Análise de critérios para definição de vazão de restrição para o controle do escoamento superficial urbano. Estudo de caso: bacia hidrográfica do riacho do Sapo, Maceió-AL

Abstract

In Brazil, the need to establish regulations to minimize flooding in urban catchments led several initiatives to control the generation of the surface runoff. An example is the specific discharge for restriction (maximum value an area can generate after the occupation, per unit area). This dissertation proposes the capacity of urban watercourses as reference for its definition and also it performs an analysis of the rational method when used for the same purpose at a pre-urban scenario. There were three main steps: application of the SWMM model at an urban catchment (modeling), simulation of the current land use scenario to find maximum capacities and the assessment of the rational method when applied in Maceió, Alagoas, Brasil. The values of discharge for restriction and runoff coefficient, both at current and pre-urban scenario, was compared to that reached for Porto Alegre, Rio Grande do Sul, Brasil. For the rational method, one should be careful with the adoption of the runoff coefficient value for pre-urban scenario; the values were considered restrictive for adoption in drainage systems already established. Finally, the adoption of a specific discharge for restriction from drainage system capacity at an urban catchment was considered a likely option, particularly in catchments with lined main watercourse and current land use scenario residential and commercial well established.