Application of DEM to Identify the Infiltration Zones Using GIS
Drainage networks are usually digitized from the existing topographic maps using GIS. Unfortunately, this method is expensive and time consuming. But, nowadays, automatic extraction of drainage network from Digital Elevation Model (DEM) with the help of GIS has become possible and used for hydrological studies. DEM consists of a sampled array of elevations for a number of ground positions at regularly spaced intervals. It is a storehouse of a variety of hydrological information along with terrain characteristics and valuable in groundwater system analysis. In this paper, the contour maps with 20 m vertical intervals were digitized to create DEM data and drainage networks were extracted from DEM. Further, a comparative study of simulated drainage networks extracted from DEM using GIS-based Arc Hydro model is carried out and the drainage digitized from surveyed topographic maps for identifying infiltration zones in an urban watershed, upper Bagmati which covers the whole Kathmandu valley. It has been verified that the automatic drainage extracted technique from DEM is an efficient and cost-effective method in comparison to manual digitization. Hence, thus obtained drainage networks may be very useful for environmental studies, watershed management, and storm water and groundwater system analysis.
Dixit, A. and M. Upadhaya (2005). Augmenting ground water in Kathmandu valley: Challenges and possibilities. Nepal Water Conservation Foundation, Kathmandu, Nepal.
ICIMOD (2000). Kathmandu valley GIS database. MENRIS/ ICIMOD.
Jension, S.K. and J.O. Domingue (1988). Extracting topographic structure from digital elevation data for geographic information systems analysis. Photogrammetric Engineering and Remote Sensing, 54: 1593-1600.
Moore, I.D., Grayson, R.B. and A.R. Ladson (1991). Digital terrain modeling: A review of hydrological, geomorphological and biological applications. Hydrological Process, 5: 3-30.
National Geographic Information Infrastructure Project
(NGIIP) (1994). Department of Survey, Government of Nepal, Kathmandu, Nepal.
Rumman, N., Lin, G. and J. Li (2005). Investigation of GIS- based surface hydrological modeling for identifying infiltration zones in an urban watershed. Environmental Informatics Archives, 3: 315-322.
Saraf, A.K., Choudhury, P.R., Roy, B., Sarma, B., Vijay, S. and S. Choudhury (2004). GIS based surface hydrological modeling in identification of groundwater recharge zones. International Journal of Remote Sensing, Taylor & Francis Group. 25: 5759-5770.
Shrestha, O.M., Koirala, A., Hanisch, J., Busch, K., Kerntke, M. and S. Jager (1999). A geo-environmental map for the sustainable development of the Kathmandu Valley, Nepal. Geo-journal, 49: 165-172.
Strahler, A.N. (1957). Quantitative analysis of watershed geomorphology. Transactions of the American Geophysical Union, 38: 913-920.
Sullivan, M., Warwick, J.J. and S.W. Tyler (1996). Quantifying and delineating spatial variations of surface infiltration in a small watershed. Journal of Hydrology, 181: 149-168.
Wang, X. and Z. Yin (1998). A comparison drainage networks derived from digital elevation models at two scales. Journal of Hydrology, 210: 221-241.