Jeon, H.S.; Obana, M.; Kim, K.H., and Tsujimoto, T., 2017. Flow and sediment transport with non-submerged riparian vegetation in 1D scheme. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 329–333. Coconut Creek (Florida), ISSN 0749-0208.

Recently depth averaged analysis has become popular and powerful even in a stream with vegetation by taking account of form drag due to vegetation. A number of studies about the drag force related with various vegetation configuration were also carried out and focus on determining the drag coefficients and empirical formulas. However, there must be some restriction for application in depth averaged model for flow with vegetation. When it is applied to a stream with vegetation, form drag due to vegetation is taken into account, but the shear stress is not properly described because the frictional resistance law due to bed roughness is not modified in vegetated area. Therefore, friction factor in depth-averaged scheme must be modified by the flow with vegetation. In this paper, the concept of “bed roughness boundary layer” is proposed and analytically formulated against the vegetation density. Sensitivity analysis were also conducted under several parameters and vegetation densities. The calculated results bring the reasonable evaluation of shear stress and proposed concept will affect other many kinds aspect in fluvial process, which will be clarified successively. Resultantly we are able to apply the depth-averaged analysis reasonably to flow and fluvial process in a stream with various density of vegetation.