Dynamics of sedimentary Capibaribe River bed after deepening dredging

Abstract

ABSTRACT The growth of urban centers in the country are increasingly dependent on the adoption of new mobility options, and before this need was developed and initiated a project to build a river corridor passenger in a part of the Capibaribe River in the city of Recife-PE. For the implementation of a navigation channel deepening are needed dredging to define a geometry of the bed of the river compatible with the needs of ships that will traverse the channel. The monitoring of dredging is done with the constant bathymetric surveys where the information volumes of dredged sediments are removed, aiming to also check the temporal behavior of deposition and erosion processes. In this context, the work aimed to evaluate the geometry of the Capibaribe river bed after the deepening dredging, using data from bathymetric surveys at different times for making longitudinal and transverse profiles, and create digital models of depth to extract information about the deposition/aggradation or erosion/removing sediments and their respective volumes. Early Profile Capibaribe river showed mild slope and heterogeneity in the bottom of the form, especially after kilometer five, with trends of deposition/aggradation downstream of the confluence region with tax arising from the weir Apipucos and upstream of the winding sections in local enlargement of the cross section, and the amount of the fork located at kilometer nine. The scenarios after the dredging to deepen indicate places with predominance of erosion and other sedimentation processes. They compared the longitudinal and transverse profiles of two areas located in western shipping channel, one with 350 meters and over 1000 meters, where it was found that the area 1 to erosion/sediment removal exceeded sedimentation/aggradation, indicating the occurrence of dredging the interval between the two surveys linked to the natural processes. In the study area 2 the sedimentation/aggradation exceeded the removal/erosion, with a volume equivalent to 1 cm thickness. The aggradation occur homogeneously in the navigation channel, while erosion was located on the banks, more intensely on the right bank of the river.