Efeito do aproveitamento de água da chuva na redução de escoamento superficial em uma sub-bacia do Riacho Pau D’Arco

Abstract

The urbanization process modifies the hydrological cycle, increasing runoff and reducing infiltration and storage processes. Therefore, it is necessary to study runoff reduction techniques, especially source control. In areas with little free space in lots, this reduction can occur through techniques such as rainwater harvesting from roofs. Thus, we studied the effect of inserting such systems in a small urban watershed, in the Jacintinho neighborhood in Maceió-AL, using the software Storm Water Management Model 5.0 to simulate scenarios before and after installation of them in several lots. We estimated water use demand after monitoring the consumption of a lot near the watershed, in the same neighborhood, and this behavior was defined as the standard for the study area. We have used a continuous rainfall series, with a discretization interval of one minute, and we have observed the effects of runoff volumes and peak flows at the watershed outlet, as well as the capacity of this type of system to supply a household's demand for water. We conclude that such a system can supply the demand of a residence for specific purposes and reduce surface runoff in a lot, although it needs adjustments to reduce the waste of collected rainwater. However, only the use of these systems is not sufficient for a large reduction in volumes and peak runoff for the whole basin due to the low amount of lots used here, as well as the conflicting application of the reservoirs – human use and peak flow control. We suggest the expansion of the number of lots for application of the system and integration with other runoff control techniques.