Application of an Index-Based Approach in Geospatial Techniques for the Mapping of Flood Hazard Areas: A Case of Cape Coast Metropolis in Ghana

Samuel Yaw Danso,Yvonne Dodzi Ami Adjakloe,Isaac Yeboah Addo,Yi Ma

doi:10.3390/w12123483

Abstract

Floods remain one of the disasters that destroy properties, livelihoods, and in extreme situations, take lives. As a way of prevention, geospatial applications have been employed in many cities to map flood zones and predict floods. For a country such as Ghana, floods have been ranked as the second fatal disaster after epidemics leading to several kinds of research to resolve them. To date, the Cape Coast Metropolis (CCM) has received little attention in terms of research, though flood cases in the area continue to escalate. This study, therefore, examines the use of geospatial techniques as tools in addressing flood problems in the CCM of Ghana. From a Digital Elevation Model, hydrologic variables were generated using the ArcGIS software (Esri, Redlands, CA, USA). The soil drainage classification for the study was generated from a downloaded African Soil Grid Drainage map, while other important factors that influenced flooding in the CCM were obtained from Landsat 8 imagery. Over 21% of the CCM was classified as high flood hazard zones with areas around the river Kakum estuary being flood hotspots. It is, therefore, recommended that the CCM Assembly fund dredging of streams/rivers and promote afforestation along river banks to reduce the risk of flooding within the metropolis.

Highlights

Floods remain among the most common and dangerous disasters that do displace and kill people and destroy livelihoods, personal properties, and public infrastructure [1,2,3].Floods often affect victims’ mental health and disrupt the social functioning of communities [4].research has shown that the devastating impact of floods can be reduced through the application of proactive technology [5].Modern technological applications, notably remote sensing (RS) and geographic information system (GIS), together known as geospatial techniques, are emerging as effective methods for preventing flood hazards [5]
Our analysis revealed that high flood hazard zones within the Cape Coast Metropolis (CCM)
The findings from this study further suggest that flood hazards in the CCM result from the interplay of several factors: elevation, slope, flow accumulation, stream density, and distance from streams; Normalized Difference Vegetation Index (NDVI), soil drainage capacity, and Land use/Land cover (LULC)

Summary

Introduction

Floods remain among the most common and dangerous disasters that do displace and kill people and destroy livelihoods, personal properties, and public infrastructure [1,2,3].Floods often affect victims’ mental health and disrupt the social functioning of communities [4].research has shown that the devastating impact of floods can be reduced through the application of proactive technology [5].Modern technological applications, notably remote sensing (RS) and geographic information system (GIS), together known as geospatial techniques, are emerging as effective methods for preventing flood hazards [5]. Floods remain among the most common and dangerous disasters that do displace and kill people and destroy livelihoods, personal properties, and public infrastructure [1,2,3]. Research has shown that the devastating impact of floods can be reduced through the application of proactive technology [5]. Notably remote sensing (RS) and geographic information system (GIS), together known as geospatial techniques, are emerging as effective methods for preventing flood hazards [5]. For instance, geospatial techniques can be used for mapping areas of flood hazard and for predicting flood occurrences [2,6,7,8]. Accurate prediction of areas of flood hazard remains an important priority in flood risk reduction initiatives [9].

Results

Discussion

Conclusion