The artificial replenishment of aquifers is not an ideal solution for Mexico City's overuse of its primary water source, architect and urban development expert Jorge Legorreta told BNamericas.
"In the case of Mexico City I am especially critical of recharging aquifers with treated water [...] because if it isn't pure, or is only purified for an inaugural event, and then there is no budget to maintain that purity for the required time, we could be introducing less than pure water to the aquifers and that will be much more costly," Legorreta said.
Replenishment is definitely needed, said Legorreta, noting that 70% of the city's water is extracted from its underground aquifers. This has caused parts of the capital to sink by up to 40cm/y, which in turn damages drainage systems.
"This act of taking water [from aquifers] is precisely what has led us to the center of the city sinking 10 meters," said Legorreta, a researcher at the Universidad Autónoma Metropolitana (UAM).
Despite these misgivings, if water purity can be guaranteed for a long-term project then artificial replenishment could be an option, Legorreta said.
However, a better strategy would be better control city growth to allow aquifers to replenish themselves naturally. As more land is given over to urbanization, water that would otherwise make its way to the aquifers is diverted, leading to the need for artificial measures, the expert added.
The full interview with Jorge Legorreta is published in this week's Water & Waste Perspectives, for subscribers only.