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Roger Alexander Falconer - One of the best experts on this subject based on the ideXlab platform.

  • Potential impacts of a Barrage on the eutrophic status of the Severn Estuary, UK
    2020
    Co-Authors: Margaret Osikhofe Kadiri, Bettina Nicole Bockelmann-evans, Reza Ahmadian, Roger Alexander Falconer
    Abstract:

    The potential impacts of a Barrage on the eutrophic status of the Severn Estuary were investigated in this study using a simple modelling approach adopted by the UK’s Comprehensive Studies Task Team (CSTT). The model predictions were compared against CSTT thresholds for assessing eutrophication in coastal waters. Under both preand post-Barrage (ebb-only generation) conditions, the estuary was found to be potentially eutrophic as the predicted equilibrium nutrient concentrations and potential maximum phytoplankton biomass exceeded the CSTT thresholds. Potential primary productivity under post-Barrage conditions was found to be significantly higher than that under pre-Barrage conditions. This is believed to be due to a combination of increased water residence time and greater light availability behind the Barrage. Keywords— Barrage; Eutrophication; Nutrients; Severn Estuary; Primary Productivity

  • The Severn Barrage: Europe's largest proposed marine renewable energy project
    2020
    Co-Authors: Roger Alexander Falconer
    Abstract:

    The Severn Barrage project proposes to develop marine renewable energy by building a Barrage (dam) stretching from the English coast to the Welsh coast across the Severn Estuary and Bristol Channel. This presentation will highlight recent research on the application of computational hydro-environmental models to predict the impacts of the proposed Severn Barrage project on tidal currents and sediment transport as well as bacterial-sediment interactions.

  • Input-output modelling of tidal renewable energy
    2020
    Co-Authors: E. K. Fenrich, Reza Ahmadian, Bettina Nicole Bockelmann-evans, W. Marks, Roger Alexander Falconer
    Abstract:

    Tidal renewable energy schemes have a variety of economic and ecological effects. It is therefore necessary to use models that can integrate these effects and sometimes conflicting requirements. An input-output model has been applied to the Severn Barrage, one of the proposed tidal Barrages on the Severn Estuary. While this project could produce around 17 TWH per annum of carbon free electricity which is around 5% of the UK electricity demand, diverse impacts on habitats as well as different users of the estuary have to be taken into account. First an input-output graph was set up to define linkages between different sectors of the project. From this a quantitative input-output model was derived. Economic and ecological requirements were specified as output demands of the system and a set of needed monetary and natural resources inputs was calculated. With these results feasible construction and management scenarios can be selected.

  • comparison of hydro environmental impacts for ebb only and two way generation for a severn Barrage
    Computers & Geosciences, 2014
    Co-Authors: Reza Ahmadian, Roger Alexander Falconer, Bettina Nicole Bockelmannevans
    Abstract:

    Marine renewable energy is playing an increasing significant role in many parts of the world, mainly due to a rise in the awareness of climate change, and its detrimental effects, and the increasing cost of natural resources. The Severn Estuary, located between South West England and South Wales, has a tidal range of up to 14m which makes it the second highest tidal range in the world. There are a number of Barrage proposals amongst various marine renewable energy schemes proposed to be built in the estuary. The Cardiff-Weston STPG (Severn Tidal Power Group) Barrage, which would be one of the world's largest tidal renewable energy schemes if built, is one of the most publicised schemes to-date. This Barrage would generate about 17TWh/annum of power, which is approximately 5% of the UK's electricity consumption, whilst causing significant hydro-environmental and ecological impact on the estuary.This study mainly focuses on investigating the hydro-environmental impacts of the STPG Barrage for the option of two-way generation, and compares this with the commonly investigated option of ebb-only generation. The impacts of the Barrage were modelled by implementing a linked 1-D/2-D hydro-environmental model, with the capability of modelling several key environmental processes. The model predictions show that the hydro-environmental impacts of the Barrage on the Severn Estuary and Bristol Channel, such as changes in the maximum velocity and reduction in suspended sediment and bacteria levels, were less significant for the two-way generation scheme when compared with the corresponding impacts for ebb-only generation. Display Omitted

  • Physical and numerical modelling of the Severn Barrage
    Science China-technological Sciences, 2014
    Co-Authors: James Brammer, Roger Alexander Falconer, Christopher Ellis, Reza Ahmadian
    Abstract:

    The Severn Estuary has one of the largest tidal ranges in the world and has long been the subject of consideration for tidal energy generation. Whilst plans to build a tidal Barrage across the estuary have existed in various forms since the 1920s, the 1989 Severn Tidal Power Group (STPG) proposal is commonly referred to as the original Severn Barrage. The UK government abandoned this ebb generation scheme as a public investment project in 2010. However, plans to build a two-way generation scheme were more recently put forward by a private consortium, namely Hafren Power. To assess the impact that a Barrage would have on the hydro-environment in the estuary a number of numerical modelling studies have previously been conducted for the STPG scheme. As this design has now been superseded by the Hafren Power proposal, new studies have been conducted to investigate the impact of a two-way scheme. In this study the hydro-environmental impacts of both ebb-only and two-way schemes were assessed using physical and numerical modelling techniques. Scale model Barrages were constructed and testing was carried out using a physical model of the Severn Estuary, located in the hydraulics laboratory at Cardiff University. A depth integrated numerical model, namely DIVAST, was applied to the physical model geometry and modifications were made to simulate the effects of the Barrage structures. The numerical model predictions showed good agreement with the corresponding laboratory data. The results were consistent with conclusions from previous studies, relating to the ebb-only scheme. These included an increase in the minimum water levels upstream of the Barrage, a reduction in the mean water levels downstream of the Barrage and a general reduction in tidal velocities. For a two-way scheme changes in the tidal elevations and velocities depended on the exact operating conditions of the Barrage. It was found that with no starting head the tidal regime was similar to the natural state, with little change in the elevations and a slight reduction in the mean velocities. As a starting head was introduced there was still little change in elevations downstream of the Barrage, however, there was an increase in the minimum water levels upstream of the Barrage, and a further reduction in the mean velocities.

Reza Ahmadian - One of the best experts on this subject based on the ideXlab platform.

  • Potential impacts of a Barrage on the eutrophic status of the Severn Estuary, UK
    2020
    Co-Authors: Margaret Osikhofe Kadiri, Bettina Nicole Bockelmann-evans, Reza Ahmadian, Roger Alexander Falconer
    Abstract:

    The potential impacts of a Barrage on the eutrophic status of the Severn Estuary were investigated in this study using a simple modelling approach adopted by the UK’s Comprehensive Studies Task Team (CSTT). The model predictions were compared against CSTT thresholds for assessing eutrophication in coastal waters. Under both preand post-Barrage (ebb-only generation) conditions, the estuary was found to be potentially eutrophic as the predicted equilibrium nutrient concentrations and potential maximum phytoplankton biomass exceeded the CSTT thresholds. Potential primary productivity under post-Barrage conditions was found to be significantly higher than that under pre-Barrage conditions. This is believed to be due to a combination of increased water residence time and greater light availability behind the Barrage. Keywords— Barrage; Eutrophication; Nutrients; Severn Estuary; Primary Productivity

  • Input-output modelling of tidal renewable energy
    2020
    Co-Authors: E. K. Fenrich, Reza Ahmadian, Bettina Nicole Bockelmann-evans, W. Marks, Roger Alexander Falconer
    Abstract:

    Tidal renewable energy schemes have a variety of economic and ecological effects. It is therefore necessary to use models that can integrate these effects and sometimes conflicting requirements. An input-output model has been applied to the Severn Barrage, one of the proposed tidal Barrages on the Severn Estuary. While this project could produce around 17 TWH per annum of carbon free electricity which is around 5% of the UK electricity demand, diverse impacts on habitats as well as different users of the estuary have to be taken into account. First an input-output graph was set up to define linkages between different sectors of the project. From this a quantitative input-output model was derived. Economic and ecological requirements were specified as output demands of the system and a set of needed monetary and natural resources inputs was calculated. With these results feasible construction and management scenarios can be selected.

  • comparison of hydro environmental impacts for ebb only and two way generation for a severn Barrage
    Computers & Geosciences, 2014
    Co-Authors: Reza Ahmadian, Roger Alexander Falconer, Bettina Nicole Bockelmannevans
    Abstract:

    Marine renewable energy is playing an increasing significant role in many parts of the world, mainly due to a rise in the awareness of climate change, and its detrimental effects, and the increasing cost of natural resources. The Severn Estuary, located between South West England and South Wales, has a tidal range of up to 14m which makes it the second highest tidal range in the world. There are a number of Barrage proposals amongst various marine renewable energy schemes proposed to be built in the estuary. The Cardiff-Weston STPG (Severn Tidal Power Group) Barrage, which would be one of the world's largest tidal renewable energy schemes if built, is one of the most publicised schemes to-date. This Barrage would generate about 17TWh/annum of power, which is approximately 5% of the UK's electricity consumption, whilst causing significant hydro-environmental and ecological impact on the estuary.This study mainly focuses on investigating the hydro-environmental impacts of the STPG Barrage for the option of two-way generation, and compares this with the commonly investigated option of ebb-only generation. The impacts of the Barrage were modelled by implementing a linked 1-D/2-D hydro-environmental model, with the capability of modelling several key environmental processes. The model predictions show that the hydro-environmental impacts of the Barrage on the Severn Estuary and Bristol Channel, such as changes in the maximum velocity and reduction in suspended sediment and bacteria levels, were less significant for the two-way generation scheme when compared with the corresponding impacts for ebb-only generation. Display Omitted

  • Physical and numerical modelling of the Severn Barrage
    Science China-technological Sciences, 2014
    Co-Authors: James Brammer, Roger Alexander Falconer, Christopher Ellis, Reza Ahmadian
    Abstract:

    The Severn Estuary has one of the largest tidal ranges in the world and has long been the subject of consideration for tidal energy generation. Whilst plans to build a tidal Barrage across the estuary have existed in various forms since the 1920s, the 1989 Severn Tidal Power Group (STPG) proposal is commonly referred to as the original Severn Barrage. The UK government abandoned this ebb generation scheme as a public investment project in 2010. However, plans to build a two-way generation scheme were more recently put forward by a private consortium, namely Hafren Power. To assess the impact that a Barrage would have on the hydro-environment in the estuary a number of numerical modelling studies have previously been conducted for the STPG scheme. As this design has now been superseded by the Hafren Power proposal, new studies have been conducted to investigate the impact of a two-way scheme. In this study the hydro-environmental impacts of both ebb-only and two-way schemes were assessed using physical and numerical modelling techniques. Scale model Barrages were constructed and testing was carried out using a physical model of the Severn Estuary, located in the hydraulics laboratory at Cardiff University. A depth integrated numerical model, namely DIVAST, was applied to the physical model geometry and modifications were made to simulate the effects of the Barrage structures. The numerical model predictions showed good agreement with the corresponding laboratory data. The results were consistent with conclusions from previous studies, relating to the ebb-only scheme. These included an increase in the minimum water levels upstream of the Barrage, a reduction in the mean water levels downstream of the Barrage and a general reduction in tidal velocities. For a two-way scheme changes in the tidal elevations and velocities depended on the exact operating conditions of the Barrage. It was found that with no starting head the tidal regime was similar to the natural state, with little change in the elevations and a slight reduction in the mean velocities. As a starting head was introduced there was still little change in elevations downstream of the Barrage, however, there was an increase in the minimum water levels upstream of the Barrage, and a further reduction in the mean velocities.

  • the severn Barrage and other tidal energy options hydrodynamic and power output modeling
    Science China-technological Sciences, 2009
    Co-Authors: Roger Alexander Falconer, Reza Ahmadian
    Abstract:

    Details are given herein of the current main proposals for tidal energy provision from the Severn Estuary, in the UK, with particular emphasis being focused on the Severn Barrage project, as originally promoted by the Severn Tidal Power Group. In particular, emphasis has focused on assessing the potential hydro-environmental impacts and power outputs of a Barrage across the estuary, with an unstructured grid, high resolution, model being developed and applied to the estuary to assess the implications of each of five shortlisted proposed schemes on the hydrodynamic, geomorphologic, flood risk and faecal indicator organism changes within the estuary. An outline is given of recent research on power refinements to the model to assess the options for power generation. The results show that the Severn Barrage has the potential to reduce the tidal currents in a highly dynamic estuary. This leads to the reduction of suspended sediment loads (particularly upstream of the Barrage), an increase of light penetration within the water column and, potentially, an increase in the benthic bio-diversity and the level of aquatic life in the estuary. The results also show that the Severn Barrage will reduce markedly the risk of flooding upstream of the Barrage and to a lesser extent downstream of the structure. In contrast the alternative options have far less impact on flood risk changes. In addition to the Severn Barrage some results are shown herein for a typical lagoon option, namely the Fleming Lagoon.

Bettina Nicole Bockelmannevans - One of the best experts on this subject based on the ideXlab platform.

  • comparison of hydro environmental impacts for ebb only and two way generation for a severn Barrage
    Computers & Geosciences, 2014
    Co-Authors: Reza Ahmadian, Roger Alexander Falconer, Bettina Nicole Bockelmannevans
    Abstract:

    Marine renewable energy is playing an increasing significant role in many parts of the world, mainly due to a rise in the awareness of climate change, and its detrimental effects, and the increasing cost of natural resources. The Severn Estuary, located between South West England and South Wales, has a tidal range of up to 14m which makes it the second highest tidal range in the world. There are a number of Barrage proposals amongst various marine renewable energy schemes proposed to be built in the estuary. The Cardiff-Weston STPG (Severn Tidal Power Group) Barrage, which would be one of the world's largest tidal renewable energy schemes if built, is one of the most publicised schemes to-date. This Barrage would generate about 17TWh/annum of power, which is approximately 5% of the UK's electricity consumption, whilst causing significant hydro-environmental and ecological impact on the estuary.This study mainly focuses on investigating the hydro-environmental impacts of the STPG Barrage for the option of two-way generation, and compares this with the commonly investigated option of ebb-only generation. The impacts of the Barrage were modelled by implementing a linked 1-D/2-D hydro-environmental model, with the capability of modelling several key environmental processes. The model predictions show that the hydro-environmental impacts of the Barrage on the Severn Estuary and Bristol Channel, such as changes in the maximum velocity and reduction in suspended sediment and bacteria levels, were less significant for the two-way generation scheme when compared with the corresponding impacts for ebb-only generation. Display Omitted

Soonmo An - One of the best experts on this subject based on the ideXlab platform.

  • study on the long term changes in water quality and benthic ecology and evaluation on effect of the Barrage in nakdong river estuary
    Journal of Wetlands Research, 2016
    Co-Authors: Sohyun Park, Jae Ung Choi, Soonmo An
    Abstract:

    (Received: 09 November 2015, Revised: 05 Janurary 2016, Accepte d: 29 Janurary 2016)요 약본 연구에서는 낙동강 하구 인근의 장기 수질 및 저서 생태변화를 파악하였고, 동시에 하굿둑이 수질 및 저서생태계에 미친 영향을 알아보았다. 수질 자료는 2013년과 2 014년에 현장 조사를 통해 획득한 실측자료와 수질 측정망 자료(환경부, 1989~2013)를 취합하여 해석하였다. 대형저서동물 자료는 2014년 현장 조사 자료와 문헌자료(1985~2013년) 분석을 통해 장기 변화를 파악하였다. 낙동강 하구 장기 수질변화는 전반적으로 유량 감소시 영양염이 증가하는 경향이 보였으나, 하굿둑 건설로 인한 급격한 변화는 관찰되지 않았다. 하지만 낙동강 하굿둑 내측의 수질은 하굿둑에 의해 해수와 담수간의 혼합이 제한되어 내측의 영양염 및 유기물의 농도가 외측보다 뚜렷하게 높게 나타났다. 특히 겨울철 유량감소로 인해 체류시간이 증가한 시기에는 하굿 둑의 효과가 나타나 하류로 갈수록 클로로필 증가가 뚜렷하였다. 즉, 하굿둑으로 인한 정체효과는 갈수기에 수질악화로 나타 났다. 저서생태계는 하굿둑 완공 이후 내측은 기수역 소실로 인해 재첩 등의 연체동물과 기수 갑각류들이 사라졌으며 종 다양 성이 매우 낮은 환경이 조성되었다. 하굿둑 외측은 유기물 유입에 영향을 받는 소형 오염지시종( Prionospio membranacea, Pseudopolydora kempi, Sinocorophium sinensis)이 높은 밀도로 출현하여 저서환경의 악화를 나타내었으며, 이것은 하굿둑 건설과 건설 이후 명지대교, 신공항 건설 및 공단조성 등과 같은 다양한 공사로 인해 서식환경이 악화되었기 때문으로 판단된다.핵심용어: 낙동강, 수질평가, 저서생태, 하굿둑AbstractThis study was performed to investigate the long-term changes i n water quality and benthic ec ology around the Nakdong River Estuary. The effect of the estuarine Barrage on the ecosystem w as also evaluated. The water quality was interpreted using the field survey (2013 and 2014) and monitoring data (MOE, 1989~201 3) and the macrobenthic-fauna was investigated through analysis of the field survey data (2014) and literatures review (1985~2013). The long-term variation of water quality of Nakdo ng River generally showed increased nutrient concentration with de creased discharge, while abrupt influence of the Barrage construction was not observed. However, the nutrient and organi c matter concentration inside the Barrage distinctly was higher than the concentration outside the Barrage because the mixing o f fresh and seawater was limited by the Barrage. Especially, in the period of low discharge during winter, the Chlorophyll-a co ncentration clearly increased more in the downstream inside the Barrage, showing the Barrage effect. In other words, stagna nt effect caused by Barrage construction had an effect on the w ater quality degradation in dry seasons. As for the benthic ecology inside Barrage after Barrage construction, molluscans and brackish-water crustaceans disappeared. Outside the Barrage, be nthic ecosystem has deteriorated and the small-sized organic indicative species like Prionospio membranacea, Pseudopolydora kempi, Sinocorophium sin ensis became dominant due to several construction such as Myeong-Gi Bridge, Airport construction, in dustrial complex after the Nakdong Barrage construction.Key words: The Nakdong river, Water quality assessment, Benthic community, Barrage

R. C. T. Rainey - One of the best experts on this subject based on the ideXlab platform.

  • Lightweight steel tidal power Barrages with minimal environmental impact: application to the Severn Barrage
    Proceedings of The Royal Society A: Mathematical Physical and Engineering Sciences, 2018
    Co-Authors: R. C. T. Rainey
    Abstract:

    For tidal power Barrages, a breast-shot water wheel, with a hydraulic transmission, has significant advantages over a conventional Kaplan turbine. It is better suited to combined operations with pumping that maintain the tidal range upstream of the Barrage (important in reducing the environmental impact), and is much less harmful to fish. It also does not require tapered entry and exit ducts, making the Barrage much smaller and lighter, so that it can conveniently be built in steel. For the case of the Severn Estuary, UK, it is shown that a Barrage at Porlock would generate an annual average power of 4 GW (i.e. 35 TWh yr −1 ), maintain the existing tidal ranges upstream of it and reduce the tidal ranges downstream of it by only about 10%. The weight of steel required, in relation to the annual average power generated, compares very favourably with a recent offshore wind farm.

  • the optimum position for a tidal power Barrage in the severn estuary
    Journal of Fluid Mechanics, 2009
    Co-Authors: R. C. T. Rainey
    Abstract:

    G. I. Taylor's approximate analytical solution for the tidal flow in the Severn estuary is extended to find the optimum location for a tidal power Barrage, from the power point of view. It appears to be at the lowest point in the estuary, between Ilfracombe and Gower – contrary to earlier computations. The analytical solution shows that Barrages radiate tidal waves out to sea, which highlights the important role of the far-field boundary condition in absorbing them. This appears to have been neglected in numerical models, which may explain the difference from the earlier results.