Normandie Univ., UNIHAVRE, UMR 6294 CNRS, LOMC, 76600 Le Havre, France; Laboratory of Geosciences of Natural Resources, Hydroinformatic section, Faculty of Sciences, Ibn Tofail University, Maamora Campus, BP.133, 14000 Kénitra, Morocco.
Normandie Univ., UNIHAVRE, UMR 6294 CNRS, LOMC, 76600 Le Havre, France.
Sci Total Environ. 2020 Aug 15;730:139107. doi: 10.1016/j.scitotenv.2020.139107. Epub 2020 May 1.
To overcome water scarcity issues in arid and semi-arid regions, Managed Aquifer Recharge (MAR) remains a viable and suitable solution to manage and restore aquifers. However, clogging represents a major issue that can affect the durability and efficiency of MAR structures. The aim of this study was to evaluate the extent of clogging in MAR sites (Berrechid, Morocco). To achieve this objective, two field-based studies were undertaken: the first one consists of implantation of sand-filled columns in the recharge sites to evaluate the surface and subsurface clogging. The second one consists of the implantation of pickets over a 750 m area in each recharge site to measure the extent of deposit thickness on the surface of the wadi bed. Results show that, despite the low rainfall (<1.4 mm/day) and the short period (91 days) of the study, the deposits thickness exceeds 3 cm in a large part of the MAR. The suspended solids concentrations measured in recharge sites ranged from 1.1 to 1.4 g/L. Due to the particles retention, the estimation of the saturated hydraulic conductivity (k) of the sand declines over 90% in the immediate entrance of the columns. The k values measured in situ during the drying period ranged from 10 to 10 m/s. The k values of the cake formed, without cracks, was about 10 m/s. The presence of cracks drives the entire infiltration. However, due to the high plasticity index of the MAR soil, a slight reduction of cracks opening during wetting cycles is observed. In addition, particles deposited in these cracks, would contribute actively to the reduction of infiltration. The results of this study clearly showed the MAR sites vulnerability in semi-arid regions due to physical clogging.
为了解决干旱和半干旱地区的水资源短缺问题，含水层人工补给（Managed Aquifer Recharge，MAR）仍然是一种可行且合适的解决方案，可用于管理和恢复含水层。然而，堵塞是一个主要问题，会影响 MAR 结构的耐久性和效率。本研究旨在评估 MAR 场地（摩洛哥贝雷基德）的堵塞程度。为了实现这一目标，进行了两项基于现场的研究：第一项是在补给场地中植入填充砂的柱状物，以评估地表和地下堵塞情况。第二项是在每个补给场地的 750 米区域内植入标杆，以测量河道床表面沉积物厚度的程度。结果表明，尽管降雨量低（<1.4 毫米/天）且研究时间短（91 天），但在很大一部分 MAR 中，沉积物厚度超过 3 厘米。补给场地中测量的悬浮固体浓度范围为 1.1 至 1.4 克/升。由于颗粒截留，砂柱入口处的饱和水力传导度（k）估计值下降了 90%以上。在干燥期进行的原位测量 k 值范围为 10 至 10 米/秒。无裂缝形成的滤饼的 k 值约为 10 米/秒。裂缝的存在驱动了整个渗透过程。然而，由于 MAR 土壤的高塑性指数，在湿循环期间观察到裂缝开度略有减小。此外，沉积在这些裂缝中的颗粒会积极促进渗透减少。这项研究的结果清楚地表明，由于物理堵塞，半干旱地区的 MAR 场地容易受到影响。
