Bathymetry Development and Flow Analyses Using Two-Dimensional Numerical Modeling Approach for Lake Victoria

Abstract

This study explored two-dimensional (2D) numerical hydrodynamic model simulations of Lake Victoria. Several methods were developed in Matlab to build the lake topography. Old depth soundings taken in smaller parts of the lake were combined with more recent extensive data to produce a smooth topographical model. The lake free surface numerical model in the COMSOL Multiphysics (CM) software was implemented using bathymetry and vertically integrated 2D shallow water equations. Validated by measurements of mean lake water level, the model predicted very low mean flow speeds and was thus close to being linear and time invariant, allowing long-time simulations with low-pass filtered inflow data. An outflow boundary condition allowed an accurate simulation to achieve the lake’s steady state level. The numerical accuracy of the linear measurement of lake water level was excellent.

Stability and Consolidation of Sediment Tailings Incorporating Unsaturated Soil Mechanics

“…The numerical analyses in this study consist of 1-D consolidation and 2-D co tion analyses using Sigma/W, seepage analyses using Seep/W and slope stability a using Slope/W [33,34]. Sigma/W is a finite element software for analyzing deform soils whereas Slope/w is a limit equilibrium software for analyzing stability of slo finite element mesh had a mesh size of approximately 0.01 m in order to obtain a results from deformation and transient seepage analyses.…”

“…The numerical analyses in this study consist of 1-D consolidation and 2-D consolidation analyses using Sigma/W, seepage analyses using Seep/W and slope stability analyses using Slope/W [33,34]. Sigma/W is a finite element software for analyzing deformation of soils whereas Slope/w is a limit equilibrium software for analyzing stability of slope.…”

Hydro-meteorological processes driving solute transport in Lake Victoria

“…The St. Venant SWEs were implemented in COMSOL Multiphysics (CM) to model Lake Victoria hydrology (Paul et al, 2019). This equation-based modeling approach makes it easy to include the transport of various types of dispersed material, including chemical and biological activity, velocity gradient, etc.…”

“…The northeastern part of the lake catchment is relatively steep and forested, while the southeastern part is drier and flatter (Lipzig & Thlery, 2017). The average depth of the lake is 40 m and the maximum depth is 80m, i.e., the lake is very shallow (Kayombo & Jorgensen, 2005;Paul et al, 2019). The surrounding areas contain different environments and 23 influential rivers (see Figure 1).…”

“…The depth-averages two-dimensional St. Venant SWEs model has been developed by Paul et al (2019). The flow model was used to check the water level variation as well as provide transportation velocities for solutes (see section 3.4).…”