USO DE GPR PARA A IDENTIFICAÇÃO DE INSTRUMENTAÇÃO EM SUBSUPERFÍCIE NA BARRAGEM DO CHASQUEIRO – ARROIO GRANDE/RS/BRASIL

Abstract

The Chasqueiro Dam, located in Arroio Grande,Brazil, is an earth dam whose main function is to increase water availability in the region and  ensure the rational use of water and soil resources for the development of irrigated agriculture. Inaugurated in 1984 under the responsibility of SUDESUL (Southern Region Development Superintendence), since 1994 it has been administered by ALM (Mirim Lagoon Development Agency). Therefore, since then, among other monitoring assessments, the agency has been reading the piezometers installed on the dam. However, the initial project included more instrumentations than that monitored by ALM. Thus, this paper makes use of a Ground Penetration Radar (GPR), a geophysical equipment that uses the propagation of high frequency electromagnetic waves in the subsurface to identify instrumentation foreseen in the initial project, but not identifiable through visual inspection at the dam. The total length analyzed, considering longitudinal and transverse directions to the dam, was 3930 m. The data were geodesically referenced with the aid of a geodetic receiver, which allowed the identification of the location of the anomalies identified on the radargrams.As a result, a piezometer and two surface markers that were buried were detected. These instrumentations have already been included on the dam monitoring system.