Gravity-driven infiltration into the shallow subsurface via small-diameter wells (SDWs), i.e., wells with an inner diameter smaller than 7.5 cm (3 inches) and no gravel pack) has proven to be a cost-efficient and flexible tool for managed aquifer recharge (MAR), as it provides relatively high recharge rates with minimal construction effort. SDWs have a significantly smaller open filter area than larger diameter wells with gravel pack, making the infiltration of low-quality waters through these wells more at risk clogging. To investigate their susceptibility for biological and physical clogging, 24 physical models with different well setups were evaluated by infiltrating either nutrient-poor but turbid water or nutrient-rich but clear water. The experiments showed that smaller diameters and the lack of a gravel pack increase the well's susceptibility to both kinds of clogging. However, this effect was observed to be much more pronounced for physical than for biological clogging. Our conclusion is that SDWs show severe disadvantages with respect to the infiltration of highly turbid waters in comparison to large diameter wells with a gravel pack. Nevertheless, this disadvantage is much less severe when it comes to the infiltration of clear but nutrient-rich waters (e.g., treated wastewater). Depending on the economic and geological circumstances of a MAR-project, this disadvantage could be outweighed by the significantly lower construction costs of SDWs.

中文翻译：

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渗透井中的生物和物理堵塞：井径和砾石充填的影响

通过小直径井 (SDW)，即内径小于 7.5 厘米（3 英寸）且无砾石充填的井），重力驱动渗透到浅层地下已被证明是一种经济高效且灵活的管理工具。含水层补给（MAR），因为它以最少的建设工作提供相对较高的补给率​​。与具有砾石充填的大直径井相比，SDW 的开放式过滤面积要小得多，这使得通过这些井渗入的低质量水更有可能发生堵塞。为了研究它们对生物和物理堵塞的敏感性，通过渗透营养贫乏但浑浊的水或营养丰富但清澈的水来评估具有不同井设置的 24 个物理模型。实验表明，较小的直径和缺乏砾石充填会增加井的 s 对两种堵塞的敏感性。然而，观察到这种效果对于物理堵塞比生物堵塞要明显得多。我们的结论是，与具有砾石充填的大直径井相比，SDW 在渗透高度浑浊的水方面表现出严重的劣势。然而，当涉及到清澈但营养丰富的水（例如，处理过的废水）的渗透时，这种缺点要小得多。根据 MA​​R 项目的经济和地质情况，这种劣势可能会被 SDW 显着降低的建设成本所抵消。我们的结论是，与具有砾石充填的大直径井相比，SDW 在渗透高度浑浊的水方面表现出严重的劣势。然而，当涉及到清澈但营养丰富的水（例如，处理过的废水）的渗透时，这种缺点要小得多。根据 MA​​R 项目的经济和地质情况，这种劣势可能会被 SDW 显着降低的建设成本所抵消。我们的结论是，与具有砾石充填的大直径井相比，SDW 在渗透高度浑浊的水方面表现出严重的劣势。然而，当涉及到清澈但营养丰富的水（例如，处理过的废水）的渗透时，这种缺点要小得多。根据 MA​​R 项目的经济和地质情况，这种劣势可能会被 SDW 显着降低的建设成本所抵消。