Runoff and sediment Transport of Portel-Melgaço Water System in an Amazonian estuarine System

Costa, M. S.; Rolnic, M., P.D., Prestes, Y.O., Rosário, R.P., and Borba, T. A.C., 2016. Runoff and Sediment Transport of Portel-Melgaço Water System in an Amazonian Estuarine System. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 18 - 22.CoconutCreek (Florida), ISSN 0749-0208. The Pará River, located in northern Brazil, receives hydrological and sediment contributions from a complex network of basins, such as the Amazon, Portel/Melgaço, and Tocantins river basins. Portel/Melgaço basin, a fluvial-estuarine system situated between the Amazon and Tocantins river basins, is still poorly known. Therefore, the objective of this study is to identify whether there is any hydrological and sediment contribution from Portel/Melgaço river basin to the Pará River. For that purpose, two campaigns were carried out: 1) June, 2013 (transitional season) and 2) March 2014 (wet season). Samplings were carried out over a tidal cycle (13 h) and consisted of a bathymetric surveys; tide measurements; cross sections of streamflows (Acoustic Doppler Current Profiler); and vertical turbidity profiles (Optical Backscatter Sensor) with water sampling (surface and bottom for Suspended Particulate Matter) at three points of the cross section. Our main conclusion is that the inflow from Pará and Amazon Rivers to Portel/Melgaço river basin is higher than the outflow and appears to be highest in the dry season. Thus, the Amazon and Pará Rivers are the main source of suspended sediments to the system, and this characterizes Portel/Melgaço river basin as a retention basin.