Numerical simulation of flow and sediment transport dynamics on the Magdalena River section of Barrancabermeja-La Coquera (Colombia).

Jose Oliveros Oliveros, Jorge Escobar-Vargas, Mohamed Yossef, Cesar Cardona, Cesar Garay, Jorge Sanchez, Wendy Ramirez, Felipe Ardila, Diana Vargas

Thursday 2 july 2015

11:15 - 11:30h at Amazon (level 1)

Themes: (T) Water engineering, (ST) River and coastal engineering

Parallel session: 11B. Engineering - River

Due to the strategic importance of river transportation on the Magdalena River at the current Colombia´s development plan, Cormagdalena, as managing entity of the Magdalena river basin in Colombia, is building an unsteady numerical model for the flow and sediment transport dynamics for the Magdalena River (Colombia). This work shows the recent advances of a case of study on the river section (Barrancabermeja - La Coquera). The numerical platform is the computer program DELFT 3D which solves the shallow water equations, and the sediment transport equation with a finite difference approximation in three dimensions XYZ. The model is constrained by four boundary conditions, one at the beginning of the computational domain, where a flow discharge is imposed, a second one being an outlet condition, where a free surface elevation is enforced, and two additional flow discharge conditions are imposed, as inlet conditions, to take into account the Sogamoso River, which acts as a tributary. On each case a hydrograph of ten years was developed based on field measurements of climatologic stations in Magdalena and Sogamoso Rivers. Two modeling scenarios, for flow and sediment transport, were established: the first scenario is the modeling of the river natural dynamics, and a second scenario involves the modeling of groynes for the future maintenance of the waterway. From the hydrodynamic results a morphological model was developed based on the Engelund & Hansen, and the Meyer-Peter-Müller equations. A grid independence test was done for each of the simulations, ensuring an optimum distribution of the cells within the computational domain. Results showed that the numerical model approximates qualitatively the current natural conditions, and additionally shows how hydrodynamics changes, and how morphology dynamics evolves on the river when groynes are present within it. Additional analysis are presented where the efficiency of the civil works on the river are assessed to ensure the navigability on that section of the Magdalena River.