A New Method for Identification of Preferential Flow Paths at Sites of Groundwater Contamination

地下水污染场地优先流路识别新方法

• 批准号: 9903103
• 负责人: James Butler
• 金额: $ 22.65万
• 依托单位: University of Kansas Center for Research Inc
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-08-15 至 2004-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9903103&HistoricalAwards=false
• 关键词: New; Method; Identification; Preferential; Flow

9903103ButlerThe spatial distribution of hydraulic conductivity is a significant control on the movement of contaminants in the subsurface. A number of theories have been developed to quantify the influence of spatial variations of hydraulic conductivity on contaminant transport by using stochastic processes or fractal representations to model the conductivity variations. It is becoming increasingly apparent; however, that the modeling of the conductivity variations at a site be inadequate may have significant limitations in units composed of a complex mixture of lithologies. Clearly site-specific hydraulic conductivity distribution at a larger scale need to be quantified to reliably predicts contaminant movement in such systems. In particular, knowledge on laterally contiguous zones of high hydraulic conductivity, which serve as preferential flow paths, is often critical. The field identification of such zones, however, has proven difficult. Conventional field techniques provide information of a highly averaged nature or restricted to the vicinity of the test well. This research would develop a new field method for the estimation of spatial in hydraulic conductivity between wells. Although developed for the general task of estimation of hydraulic conductivity variations in saturated formations and this effective for the identify of preferential flow paths. This methodology involves three primary elements: 1) a recently proposed method for hydraulic tomography, 2) low-cost pressure sensors for drawdown measurements in the tubing used in multilevel sampling wells, and 3) geophysical survey data for stratigraphic control. Hydraulic tomography has the potential to produce images of the hydraulic conductivity distribution between wells at most detail than previously possible. Detailed information about vertical variations in pumping-induced head changes would be at obtained from the low-cost pressure sensors. Nonuniqueness would be addressed by using cross-hole ground-penetrating radar surveys to constrain the inversion process. The primary purpose of the research is a thorough theoretical and field assessment of this promising new methodology. The incorporation of such features into a site model should dramatically improve the quality of model predictions, thus leading to more reliable risk assessments and a more efficient allocation of resources for site characterization and remediation activities. The descriptions of hydraulic conductivity variations in the subsurface would have a level of detail that has not previously been possible. In addition, the information should help better relate hydraulic conductivity variations to their geologic origins and thus facilitate incorporation of geologic information into hydrogeologic investigations.9903103ButlerThe spatial distribution of hydraulic conductivity is a significant control on the movement of contaminants in the subsurface. A number of theories have been developed to quantify the influence of spatial variations of hydraulic conductivity on contaminant transport by using stochastic processes or fractal representations to model the conductivity variations. It is becoming increasingly apparent; however, that the modeling of the conductivity variations at a site be inadequate may have significant limitations in units composed of a complex mixture of lithologies. Clearly site-specific hydraulic conductivity distribution at a larger scale need to be quantified to reliably predicts contaminant movement in such systems. In particular, knowledge on laterally contiguous zones of high hydraulic conductivity, which serve as preferential flow paths, is often critical. The field identification of such zones, however, has proven difficult. Conventional field techniques provide information of a highly averaged nature or restricted to the vicinity of the test well. This research would develop a new field method for the estimation of spatial in hydraulic conductivity between wells. Although developed for the general task of estimation of hydraulic conductivity variations in saturated formations and this effective for the identify of preferential flow paths. This methodology involves three primary elements: 1) a recently proposed method for hydraulic tomography, 2) low-cost pressure sensors for drawdown measurements in the tubing used in multilevel sampling wells, and 3) geophysical survey data for stratigraphic control. Hydraulic tomography has the potential to produce images of the hydraulic conductivity distribution between wells at most detail than previously possible. Detailed information about vertical variations in pumping-induced head changes would be at obtained from the low-cost pressure sensors. Nonuniqueness would be addressed by using cross-hole ground-penetrating radar surveys to constrain the inversion process. The primary purpose of the research is a thorough theoretical and field assessment of this promising new methodology. The incorporation of such features into a site model should dramatically improve the quality of model predictions, thus leading to more reliable risk assessments and a more efficient allocation of resources for site characterization and remediation activities. The descriptions of hydraulic conductivity variations in the subsurface would have a level of detail that has not previously been possible. In addition, the information should help better relate hydraulic conductivity variations to their geologic origins and thus facilitate incorporation of geologic information into hydrogeologic investigations.

9903103Butler渗透系数的空间分布是地下污染物运动的重要控制因素。 许多理论已经发展到量化的水力传导系数的空间变化对污染物传输的影响，通过使用随机过程或分形表示来模拟传导系数的变化。 这一点变得越来越明显;然而，在由复杂的岩性混合物组成的单元中，不充分的现场电导率变化建模可能具有显著的局限性。 显然，在更大的尺度上，需要量化特定场地的水力传导率分布，以可靠地预测此类系统中的污染物运动。 特别是，关于作为优先流动路径的高水力传导率横向邻接区的知识往往至关重要。然而，事实证明，很难在实地确定这些区域。 常规的现场技术提供高度平均性质的信息或仅限于测试井附近的信息。该研究为威尔斯井间水力传导系数的空间估算提供了一种新的现场方法。 虽然开发的一般任务，估计在饱和地层中的水力传导性的变化，这有效的识别优先流路。 该方法包括三个主要要素：1）最近提出的水力层析成像方法，2）用于多级采样威尔斯中使用的油管中压降测量的低成本压力传感器，以及3）用于地层控制的地球物理勘测数据。 水力层析成像有可能产生比以前可能的更详细的威尔斯井之间的水力传导率分布的图像。 关于泵送引起的水头变化的垂直变化的详细信息将从低成本压力传感器获得。非唯一性将通过使用跨孔探地雷达勘测来解决，以约束反演过程。 研究的主要目的是对这种有前途的新方法进行全面的理论和实地评估。 将这些特征纳入场地模型应能大大提高模型预测的质量，从而使风险评估更加可靠，并能更有效地分配资源，用于场地特征描述和补救活动。 地下水渗透率变化的描述将具有以前不可能的详细程度。 此外，这些信息应有助于更好地将水力传导性变化与其地质起源联系起来，从而促进将地质信息纳入水文地质调查。9903103巴特勒水力传导性的空间分布是地下污染物运动的重要控制因素。 许多理论已经发展到量化的水力传导系数的空间变化对污染物传输的影响，通过使用随机过程或分形表示来模拟传导系数的变化。 这一点变得越来越明显;然而，在由复杂的岩性混合物组成的单元中，不充分的现场电导率变化建模可能具有显著的局限性。 显然，在更大的尺度上，需要量化特定场地的水力传导率分布，以可靠地预测此类系统中的污染物运动。 特别是，关于作为优先流动路径的高水力传导率横向邻接区的知识往往至关重要。然而，事实证明，很难在实地确定这些区域。 常规的现场技术提供高度平均性质的信息或仅限于测试井附近的信息。该研究为威尔斯井间水力传导系数的空间估算提供了一种新的现场方法。 虽然开发的一般任务，估计在饱和地层中的水力传导性的变化，这有效的识别优先流路。 该方法包括三个主要要素：1）最近提出的水力层析成像方法，2）用于多级采样威尔斯中使用的油管中压降测量的低成本压力传感器，以及3）用于地层控制的地球物理勘测数据。 水力层析成像有可能产生比以前可能的更详细的威尔斯井之间的水力传导率分布的图像。 关于泵送引起的水头变化的垂直变化的详细信息将从低成本压力传感器获得。非唯一性将通过使用跨孔探地雷达勘测来解决，以约束反演过程。 研究的主要目的是对这种有前途的新方法进行全面的理论和实地评估。 将这些特征纳入场地模型应能大大提高模型预测的质量，从而使风险评估更加可靠，并能更有效地分配资源，用于场地特征描述和补救活动。 地下水渗透率变化的描述将具有以前不可能的详细程度。 此外，这些信息应有助于更好地将导水率变化与其地质来源联系起来，从而促进将地质信息纳入水文地质调查。