The solution of the hydrodynamic problems with the MECA ffillodel For Estuarine and Coastal Circulation Assessment) model requires me determination qf thermical boundary conditions al the bottorn.The authors have carried out an estimation qf the possibilities qf utilization qf severa!boundary conditions at the bottom.In particular..formulation of coupled model for thermical interaction between the sediment and water cohimn is discus sed. Results of mis work show a practica! equivalence between the first type boundarycondition and the coupled probkm for me .shallowwater dynamics. RESUMENLa solución de problemas hidrodinámicos mediante la utilización del modelo MECA