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III. RESEARCH METHODOLOGY
3.1. Physical Condition of the Study Area 3.1.1. Location
The Bandung regency which include major portion in the catchments area of the Saguling Reservoir is so called Bandung basin Indonesia, with an area
approximately 2,283 square km2, geographically located between 6° 4 S to 7° 10 S and 107° 15 E to 107° 45 E. The Bandung regency include 40 districts. For
doing sensitivity analysis, the study area need to make zone into three portions, i.e. upper, middle and lower portion. Upper portion of study area consist of 12
sub-districts and middle and lower portion of study area consist of 14 sub- districts. The detail list of sub-district which include in each portion was mention
in Appendix 18. The topography of the Bandung basin in Bandung regency various from
flat to mountainous with a height from 650 meter to 2,000 meter above sea level. And also the slope varies from gentle to very steep.
3.1.2. Climate
The study area has tropical climate under the influence of monsoon wind as the same as other places in Indonesia. There are two seasons in this area, rainy
and dry season. The rainy season occurs from October until April, whereas the dry season is taken place from June till October. The period from May till June can be
considered as transition period. Average rainfall in the surrounding area is between 1,782 millimeter to 3,426 millimeter, for 30 years under consideration,
and the average temperature of 220° C to 240° C and average humidity 83.
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3.1.3. Geology and Geomorphology
The Land Mapping Units comprised: 1 flood plains, 2 alluvio- lacustrine plains, 3 colluvial plains, 4 volcanic plains, 5 alluvio-volcanic fan,
6 volcanic fans, 7 volcanic foot-slopes, 8 lower volcanic ridges, 9 middle volcanic ridges, 10 upper volcanic ridges, 11 hills, and 12 mountains.
In general the Lithology of the upper portion of the study area which is the location of Cikapundung catchment, consists of volcanic rock which has been
resulted from eruption of Tangkuban Perahu mountain. According to Silitonga 1973, the study area consists of four units as
fallows: 1. The differentiated rock unit coming from the old sunda volcano comprises
volcano breccia, lahar and lava alternately. 2. The differentiated rock coming from the Tangkuban Perahu eruptions,
comprises sandy tuff, lapilly and breccia, lava and conglomerate. 3. Tuff pumice which came from Tangkuban Perahu eruption phase A,
comprises sandy tuff, lapilly, bombs, halloured lava, solid andest and fractions of pumice
4. Lava which consist of basalt and gastubes, coming from the lava flows of the Tangkuban Perahu.
The catchments can be divided into two main geomorphologic units, which are volcanic origin and structural origin. Volcanic origin can be divided into four
sub units, which are volcanic cone, volcanic middle slope, volcanic lower slope and fluvial volcanic plain. While the structural origin unit can be divided into two
26 parts; northern and western part, separated by an east-west running normal fault
Lembang fault.
Indonesia Map
Fig 3.1: The location of study area
3.1.4. Time
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