SPACE DISTRIBUTION AND MAXIMUM MIRROR AREA WATER FROM SMALL EARTH DAMS IN THE PRETO RIVER BASIN

Abstract

In the last years, hundreds of small dams were built in the Preto river basin, contributing for the improvement of the irrigated agriculture in the region. The lack of technical information about the majority of these dams, however, is causing problems to understand their hydraulic characteristics, their impact on hydrologic dynamics of the basin and to plan the water resources usage in the region. The objectives of this paper were to identify the small dams in the Preto river basin, their spatial distribution and size. For this purpose it was used three scenes of the satellite Landsat ETM+. After the identification of the locations of the dams and the estimation of their corresponding areas, it was conducted a field survey in a set of 51% of the dams to obtain technical information and to measure their boundary contours. The remote sensing data showed the existence of 252 dams varying from 1 to 413 hectares in size. It was also observed a good correlation between remote sensing and field measurements of reservoir sizes.