Two-dimensional Hydrodynamic Modeling of the Ancachí River (Colombia), and its Impact on the Geotechnical Stability of the Shores due to Variations in Pore Pressure.

Estuaries are zones where two environments converge, the marine environment and the fluvial, contain combined characteristics of both such as tidal variations and floods of rivers, but at the same time their behavior is different because it mainly depends on what dynamic is predominant in the estuary. This is the case of the Ancachí River, located in the northwest of Colombia, is one of the many effluents that leads its waters to the Pacific Ocean, and its dynamic is influenced in majority by tides as seen in many tests like water level variations which were taken through the day showing the rise and drop of the water level and velocities of flow taken which were relatively low. Because of the water level variations, the shores, constituted mainly by sands and silt, are presenting tension cracks alongside its length and eventually turning into landslides, affecting places like the landing track of the Reyes Murillo airport that is located near the shore of the river. The solution given to the problem was to place soil-cement bags alongside the shore to diminish erosion but the problem continued, so there was the need to build containment structures, this alternative could eventually diminish the problem in the area but it is not viable in terms of construction and costs to make it in every place showing this conditions. In order to a better understanding of the phenomena in this estuary is needed to study it roughly, therefore a two-dimensional numerical modeling using shallow water equations will be done to represent the hydrodynamic processes that occur there, mainly to show the water level variations, then with the geotechnical information establish the moisture retention characteristics of the soil to determine the variation of the saturation front through numerical modelling in a finite element software, then find the relation between the variation of the level of tides with the suction to finally establish the relation between the geotechnical stability of the shore and the tide level from numerical modelling in finite element software.