Geomática aplicada à estimativa do coeficiente de escoamento superficial do método racional

Abstract

Accelerated urban growth, inadequate land use, absence of planning and inadequate infrastructure alter the natural hydrological cycle by decreasing water infiltration into the soil and increasing runoff. Thus, it is necessary to know the maximum flow and capacity of the basin to support it, aiming at an appropriate design of the hydraulic works. One of the most widely used methods to estimate flow rates for hydraulic works is the Rational Method, whose main parameter is the runoff coefficient (C). In this context, the objective of this work was to obtain the value of C for the return periods of 2, 5, 10 and 25 years for the Cohab neighborhood located in the city of Itaqui-RS, using techniques of the science called Geomatics. For the execution of this work, a planialtimetric survey and subsequent data processing were performed for the generation of a Digital Elevation Model (MDE), used to calculate the slope of the study area. The classes of land use and land cover were also determined by supervised classification of a satellite image. Finally, the values of C were estimated from the overlap of slope maps and land use and cover, considering the different periods of return under analysis. It is believed that the results obtained through this study may serve as an aid to determine the maximum flow of urban drainage projects to the Cohab neighborhood after the validation of the same.