The Aquifer as a Water Resource

The Mexico Basin aquifer supplies about 70% of the water used in the Mexico City (Chavez Guillen, 2007). This aquifer supports the need for domestic, industrial, ang agricultural uses, primarily in the urban areas where water infrastructure is limited (Rios Sanchez et al., 2024). However, this resource is under stress due to decades of extensive pumping, which has led to a significant decline in groundwater levels by more than 10 meters (Carrera Hernandez et al., 2007). The decline in groundwater levels has resulted in land subsidence, with rates of 40 centimeters per year in the central Mexico City (Rivera et al., 1991). This land subsidence damages building, lowers aquifer storage capacity, and increases the risk of flooding (Rivera et al., 1991).

The National Water Commission (CONAGUA) manage water allocation and regulations at federal levels, while agencies such as Sistema de Aguas de la Ciudad de Mexico (SACMEX) regulate local water distribution, infrastructure maintenance, and monitoring the metropolitan area (Cruz Ayala et al., 2020). To address the declining water levels MAR projects have been implemented, demand reduction, and pollution control (Palma Nava et al., 2022). Despite these efforts, the aquifer remains threatened by population growth, climate change, and the limited availability of surface water sources for recharge and supply (Palma Nava et al., 2022). 

Groundwater Contamination

Groundwater contamination in the Mexico City aquifer comes from point and non-point source. Agricultural runoff releases nitrates and pesticides onto the surface, which are then transported downward through the unsaturated zone into the aquifer, primary in urban areas where farming persist (Rios Sanchez et al., 2024). Industrial activities introduce heavy metals and organic pollutants, while in urban areas, leaky sewer systems release contaminants and landfills pathogens to the shallow aquifer (Mazari Hiriart et al., 1193). In some areas such as Tlahuac and Iztapaluca, groundwater is not suitable for drinking due to the elevated levels of arsenic, lead, and organic matter (Rios Sanches et al., 2024).

The geological complexity of the aquifer and permeability differences complicates contaminant transportation and remediation because pollutants get trapped in low permeability zones or transported to less resistant pathways (Rios Sanches et al., 2024).

Groundwater Modeling 

Simple flow model of the Mexico City Basin using HydrogeoPT program in Excel with the hydraulic conductivity (K), thickness of 50 meters, and distance of 13000 meters using the equipotential surface map from Palma Nava et al., 2022. 

Conclusion

The Mexico Basin aquifer is a vital water resource for Mexico City, supporting millions of people and economic activities (Chavez Guillen, 2007). However, it faces challenges from over pumping, contamination, and climate change (Palma Nava et al., 2022). Effective management strategies such as MAR, pollution control, and planning, are important for the sustainability of the aquifer (Cruz Ayala et al., 2020).

Continued monitoring, research, and collaboration between government agencies, researchers, and local people are necessary to overcome these complex issues. With strategic and responsive management, the aquifer can continue to remain a reliable water source for future generations (Palma Nava et al., 2022).