Banca de DEFESA: CAMILA FARIAS VITORINO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : CAMILA FARIAS VITORINO
DATA : 29/08/2017
HORA: 14:30
LOCAL: Sala de Reunioes da Engenharia Ambiental - CTEC
TÍTULO:

RESISTANCE TO FLOW DUE TO MACROPHITE VEGETATION IN A PITIMBU RIVER, NATAL-RN

PALAVRAS-CHAVES:

macrophyte; Resistance to flow; Aninga; Manning

PÁGINAS: 64
GRANDE ÁREA: Engenharias
ÁREA: Engenharia Sanitária
SUBÁREA: Recursos Hídricos
ESPECIALIDADE: Planejamento Integrado dos Recursos Hídricos
RESUMO:

Macrophyte vegetation plays an important role to keep balanced aquatic environments in rivers and lakes in tropical regions. In small water courses, these plants provide ecological benefits since they act on sedimentation and nutrients retention, leading to an improvement in the water physicochemical properties. The presence of macrophytes in the river channel changes the velocity behaviour and increases the resistance to flow, causing reduction in speed and increase of depth in the section. Generally, flow retardation is associated to unwanted events, such as flooding of occupied areas. The aim of this study was to investigate the hydraulic resistance behaviour to flow caused by the presence of rigid and emersed macrophyte vegetation of the species Aninga (Montrichardia linifera) in a section into Pitimbu River located in the metropolitan region in Natal. This species is present in shallow waters of rivers of the tropical east coast of South America. Among the factors that influence the resistance to flow in small rivers, it is worth mentioning the flow-vegetation interaction, especially when the vegetation occupies the entire wet perimeter. The methodology used included in situ survey of vegetation characteristics, measurement of hydraulic variables in the section of study and in two cross sections into the river, and analysis of the flow-vegetation interaction. Vegetation analysis involved the delimitation of three quadrants (area 4 m²) randomly defined in the study area. In these quadrants, the morphological characteristics of the plants and the spatial distribution were raised. The hydraulic variables were measured with the discretization of the cross sections in verticals, where the average speeds were measured. The field data made it possible to quantify the resistance, expressed by the Manning number at 0.127 m-^1/3s, associated to a flow rate of 0.274 m³/s. The analysis of the velocity behaviour in the cross section S1 revealed the occurrence of high spatial variability, with points which velocity were above the mean value (2x) in 5 verticals, demonstrating the effect of macrophyte vegetation on this parameter. Negative velocities were recorded in some regions downstream of the plants, indicating the generation of mats and reverse flow at these sites. The analysis of the spatial distribution pattern of vegetation indicated the occurrence of aggregate distribution in some regions of the community. The analysis of the in situ flow-vegetation interaction revealed that the dissipative effect of vegetation is associated to its spatial distribution (density 8.12 plants / m²), stiffness and roughness of the stem

MEMBROS DA BANCA:
Presidente - 1242829 - LUCIO FLAVIO FERREIRA MOREIRA
Externo ao Programa - 2190974 - JOANA DARC FREIRE DE MEDEIROS
Externo à Instituição - Dayse Luna Barbosa - UFCG