A Review of Coupled Hydrologic-Hydraulic Models for Floodplain Assessments in Africa: Opportunities and Challenges for Floodplain Wetland Management

Innocent C Chomba,Mulema Mataa,Machaya J Chomba,Hessel C Winsemius,Kawawa E Banda,Imasiku A Nyambe,Henry M Sichingabula,Victoria Ngwenya,Bruce Ellender

doi:10.3390/hydrology8010044

Innocent C Chomba, Mulema Mataa + Show 7 more

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https://doi.org/10.3390/hydrology8010044

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Abstract

Floodplain wetlands are a fundamental part of the African continent’s ecosystem and serve as habitat for fish and wildlife species, biodiversity, and micro-organisms that support life. It is generally recognised that wetlands are and remain fragile ecosystems that should be subject to sustainable conservation and management through the use of sustainable tools. In this paper, we propose a synthesis of the state of art concerning coupled hydrologic and hydraulic models for floodplains assessments in Africa. Case studies reviewed in this paper have pointed out the potential of applying coupled hydrologic and hydraulic models and the opportunities present to be used in Africa especially for data scarce and large basin for floodplain assessments through the use of available open access models, coupling frameworks and remotely sensed datasets. To our knowledge this is the first case study review of this kind on this topic. A Hydrological model coupled with Hydraulic Model of the floodplain provides improvements in floodplain model simulations and hence better information for floodplain management. Consequently, this would lead to improved decision-making and planning of adaption and mitigation measures for sound floodplain wetland management plans and programmes especially with the advent of climate change and variability.

Highlights

IntroductionAccording to [1], wetlands often occur as ecotones (transition zones) between dryland and a water body (e.g., along the margins of lakes, ponds, reservoirs, rivers, and streams) or in channels of sluggish or intermittent streams and rivers
According to [1], wetlands often occur as ecotones between dryland and a water body or in channels of sluggish or intermittent streams and rivers
Since floodplain responses highly depend on the inflow coming from other parts of the basin, floodplain inundation models are usually forced with observed upstream discharges or coupled to hydrologic models, where the hydrologic model is providing the upstream boundary conditions such as discharge to the hydraulic model [24]

Summary

Introduction

According to [1], wetlands often occur as ecotones (transition zones) between dryland and a water body (e.g., along the margins of lakes, ponds, reservoirs, rivers, and streams) or in channels of sluggish or intermittent streams and rivers. Form in areas not adjacent to a water body. Because a wetland is found where the land is wet enough (i.e., saturated or flooded) for long enough to be unfavourable to most flora but are favourable to flora adapted to anaerobic soil conditions. In areas which are not wetlands, water drains away quickly and the soil does not remain saturated. In wetlands the water persists or drains away very slowly and the soil remains saturated or flooded for long periods [2]. These interactions suggest complex hydrologic-hydraulics processes that need to be evaluated to sustain wetlands

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