Avaliação da viabilidade do uso da água de chuva na agricultura familiar no semi-árido nordestino através da transformada Wavelet.

Abstract

: The use of rainwater depends on the analyses of several factors such as technical, economical and social acceptance, according to the technical viability, it depends basically on three factors: precipitation, catchment area and demand. Thus, this paper treats about the evaluation of the precipitation in the semiarid area of northeastern Brazil, according to the analyses of the signal frequency and significance test. Thus, it was applied a new robust technique for analyses to 65 precipitation series from eight states of northeastern Brazil, named Wavelet Trasnform, which is appropriated to analyze irregularly distributed events and time series with non-stationary power in several different frequencies. The analyzed series showed several frequency components, in which the annual component was present in all time series. Additional information about dry or wet periods were obtained by the modulation is separated bands; e.g., 8–16 months. This identification was very important, because the low precipitation volume, and identified in several studied series, could led to low reservoir volume, and it is exactly during this period that the small structures for rainwater storage could be explored for application in familiar agriculture, water for animals, and even for simple uses for the human beings. Thus, from the point of view of the precipitation analyses, the presented results show the viability of the use of rainwater in the semiarid area of northeastern Brazil.