Modelagem hidrodinâmica 1D, 1D/2D e 2D do efeito de maré no Rio Cocó

Abstract

This work presents an update on hydrodynamic models for the Cocó River, based on the latest version and new tools available in HEC-RAS. One-dimensional (permanent and transient) hydraulic modeling (for main channel) connected with a two-dimensional modeling (for the floodplain) and a complete two-dimensional modeling for the Cocó River in the State of Ceará were performed using the HEC- RAS (version 5.0.3) developed by the US Army Corps of Engineers. The computational system was used to simulate the effects of tide (at the mouth of the river) on the hydrodynamics of the Cocó River and its environments, particularly in the Lagamar community. The study showed that the transient one-dimensional model of the HEC-RAS is able to give acceptable results in obtaining the water profiles (considering the transient regime) in version 5.0.3, although it does not completely capture the damping effect produced by the floodplain. The 1D / 2D model was very unstable and with a longer processing time than the other models implemented, due to the iterations necessary to guarantee an acceptable error in the conservation of the mass in the connection between the 1D and 2D models. The complete 2D model proved to be very efficient in capturing hydrodynamics of the river, besides being more stable and allowing greater flexibility than the other models in choosing the simulation time and cell size (in the case of the 2D model) or spacing (in the case of the 1D model). The results obtained were consistent with previous work. A preliminary analysis showed that the Lagamar region presents a tendency to sedimentation. The 2D model was promising for application in real-time forecasting simulations due to its low processing time and flexibility.