FLOW RESISTANCE IN A MIXED BEDROCK-ALLUVIAL STREAM

Código

XXIV-SBRH0493

Autores

Guilherme Krüger Bartels, GEORGE MARINO GONÇALVES, Pedro Loguercio de Ávila, Nilza Maria dos Reis Castro, GILBERTO LOGUERCIO COLLARES, Fernando Mainardi Fan

Tema

SR03 - Sedimentologia, geomorfologia fluvial

Resumo

The term mixed bedrock?alluvial characterize streams with patches of exposed bedrock associated with some degree of alluvial cover. In these environments, the presence of large elements (e.g., cobbles, boulders, and bedrock protrusion) are common and cause an increase in resistance to flow due to additional roughness. In the absence of data collected in mixed bedrock -alluvial streams have generally adopted standard flow resistance equations developed for alluvial channels. Thus, we evaluated whether we can apply the empirical flow resistance equations developed for alluvial channels satisfactorily in a mixed bedrock?alluvial stream in Southern Brazil. Our results indicate that the energy loss considered in standard flow resistance equations is underestimated for the flow characteristics of mixed bedrock?alluvial channels. Therefore, in future studies, it is suggested to review the use of standard flow resistance equation, such as investigating different methods to estimate the bed roughness height.