Injection into the shallow aquifer-aquitard system beneath Mexico City for counteracting pore pressure declines due to deeper groundwater withdrawals: Analysis of one injection well

Abstract

Aquifers are being severely overexploited in several sites around the world as urban populations continue to grow. Excessive groundwater subtraction of aquifers has also accelerated the consolidation of the overlying aquitards dramatically, creating severe land subsidence and many other related issues. Mexico City, with its population of 20 million inhabitants and depleted main aquifer, is a prime site for experimental approaches for redress. In this paper, a purpose-specific strategy for the land subsidence mitigation of Mexico City is suggested. The strategy consists of rising depleted pore pressure in the shallow aquifer beneath Mexico City to induce a diffusion process through the upper and lower aquitards that generate increments of pore pressure in the system to counteract current pore pressure declines associated to groundwater withdrawals of the main aquifer unit. The strategy is analyzed on the basis of analytical solutions and typical hydraulic parameters for the shallow aquifer-aquitard system beneath Mexico City subject to one injection well. The results provide for the first time the coupled hydraulic responses of the shallow aquifer-aquitard system beneath Mexico City subject to water injection and provides useful data for field injection tests to be conducted in the near future.