Produção de sedimentos da Bacia Hidrográfica do Rio Capibaribe para a Zona Costeira da Região Metropolitana do Recife

Abstract

The sediments produced in watersheds are transported by rivers towards the coastal zones. Many researchers have tried to estimate the amount of sediment produced on the continent and transported toward the ocean since the 60's. Moreover, many anthropogenic activities influence in transport capacity which may result in an accumulation or deficit of sediment in coastal areas. The state of Pernambuco shows along its coastline stretches susceptible to coastal erosion, where the coast of the Metropolitan Region of Recife (RMR) receives delivery of sediment produced in various rivers, such as, Beberibe, Capibaribe, Jaboatão and Timbó. The current study had the aim of determinate the current rate of the sediment yield in Capibaribe watershed. Thereby, collect measurement were carry out during the rainy season and non-rainy years of 2009 and 2010 following the methodology of equal width increment (IIL) sampling through the DH-48 sampler for suspended sediment sampling and for bedload sampling was used the U.S. BLH-84. The occurrence of higher concentrations of suspended sediment was observed during the rainy season with an amount equivalent to 594.95 mg L-1 for the years 2009 and 1071.55 mg L-1 to 2010. The suspended sediment yield of the rainy season was 3.42 t km-2 year-1 and 3.75 t km-2 year-1, respectively, for the years 2009 and 2010. The bedload of Capibaribe had uniform distribution a long the bed and distributed well-graded as well. The total sediment yield in Capibaribe watershed in the years 2009 and 2010 was low due to the action of the sediment retention dams, generating a deficit of sediment flux, both suspended and bedload, in the coastal zone in the Metropolitan Region of Recife.