Abstrak 
Watershed Morphometry on Quaternary Volcanic Terrain in Southern Margin of The Bandung Basin: Its Implication in Distribution of Flood Area
Emi Sukiyah
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Inggris
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and pattern of curve line, distribution of flood area, GIS, morphometry, stream order, volcanic terrain
Southern part of Bandung basin was hilly and mountainous terrain that composed of Quaternary volcanic rocks. Volcanic terrain, mainly in mature stage, shows the tendency to have irregular pattern with is not easily classified into several type. Drainage basin morphometry is indices of geomorphologic aspects used to analyze the characteristics of flood area. Several criteria of drainage basin morphometry were measured in the field, i.e. river order, length of river segment, cumulative length of river segments (Lu), bifurcation ratio (Rb), ratio of Lu of different orders (Lu/Lu+1).
The quantitative approach used to calculate numerical data of drainage basin characteristics. In this region, several types of flood area occur. Every type characterized by specific curve representing relationship between morphometric variables. For geo-spatial analysis encompassing terrain mapping, flood area distribution, and numerical data calculation, the Geographic Information System (GIS) is used.
Several aspects, i.e. climate, rainfall intensity, slope, land use, stream order and rock type control distribution of flood area. Result of geo-spatial analysis shows research area divided four zones, i.e. vulnerable flood, flood potency, little flood probability and lost flood.
The analyses of morphometry indices show that several parameters are inter-related. There are relation between length of river segments and stream order. On the graph, the region of vulnerable flood showed by pattern of curve lines to be far apart. The non-vulnerable area indicated by pattern of curve lines to be very close together. There are real relationships between variables of stream order and flood area distribution. This relation demonstrated by the correlation index (r) with the value of 0.676 to 0.999. The phenomena exhibit that the Quaternary volcanic terrain has a little regularity of patterns to explain flood vulnerable area.