Coupling Hydrologic-Hydrodynamic Processes in a Groundwater dependent
Tropical Floodplain: Case of Barotse Floodplain
Abstract
The rapid development of free and open access hydrological models and
coupling frameworks tools continue to present more opportunities for
coupled model development for improved assessment of floodplain
hydrology. In this study, we set up a The 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 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; Lukulu, nse=0.736; kge = 0.795; pbias = 10.437 and RSR = 0.509.
However, even though 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 channels hydrodynamics and vertical
hydrological processes are necessary to correctly capture floodplain
dynamics. Thus, the need for an approach that saves as a basis for
developing a 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 floodplains assessments. A fully model
coupling has the potential of been used in implementing adaptive wetland
management strategies for water resources allocation, environmental flow
(eflows), flood control, land use and climate change impact assessments.