Paper
GIS Based Demarcation of Natural Flow Routes Using Old Topographic Data
- Authors:
- Akajiaku C. Chukwuocha; Joel I. Igbokwe
- Abstract
- Demarcation of runoff natural flow routes is inestimable in mitigating flooding and erosion. It is useful also in planning urban areas and designing drainage networks. Devastating flooding and erosion are being recorded across the globe as a result of increases in the intensity and duration of storm water precipitation due to global warming. In the developing parts of the world state of the art topographical data is not always available, but it should not be necessary to stop state of the art geospatial topographical analyses especially if there are sources of old topographic data that may be authenticated. In this study, Geographic Information Systems (GIS) were used to create a Digital Elevation Model (DEM) of Owerri in Southeast Nigeria, using data from topographical maps of the city of 1977. The data was authenticated using three dimensional (3D) coordinates of sample points derived from Global Navigational Satellite Systems (GNSS) surveys. The DEM was processed using the ArcGIS and ArcHydro software to determine heavily accumulating flow routes. The accuracy of the result was confirmed by using the coordinates of the delineated flow routes to locate their ground positions with handheld GPS receivers after some heavy storm event.
- Keywords
- Digital Elevation Model (DEM); Flow Routes; Flow Direction Grid; Flow Accumulation Grid; Stream Definition Threshold
- StartPage
- 25
- EndPage
- 36
- Doi