknologi Bandung, Jl. Ganesha No. 10, 40132 Bandung, Indonesia (e-mail: [email protected])
2Research Group on Earth Resources Exploration, Faculty of Mining and Petroleum Engineering, Institut
Teknologi Bandung, Jl. Ganesha No. 10, 40132 Bandung, Indonesia (e-mail: [email protected])
Abstract
Volcanic slopes are important sources of water. Groundwater observation in east slope of
Ciremai was conducted in period of dry season of May until June 2006 on 119 springs.
Fourteen variables was measured: elevation, spring discharge, TDS, EC, pH, T water, T air,
calcium, magnesium, chloride, sodium, sulphate, potassium, bicarbonate.
Cluster analysis has successfully extracted 3 clusters: cluster 1 (112 obs), cluster 2 (5 obs),cluster 3 (2 obs). The hydrogeological schematization has been constructed based on
interpretations of 3 clusters. There are 3 hydrogeological systems: 1) Hydrogeological system
1 is characterized by: cluster 1, heterogeneous data, normal water temperature, TDS, EC, and
major elements concentrations, and many chemical influences. 2) Hydrogeological system 2
is characterized by: cluster 2, homogeneous data, high water temperature, TDS, EC, the result
of interaction between normal meteoric water and hot water of volcanic origin. 3)
Hydrogeological system 3 is characterized by: cluster 3, high water temperature, TDS, and
EC with homogeneous characters, deep flow system, and interaction with sedimentary layers
of Fm. Kaliwungu.
1. Introduction
Indonesia is a part of ring of fire, consisting of almost 128 volcanoes. In other figure, 13
17% of worlds volcanoes are located in Indonesia. Such large number of volcanoes makes
Indonesia one of important country to solve volcanoes problems. Subduction zone lies across
the country forming volcanic belt, most of it are strato volcano. Hundreds of volcanoes
produce volcanic deposit which covers 33,000 km2or one sixth of Indonesias land (Dept. of
Mining and Energy, 1979).
At this volcano, volcanic deposit plays role as productive aquifer, as shown by the emergence
of spring belt with enormous discharge and excellent quality. The aquifer comes as porous
system as well as fracture system. For an example on Mt. Ciremai, there are at least 116
springs with variable discharge, from 10 liter/seconds to 1000 liter/seconds.
This paper describes the hydrological assessment performed on the Mt. Ciremai (Figure 1).
Here we analysed 116 springs around the volcano on water quality and quantity. The results
show radial flow patterns, a dependency on slope aspect and altitude and lithology. This paper
will elaborate on the relationship between volcanic geomorphology and hydrology that was
found and discuss how this information could be used for assessing the spatial patterns of
local groundwater systems on volcanic slopes. Lastly, we make a spatial water balance to
illustrate the regional differences in water availability.
8/6/2019 PDF 2007 Erwin Ciremai Bali
3/16
2. Problem Statement
On the Java island Indonesia, the water demand increases due to population growth and rising
water consumption per capita (Puradimaja et.al, 2004). Although Indonesian islands receive
abundant precipitation (2000 - 4000 mm/yr), it is not well distributed both spatially and
temporarily. For example the Java Island shows large spatial differences of rainfall betweenthe coastal areas (less than 250 mm/yr) and volcanic areas (more than 2500 mm/yr). The
monsoon climate divides the year in a clear dry and wet period.
Water scarcity, especially for agriculture is a well-known problem in Indonesia. However, the
water resources are not managed yet in this respect. By example, upslope movement of
habitation and agriculture changes the water budget of that particular region and influences
the amount of stream water available downstream.
3. Literature Review
3.1 Hydrogeological SettingMount Ciremai is a solitaire-strato volcano with elevation of 3072 masl, situated at
Majalengka (west flank) and Kuningan Regency (East flank) (Figure 2), 20 km south of
Cirebon, Indonesia. It lies at 6 53 30 latitude and 10824 00 longitude. The diameter of
this volcano, from the peak to the foot slope is about 10 km. Mt. Ciremai has recorded 5
eruptions in 1698, 1772, 1775, 1805, and 1937, with 3 -112 years interval, historically. Those
eruptions produced 22 volcanic deposits, consist of: 11 lava flows, 9 pyroclastic materials,
and 2 laharic breccias. Many studies have been conducted in the area.
Situmorang (1995) has published the volcanic geological map of Mt. Ciremai. According to
the author, the exposed volcanic deposit was produced by 4 generation of eruptions, which
generated 3 types of deposits. Lava flow consists of andesite rock, black to brownish incolour. It has fractures, cooling joints and columnar joints due to mass unloading and cooling
processes. Pyroclastic materials consist of andesite fragments planted in tuff lithic and tuff
crystal. It comes in flowing and falling mechanisms. Laharic breccias consist of andesite
fragments planted in volcanic sands, tuff lithic, and tuff crystal. It comes in water dominant
flowing mechanisms. The first regional hydrogeology condition was introduced by IWACO
WASECO (1989). Regional aquifer system at Mt. Ciremai area is divided in to 3 systems:
Surficial Alluvium, Quaternary Volcanic (Young Volcanic), and Tertiary Sediment system.
More details study was conducted by Puradimaja et.al (2003). According to the author, there
are 3 main aquifer units: pyroclastic breccias, lava, and laharic breccias. All of the observed-
aquifers are unconfined aquifers. The aquifer feeds water to spring zone encircling Mt.
Ciremai. The spring zone is interpreted to be following slope morphology which controlled by
change of rock distribution. Such condition forms 2 slope breaks at 750 masl (4o difference)
and 1350 masl (19o difference).
Irawan (2006) stated that there 3 factors which control the spring emergence. First factor is
the change of rock distribution from lava to laharic breccias. Morphological features in form
of ridges and valleys also contribute to control groundwater flow pattern. Second factor is
fracture and continuous voids zone controls the level of spring discharge in volcanic terrain.
Third factor is the weathering processes in the study area is very intensive, resulting in thick
residual soil and high final infiltration rate, which is very potential to store and to be
infiltrated by rain water and surface water.There were 3 thermal groups of spring, based on 23 spring observations, consists of:
hypothermic, mesothermic, and hyperthermic (Figure 3). Based on the thermal classification,
8/6/2019 PDF 2007 Erwin Ciremai Bali
4/16
it can be interpreted that thermal differences were triggered by interaction between
groundwater temperature and environmental temperature. The hypothermic group shows the
closed system of groundwater. Mesothermic group shows the interaction between
groundwater and surface temperature. Hyperthermic groups were characterized by the
interaction of groundwater with specific subsurface heat source. (Hem, 1970 and Matthess,
1982). Piper plot is presented in Figure 4, to show the differentiation of chemical characters.
The intensity of weathering processes in the study area is very high, indicated by 2 m tonearly 10 m of soil thickness. Such thick residual soil is very potential to store and to infiltrate
rain and surface water in to the aquifer. Infiltration tests (according to Chow et.al. 1964;
Miyazaki, 1993) was carried out to verify the final infiltration rate of residual soils. Residual
soil from lahars shows the largest values of 1.26 2.53 cm/min, followed by residual soil
from pyroclastic breccias 1.5 cm/min, and from lava flow 0.5 1.2 cm/min. High final
infiltration rate (Linsley & Franzini, 1978) indicates the high capacity of residual soil to be
infiltrated by rain water and surface water.
Subsequently, in 2002, Bapeda Kuningan Regency has mapped 161 springs with total of
8285.2 l/sec. The result is five classes of spring discharge magnitude (Meinzer 1923, op.cit
Todd, 1980): Six springs of Class II (4%), 44 springs of Class III (27%), 15 springs of ClassIV (9%), 40 springs of Class V (25%), 56 springs of Class VI (35%). Both preceding studies
have not analysed the control of geological setting to groundwater springs.
3.2 Cluster Analysis
Cluster analysis is an unsupervised-multivariate statistical method that identifies the
hierarchial structure of similarity of large number observations in to into groups. Thus, that
the objects within a group are very similar and objects from different groups are significantly
different in their characteristics (Smith, 2002). There are 3 steps in cluster analysis (McGraw-
Hill, 2007)
Step 1: Select cluster variables and distance measures. How many and which variables are to
be selected will affect the analysis results. In cluster analysis, it is implicitly assumed
that every variable is equally important.
Step 2: Select cluster algorithm. Cluster algorithm is the procedure to determine clusters,
or groups. There are two categories of cluster algorithms, hierarchical and non-
hierarchical. In this paper, we are going to use hierarchical algorithms.
Step 3: Perform cluster analysis. Cluster analysis will determine the cluster structure
specifically, which objects form a cluster, how many clusters, the features of clusters,
etc.
Step 4: Interpretation. We need to explain what these clusters mean and how should wename and make sense of these clusters. The interpretation is based on geological
facts.
According to McGraw-Hill (2007), in cluster analysis, distance is used to represent how
close each pair of objects is. The most common distance measurement is Euclidean Distance
(Figure 6). The Euclidean distance between any two objects, that is, the distance between
object i and object k(dik), is
N
j
kjijik xxd
1
2)( Equation 1
8/6/2019 PDF 2007 Erwin Ciremai Bali
5/16
In cluster analysis, it is desirable that the distances between objects within a cluster (group)
are small and the distances between different clusters are large, as illustrated in Figure 6. The
definition of the distance between clusters depends on the methods to determined relationship
between clusters, called linkage. There are several different linkage methods which we will
discuss as follows. In single linkage method, the distance between two clusters is defined to
be the distance of the nearest neighbours (Figure 6). Specifically, assume that we have two
clusters, clusterR and cluster S. Let rrepresent any element in cluster R, and let s representany element in cluster S. Then the distance between cluster R and cluster S in single linkage
method is defined as
SsRrdd rsSR ,min))(( Equation 2
In a dendogram, the distances between clusters and the joining process are described very
well. We usually want to form more than a cluster in further analysis. As we discussed earlier,
a good clustering should be as follows:
1. The objects within a cluster should be similar one another, in other words, the distances
between the objects within a cluster should be small.
2. The objects from different clusters should be dissimilar, significantly, or the distancesbetween them should be large.
4. Methodology
The delineation of groundwater systems aims: 1). the recognition of the hydrogeological
boundaries enclosing the system; 2) the mechanisms of recharge, and discharge, along with
the flow paths of groundwater from recharge areas to discharge areas Mandel & Shiftan
(1981). In order to map the hydrogeological boundaries and rechargedischarge mechanism,
this research used 3 main approaches: desk study, hydrogeological mapping, hydrochemical
sampling and analysis. Detailed work describes as follows.
1) Desk study: The desk study consisted of studying the topographical map, geological maps,
hydrogeological maps, and re-analyses of previous studies;
2) Hydrogeological mapping: The hydrogeological mapping is based spring observations;
consist of: coordinates, local geological observations, measurement of the spring
discharges and the water qualities. The discharge was measured using the area-velocity
method. The water velocity was measured using current meter. For small discharge (less
then 1 l/s), the measurements were taken using volumetric method with a 10 liter bucket
and stopwatch. Duplets measurements were taken at each observation.
3) Hydrochemical sampling: At each location, physical parameters measurements were takenconsist of: air temperature, water temperature, Electro-Conductivity (EC), Total Dissolved
Solids (TDS), and pH. The air temperature was measured only during sampling using a
standard thermometer, while other above parameters were measured using Lutron portable
equipment. For laboratory chemical analysis, the spring water was sampled using 1 litre
plastic bottles. The duplets laboratory analysis comprises: the calculation of major
elements concentrations using titration method. Chemical test results have to be validated
using ion balance equation (see equation 3), before further analyses. We determined 20%
error balances as permit-able limit. Samples have higher than 20% of error balance will be
re-tested while samples have lower than 20% error will be analyzed.
[( cations - anions) / ( cations + anions)] x 100% equation 3
8/6/2019 PDF 2007 Erwin Ciremai Bali
6/16
4) Statistical analysis: The hydrochemical parameters and the result from field observations
were analyzed using basic statistical analysis and cluster analysis to assist the
hydrogeological analysis, by using Minitab (trial version).
5) Interpretation: The interpretation aims to schematization of hydrogeological system based
on each spring clustering.
5. Analysis and Interpretations
The survey was conducted in period of May until June 2006, in dry season. As much as 119
springs from east slope. At each spring, there were 14 variables measurements (see Table 3):
Elevation (Elev) in masl, Discharge (Q) in liter/sec, Total Dissolved Solids (TDS) in ppm,
Electro Conductivity (EC) in micro Siemens/cm, Acidity (pH), Water temperature (W.temp)
(oC), Air temperature (A. temp) in oC, Major elements concentration (mg/l): calcium (Ca2+
),
magnesium (Mg2+
), chloride (Cl-), sodium (Na
+), sulfate (SO4
2-), potassium (K
+), bicarbonate
(HCO3-).
Large deviations as shown by several variables: TDS, EC, hardness, chloride, sodium, andbicarbonate. This should affect to the clusters. Observations with maximum value of those
variables should separate relatively from the other observations with normal value. In this
section, we are going to discuss the spring clustering and dominant variables which control
the springs.
5.1 Cluster Analysis
Cluster analysis, with Minitab (trial version) has successfully extracted 3 clusters. Cluster 1
consists of 112 observations, cluster 2 comprises 5 observations, cluster 3 consists of 2
observations (see table 4 and figure 7). Cluster 1 shows more variation as shown by the large
maximum distance from centroid (9.23), relatively to cluster 2 (3.05).
5.2 Outlining Hydrogeological Systems
The outline of hydrogeological system is based on schematization of 3 clusters. The
interpretations lead to 3 hydrogeological systems (Figure 8): Hgl 1, Hgl 2, and Hgl 3.
Hydrogeological system 1 (Hgl 1 112 obs) is characterized by large variations of data with
normal values of water temperature, TDS, EC, and major elements concentrations. This
condition is due to the many chemical influences as the groundwater flow from recharge area
to discharge area in unconfined aquifer system of 3 lithological type (from up to down):
pyroclastic breccias, lava, and laharic breccias.Hydrogeological system 2 (Hgl 2 5 obs) is described as more homogeneous observations
with anomalous values: high water temperature, TDS, and EC. The groundwater is interpreted
as the result of interaction between normal meteoric water and hot water of volcanic origin.
Hydrogeological system 3 (Hgl 3 2 obs) is separated by other 2 clusters due to the
homogeneous characters (spring number 65 and 100) with deeper flow system, compared to
Hgl 2. The 2 springs, Cikalamayan (65) and Liang Panas (100), have high concentrations of
chloride along with high water temperature. Major elements concentration is interpreted to
be the effect of interaction between hot water with sedimentary layers of Fm. Kaliwungu,
which deposited in sea environment. Layers of sand and clay in the formation below
Ciremais volcanic deposits, contribute to the high chloride content in the groundwatersamples.
8/6/2019 PDF 2007 Erwin Ciremai Bali
7/16
6. Conclusions
Cluster analysis has successfully extracted 3 clusters: cluster 1 (112 obs), cluster 2 (5 obs),
cluster 3 (2 obs). The hydrogeological schematization has been constructed based on
interpretations of 3 clusters. There are 3 hydrogeological systems: 1) Hydrogeological system
1 (Hgl 1112 obs) is characterized by: heterogeneous data, normal water temperature, TDS,
EC, and major elements concentrations. This condition is due to the many chemical
influences as the groundwater flow from recharge area to discharge area in unconfined aquifersystem. 2) Hydrogeological system 2 (Hgl 2 5 obs) is characterized by: homogeneous data,
high water temperature, TDS, EC. The groundwater is interpreted as the result of interaction
between normal meteoric water and hot water of volcanic origin. 3) Hydrogeological system 3
(Hgl 3 2 obs) is characterized by: homogeneous characters with deeper flow system. High
concentrations of chloride along with high water temperature are interpreted to be the effect
of interaction between hot water with sedimentary layers of Fm. Kaliwungu, which deposited
in sea environment.
Acknowledgement
The authors would like to thank The Board for Regional Planning Kab. Kuningan for
facilitating data and Director of PDAM Kab. Kuningan for access to spring abstraction site.
We also would like to thank our team of undergraduate students that gave their time and effort
to help us surveying spring data and gathering the first level analysis.
8/6/2019 PDF 2007 Erwin Ciremai Bali
8/16
References
Bapeda Kuningan, 2002, Inventarisasi Mataair Kab. Kuningan, Bapeda Kuningan.
Chow, 1964, Soil Water, Prentice-Hall.
Costello, A.B. and Osborne, J.W., 2005, Best Practices in Exploratory Factor Analysis: FourRecommendations for Getting the Most From Your Analysis, Practical
Assessment Research & Evaluation, Vol 10, No 7.
Dept. Pertambangan dan Energi, 1979, Data Dasar Gunungapi Indonesia, Dept. Pertambangan
dan Energi.
Hem. J.D., 1973, Study and Interpretation of Natural Water, USGS Water Supply Paper.
Irawan, D.E. and Puradimaja, D.J., 2006, The Differentiation of Hyperthermal Groundwater
Origin by using Multivariate Statistics on Water Chemistry, Journal Geoaplika,
vol 1, no 2.
Irawan, D.E.and Puradimaja, D.J., 2006, The Hydrogeology of The Volcanic Spring Belt,East Slope of Gunung Ciremai, West Java, Indonesia, Proceeding of IAEG
Conference.
IWACO WASECO, 1989, Kuningan Regency Provincial Water Supply Report, Dept. of
Public Works.
Kitano, Y. (ed), 1975, Geochemistry of Water, Benchmark Paper in Geology, Hutchinson &
Ross, Pennsylvania, pp. 273296.
Linsley, R.K., Franzini, J.B., Freyberg, D.L., Tchobanoglus, G., 1992, Water resources
engineering, McGraw-Hill, New York.
Mandel and Shiftan, 1981, Groundwater resources: Investigation and Development,
Academic Press.
Matthess, G., 1982, Properties of Groundwater, McGraw-Hill.
Miyazaki, T., 1993, Groundwater Basin Management, Tokai University Press
Multivariate Statistical Methods and Quality, Downloaded from Digital Engineering Library
@ McGraw-Hill (www.digitalengineeringlibrary.com), McGraw-Hill.
Puradimaja, D.E., Sukarno, I., Abidin, Z., Irawan, D.E., 2002, Sistem Pengembangan dan
Pengusahaan Air Bersih di Jawa Barat. Potensi dan Pola Bisnis Air Bersih serta
Air Minum, Dipresentasikan pada acara Seminar Pemanfaatan dan Pengelolaan
Air Bersih Guna Meningkatkan Kesehatan Masyarakat Jawa Barat Menuju Era
Globalisasi, Aula Barat ITB, 22 Nopember 2002.
Puradimaja, D.J, Irawan, D.E., Hutasoit, L.M., 2003, The Influence of Hydrogeological
Factors on Variations of Volcanic Spring Distribution, Spring Discharge, and
Groundwater Flow Pattern, Bulletin of Geology, Vol 35, No 1/2003, pp: 1523,
ISSN: 0126-3498.
Situmorang, 1995, Peta Geologi Gunung Ciremai, Direktorat Vulkanologi.
Smith, L.I., 2002, A Tutorial on Cluster Analysis, downloaded from
http://www.cs.montana.edu.
8/6/2019 PDF 2007 Erwin Ciremai Bali
9/16
Figures and tables
Figure 1 The location map of Mt. Ciremai. Box marks the study area. The area is moreless20 km south from Cirebon, West Java.
Scale 1 :
Locati
8/6/2019 PDF 2007 Erwin Ciremai Bali
10/16
8/6/2019 PDF 2007 Erwin Ciremai Bali
11/16
Figure 3 Chart of thermal gradient of groundwater at Ciremai (Puradimaja, D.J., et.al. 2003).
Figure 4 Piper plots of chemical composition (Puradimaja, et.al, 2003).
K L A S I F I K A S I T E R M A L M A T A A I R
y = 4 0 9 3 . 4 0 9 - 1 5 2 . 6 9 9 * x
T A
E
1 12 1
3 24 3
5 3
6 37 38 39 3
1 2 3
1 4 3
1 5 3 1 6 31 7 3
1 8 3 1 9 32 0 3
2 1 12 2 1
1 0 2 1 1 2
2 3 32 4 3
2 5 3
2 0 0
4 0 0
6 0 0
8 0 0
1 0 0 0
1 2 0 0
1 4 0 0
k e lo m p o k m e s o t e r m a l
k e lo m p o k h i p o t e r m a l k e lo m p o k h i p e r t e r m a l
k e lo m p o k h i p e r t e r m a lTransition zone
Elevation
(masl)
Water Temperature (oC)
R2=0,81
Mg
Ca
100
0
0
100
Cl
SO4
0
100
100
0
SO
+C
l
4
Ca+Mg
Na+K
100
100
0
100
0
CO
+
HCO
3
3
100
0
0
2
4
67
89
2
4
4
6
6
7
7
8
8
9
9
1
1
2
1
8/6/2019 PDF 2007 Erwin Ciremai Bali
12/16
GEOLOGICALMAP
HYDROGEOLOGICALMAP
HYDROGEOLOGICALSURVEY
SPRINGOBSERVATION
PHYSICO-CHEMICAL
MEASUREMENTS
CLUSTERANALYSIS
INTERPRETATION
Table 1 Characteristics of various multivariate analyses
Method Interdependencevs. dependence
Exploratory vs.confirmatory
Metric vs.non metric
Objectives
Principal ComponentAnalysis
interdependence Exploratory Metric Dimension reduction
Exploratory Factor
Analysis
interdependence Confirmatory Metric Understand correlation
patterns, uncover latent
traits
Multidimensional
Scaling
interdependence Exploratory Metric or non
metric
Verify measurement
model
Cluster Analysis interdependence Exploratory Metric or non
metric
Create spatial
representation from
object similarities
Canonical Correlation dependence Exploratory Metric Explain covariationbetween 2 sets multiple
variables
Analysis of Variance dependence Confirmatory Metric andnon metric
Special case ofcanonical correlation
with discrete X
variables.
Discriminant
Analysis
dependence Exploratory or
confirmatory
Metric and
non metric
Special case of
canonical correlation
with discrete Y
variables.
Figure 5 The work flow of the research
8/6/2019 PDF 2007 Erwin Ciremai Bali
13/16
Table 2 Laboratorymethods for major element measurements
No Parameters Units Methods
1 Hardness (CaCO3) mg/l SMEWW 2340-C
2 Calcium (Ca2+) mg/l SMEWW 3500-Ca
3 Magnesium (Mg2+) mg/l SMEWW 3500-Mg
4 Chloride (Cl-) mg/l SMEWW 4500-Cl
5 Sodium (Na+) mg/l SMEWW 4500-Na
6 Sulphate (SO42-) mg/l SMEWW4500-SO4
7 Potassium (K+) mg/l SMEWW 3500-K
8 Bicarbonate (HCO3-) mg/l SNI 06-2420
Figure 6 Illustration of what is Euclidean distance (upper left), cluster distance and between
cluster distance (upper right), and dendogram as the final results of cluster analysis (lower).
8/6/2019 PDF 2007 Erwin Ciremai Bali
14/16
Table 3 Descriptive analysis of the variables. Large deviations as shown by several variables:
TDS, EC, hardness, chloride, sodium, and bicarbonate should affect the clustering processes.
Observations with maximum value of those variables should separated relatively from the
other observations with normal value.
Variable Mean StDev Minimum Maximum
Elevation (Masl) 491.6 237 111 1273
Discharge (Q) (l/s) 17.522 8.6 1.3 40.3
TDS (ppm) 159.6 221.7 16 1001
EC (mS/cm) 130.3 102.8 16.3 515.5
pH 7.221 0.6 6.2 9
W.temp 25.635 4.4 18.4 61.4
A.temp 28.581 3.1 21.5 42
Hardness (CaCO3) 144.4 331.7 28.2 2488.8
Calcium (Ca2+
) 26.07 39.5 8 283.4
Magnesium (Mg2+
) 21.87 61.5 1.4 432
Chloride (Cl-) 564 2536 2 13100
Sodium (Na+) 426 1916 5 10000
Sulfate (SO42-
) 14.34 23 0 120
Potassium (K+) 13.96 41 2 210
Bicarbonate (HCO3-) 181.9 409.5 12 2098.4
Table 4 Cluster analysis results (Minitab trial version). Centroid is the focal point of cluster.
Maximum distance of observation from centroid is measured on each cluster. Cluster 1 shows
more variation as shown by the large maximum distance from centroid (9.23), relatively to
cluster 2 (3.05).
Average Maximum
distance distance
Cluster basics description Number of from from
observations centroid centroid
Cluster1 112 1.99 9.23Cluster2 5 1.55 3.05
Cluster3 2 0 0
Centroid distance
Cluster1 Cluster2 Cluster3
Cluster1 0 13.97 15.68
Cluster2 13.97 0 9.28
Cluster3 15.68 9.28 0
8/6/2019 PDF 2007 Erwin Ciremai Bali
15/16
V48
V29
V86
V84
V85
V56
V65
V106
V108
V9
V76
V67
V38
V105
V94
V77
V101
V107
V104
V54
V98
V128
V62
V134
V130
V93
V10
V21
V5
V87
V111
V57
V11
V26
V19
V39
V37
V88
V40
V68
V70
V64
V71
V74
V52
V109
V31
Cluster 1 (continuation)
(112 obs)
Cluster 2
(5 obs)
Cluster 3
(2 obs)
V100
V14
V59
V81
V96
V73
V95
V35
V13
V34
V92
V53
V15
V55
V102
V131
V91
V97
V17
V6
V18
V4
V72
V99
V69
V90
V51
V103
V80
V60
V27
V20
V3
V46
V28
V133
V79
V132
V110
V22
V112
V129
V61
V89
V58
V36
V47
V7
V44
V66
V83
V30
V82
V41
V78
V75
V45
V32
V25
V63
V33
V24
V2
V1
V42
V12
V23
V50
V8
V43
V49
V16
26,38
50,92
75,46
100,00
Observations
Similarity
Cluster 1 (continuation)
(112 obs)
Figure 7 Dendogram of cluster analysis (Minitab trial version). The lower dendogram is the
continuation of the upper dendogram. There are 3 clusters: cluster 1 (112 observations. cluster
2 (5 observations). and cluster 3 (2 observations).
8/6/2019 PDF 2007 Erwin Ciremai Bali
16/16
0
500
1000
1500
2000
2500
3000
3500
108.15 108.2 108.25 108.3 108.35 108.4 108.45 108.5 108.55 108.6 108.65
Elevasi
Hgl 1
Normal waterdescent
Tertiary sedim ents
0
500
1000
1500
2000
2500
3000
3500
108.15 108.2 108.25 108.3 108.35 108.4 108.45 108.5 108.55 108.6 108.65
Elevasi
Hgl 2Hot water rising
Normal waterdescent
Tertiary sedim ents
Figure 8 The schematization of 3 hydrogeological systems. The schematization is based on
interpretations of 3 clusters, lead to 3 hydrogeological systems: Hgl 1, Hgl 2, and Hgl 3. Hgl 1
is volcanic-meteoric type groundwater, Hgl 2 is volcanic-transition type groundwater, Hgl 3 issedimentary-formation type groundwater.
0
500
1000
1500
2000
2500
3000
3500
108.15 108.2 108.25 108.3 108.35 108.4 108.45 108.5 108.55 108.6 108.65
Elevasi
Normal waterdescent
Hgl 3Tertiary sediments