A vertical dispersion model for solute exchange induced by underflow and periodic hyporheic flow in a stream gravel bed

ABSTRACT The methods used to forecast the movement of spilled oil have not changed significantly since the Argo Merchant spill. Little has been done to improve the deficiencies brought to light during this incident. Some of the deficiencies in the state-of-the-art are examined here, particularly those related to our incomplete knowledge of the physical mechanisms involved in oil spill movement. A basic framework for the development of an improved forecasting system is presented. It is based on the integration of a horizontal transport model, an evaporation model, and a vertical dispersion model.

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Water quality changes in hyporheic flow paths between a large gravel bed river and off-channel alcoves in Oregon, USA

River Research and Applications ◽

10.1002/rra.961 ◽

2006 ◽

Vol 22 (10) ◽

pp. 1111-1124 ◽

Cited By ~ 26

Author(s):

Alexander G. Fernald ◽

Dixon H. Landers ◽

Parker J. Wigington

Keyword(s):

Water Quality ◽

Quality Changes ◽

Flow Paths ◽

Gravel Bed ◽

Hyporheic Flow ◽

Gravel Bed River

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Effect of bar topography on hyporheic flow in gravel-bed rivers

River, Coastal and Estuarine Morphodynamics ◽

10.1201/9781439833896.ch50 ◽

2006 ◽

Author(s):

A Bellin ◽

M Tubino ◽

G Vignoli ◽

A Marzadri

Keyword(s):

Gravel Bed ◽

Hyporheic Flow ◽

Gravel Bed Rivers

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Hyporheic flow as a potential geomorphic agent in the evolution of channel morphology in a gravel-bed river

CATENA ◽

10.1016/j.catena.2007.10.004 ◽

2008 ◽

Vol 73 (3) ◽

pp. 239-248 ◽

Cited By ~ 4

Author(s):

Goichiro Takahashi ◽

Takashi Gomi ◽

Kaichiro Sasa

Keyword(s):

Channel Morphology ◽

Gravel Bed ◽

Hyporheic Flow ◽

Gravel Bed River

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Influence of hyporheic flow and geomorphology on temperature of a large, gravel-bed river, Clackamas River, Oregon, USA

Hydrological Processes ◽

10.1002/hyp.6984 ◽

2008 ◽

Vol 22 (7) ◽

pp. 941-953 ◽

Cited By ~ 74

Author(s):

Barbara K. Burkholder ◽

Gordon E. Grant ◽

Roy Haggerty ◽

Tarang Khangaonkar ◽

Peter J. Wampler

Keyword(s):

Gravel Bed ◽

Hyporheic Flow ◽

Gravel Bed River

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CityFlux perfluorocarbon tracer experiments

Atmospheric Chemistry and Physics ◽

10.5194/acp-10-5991-2010 ◽

2010 ◽

Vol 10 (13) ◽

pp. 5991-5997 ◽

Cited By ~ 7

Author(s):

F. K. Petersson ◽

D. Martin ◽

I. R. White ◽

S. J. Henshaw ◽

G. Nickless ◽

...

Keyword(s):

Dispersion Model ◽

Atmospheric Stability ◽

Ground Level ◽

Street Network ◽

Urban Dispersion ◽

Vertical Dispersion ◽

Urban Topography ◽

Roof Level ◽

The Impact ◽

Tracer Experiments

Abstract. In June 2006, two perfluorocarbon tracer experiments were conducted in central Manchester UK as part of the CityFlux campaign. The main aim was to investigate vertical dispersion in an urban area during convective conditions, but dispersion mechanisms within the street network were also studied. Paired receptors were used in most cases where one receptor was located at ground level and one at roof level. One receptor was located on the roof of Portland Tower which is an 80 m high building in central Manchester. Source receptor distances in the two experiments varied between 120 and 600 m. The results reveal that maximum concentration was sometimes found at roof level rather than at ground level implying the effectiveness of convective forces on dispersion. The degree of vertical dispersion was found to be dependent on source receptor distance as well as on building height in proximity to the release site. Evidence of flow channelling in a street canyon was also found. Both a Gaussian profile and a street network model were applied and the results show that the urban topography may lead to highly effective flow channelling which therefore may be a very important dispersion mechanism should the right meteorological conditions prevail. The experimental results from this campaign have also been compared with a simple urban dispersion model that was developed during the DAPPLE framework and show good agreement with this. The results presented here are some of the first published regarding vertical dispersion. More tracer experiments are needed in order to further characterise vertical concentration profiles and their dependence on, for instance, atmospheric stability. The impact of urban topography on pollutant dispersion is important to focus on in future tracer experiments in order to improve performance of models as well as for our understanding of the relationship between air quality and public health.

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Tracer concentration profiles measured in central London as part of the REPARTEE campaign

Atmospheric Chemistry and Physics ◽

10.5194/acp-11-227-2011 ◽

2011 ◽

Vol 11 (1) ◽

pp. 227-239 ◽

Cited By ~ 6

Author(s):

D. Martin ◽

K. F. Petersson ◽

I. R. White ◽

S. J. Henshaw ◽

G. Nickless ◽

...

Keyword(s):

Urban Areas ◽

Dispersion Model ◽

Vertical Mixing ◽

Mixing Times ◽

Empirical Correlations ◽

Tracer Concentration ◽

Vertical Dispersion ◽

Regent's Park ◽

Lateral Advection ◽

Tracer Experiments

Abstract. There have been relatively few tracer experiments carried out that have looked at vertical plume spread in urban areas. In this paper we present results from two tracer (cyclic perfluorocarbon) experiments carried out in 2006 and 2007 in central London centred on the BT Tower as part of the REPARTEE (Regent's Park and Tower Environmental Experiment) campaign. The height of the tower gives a unique opportunity to study vertical dispersion profiles and transport times in central London. Vertical gradients are contrasted with the relevant Pasquill stability classes. Estimation of lateral advection and vertical mixing times are made and compared with previous measurements. Data are then compared with a simple operational dispersion model and contrasted with data taken in central London as part of the DAPPLE campaign. This correlates dosage with non-dimensionalised distance from source. Such analyses illustrate the feasibility of the use of these empirical correlations over these prescribed distances in central London.

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CityFlux perfluorocarbon tracer experiments

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-10-27-2010 ◽

2010 ◽

Vol 10 (1) ◽

pp. 27-44

Author(s):

F. K. Petersson ◽

D. Martin ◽

I. R. White ◽

S. J. Henshaw ◽

G. Nickless ◽

...

Keyword(s):

Dispersion Model ◽

Atmospheric Stability ◽

Ground Level ◽

Street Network ◽

Urban Dispersion ◽

Vertical Dispersion ◽

Urban Topography ◽

Roof Level ◽

The Impact ◽

Tracer Experiments

Abstract. In June 2006, two perfluorocarbon tracer experiments were conducted in central Manchester UK as part of the CityFlux campaign. The main aim was to investigate vertical dispersion in an urban area during convective conditions, but dispersion mechanisms within the street network were also studied. Paired receptors were used in most cases where one receptor was located at ground level and one at roof level. One receptor was located on the roof of Portland Tower which is an 80 m high building in central Manchester. Source receptor distances in the two experiments varied between 120 and 600 m. The results reveal that maximum concentration was sometimes found at roof level rather than at ground level implying the effectiveness of convective forces on dispersion. The degree of vertical dispersion was found to be dependent on source receptor distance as well as on building height in proximity to the release site. Evidence of flow channelling in a street canyon was also found. Both a Gaussian profile and a street network model were applied and the results show that the urban topography may lead to highly effective flow channelling which therefore may be a very important dispersion mechanism should the right meteorological conditions prevail. The experimental results from this campaign have also been compared with a simple urban dispersion model that was developed during the DAPPLE framework and show good agreement with this. The results presented here are some of the first published regarding vertical dispersion. More tracer experiments are needed in order to further characterise vertical concentration profiles and their dependence on, for instance, atmospheric stability. The impact of urban topography on pollutant dispersion is important to focus on in future tracer experiments in order to improve performance of models as well as for our understanding of the relationship between air quality and public health.

Download Full-text