A METHODOLOGY TO ASSIST IN GROINS DESIGN BASED ON NUMERICAL MODELLING

摘要

A methodology to assist in groins design is presented, which is based on the use of a 2D hydrodynamic/sedimentologic/morphologic model. It is applied to a stretch of the Pescado River, the main tributary of the Bermejo River, belonging to the Plata Basin, the second largest basin in South America. The particular stretch of Pescado River under study, in Argentina, is adjacent to an agrarian zone which has suffered bank erosion, and has now a series of groins designed, implemented and maintained by INMAC. Two hydrodynamic models are implemented: a regional model embracing the adjacent island, and a nested local model concentrated in the threatened bank. The hydrodynamics drives a sedimentologic/morphologic model. Based on the obtained results, different indicators of the bank erosion vulnerability are built as spatial distributions (maps), namely, stream power, armour stability coefficient, and bottom erosion during the passage of a flood wave. It is concluded that only the latter acts as an appropriate indicator for the present problem. The methodology is applied to optimize the performance of the present groins configuration, suggesting extensions for some of the groins. It is later used to produce an optimal configuration irrespective of present conditions, as a way to show the potential benefit of its application at the design stage.