Reply to comment by D. R. Lester et al. on “Plume spreading in groundwater by stretching and folding”: COMMENTARY
Reply to comment by D. R. Lester et al. on “Plume spreading in groundwater by stretching and folding”: COMMENTARY
复制标题
回复 D. R. Lester 等人的评论。
DOI：
10.1002/wrcr.20081
复制
发表时间：
2013
影响因子：
5.4
通讯作者：
Neupauer, Roseanna M.
中科院分区：
文献类型：
--
作者：
Mays, David C.;Neupauer, Roseanna M.
[1]我们感谢莱斯特等人。[2013]他们对我们最近关于混沌平流羽流扩散的工作发表了发人深省的评论[Mays和Neupauer，2012]。我们完全同意他们的意见，混沌平流提供了一个框架，加深理解多孔介质中的流体混合和运输过程，并通过工程注入和提取拉伸和折叠显示改善地下水修复的希望。在这篇评论中，我们解决了他们的评论所提出的两个问题。[2]第一个问题如下。放松以确定性角度再注入的假设是否消除了周期性注入和提取方案的混乱，例如脉冲偶极子[例如，Jones和Aref，1988]和周期性重定向偶极子[例如，Lester等人，2009年]？在这里，我们同意的评论，答案是否定的：放宽假设的再注入在一个确定性的角度并没有从系统中删除混沌，而是产生随机混沌，而不是确定性的混沌在该地区的增强混合。作为一个技术点，我们在Mays和Neupauer [2012]中提出的确认确定性混沌存在的分析（找到周期点，将其分类为椭圆或双曲，绘制稳定和不稳定流形，然后识别异宿点）将不适用于随机混沌的情况，其中周期点不存在。但是我们同意，采用关于再注入性质的现实假设，特别是关于再注入角度，不会改变脉冲偶极子和相关方法的潜在动力学的混沌性质。这一点已在评论和其中引用的以前的作品中明确指出。[3]第二个问题如下。需要回注的注入和抽取方案是否切实可行的地下水干预和工程工具？在这里，我们不同意的评论，因为在我们看来，回注提出了一些实际和理论的地下水修复方面的问题。首先谈谈实际问题，回注需要从监管的角度加以关注，至少在回注流体有可能危及饮用水的情况下，因为将受污染的水注入含水层是出于环境保护的目的而加以监管的。例如，在美国，《安全饮用水法》建立了州管理的地下注入控制计划，该计划管理污染物注入含水层[42 USC 300f-300j-9，2002，} 1421 et seq]，《资源保护和回收法》（RCRA）禁止通过地下注入方式将危险废物注入0.4公里内（1/4英里）的地下饮用水源或在这样的地层之上。RCRA规定了地下水修复期间回注的例外情况，但仅当修复是RCRA [42 USC 6901 - 6992k，2002，} 3020]或综合环境响应、赔偿和责任法案[42 USC 9601 - 9675，2002，} 104或} 106]下响应行动的一部分时，并且仅当在回注之前将处理溶液添加到地下水中时。在原位修复的情况下，添加处理溶液的要求提出了一个水力问题，因为处理溶液将触发原位修复反应，这可能导致化学或生物副产物堵塞注入威尔斯附近的含水层[Bagtzoglou和Oates，
[1] We thank Lester et al.[2013] for their thoughtprovoking comment on our recent work on plume spreading by chaotic advection [Mays and Neupauer, 2012]. We agree completely with their opinion that chaotic advection provides a framework for deepened understanding of fluid mixing and transport processes in porous media, and that stretching and folding via engineered injection and extraction shows promise for improved groundwater remediation. In this commentary, we address two questions posed by their comment.[2] The first question is the following. Does relaxing the assumption of reinjection at a deterministic angle remove chaos from periodic injection and extraction schemes, such as the pulsed dipole [eg, Jones and Aref, 1988] and the periodically reoriented dipole [eg, Lester et al., 2009]? Here we agree with the comment that the answer is no: relaxing the assumption of reinjection at a deterministic angle does not remove chaos from the system but instead produces stochastic chaos rather than deterministic chaos in the region of enhanced mixing. As a technical point, the analysis we presented in Mays and Neupauer [2012] to confirm the presence of deterministic chaos (finding periodic points, classifying them as elliptic or hyperbolic, plotting stable and unstable manifolds, and then identifying heteroclinic points) would not apply to the case of stochastic chaos, in which periodic points are absent. But we agree that adopting realistic assumptions about the nature of reinjection, specifically with regard to reinjection angle, would not change the chaotic nature of the underlying dynamics of the pulsed dipole and related approaches. This point has been made clearly by the comment and previous works cited therein.[3] The second question is the following. Are injection and extraction schemes requiring reinjection practical and feasible groundwater intervention and engineering tools? Here we disagree with the comment because in our opinion reinjection presents a number of practical and theoretical concerns in the context of groundwater remediation. Turning first to the practical concerns, reinjection demands attention from a regulatory perspective, at least in cases where the reinjection fluid has the potential to endanger drinking water, because injection of the contaminated water into aquifers is regulated for the purposes of environmental protection. In the United States, for example, the Safe Drinking Water Act establishes the state-administered underground injection control programs that regulate injection of contaminants into aquifers [42 USC 300f–300j–9, 2002,} 1421 et seq], and the Resource Conservation and Recovery Act (RCRA) prohibits the injection of hazardous waste by underground injection into or within 0.4 km (1/4 mile) of an underground source of drinking water or above such a formation. The RCRA provides an exception for reinjection during groundwater remediation, but only when the remediation is part of a response action under the RCRA [42 USC 6901–6992k, 2002,} 3020] or the Comprehensive Environmental Response, Compensation, and Liability Act [42 USC 9601–9675, 2002,} 104 or} 106], and only when a treatment solution is added to the groundwater prior to reinjection. In the context of in situ remediation, the requirement to add treatment solution presents a hydraulic concern, because the treatment solution will trigger the in situ remediation reactions that may result in chemical or biological byproducts that clog the aquifer in the vicinity of the injection wells [Bagtzoglou and Oates,