Institute of Groundwater Management, Technische Universität Dresden, Bergstraße 66, 01069, Dresden, Germany.
Section of Hydrogeology and Hydrochemistry, Technische Universität Bergakademie Freiberg, Freiberg, Germany.
Ground Water. 2021 Nov;59(6):819-828. doi: 10.1111/gwat.13104. Epub 2021 May 5.
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.
通过小直径井（内径小于 7.5 厘米（3 英寸）且无砾石填充的井）实现重力驱动的浅层地下水补给，已被证明是一种具有成本效益和灵活性的含水层管理补给（MAR）工具，因为它在最小的施工工作量下提供了相对较高的补给率。小直径井的开放过滤面积明显小于带砾石填充的较大直径井，这使得低质量水通过这些井渗透更有可能发生堵塞。为了研究它们对生物和物理堵塞的敏感性，通过渗透贫营养但浑浊的水或富营养但清澈的水，评估了 24 个具有不同井设置的物理模型。实验表明，较小的直径和缺乏砾石填充会增加井对这两种堵塞的敏感性。然而，与带砾石填充的大直径井相比，这种影响在物理堵塞方面比生物堵塞方面更为明显。我们的结论是，与带砾石填充的大直径井相比，小直径井在渗透高浑浊度水方面存在严重的劣势。然而，当涉及到渗透清澈但富含营养的水（例如处理后的废水）时，这种劣势要小得多。根据 MAR 项目的经济和地质情况，小直径井的建设成本显著降低，这可能会超过其劣势。
