نتایج جستجو برای: bed rivers
تعداد نتایج: 67553 فیلتر نتایج به سال:
Gravel-bed river floodplains in mountain landscapes disproportionately concentrate diverse habitats, nutrient cycling, productivity of biota, and species interactions. Although stream ecologists know that river channel and floodplain habitats used by aquatic organisms are maintained by hydrologic regimes that mobilize gravel-bed sediments, terrestrial ecologists have largely been unaware of the...
To ensure a healthy and biodiverse ecosystem in cobble and boulder bed rivers, it is imperative that the channel bed is maintained. In pristine catchments this is achieved by the range of flows characteristic of the natural flow regime, which typically incorporates “maintenance” flood flows of different timing, duration and frequency. The construction of dams however, leads to a change in the f...
The river’s Geomorphology and its evaluation explore explanation of erosion, the longitudinal profile of the river bed and different forms of the rivers. Alvand River as the main river of the Alvand basin is located in Kermanshah Province W, Iran. The aim of this study is to investigate changes in longitudinal and longitudinal profiles of the river bed using mathematical functions and their rel...
In many gravel-bedded rivers, floods that fill the channel banks create just enough shear stress to move the median-sized gravel particles on the bed surface (D50). Because this observation is common and is supported by theory, the coincidence of bankfull flow and the incipient motion of D50 has become a commonly used assumption. However, not all natural gravel channels actually conform to this...
Providing faultless proceeding of the engineer in order to protect the rivers, requires understanding the morphological behavior of the river and studying the hydrodynamic phenomena of the area. The intersection of the Karun rivers as the largest and longest river in Iran with the Arvand border river is of considerable importance due to its strategic location. In this paper, using field measure...
A tidal bore impacts significantly on the estuarine ecosystem, although little is known on the flow field, mixing and sediment motion beneath tidal bores. In the absence of detailed systematic field measurements, a quasi-steady flow analogy was applied to investigate undular tidal bores with inflow Froude numbers between 1.25 and 1.6. Experimental results indicated that rapid flow redistributio...
The river’s Geomorphology and its evaluation explore explanation of erosion, the longitudinal profile of the river bed and different forms of the rivers. Alvand River as the main river of the Alvand basin is located in Kermanshah Province W, Iran. The aim of this study is to investigate changes in longitudinal and longitudinal profiles of the river bed using mathematical functions and their rel...
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