Frind E O, Muhammad D S, Molson J W
Department of Earth Sciences, University of Waterloo, Ontario.
Ground Water. 2002 Nov-Dec;40(6):586-98. doi: 10.1111/j.1745-6584.2002.tb02545.x.
The delineation of well capture zones is a basic component of ground water protection. The conventional methodology for capture zone delineation is backward advective particle tracking, often applied under the assumption of a two-dimensional aquifer. The suitability of the conventional approach for complex heterogeneous multi-aquifer systems was investigated, using the Waterloo Moraine aquifer system as an example. It was found that the conventional approach produces irregular particle tracks that require judgment to interpret in a meaningful way, and it can raise questions that may affect the credibility of the capture zone delineation. As an alternative, the potentially powerful but little-used backward-in-time advective-dispersive transport approach was investigated. A key advantage of this approach is its capability to represent local heterogeneities through the dispersion term. The dispersion process has a natural smoothing effect that results in unambiguous capture zones without the need for interpretation, thus enhancing credibility. The question of capture zone validation is also addressed. The meaning of a three-dimensional capture zone is considered, and it is shown that a fully three-dimensional representation of the system is crucial for valid results. The distinction between the maximum extent capture zone and the surface capture zone is also explained. In the case of complex heterogeneous systems, advective particle tracking can be used as an initial screening tool, whereas the more realistic backward-transport modeling approach can be used for final capture-zone delineation.
确定良好的捕获区域是地下水保护的一个基本组成部分。传统的捕获区域划定方法是反向平流粒子追踪，通常在二维含水层的假设下应用。以滑铁卢冰碛含水层系统为例，研究了传统方法对复杂非均质多层含水层系统的适用性。结果发现，传统方法产生的粒子轨迹不规则，需要进行判断才能以有意义的方式进行解释，并且可能会引发一些问题，这些问题可能会影响捕获区域划定的可信度。作为一种替代方法，研究了潜在强大但很少使用的时间反向平流-弥散输运方法。这种方法的一个关键优势是它能够通过弥散项来表示局部非均质性。弥散过程具有自然的平滑效果，无需解释就能得到明确的捕获区域，从而提高了可信度。还讨论了捕获区域验证的问题。考虑了三维捕获区域的含义，结果表明系统的全三维表示对于获得有效的结果至关重要。还解释了最大范围捕获区域和地表捕获区域之间的区别。在复杂非均质系统的情况下，平流粒子追踪可以用作初始筛选工具，而更符合实际的反向输运建模方法可用于最终的捕获区域划定。
