Transporte de sedimentos em suspensão e de fundo na bacia hidrográfica do Rio Piancó Piranhas Açu.

Abstract

With the intense development of human activities on soil in search to supply their needs, has accelerated erosion processes, increasing production, the transport and deposition of sediments in the environments hydric. The referent work had as objective conduct a study of transport of suspended sediment and fund in river hydrographic basin Piancó Piranhas Acu. The study was conducted the sub-basin hydrographic river Piranhas, in section control next the bridge about the Piranhas river, in BR-230, distant 5 km the city of Pombal-PB, at coordinates 6°43’32’’S e 37º49,54’’W. Were performed 15 measurement campaigns hydrosedimentometrics, the period November/2012 to may/2013, involving the measurements the concentration suspended sediment, liquid discharges, solid in suspension, not as solid in suspension and total suspended solid and the parameters quota river, width of the top, mean velocity of the water and depth average. The determination of flow was taken using a Acoustic profiler Corrent Doppler – ADCP, while that for the analysis on concentration and granulometry suspended sediments were utilized the methods tube withdrawal by the base and curve Oden, respectively. For evaluation the material of the bed has used to granulometric analysis by sieving to identify the distribution of size of the particles. The values the concentration sediment in suspension varied between 2,53 mg L-1 and 161,99 mg L-1, with a average value of 46,59 mg L-1 with standard deviation of 43,93 mg L-1 for an average flow of 12,87 m3 s-1. Besides, were plotted curves keys suspended sediments, for the periods dry and rainy, what presented good coefficient of determination. It was verified the type suspended material that is adduced in Piranhas River consists of silt and clay, while in the bed is boulder and fine sand.