Author(s)

F C B Mascarenhas, M G Miguez & R O G Campos

Abstract

The urban flood problem has becoming very frequent at great cities in developing countries. The interest in the mitigation of the related effects has been widely increased due mainly to hazardous situations that arise in wet seasons. Those urban floods have been aggravated either in magnitude and frequency because of problems related to disordered urban land occupation and to inefficient drainage system. An important cause of those problems is frequently associated to the lack of public services integration and poor substructure for the city growth. The drainage system of an urban watershed is not designed to work at very unfavorable conditions related to the presence of all sort of solid material mixed with the water flow. The general picture becomes more significant when the urban waste is added to the basin wash load, due to inefficient urban garbage collect system, and the water flow may be contaminated, favouring proliferation of diseases through the city inhabitants. Regarding the mathematical flood flow modelling, most models are not able to simulate the solid material embodiment. The usual approaches consider only the flood flow running through full hydraulic transverse sections and by increasing the roughness coefficient to simulate flow restrictions. When communities occupy watershed slopes not provided of basic substructure services, there are source of garbage and solid material whose will be added to the water flow along the drainage net. This work presents a mathematical cell model capable to represent the presence of solid material combined with the water flow. This is done through the introduction of a time varying reduction factor for the

Keywords