Carla Sofia Santos Ferreira,Daniel Soares,António J. Dinis Ferreira,Tammo S. Steenhuis,João L. M. P. de Lima,Celeste O. A. Coelho, CESAM, Ambiente e Planeamento, carla.ssf@gmail.com
ABSTRACT
Land use changes and impermeable surface areas expansion alters the hydrological cycle. This paper presents the methodology and the first results of a study to assess the impact of urbanization process on the hydrological regime of a small Mediterranean catchment (6 km2 ), Ribeira dos Covões, located in Portugal. The study uses a combined approach of field survey and hydrological monitoring to assess spatiotemporal hydrological dynamics. A monitoring network, integrating a weather station and eleven water level recorders, provides information on the sub-catchments’s hydrological response to rainfall considering different geology, soil characteristics, land-use and urbanization intensity, and their contribution to the catchment outlet. In addition, six 16m2 bounded plots are used to obtain the rainfall-runoff relationship of the forested areas. Infiltration experiments have been performed for spatial and temporal evaluation of the soil catchment. The results indicate distinct spatial and temporal variations in hydrological processes and different responses according with geology. Despite the low average runoff coefficient of the catchment (smaller than 10%), the streamflow increases quickly during the rainfall events, exhibiting a high susceptibility of the study site to flash floods.
Keywords: urbanization, catchment hydrology, rainfall-runoff relationship.