Catchment-Scale Flood Modelling in Data-Sparse Regions Using Open-Access Geospatial Technology

Abstract

<jats:p>Consistent data is seldom available for whole-catchment flood modelling in many developing regions, thus this study demonstrates how the complementary strengths of open and readily available geospatial datasets and tools can be leverage to map flood risk within acceptable levels of uncertainty for flood risk management. Available fragmented remotely-sensed and in situ datasets (including hydrological data, altimetry, digital elevation model, bathymetry, aerial photos, optical and radar imageries) are systematically integrated using 2-dimensional CAESAR-LISFLOOD model to quantify and recreate the extent and impact of the historic 2012 flood in Nigeria. Experimental modelling, calibration and validation is undertaken for the whole Niger-South hydrological catchment area of Nigeria, then segmented into sub-domains for re-validation to understand how data variability and uncertainties impact on the accuracy of model outcomes. Furthermore, aerial photos are applied for the first time in the study area for flood model validation and to understand how different physio-environmental properties influence synthetic aperture radar flood delineation capacity in the Niger Delta region of Nigeria.</jats:p>

Comparative Analysis of Some Existing Models for Estimating the Time of Concentration for Watersheds in Anambra State, Nigeria

“…The study by Fang et al [4] found many differences among time of concentration that were estimated using different formulas using parameters of watersheds. The importance of a suitable model for estimating the concentration-time useful for accurately predicting flow rates from hypothetical storms becomes necessary in the study area [5,6]. This is because Anambra State has recently been hit by floods and the government is looking for ways to effectively manage and avoid subsequent devastation.…”