| 项目编号: | 1437021
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| 项目名称: | Natural Attenuation of Groundwater Contaminant Plumes in Riverbeds: Control of Hyporheic Zone Mixing |
| 作者: | Erich Hester
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| 承担单位: | Virginia Polytechnic Institute and State University
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| 批准年: | 2013
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| 开始日期: | 2014-08-01
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| 结束日期: | 2018-07-31
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| 资助金额: | USD330000
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| 资助来源: | US-NSF
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| 项目类别: | Standard Grant
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| 国家: | US
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| 语种: | 英语
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| 特色学科分类: | Engineering - Chemical, Bioengineering, Environmental, and Transport Systems
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| 英文关键词: | hyporheic zone
; hyporheic natural attenuation
; surface water
; project
; contaminant
; organic contaminant
; groundwater
; specific contaminant
; river
; mixing-dependent reaction
; such control
; upwelling contaminant
; groundwater contaminant plumes
; groundwater contaminant
; groundwater remediation
; groundwater contamination
; 1437021hesternatural attenuation
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| 英文摘要: | 1437021
Hester
Natural Attenuation of Groundwater Contaminant Plumes in Riverbeds: Control by Hyporheic Zone Mixing
Contaminated groundwater eventually exits to surface water including streams, rivers, and estuaries, posing a threat to human and ecological health. In fact, the US EPA found that half of identified hazardous waste sites impact surface water. Excess nutrients also frequently well-up into rivers in agricultural areas. As groundwater contaminants move toward rivers, they eventually cross through the hyporheic zone beneath and adjacent to rivers, where mixing of surface water and groundwater in shallow sediments creates conditions that are often far more reactive than in overlying surface water or deeper groundwater. Contaminants that have degraded little in up-gradient aquifers can degrade up to 100 % once they reach the hyporheic zone (hyporheic natural attenuation). Yet upwelling contaminants often require mixing with reactants from surface water in the hyporheic zone in order to capitalize on this great potential for hyporheic natural attenuation. The results of this project will transform groundwater remediation, risk assessment, and total maximum daily loads to address ecological, human health, and human recreational risks and impairments due to groundwater contamination intersecting surface water. Knowing how hyporheic natural attenuation potential varies with hydrologic and geomorphic conditions will allow calculating the amount of hyporheic natural attenuation expected at specific sites. The proposed project will also lead to subsequent projects addressing specific contaminants and engineering approaches to enhance hyporheic natural attenuation, such as carbon amendment by riparian reforestation. These lab experiments will serve as excellent tools for students in the PI's surface water-groundwater class to visualize hyporheic zone processes in ways that are otherwise not possible. The PI will work with the School of Engineering's Center for the Enhancement of Engineering Diversity to recruit under-represented undergraduates to participate in project research.
Controls on such mixing have received almost no attention, yet recent work shows that such mixing is highly sensitive to hydrologic conditions. To tap the potential for hyporheic natural attenuation, it is necessary to better understand such controls on hyporheic mixing, and better distinguish mixing-dependent reactions from related processes such as dilution. This will allow prediction of how hyporheic natural attenuation varies among rivers of differing hydrologic, climatic, and biogeochemical conditions; among different types of contaminants; across time scales such as storms and seasons; and in response to engineered enhancements. This project will be the first to examine how the behavior of upwelling contaminants is affected by realistically complex hydrologic flow paths in the hyporheic zone. Both the tracer and biogeochemical portions of this study are therefore fundamentally novel. For example, this project will produce the first measurements of local dispersivities and first estimates of microbial growth parameters for riverine sediment subject to realistic hyporheic zone flow conditions. Such parameters are required for a wide range of biogeochemical reaction modeling of hyporheic zone processes. This project will also be groundbreaking methodologically, including the first laboratory simulation of upwelling of tracer and mixing with surface water advecting through the hyporheic zone. By focusing on broadly relevant processes like transport and transformation of tracers, oxygen, and carbon, this project will shed light on transformations of a wide range of pollutants in the hyporheic zone, including metals, organic contaminants that act as electron acceptors (e.g., chlorinated solvents), and organic contaminants that act as electron donors (e.g., petroleum hydrocarbons). This work will support future studies that evaluate other electron acceptors (e.g., nitrate, iron), specific contaminants, and entrained particular carbon, as well as extension of these experiments to larger lab experiments (flowing flume) and field sites. |
| 资源类型: | 项目
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/96260
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| Appears in Collections: | 影响、适应和脆弱性
气候减缓与适应
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| Recommended Citation: | |
Erich Hester. Natural Attenuation of Groundwater Contaminant Plumes in Riverbeds: Control of Hyporheic Zone Mixing. 2013-01-01.
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