Espacialização da precipitação na bacia hidrográfica do rio Brígida no sertão pernambucano para suporte à gestão dos recursos hídricos

Abstract

The water availability has been affected by the increasing water demand, especially for the agricultural sector, due to meteorological phenomena, which contribute to the temporal irregularity and spatial variability of rainfall, aggravated by climate change. The rainfall regime is crucial for the water supply, particularly for water allocations in small reservoirs in the semiarid, and may even affect the safety of such dams. Geostatistics is a methodology able to incorporate spatial correlation in its procedures, being relevant in hydrological and precipitation dynamics studies. The present study analysed the spatial and temporal distribution of precipitation in the Brígida River Basin. Records from 41 rainfall stations, with an annual temporal series of 55 years (1963 to 2017) made available through the official Pernambuco's Water and Climate Agency network and complemented by the Tropical Rainfall Measuring Mission (TRMM) was used to identify this variability. Direct rainfall data (manual and automatic) and indirect (satellite) data were systematized and classified in dry, normal and rainy periods using the Quantile Technique. According to the results, all the semivariograms presented high and medium spatial dependence, and through the descriptive analyses of the data, with ranges from 20 km to 45 km. The coefficients of variation showed intermediate dispersion (CV> 20%), indicating an intermediate variability of the rainfall indices in the basin, requiring a monitoring strategy based on an intensely distributed network.