Data: 17/09/2014 à 19/09/2014
Local: São Paulo - Brazil
Hydrological Fast Response Change Due to Catchment Urbanization (PAP014813)
Flood forecasting and early warning systems
The forecast of hydrological risks in warning systems is an effective and economical way to reduce the loss of life and property damage. The Brazilian Centre for Monitoring and Alerts of Natural Disasters (Cemaden, Centro Nacional de Monitoramento e Alertas de Desastres Naturais) is responsible for forecasts of natural disasters risk (slow floods, flash floods and landslides) in national scale, with the integration of operational functions of monitoring and alerting, providing forecasts and sending reports to the Civil Defense in the short term. In the same context, only on a regional scale, the Early Warning System Medellin (SIATA, Sistema de Alerta Temprana de Medellín) is responsible for monitoring and providing alerts for the Metropolitan Area of the Aburrá Valley, in Medellín, Colombia. New tools for modeling watersheds rapid response are being developed and tested, in particular, distributed hydrological models based on Geographic Information Systems (GIS). Anticipate short-term forecasting, or nowcasting, is the challenge of alert systems, considering that precipitation has the capacity to evolve rapidly as a function of wet convective processes. The aim of this study was to investigate and to apply two hydrological models, both calibrated for two highly urbanized relatively and small watersheds, one in Brazil, Sao Carlos city (116 km²), State of Sao Paulo, and the other in Medellin city, in the Valle de Aburrá, Colombia (422 km²), to simulate the response of the basins under scenarios of population growth and estimates of the expansion of urbanized from GIS tools, contributing to the dissemination of methodologies for hydrological modeling in scale urban watershed and application of acquired knowledge in alert systems. The processing of raster file Digital Elevation Model (DEM) was performed in GIS environments, with the tool TauDEM for ArcgGIS 10.1 and MapWindow 4.2. The hydrological models used were CUENCAS and SHIA, both conceptual and distributed, through which it could reach to detect changes in land use, enabling the display hydrologic response in different population growth scenarios. In both models the spatial scale is 30 meters, the performance of both models is tested and compared. Different authors in the literature have been working with this problem, whereas a higher speed hydrological response relates to the probability of the occurrence of natural disasters such as landslides and floods. Has provided further work with a view to the ratio of the areas of the sudden flood risk in relation to the type of use and occupation of land, urban expansion areas, areas of impervious surface and slope classes.