Sasidharan Salini, Bradford Scott A
Department of Biological & Ecological Engineering, Oregon State University, 116 Gilmore Hall, Corvallis, OR, 97331-3906, USA.
USDA, ARS, Sustainable Agricultural Water Systems (SAWS) Unit, UC Davis, 239 Hopkins Road, Davis, CA, 95616, USA.
Sci Rep. 2025 Jan 13;15(1):1829. doi: 10.1038/s41598-024-84865-4.
This study explores innovative drywell designs for managed aquifer recharge (MAR) in agricultural settings, focusing on smaller diameter and deeper drywells, including the repurposing of dried or abandoned wells. Numerical simulations assessed the impact of drywell diameter (5-120 cm), depth (15-55 m), screen height, and subsurface heterogeneity on infiltration (I) and recharge (R) volumes over a one-year period under constant head conditions. Results indicate that smaller diameter drywells can effectively infiltrate and recharge significant water volumes. A 5 cm diameter drywell exhibited only a 48% decrease in infiltration efficiency compared to a standard 120 cm drywell, while being easier to install and requiring less space. Deeper drywells substantially enhanced both I and R; a 20 cm diameter drywell at 55 m depth infiltrated 1.9 × 10 m and recharged 3.56 × 10 m within a year, with faster arrival times of recharge water. The study also proposes integrating drywells into existing irrigation canal networks. Simulations suggest that installing drywells every 70 m along canals could infiltrate 7.14 × 10 to 1.43 × 10 m of water per kilometer annually, significantly enhancing groundwater recharge in regions where traditional MAR methods are limited. Subsurface heterogeneity was found to increase I and R volumes compared to homogeneous conditions, emphasizing the importance of site-specific assessments. An economic analysis revealed that deeper, small-diameter drywells offer lower levelized costs, down to $0.46 per cubic meter of recharged water, making them economically viable alternatives. However, technical challenges such as clogging, water quality concerns, and regulatory requirements were identified. Pretreatment measures like sedimentation chambers and geotextile membranes are recommended to mitigate clogging, though their costs require further evaluation. Pilot-scale studies are recommended to validate simulation findings, assess technical and regulatory challenges, and refine designs for practical implementation.
本研究探索了农业环境中用于有管理的含水层补给（MAR）的创新型渗水井设计，重点关注较小直径和更深的渗水井，包括对干涸或废弃水井的重新利用。数值模拟评估了渗水井直径（5 - 120厘米）、深度（15 - 55米）、筛管高度和地下非均质性在恒定水头条件下对一年时间内入渗（I）量和补给（R）量的影响。结果表明，较小直径的渗水井能够有效地使大量水入渗并实现补给。一口直径5厘米的渗水井与标准的120厘米渗水井相比，入渗效率仅降低了48%，同时更易于安装且所需空间更小。更深的渗水井显著提高了入渗量和补给量；一口直径20厘米、深度55米的渗水井在一年内入渗了1.9×10立方米的水，并补给了3.56×10立方米的水，补给水流到达时间更快。该研究还提议将渗水井整合到现有的灌溉渠系网络中。模拟表明，沿渠道每隔70米安装渗水井，每年每公里可使7.14×10至1.43×10立方米的水入渗，在传统MAR方法受限的地区显著增强了地下水补给。与均质条件相比，发现地下非均质性增加了入渗量和补给量，强调了进行特定场地评估的重要性。经济分析表明，更深的小直径渗水井提供了更低的平准化成本，低至每立方米补给水量0.46美元，使其成为经济上可行的替代方案。然而，也识别出了诸如堵塞、水质问题和监管要求等技术挑战。建议采用沉淀池和土工膜等预处理措施来减轻堵塞，不过其成本需要进一步评估。建议进行中试规模研究以验证模拟结果，评估技术和监管挑战，并优化设计以便实际应用。
