Two-Dimensional Flood Plain Flow. I: Model Description

Beffa, Cornel; Connell, Robert J.

doi:10.1061/(asce)1084-0699(2001)6:5(397)

Cited by 81 publications

(42 citation statements)

References 22 publications

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“…The latter rely on the CFD equations alone, and can be used to investigate hydraulic flow properties over an unchanging topography, notably the simulation of flood propagation and inundation extent [76][77][78][79] and studies of habitat suitability for aquatic species [80,81]. These types of applications are mainly used in planning or river engineering studies, but they can also be used to gain insight into specific historic events [82].…”

Section: (E) Reach-based Cellular Modelsmentioning

confidence: 99%

Modelling river history and evolution

Coulthard

Wiel

2012

Phil. Trans. R. Soc. A.

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Over the last few decades, a suite of numerical models has been developed for studying river history and evolution that is almost as diverse as the subject of river history itself. A distinction can be made between landscape evolution models (LEMs), alluvial architecture models, meander models, cellular models and computational fluid dynamics models. Although these models share some similarities, there also are notable differences between them, which make them more or less suitable for simulating particular aspects of river history and evolution. LEMs embrace entire drainage basins at the price of detail; alluvial architecture models simulate sedimentary facies but oversimplify flow characteristics; and computational fluid dynamics models have to assume a fixed channel form. While all these models have helped us to predict erosion and depositional processes as well as fluvial landscape evolution, some areas of prediction are likely to remain limited and short-term owing to the often nonlinear response of fluvial systems. Nevertheless, progress in model algorithms, computing and field data capture will lead to greater integration between these approaches and thus the ability to interpret river history more comprehensively.

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Section: (E) Reach-based Cellular Modelsmentioning

confidence: 99%

Modelling river history and evolution

Coulthard

Wiel

2012

Phil. Trans. R. Soc. A.

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“…(Mosley, 1983). Some results are also available for comparison from other modelling studies of South Island braided rivers using the 2-dimensional model Hydro2de (Beffa & Connell, 2001;Beffa, 1996). (Nicholas, 2003).…”

Section: Hydraulic Modellingmentioning

confidence: 99%

Flood Hydraulics and Impacts on Invasive Vegetation in a Braided River Floodplain, New Zealand

Caruso¹,

Ross²,

Shuker³

et al. 2012

ENRR

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This study evaluates the effects of floods and their hydraulic characteristics on invasive vegetation in the Ahuriri River floodplain, a braided gravel-bed river in the eastern high country of the South Island, New Zealand. Invasive vegetation alters the natural braiding tendency of rivers such as the Ahuriri and has severe negative impacts on threatened and endangered native wading birds and floodplain ecology. Aerial photographs for a 10-year period (1991 to 2000) that includes the largest flood on record in 1994 (recurrence interval of almost 50 years) based on a 46-year record were analysed to determine changes in aerial cover of water, bare substrate, and several different vegetation classes. This was complemented by hydraulic modelling using HEC-RAS software for a representative 1.1-km reach to evaluate flood hydraulic characteristics that can impact vegetation, including water inundation area, depth, velocity, and shear stress. The 1994 flood (570 m 3 /s) removed up to 25% of the invasive vegetation in the study reach, with preferential removal of lupin and less removal of willow and grassland. However, flood effects varied considerably with overall minor effects on total vegetation cover over the entire lower 21-km reach. The spatial distribution of vegetation cover changed considerably in response to this flood event, in a pattern resembling a shifting-mosaic steady state model. Modelling showed that a 600 m 3 /s (50-year) flood is likely to result in almost total inundation of the study reach floodplain and significant velocities and shear stresses on floodplain vegetation. Over the study reach linear models approximate the relationships between flood peak magnitude with average water area, depth, velocity, and shear stress. Depth and velocity do not increase as fast as flow area or shear stress, and differences between hydraulic characteristics for the 600 and 155 m 3 /s floods ranged from 37% for velocities to 179% for flow inundation areas. Much of the vegetation appeared to recover relatively quickly after flood events so that vegetation removal effects are short-lived. Although large floods can remove a considerable amount of invasive vegetation in some reaches of the river, natural flood events are unlikely to significantly reduce invasive vegetation cover throughout the river.

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“…The twodimensional model, Hydro2de (Beffa, 1996;Beffa & Connell, 2001), solves the depth-averaged shallowwater equations for a grid using a finite volume scheme. Given riverbed elevation and hydraulic resistance across the model domain, and specifying a discharge across the upstream boundary, the model computes water depth, depth-averaged velocity, and bed shear at each grid cell.…”

Section: Applicationsmentioning

confidence: 99%

Use of Remote‐Sensing with Two‐Dimensional Hydrodynamic Models to Assess Impacts of Hydro‐Operations on a Large, Braided, Gravel‐Bed River: Waitaki River, New Zealand

et al. 2006

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The Waitaki River is a large gravel-bed river draining the eastern slopes of the Southern Alps, South Island, New Zealand. Hydroelectric power development since 1935, including dams, diversion canals and natural lake control, has damped flood runoff and reduced bed-material supplies to the lower, 60-km long, braided segment of river. A recent proposal aims to divert a substantial component of the lower river flow through a canal for further hydroelectric power generation. Investigations for this proposal have used remote-sensing techniques to help assess environmental impacts. Airborne laser scanning (ALS), in combination with vertical aerial photography and multispectral (MS) scanning, was used to survey river topography and ground cover to provide boundary data for a two-dimensional hydrodynamic model. Ground topography was mapped using last-return ALS. Submerged channel-bed topography was obtained by subtracting water-depth mapped from MS imagery from the water surface elevations surveyed by ALS. By comparison with the MS approach, the ALS proved a powerful means of classifying ground cover. The hydrodynamic modelling was used to assess issues such as habitat conditions in the river, the effectiveness of fine sediment flushing flows, the sensitivity of flood levels to riparian vegetation cover, and visualizing the future river environment.

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Two-Dimensional Flood Plain Flow. I: Model Description

Cited by 81 publications

References 22 publications

Modelling river history and evolution

Modelling river history and evolution

Flood Hydraulics and Impacts on Invasive Vegetation in a Braided River Floodplain, New Zealand

Use of Remote‐Sensing with Two‐Dimensional Hydrodynamic Models to Assess Impacts of Hydro‐Operations on a Large, Braided, Gravel‐Bed River: Waitaki River, New Zealand

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