Cálculo de Áreas Inundáveis Devido a Enchentes para o Plano Diretor de Drenagem Urbana de São Carlos (PDDUSC) na Bacia Escola do Córrego do Gregório

Since 2002, the Municipality of São Carlos, SP, Brazil (PMSC) has developed a Master Plan, thereby establishing guidelines for flood prevention and control. However, the present scenario shows expensive, on-site antiflood works in São Carlos. Due to the absence of previous watershed planning, the area around the Municipal Market (MMSC) is continuously threatened by overspill flood events in the floodplain of Gregorio River. The purpose of this work is to provide information to support decision-making in the Master Plan using structural and nonstructural measures, such as flood zoning of risk-prone RBRH — Revista Brasileira de Recursos Hídricos Volume 12 n.2 Abr/Jun 2007, 05-17 17 areas. Critical flood events that produced inundation at MMSC were identified by interviewing people living in these urban risk-areas. Those critical events were simulated using integrated rainfall-runoff transformation and wave routing with the IPHS-1 concentrated model and the distributed model, HIDRORAS, whose results were compared. Input data were calibrated from monitored flood events. Uncertainties inherent to each model were identified. Results depict initial yardsticks for flood mapping to be included in the Master Plan agenda. Structural flood control measures consisting of a retention basin without excavation and non-structural measures such as increased infiltration area, were investigated. It was concluded that for urban watersheds like the Gregório basin, changes in the flow patterns due to urban streets are better represented by the distributed model, HIDRORAS. However, a number of uncertainties still remain for this model, such as the influence of saturated hydraulic conductivity of the soil. Key-words: Floods, urban drainage, flood-prone areas.