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Article History Keywords Bathymetry Evaporation GIS Hydrological regimes Livestock Monze District-Zambia Reservoir Sedimentation Water.The objectives of the study were to: determine bathymetry of the reservoir; understand seasonal hydrological regimes of the reservoir; determine factors influencing reservoir bathymetry and, examine the implications of the reservoir's bathymetry on livestock water demand and policy decision making. The determined reservoir bathymetries and capacities at low, medium and full levels confirmed drastic changes in water volumes and eventually, a threat to water security for livestock. This unsteady equilibrium in reservoir's bathymetry and water volumes was mainly due to high mean annual siltation rates (>5,000 tyr -1 ). Using 3D spatial analysts tools in ArcGIS 10.3 and spreadsheet Microsoft Excel to analyze the data based on the study, hypsometric curves showed strong non-linear relationships among water depth and water surface; water depths and water volume, as well as water surface area and water volume. Generally, through inter-seasonal comparisons of reservoir's bathymetries and water volumes between 2015 and 2017, this study illustrates the significance of bathymetric study of small reservoirs as a plinth to provide policy context and guidelines on water resource management for livestock, as a missing component in general studies of bathymetry, which are usually predominated by understanding the physical processes, but with little or no emphasis on their meaning towards addressing societal needs. Hence, a community engaged strategy to addressing upstream sediment-generating activities would help in stabilizing the bathymetry of the reservoir and eventually enhance water security for livestock. Contribution/Originality:This study is one of very few studies which have investigated implications of bathymetric surveying on sustainable water resource management for livestock. The study documents how bathymetric surveying can be used to understand seasonal hydrological regimes and storage capacity loss of small reservoirs so as to prepare for water security.

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.

The rapid development of free and open-access hydrological models and coupling framework tools continues to present more opportunities for coupled model development for improved assessment of floodplain hydrology. In this study, we set up an Upper Zambezi hydrological model and a fully spatially hydrological-hydrodynamic coupled model for the Barotse Floodplain using GLOFRIM (GLObally applicable computational FRamework for Integrated hydrological–hydrodynamic Modelling). The hydrological and hydrodynamic models used are WFLOW and LISFLOOD-FP, respectively. The simulated flows generated by the wflow model for the upstream gauge stations before the Barotse Floodplain were quite similar and closely matched the observed flow as indicated by the evaluation statistics; Chavuma, nse = 0.738; kge = 0.738; pbias = 2.561 and RSR = 0.511; Watopa, nse = 0.684; kge = 0.816; pbias = 10.577 and RSR = 0.557; and Lukulu, nse = 0.736; kge = 0.795; pbias = 10.437 and RSR = 0.509. However, even though the wflow hydrological model was able to simulate the upstream hydrology very well, the results at the floodplain outlet gauge stations did not quite match the observed monthly flows at Senanga gauge station as indicated by the evaluation statistics: nse = 0.132; kge = 0.509; pbias = 37.740 and RSR = 0.9233. This is mainly because the representation of both floodplain channel hydrodynamics and vertical hydrological processes is necessary to correctly capture floodplain dynamics. Thus, the need for an approach that saves as a basis for developing fully spatially distributed coupled hydrodynamic and hydraulic models’ assessments for groundwater dependent tropical floodplains such as the Barotse floodplain, in closing the gap between hydrology and hydrodynamics in floodplain assessments. A fully coupled model has the potential to be used in implementing adaptive wetland management strategies for water resources allocation, environmental flow (eflows), flood control, land use and climate change impact assessments. Doi: 10.28991/HEF-2022-03-02-09 Full Text: PDF

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