An important feature of most rivers and canals is their habitats for a rich of aquatic vegetation which is extremely important from an environmental and ecological point of view. These variations in habitat mean that it is rare to find a cross-section of a natural channel which has the same roughness along its perimeter. In these channels, flow conditions lead to a complex flow situation with i...

Vegetation growing in the water along rivers plays an important role on the hydrodynamic behavior, on the ecological equilibrium and on the characteristics of the river. It has effects on the flow resistance and, as a result, has a large impact on water levels. The influence of non-submerged vegetation on flow is not so clear as yet; it needs to be further studied. The Acorus Calmus L is a kind...

An increase in the flow velocity in flowthrough large porous media and deflection of flow regime from Darcy law causes a nonlinear relationship between hydraulic gradient and pore velocity of media. So many investigations have done previously in such Medias. One of the most important subjects in flowthrough large porous media is relationship between friction coefficient and flow characteristics...

In environmental flood management, an essential task is to improve channel conveyance using environmentally preferable methods, which aim to preserve natural morphological and hydraulic characteristics of a river. This requires a reliable channel design method that accounts for complex hydraulics, i.e. two-stage channel or considerable bank vegetation. Hydraulic field measurements were carried ...

Estuarine tidal dynamics are influenced by changes in morphology and friction. In this work, we quantified damping the Yangtze Estuary explored impact of friction using a numerical model. In-depth analyses data reveal strong reduction from 1990 to 2010, followed slightly enhanced 2010 2020 South Branch. The reduced Branch is controlled sediment decline which induces an increase water depth (ero...

With rapid flood extent mapping capabilities, Synthetic Aperture Radar (SAR) images of river inundation prove to be very relevant to operational flood management. In this context, a recently developed method provides distributed water levels from SAR images. Furthermore, in view of improving numerical flood prediction, a variational data assimilation method (4D-var) using such distributed water...

Abstract Assessment of Manning’s unevenness factor is critical significance in hydraulic readings open channel stream. ( n n ) obligatory for the computation releases, water levels, and backwater curves, as well plan curve additions. The correct value roughness coefficient ), i. H. a that accurately reflects observed d...

Hydraulic models of rivers are essential for vulnerability assessment in disaster management. This study simulates the 2019 Typhoon Hagibis at Nanakita River using a dynamic roughness model. The model estimates river on pixel level from relationship between Manning coefficient and degree submergence vegetation. is defined as ratio water depth to plant height. After validating model, effect vege...