Fig 1 - uploaded by Nawa Raj Pradhan
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Comparison of upslope contributing area distribution function from different DEM resolutions in Kamishiiba catchment (210 km 2 ) (a) without downscaling method for upslope contributing area (b) with downscaling method for upslope contributing area.
Source publication
Synopsis It is found that a basin hydrological simulation in relations with drainage basin dominating geomorphological parameters is directly influenced by the scale of DEM resolution. A Scale Invariant model for the topographic index distribution (Pradhan et al., 2004a) has fulfilled a part of this gap. A scale independent relationship in flood ro...
Citations
... In recent years, the accuracy of flood forecasting tools has been greatly enhanced with the application of geographic information systems (GIS) in flood risk analysis. The spatial analysis provided by GIS, combined with the temporal analysis provided by hydrological and hydraulic models, would lead to a better understanding of basin behavior and has been used greatly to elucidate flood vulnerability and risk assessment [1,3, [9][10][11] . This approach for the development and management of river basin is still in its infancy in sub-Saharan Africa, especially in Nigeria. ...
Many rivers in Nigeria had been ungauged in the last three decades; this worrisome scenario has impacted negatively on the livelihood of people who live in flood plains. The general lack of up to date streamflow data has made river basin management problematic especially in the area of flood risk management and the development of a real time flood warning system. Flood studies were carried out in the Ogun River Basin in the southwest Nigeria using synthetic data generated by Rainfall-Runoff Modeling using a combination of the Natural Resources Conservation Service (NRCS) curve number model and digital terrain modeling using ArcGIS (R) 9.3 software to identify vulnerable areas in relation to synthesized flood waves generated from the basin, extent of inundation and ranking of the flash points that was equally done using proximity to hazard source as a criteria. The total area in the basin covered by fresh water swamps, salt marsh, and tidal flats at the lower course of Ogun river is 49 km(2), while the spatial extent of the entire wetland is 556 Km(2) accordingly. When a peak flood volume of 4 270 million m(3) generated in September is routed into the fresh water swamp, about 33.4 m of flood depth was left unaccommodated, which will cause inundation of the entire flood plain and severe damage on its path. Over 1.4 million inhabitants were identified to be at risk in the area. When the entire wetland was considered, the flood wave was reduced to an average depth of 8.5 m which is still capable of causing grave damages in the remaining parts of the flood plain. The flood wave was found to have a residence time of about 45 days. Appropriate recommendations were given for practical adaptations.
