Fluxos hídricos na microbacia do córrego do Queixada no município de Jataí

Abstract

The diagnosis of hydrological flow and the rainfall interception by vegetation is justified by the need for knowing the influence of these elements in river basins, where weeds and appropriate use of land are responsible for maintaining the quality of the slopes, avoiding erosion, soil loss, silting of waterways and induces the maintenance of groundwater reserves. This work is a pilot study that gathered data components of the hydrological system of the watershed of the stream Queixada (MHQ), tributary of Rio Claro, represented in the letter of Jataí SE-22 (GO), quadrant understood by the UTM coordinates: E 419124.99 m, N 8028060.83 m, E 423105.19 m e N 8021056.99 m. The MHQ was mapped in its aspects of land use and occupation through satellite images of the years 2007/2008 (Google Earth) and through a vertical panchromatic aerial photograph of 1965 (U.S. Air Force - USAF). Specific equipment was installed in a hillside forest of MHQ for data collection of rainfall, throughfall and effective precipitation, obtaining data from the rainfall interception by vegetation and the initial abstraction. Rain gauges were installed in predefined points of MHQ to collect rainfall data. We measured monthly flow at the mouth of the mainstream of MHQ to obtain the average flow data. Data required for calculation of evapotranspiration were obtained at Jataí Meteorological Station of the National Institute of Meteorology (INMET). The actual evapotranspiration (ETR) was obtained from the equation of Penman (TUCCI; BELTRAME, 2009). The ground water recharge and runoff for uses of land in 2007/2008 and 1965 were determined by the method of Palmer (1965) cited in Alley (1984). The water storage (S) was determined by CN method (curve number - Soil Conservation Service "SCS"), adopting for uses considered the following values of CN: capoeira - 71; gravel - 86; crops - 71; kills - 70; pasture - 70, urban - 90. The data were manipulated through the software Excel and Surfer. It was found that partitions rainfall (throughfall, effective precipitation, interception and initial abstraction) showed differences in the analysis of variance from the seasonality and, consequently, by volume, intensity of rainfall and vegetation type examined. It was found that the highest runoff occurred in impermeable areas, which was the city where there were lower rates for recharging groundwater. The lowest and the highest runoff rates went to the recharge areas of forest, scrub and grassland. The results showed that the basin has lost 73,963,427 m³ of water storage capacity land use in 1965 in relation to the use made in 2007/2008.We conclude that need of measures to preserve recharge areas, because with the advancement may increase the urban runoff, reducing the recharge underground water, causing the reduction of water level, the silting of watercourses, erosion, death of springs and watercourses, affecting the entire ecosystem. Preserving the Forest of complaints should be maintained, restricted urban sprawl and rural areas must comply with the determinations of Brazilian environmental legislation.