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

Chomba, Innocent C.; Banda, Kawawa; Winsemius, Hessel; Chomba, Machaya; Mataa, Mulema; Ngwenya, Victoria; Sichingabula, Henry M.; Nyambe, Imasiku; Ellender, Bruce R.

doi:10.3390/hydrology8010044

Cited by 21 publications

(13 citation statements)

References 51 publications

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“…There is a natural water cycle overlap between hydrology and hydraulic modeling and many studies that benefit from Earth Observation combine both approaches, for example for floodplain wetland management in Africa (Chomba et al 2021 ). At the global scale, this can be seen through the development of Global Flood Models (GFMs) (Trigg et al 2021 ), which would not be possible without increasing availability of satellite-derived open datasets.…”

Section: The Use Of Earth Observations For Modeling Surface Waters An...mentioning

confidence: 99%

Water Resources in Africa under Global Change: Monitoring Surface Waters from Space

et al. 2022

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The African continent hosts some of the largest freshwater systems worldwide, characterized by a large distribution and variability of surface waters that play a key role in the water, energy and carbon cycles and are of major importance to the global climate and water resources. Freshwater availability in Africa has now become of major concern under the combined effect of climate change, environmental alterations and anthropogenic pressure. However, the hydrology of the African river basins remains one of the least studied worldwide and a better monitoring and understanding of the hydrological processes across the continent become fundamental. Earth Observation, that offers a cost-effective means for monitoring the terrestrial water cycle, plays a major role in supporting surface hydrology investigations. Remote sensing advances are therefore a game changer to develop comprehensive observing systems to monitor Africa’s land water and manage its water resources. Here, we review the achievements of more than three decades of advances using remote sensing to study surface waters in Africa, highlighting the current benefits and difficulties. We show how the availability of a large number of sensors and observations, coupled with models, offers new possibilities to monitor a continent with scarce gauged stations. In the context of upcoming satellite missions dedicated to surface hydrology, such as the Surface Water and Ocean Topography (SWOT), we discuss future opportunities and how the use of remote sensing could benefit scientific and societal applications, such as water resource management, flood risk prevention and environment monitoring under current global change. Article Highlights The hydrology of African surface water is of global importance, yet it remains poorly monitored and understood Comprehensive review of remote sensing and modeling advances to monitor Africa’s surface water and water resources Future opportunities with upcoming satellite missions and to translate scientific advances into societal applications

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Section: The Use Of Earth Observations For Modeling Surface Waters An...mentioning

confidence: 99%

Water Resources in Africa under Global Change: Monitoring Surface Waters from Space

et al. 2022

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“…Therefore, a hydrological modelling, first, and a hydraulic analysis, second, have been performed to assess the flood hazard of the area for a relatively low return period. A coupled modelling procedure, like the one of this study, is a viable way forward in several similar other studies undertaken in the Africa continent and, in particular, in data scarce basins, as recently reviewed by [18].…”

Section: Discussionmentioning

confidence: 98%

“…The latter requires a particular effort due to the data scarcity that typically characterizes less developed countries [16,17]. In this study a coupled hydrological and hydraulic model is presented, which provides improvement in floodplain simulation, especially in data scarce regions [18]. The study presented in this manuscript is part of a cooperation project called ADAPT, funded by the Italian Agency for Cooperation to Development.…”

Section: Hydraulic Conditions Of the Study Sitementioning

confidence: 99%

Flood Mitigation Measure and Water Storage in East Africa: An Analysis for the Rio Muaguide, Mozambique

Rrokaj

Corti

Giovannini³

et al. 2021

Hydrology

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In the last century, floods have been more frequently hitting population and human activity, especially in the sub-Saharan context. The aim of this study is to propose suitable flood mitigation measures for the downstream part of the Rio Muaguide, which flows in northern Mozambique. In this terminal part of the river, the bed has been buried by sediment in many reaches; due to the reduction of the section conveyance, wide areas are inundated during the rainy season with negative consequences for several villages relying on subsistence agriculture. The design of any measure requires quantitative determinations but, as many less developed countries, Mozambique is affected by data scarcity. Therefore, in this study global and freely available data have been used to perform hydrologic and two-dimensional hydro-dynamic modelling, finally producing a flood hazard map. Particular care has been put into a critical analysis of several data sources, in terms of their suitability for the purposes of the work. Based on the modelling results and on field evidence, an intervention has been proposed with a double functionality of mitigating the effects of periodic floods and storing water to be used by the agricultural community during drier seasons. The proposed intervention combines restoring a sedimentation-less shape of the river sections and exploiting a natural basin as a storage basin. The methods applied and the intervention proposed for the Rio Muaguide are prototypal for several analogous streams in the coastal portion of Mozambique.

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“…SWAT (Arnold et al, 1998), a common conceptual rainfallrunoff model, has been used as a predictive tool to assess the impact of different climate change projections on the future water resource availability in different African settings (Akoko et al, 2021;Chomba et al, 2021;Maviza and Ahmed, 2021;Osman et al, 2021). Using historical conditions, hydrological process simulations for rainfall-runoff models have been calibrated with historical streamflow measurements and other hydroclimatic observations.…”

Section: Introductionmentioning

confidence: 99%

How Climate Extremes Influence Conceptual Rainfall-Runoff Model Performance and Uncertainty

et al. 2022

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Rainfall-runoff models are frequently used for assessing climate risks by predicting changes in streamflow and other hydrological processes due to anticipated anthropogenic climate change, climate variability, and land management. Historical observations are commonly used to calibrate empirically the performance of conceptual hydrological mechanisms. As a result, calibration procedures are limited when extrapolated to novel climate conditions under future scenarios. In this paper, rainfall-runoff model performance and the simulated catchment hydrological processes were explored using the JAMS/J2000 model for the Berg River catchment in South Africa to evaluate the model in the tails of the current distribution of climatic conditions. An evolutionary multi-objective search algorithm was used to develop sets of parameters which best simulate “wet” and “dry” periods, providing the upper and lower bounds for a temporal uncertainty analysis approach to identify variables which are affected by these climate extremes. Variables most affected included soil-water storage and timing of interflow and groundwater flow, emerging as the overall dampening of the simulated hydrograph. Previous modeling showed that the JAMS/J2000 model provided a “good” simulation for periods where the yearly long-term mean precipitation shortfall was <28%. Above this threshold, and where autumn precipitation was reduced by 50%, this paper shows that the use of a set of “dry” parameters is recommended to improve model performance. These “dry” parameters better account for the change in streamflow timing of concentration and reduced peak flows, which occur in drier winter years, improving the Nash-Sutcliffe Efficiency (NSE) from 0.26 to 0.60 for the validation period 2015–2018, although the availability of climate data was still a potential factor. As the model performance was “good” (NSE > 0.7) during “wet” periods using parameters from a long-term calibration, “wet” parameters were not recommended for the Berg River catchment, but could play a large role in tropical climates. The results of this study are likely transferrable to other conceptual rainfall/runoff models, but may differ for various climates. As greater climate variability drives hydrological changes around the world, future empirically-based hydrological projections need to evaluate assumptions regarding storage and the simulated hydrological processes, to enhanced climate risk management.

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

Cited by 21 publications

References 51 publications

Water Resources in Africa under Global Change: Monitoring Surface Waters from Space

Water Resources in Africa under Global Change: Monitoring Surface Waters from Space

Flood Mitigation Measure and Water Storage in East Africa: An Analysis for the Rio Muaguide, Mozambique

How Climate Extremes Influence Conceptual Rainfall-Runoff Model Performance and Uncertainty

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