A relação entre o caudal do rio e a área de inundação na bacia hirográfica do rio Limpopo

Abstract

The study of forecasting and preventing flood flows is important, as in-depth knowledge of these contributes to the security of human lives and rural socio-economic development. The general objective of the investigation is to draw a map of the risks of flooding-the.Limpopo.basin.from the hydrometric stations of chókwè and de' macarretane. In the investigation, the historical data of hydrometric levels from the measuring stations and the flow curves were used to convert the water heights into flows. It had as field data the elevations and the distances of the points and between the points in each transect of the transversal section of the flooded basin of the Limpo River. Also, a description of the occupation and use of land in the study area was made. The water height data series comprise the period from 1954 to 2000 for stations e-35 and e-372 in the Limpo River. The flood flows in the Limpo Valley at the chókwè e-35 station were determined using the models of the equations of flow curves applied at that point. Finding it started, the flood of 2000 was outside the standards and the determination of its magnitude was necessary to use the river with floodsplains model described by jansen (1994) and it is considered the most adequate in the topographical conditions of the section. In the Jansen equation, the roughness factor was considered the minimum value, taking into account the time when the floods occurred, when the vegetation cover was greater and the hypothesis of reducing the calculation error was not possible to fully cover the survey in the field for what was the design of the activities to be developed in the field. For the missing information, we used the level curves of the region from the arcview gis software. Thus, the 2000 flood for the e-35 station had a maximum peak of j 0.54 meters corresponding to ,one-altitude, of. 3.1.57 meters, a flow of 12973 m3/s and a flooded width of around 8770 meters. From the ratio of river flow and flood width, the flood map was drawn with the help of the cross-section profile of the basin. For the analysis of the flood return period, the pearson 3-parameter distribution was used. The 2000 flood was characterized by a return period of 5000 years