Global S&T Development Trend Analysis Platform of Resources and Environment
DOI | 10.1029/2017WR021992 |
Turbulence Links Momentum and Solute Exchange in Coarse-Grained Streambeds | |
Roche, K. R.1,2; Blois, G.3; Best, J. L.4,5,6; Christensen, K. T.2,3,7; Aubeneau, A. F.8; Packman, A. I.1 | |
2018-05-01 | |
发表期刊 | WATER RESOURCES RESEARCH |
ISSN | 0043-1397 |
EISSN | 1944-7973 |
出版年 | 2018 |
卷号 | 54期号:5页码:3225-3242 |
文章类型 | Article |
语种 | 英语 |
国家 | USA; Japan |
英文摘要 | The exchange of solutes between surface and pore waters is an important control over stream ecology and biogeochemistry. Free-stream turbulence is known to enhance transport across the sediment-water interface (SWI), but the link between turbulent momentum and solute transport within the hyporheic zone remains undetermined due to a lack of in situ observations. Here, we relate turbulent momentum and solute transport using measurements within a streambed with 0.04 m diameter sediment. Pore water velocities were measured using endoscopic particle image velocimetry and used to generate depth profiles of turbulence statistics. Solute transport was observed directly within the hyporheic zone using an array of microsensors. Solute injection experiments were used to assess turbulent fluxes across the SWI and patterns of hyporheic mixing. Depth profiles of fluctuations in solute concentration were compared with profiles of turbulence statistics, and profiles of mean solute concentration were compared to an effective dispersion model. Fluorescent visualization experiments at a Reynolds number of Re >= 27,000 revealed the presence of large-scale motions that ejected tracer from the pore waters, and that these events were not present at Re = 13,000. Turbulent shear stresses and high-frequency concentration fluctuations decayed greatly within 1-2 grain diameters below the SWI. However, low-frequency concentration fluctuations penetrated to greater depths than high-frequency fluctuations. Comparison with a constant-coefficient dispersion model showed that hyporheic mixing was enhanced in regions where turbulent stresses were observed. Together, these results show that the penetration of turbulence into the bed directly controls both interfacial exchange and mixing within a transition layer below the SWI. Plain Language Summary Streams and rivers continuously exchange water with their underlying sediments in a region called the hyporheic zone. This zone is a hotspot of transformation for many societally relevant chemicals, including carbon, nutrients, and contaminants. Accurate predictions for how much transformation occurs in the hyporheic zone requires an improved understanding of how reactive chemicals are transported into, and within, this region of a riverbed. Although fluid turbulence can be the dominant process controlling surface-subsurface exchange in gravel-bed streams, its influence is poorly understood due to the difficulty of measuring turbulent fluid velocities and concentrations within the streambed. In this experimental study, we show that turbulence strongly couples surface waters with hyporheic waters in a thin layer where the water column and stream sediments meet. As a result, fluid transport and mixing are enhanced several centimeters into the hyporheic zone of gravel-bed streams. These findings support recent theoretical arguments that surface and subsurface waters are not independent and must instead be treated as a single unit to accurately model solute, particulate and pollutant transport in streams and rivers. |
领域 | 资源环境 |
收录类别 | SCI-E |
WOS记录号 | WOS:000442351300001 |
WOS关键词 | HYPORHEIC EXCHANGE ; BED FORMS ; SEDIMENT TRANSPORT ; NONSORBING SOLUTES ; TRANSIENT STORAGE ; CHANNEL FLOW ; PERMEABILITY ; SURFACE ; MODEL ; WATER |
WOS类目 | Environmental Sciences ; Limnology ; Water Resources |
WOS研究方向 | Environmental Sciences & Ecology ; Marine & Freshwater Biology ; Water Resources |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/20437 |
专题 | 资源环境科学 |
作者单位 | 1.Northwestern Univ, Dept Civil & Environm Engn, Evanston, IL 60208 USA; 2.Univ Notre Dame, Dept Civil & Environm Engn & Earth Sci, Notre Dame, IN 46556 USA; 3.Univ Notre Dame, Dept Aerosp & Mech Engn, Notre Dame, IN 46556 USA; 4.Univ Illinois, Dept Geol Geog & GIS, Urbana, IL USA; 5.Univ Illinois, Dept Mech Sci & Engn, Urbana, IL USA; 6.Univ Illinois, Ven Chow Hydrosyst Lab, Urbana, IL USA; 7.Kyushu Univ, Int Inst Carbon Neutral Energy Res I2CNER, Fukuoka, Fukuoka, Japan; 8.Purdue Univ, Lyles Sch Civil Engn, W Lafayette, IN 47907 USA |
推荐引用方式 GB/T 7714 | Roche, K. R.,Blois, G.,Best, J. L.,et al. Turbulence Links Momentum and Solute Exchange in Coarse-Grained Streambeds[J]. WATER RESOURCES RESEARCH,2018,54(5):3225-3242. |
APA | Roche, K. R.,Blois, G.,Best, J. L.,Christensen, K. T.,Aubeneau, A. F.,&Packman, A. I..(2018).Turbulence Links Momentum and Solute Exchange in Coarse-Grained Streambeds.WATER RESOURCES RESEARCH,54(5),3225-3242. |
MLA | Roche, K. R.,et al."Turbulence Links Momentum and Solute Exchange in Coarse-Grained Streambeds".WATER RESOURCES RESEARCH 54.5(2018):3225-3242. |
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