Numerical simulation of surface flow through the lattice boltzmann method using sub-basin junction

The watershed surface runoff was investigated through the one-dimensional numerical simulation using the Lattice Boltzmann Method (LBM). A computational model was developed where the watershed is represented by the junction of nine sub-basins. For this, two equilibrium distribution functions were established through the Chapman-Enskog Expansion on a D1Q5 lattice, one suitable for flow on the basin surface and another for the main channel, obtaining the water depth on the basin surface and the channels cross-sectional area. In addition, the boundary condition was established in the flow passage from one sub-basin to another, taking into account the mass conservation and, in order to obtain a simulation closer to reality, it was considered an initial river flow (baseflow) of each channel stretch. The numerical results obtained by the LBM were compared with data measured in field.