The relation between urban green spaces, shallow aquifers and water availability for cities: A case study in Mexico City

Urbanization reduces water infiltration areas in cities, decreasing aquifer recharge and affecting water availability and flood control. Urban green spaces (UGS) mitigate these effects by increasing rainwater infiltration. This is particularly vital in cities with water scarcity and shallow aquifers, like Mexico City, as aquifers are more susceptible to surface impacts. However, there is still no information about the direct relationship between shallow aquifers and UGS. This research focused on understanding the relationship between an UGS, the Reserva Ecológica del Pedregal de San Ángel (REPSA), and the shallow aquifer beneath it. The infiltration rate was determined using the double-ring infiltrometer method, and the results indicated that 84% of the sites exceeded the value of 1m day-1. Consequently, based on the maximum recorded rainfall event (0.69 m day⁻¹) in this location’s recent history, the results suggest that REPSA can infiltrate all precipitation within its boundaries, facilitating water entrance into the shallow aquifer. This phenomenon enhances water availability and contributes to flood mitigation in the region. The conservation policies and biophysical characteristics of REPSA allow for a high percentage of infiltration. Consequently, the relationship between this UGS and the shallow aquifer is an essential factor in the water cycle in the south of Mexico City. The results indicate that urban green spaces contribute significantly to the sustainability of cities by expanding infiltration areas. Urban planning should incorporate knowledge of soil, subsoil, and evapotranspiration to enhance water resilience. Urban green spaces should be recognized not only for their surface-level benefits, including heat reduction, the creation of biodiversity islands, and improvements to mental health, but also for their critical role in groundwater recharge.