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E-International Scientific Research Journal
ISSN: 2094-1749 Volume: 3 Issue: 2, 2011
In scalogram modelling approach (Cruz, 1992), an arithmetic operation was combined with the
corresponding numerical weights for the vulnerable factors. To assess the combined vulnerability
level a multiple hazard vulnerability map has been carried out through integration and overlaying
of all existing natural hazards vulnerability with in third order subbasins (TOSBs).
Result and Discussion
Geo-informatics
Geo-informatics module consists of GIS mapping for location map, drainage map, drainage order
map, lineament map, structural map, geological map etc. a brief discussion is given as below:
Drainage Pattern: Drainage network is a significant indicator of the process of landform
development in a geographical unit. Horton (1932) advocated, a drainage basin is an ideal unit
for understanding the geo-morphological and hydrological processes and for evaluating the
runoff pattern of the streams. The geological settings of the area as portrayed by the main steams
and their tributaries generally control the drainage of the watershed. Generally the rectangular
drainage pattern has developed at many places in the watershed. The drainage pattern of the
Lesser Himalayan Ranges is quite different from that of Siwalik Hills falling in watershed. This
difference in the drainage pattern is mainly due to the presence of active Main Boundary Thrust
(MBT) in the watershed that separates the Lesser Himalaya from Siwaliks. Dabak river is a Sixth
order stream includes as many as 495 first, 105 second, 22 third, 5 fourth and 2 fifth order
streams (Fig. 3 and Table 1).
Third order Sub-Basins (TOSBs): As discussed introduction and methodological section that
through out the study area third order sub basins found highly vulnerable for several types of
natural hazards and also responsible to accelerate the vulnerability for down order river basins.
Therefore the study concentrated on third order sub basins (TOSBs) morphometric analysis. Fig.
4 and Table 1 showing that there are total twenty three third order sub basins in the study area
which all have been selected for comprehensive morphometric analysis.
Table 1: Number of Streams in different stream orders
Stream order
No. Of Stream
1 st 495
2 nd 105
3 rd 23
4 th 5
5 th 2
6 th 1
74