Banca de DEFESA: FLÁVIA VALÂNEA SOUZA BELCHIOR

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : FLÁVIA VALÂNEA SOUZA BELCHIOR
DATE: 14/12/2019
TIME: 14:00
LOCAL: Sala 2 - PPGG
TITLE:

Morphology and subaqueous dunes distribution in the Potengi Estuary (Natal-RN)

KEY WORDS:

estuary; dunes; morphologic features; dynamic

PAGES: 71
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUMMARY:

The Potengi River extends for more than 170 km and flows into the eastern coast of Rio Grande do Norte, its estuarine region being surrounded by the metropolitan region of the city Natal. The main channel has suffered periodic dredging and its margins with intense urbanization. Such interferences directly influence the estuarine sedimentary dynamics, resulting in redistribution of erosion and silting zones. Due to the semi-diurnal regime of mesomaré, the circulation of the estuary is dominated by currents of ebb and flood which, in different zones of the estuarine channel, form patterns of bedforms and subaquatic dunes that show the transport of sediment sand the modifications in the morphology of the channel. The main aim this work is to analyze the spatialization and morphology of the background features, to investigate morpho-sedimentary processes and possible anthropic influences. Sonographic and bathymetric data was acquired in the main channel of the estuary in August of 2017 were used by means of an interferometric sonar (Edgetech 4600), operating in the frequency of 540 KHz, with lateral reach of 125m per sensor. The sonographic data were processed using the software SonarWiz 6 that allowed to generate the mosaic and the interpretation of zones and forms of background, map sand 3D models. The bathymetric data were filtered using Hypack 2014 software and are in the modeling phase. The estuary has an asymmetric main channel with depths varying from 3 m to 20 m upstream and downstream, respectively. Bottom shapes were mapped along the estuary as 2D dunes, 3D dunes, small, medium and large dunes, flat bottom, rough bottom, anthropized regions. Flat an drugged flat bottoms are common on the banks of the channel with depth ranging from 2 to 6 m. In addition, they are found in the central region surrounding 2D dunes. Both the 2D and 3D dunes are asymmetric dunes and vary according to the spacing between them: from 0.6 to 5 m (small size), 5 to 10 m (medium size) and from 10 to 100m (large size). Both have depths ranging from 6 to 12 m. Although these dunes are well distributed throughout the channel, the 2D has more predominance in relation to 3D. The preliminary results indicate that the bedforms are related to the different flows in the canal, giving an irregular distribution of these sedimentary features

BANKING MEMBERS:
Presidente - 2042405 - MOAB PRAXEDES GOMES
Externo à Instituição - Andre Giskard Aquino da Silva - UFRN
Externo à Instituição - WERNER FARKATT TABOSA - UNI-RN