CUED Publications database

Digital Elevation Models and GIS for watershed modelling and flood prediction - A case study of Accra Ghana

Konadu, DD and Fosu, C (2009) Digital Elevation Models and GIS for watershed modelling and flood prediction - A case study of Accra Ghana. Appropriate Technologies for Environmental Protection in the Developing World - Selected Papers from ERTEP 2007. pp. 325-332.

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Abstract

Geographical Information Systems (GIS) and Digital Elevation Models (DEM) can be used to perform many geospatial and hydrological modelling including drainage and watershed delineation, flood prediction and physical development studies of urban and rural settlements. This paper explores the use of contour data and planimetric features extracted from topographic maps to derive digital elevation models (DEMs) for watershed delineation and flood impact analysis (for emergency preparedness) of part of Accra, Ghana in a GIS environment. In the study two categories of DEMs were developed with 5 m contour and planimetric topographic data; bare earth DEM and built environment DEM. These derived DEMs were used as terrain inputs for performing spatial analysis and obtaining derivative products. The generated DEMs were used to delineate drainage patterns and watershed of the study area using ArcGIS desktop and its ArcHydro extension tool from Environmental Systems Research Institute (ESRI). A vector-based approach was used to derive inundation areas at various flood levels. The DEM of built-up areas was used as inputs for determining properties which will be inundated in a flood event and subsequently generating flood inundation maps. The resulting inundation maps show that about 80% areas which have perennially experienced extensive flooding in the city falls within the predicted flood extent. This approach can therefore provide a simplified means of predicting the extent of inundation during flood events for emergency action especially in less developed economies where sophisticated technologies and expertise are hard to come by. © Springer Science + Business Media B.V. 2009.

Item Type: Article
Uncontrolled Keywords: ArcGIS ArcHydro DEM Drainage modelling Flood modelling GIS Watershed
Subjects: UNSPECIFIED
Divisions: Div D > Sustainable Development
Div D > Structures
Depositing User: Cron Job
Date Deposited: 02 May 2014 17:45
Last Modified: 08 Dec 2014 02:15
DOI: