Dynamics and Biogeochemistry of River Corridors and Wetlands (Proceedings of symposium S4 held during the Seventh IAHS Scientific Assembly at Foz do Iguaçu, Brazil, April 2005). IAHS Publ. 294, 2005, 78-85

Abstract Water circulation plays an important ecological role in ecosystems such as wetlands. Thus, understanding wetland hydrodynamics becomes an essential factor to the success of conservation and restoration projects. This paper describes the application of a two-dimensional, depth-averaged, hydrodynamic model to the system formed by Lake Mangueira and the Taim Wetland (Brazil). Vegetation resistance to flow was represented in a modelling system using a Manning roughness coefficient higher than that in unvegetated areas. The wind protection effect of vegetation was modelled by decreasing water surface shear stress in vegetated areas. Three spatial vegetation distributions were considered, resulting in very different water circulation patterns in the Taim Wetland. The influence of Lake Mangueira on the Taim Wetland was found to be completely dependent on vegetation occurrence in the interface between these ecosystems. Simulation results illustrate how spatial vegetation distribution changes may alter Taim Wetland hydrodynamics, having potentially detrimental ecological effects on the entire ecosystem.

Key words Taim Wetland; two-dimensional hydrodynamic modelling; vegetation resistance