Assessment of clogging of managed aquifer recharge in a semi-arid region

Mohammed Zaidi; Nasre-Dine Ahfir; Abdellah Alem; Bouabid El Mansouri; Huaqing Wang; Said Taibi; Benoît Duchemin; Abdesselam Merzouk

doi:10.1016/j.scitotenv.2020.139107

Assessment of clogging of managed aquifer recharge in a semi-arid region

Sci Total Environ. 2020 Aug 15:730:139107. doi: 10.1016/j.scitotenv.2020.139107. Epub 2020 May 1.

Authors

Mohammed Zaidi¹, Nasre-Dine Ahfir², Abdellah Alem³, Bouabid El Mansouri⁴, Huaqing Wang³, Said Taibi³, Benoît Duchemin³, Abdesselam Merzouk⁴

Affiliations

¹ 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.
² Normandie Univ., UNIHAVRE, UMR 6294 CNRS, LOMC, 76600 Le Havre, France. Electronic address: ahfirn@univ-lehavre.fr.
³ Normandie Univ., UNIHAVRE, UMR 6294 CNRS, LOMC, 76600 Le Havre, France.
⁴ Laboratory of Geosciences of Natural Resources, Hydroinformatic section, Faculty of Sciences, Ibn Tofail University, Maamora Campus, BP.133, 14000 Kénitra, Morocco.

PMID: 32402970
DOI: 10.1016/j.scitotenv.2020.139107

Abstract

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 m² 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^-5 to 10^-6 m/s. The k values of the cake formed, without cracks, was about 10^-8 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.

Keywords: Clogging; Hydraulic conductivity; Managed aquifer recharge; Particles transfer; Semi-arid region; Soil cracks.