Abstract:
Modelling a watershed accurately is an important step in water
management. Geographic Information Systems (GIS) together with
mathematical models have made modelling watersheds an easy task. Digital
Elevation Model (DEM) ts a primary data set necessary to model a watershed. DEMs
developed using many methods and DEMs are developed from remotely sensed data
are the cheapest. Some of them are freely available on-line. In modelling watersheds,
it is a common practice to delineate the stream network from a DEM. Matching of the
delineated stream network with the natural stream network will depend on the
accuracy of the DEM. Some hydrologic models contain built-in functions to edit
DEMs to overcome this problem. Hydrologic model, HEC GeoHMS, contains such a
function to edit DEM as required by the user. To edit the DEM it is necessary to have
the exact stream network to compare with the delineated network. In this work, Kaluganga
River stream network was delineated using a DEM available freely on-line and
it was compared with the natural stream network of Kalu-ganga River digitized from
1:50,000 maps produced by the Department of Survey. Then the DEM was edited
using the HEC GeoHMS model to achieve the desired stream network.
Citation:
Nandalal, H.K., & Ratnayake, U.R. (2009). Editing a digital elevation model to achieve a correct stream network: an application to Kalu-Ganga River in Sri Lanka. In S. Karunaratne (Ed.), Proceedings of the 4th Annual Conference on Towards the Sustainable Management of Earth Resources – A Multidisciplinary Approach (pp. 9-12). Department of Earth Resources Engineering, University of Moratuwa.