Author(s): Rahma Yanda; Morihiro Harada; Ichiro Tamagawa
Linked Author(s): Morihiro Harada
Keywords: No Keywords
Abstract: Two-dimensional (2D) depth-averaged model is sufficient for use in ecological modeling and assessment of streams habitat, as well as 2D vertical velocity profile. However, because of the significant effect of streambed on flow in shallow streams (with low water depth), the velocity profile cannot always be represented by a logarithmic law for the entire depth (from the bed to the water surface). This study presents investigation to determine the lower limit of logarithmic velocity distribution (also called as the logarithmic layer). It as well can be used to determine the upper limit of roughness layer, which has important functions for fish and living place for benthic invertebrates. Velocity data taken from natural and experimental flume over gravel-and cobble-bed streams was analyzed by fitting with logarithmic velocity distribution equation. The scaling for the upper limit of roughness layer was presented. This result may help to improve the evaluation of fish habitat as the information about the existence of roughness layer area can affect the fish habitat selection.
Year: 2018