Sand tank and field scale investigation of the impact of bioengineering and soil siphoning in controlling shallow water table levels in urban areas

The shallow water table (SWT) in urban areas of cities located in arid areas emerges as a challenge threatening the existing infrastructure. It is essential to explore practical solutions to mitigate SWT rise in unconfined aquifers, where waterlogging and drainage/dewatering dynamics have not yet been adequately studied. This study investigates the feasibility of using bioengineering (planting of actively evapotranspiring Reeds) and smart heterogenization of the pore space (soil siphoning) aimed at controlling SWT levels. The performance of both approaches was evaluated using both controlled sand tank and larger-scale concrete-basin experiments to assess their practical applicability. Water loss from Reed-planted tanks was 187.5–237.3% greater than evaporation from bare-soil controls, while soil siphoning enhances evaporation by 36.8%–51.2%, depending on seasonal climatic conditions. These findings provide experimental evidence that Reeds and soil siphoning can increase water loss and reduce water table levels under the tested experimental conditions. The results indicate that these approaches warrant further investigation as low-energy options for SWT management in arid urban environments. However, their effectiveness under field conditions will depend on site-specific soil, hydrological, climatic, and operational conditions.