Evaluating the Natural Development of the Meta River for Proposing Hydraulic Works Oriented to River Training for Fluvial Navigation

The navigability capacity under the natural development of the Meta River was evaluated to identify the hydrologic, hydrodynamic, sedimentologic, and morphologic conditions to propose hydraulic works for establishing a navigation channel. The Meta River is one of the main rivers in Colombia with a high economical potential through its fluvial navigation. A 2D numerical modeling was conducted by using MIKE-21C for a representative sector of 75 km with braided and sinuous segments. The 2D model was calibrated by using water level and flow rate time series data, sediment data, and field data of velocity with ADCP, bed sediment sampling, and bed morphological changes with bathymetries performed in August 2012 and February 2013. The evaluation also included hydrological analysis; the morphology of banks, islands, and sandbars; and the analysis of satellite images from 2000 to 2012. Results of depth, velocity, shear stress, and spatial and temporal bed level changes were obtained and analyzed. The results showed that the natural development of the river allows navigation eight months per year on average (between May and December) without need of hydraulic works. However, between January and April, the depths are not enough for navigation. The river has a high morphological dynamic linked to the wide flow rate variation that influences the hydrodynamic and sedimentologic conditions. This dynamic causes important short-term morphological changes on the thalweg's alignment, changes in the flow rate distribution percentage on river branches, and other morphological changes that modify the active river channel. These results suggested that, based on the natural river behavior, the hydraulic works oriented to river training, which progressively establish the alignment and depth of a navigation channel, are more appropriate for the Meta River than fixed and hard solutions.