River engineering

About: River engineering is a research topic. Over the lifetime, 435 publications have been published within this topic receiving 10286 citations. The topic is also known as: Channelisation.

Nile river sediment transport simulation (case study: damietta branch)

Abstract: Sediment transport is an important element in the quantitative and qualitative management of river engineering. The rate of sediment transport, at any given river cross section, depends mainly on the availability of the transported material and transport ability of the stream. Many different formulas have been used to predict the amount of sediment discharge in the Nile River, but only few equations give reasonable results compared with field measurements. Some examples of these equations are Ackers and White, Engelund and Hansen and Yang equations. Damietta Branch was selected as a case study for this analysis. This study has been performed to simulate the period from 1982 to 2001 for Damietta Branch. Analysis and comparison of the selected formulas for both trend and value are discussed at each cross section. Keyword: Damietta Branch, Nile River Sediment, Sediment Transport Equation, Sediment Transport Simulation.

Floodplains : the forgotten and abused component of the fluvial system

Abstract: River restoration is strongly focussed on in-channel initiatives driven by fisheries interests and a continued desire for river stability. This contrasts greatly with the inherently mobile nature of watercourses. What is often overlooked is the fact that many rivers have developed floodplain units that would naturally operate as integrated functional systems, moderating the effects of extreme floods by distributing flow energy and sediment transport capacity through out of bank flooding. Floodplain utilisation for farming activities and landowner intransigence when it comes to acknowledging that the floodplain is part of the river system, has resulted in floodplains being the most degraded fluvial morphologic unit, both in terms of loss of form and function and sheer levels of spatial impact. The degradation has been facilitated by the failure of regulatory mechanisms to adequately acknowledge floodplain form and function. This is testament to the ‘inward looking’ thinking behind national assessment strategies. This paper reviews the state of floodplain systems drawing on quantitative data from England and Wales to argue for greater consideration of the floodplain in relation to river management. The database is poor and must be improved, however it does reveal significant loss of watercourse-floodplain connectivity linked to direct flood alleviation measures and also to altered flood frequency as a result of river downcutting following river engineering. These latter effects have persisted along many watercourses despite the historic nature of the engineering interventions and will continue to exacerbate the risk of flooding to downstream communities. We also present several examples of the local and wider values of reinstating floodplain form and function, demonstrating major ecological gains, improvement to downstream flood reduction, elevation of water quality status and reductions in overall fine sediment loss from farmland. A re-think is required regarding our approach to managing floodplains and funding floodplain restoration, arguing for greater recognition of the natural role of the floodplain as a resource for upstream flood management and as an agent for overall biotic improvement in line with restoration objectives.

A finite volume method for numerical modeling of 2-D flow and sediment movements on unstructured grids

Abstract: Based on the algorithm frame of finite volume on unstructured grids, by introducing upwind decomposition of flow and sediment numerical fluxes in the normal direction to and across each side of cells, a 2 D finite volume method for flow and sediment movements is established, including exchange modes between suspend sand and bed sand, and sediment carrying capacity formula of different grain The algorithm is used to simulate the numerical value on flow and sediment transport and riverbed deformation It is proved that this algorithm can reflect the dynamic process of flow and sediment transport and river bed deformation, and that the precisions satisfy the analytic need of the river engineering.

Rethinking the Mississippi River diversion for effective capture of riverine sediments

Abstract: . Many river deltas in the world are vibrant economic regions, serving as transportation hubs, population centres, and commercial hotspots. However, today, many of these deltaic areas face a tremendous challenge with land loss due to a number of factors, such as reduced riverine sediment supply, coastal land erosion, subsidence, and sea level rise. The development of the Mississippi River Deltaic Plain (MRDP) in southeast Louisiana, USA, over the past century is a good example. Since 1932, approximately 4877 km2 of the coastal land of MRDP has become submerged. The lower Mississippi River main channel entering the Gulf of Mexico has become an isolated waterway with both sides losing land. In contrast, large open water areas in the Mississippi River’s distributary basin, the Atchafalaya River basin, have been silted up over the past century, and the river mouth has developed a prograding delta feature at its two outlets to the Gulf of Mexico. The retrospective analysis of this paper makes it clear that the main cause of the land loss in the MRDP is not the decline of riverine sediment, but the disconnection of the sediment sources from the natural flood plains. Future sediment management efforts in the MRDP should focus on restoring the natural connection of riverine sediment supplies with flood plains, rather than solely using channelized river diversion. This could be achieved through controlled overbank flooding (COF) and artificial floods in conjunction with the use of a hydrograph-based sediment availability assessment.