Challenges and Experiences of Managed Aquifer Recharge in the Mexico City Metropolitan Area

The Mexico City Metropolitan Area (MCMA) is a significant and important urban center in North America, covering an area of approximately 9500 km² with a population of almost 23 million, yet the water supply remains unsustainable. The total water demand in the MCMA is 84 m³ /s and is provided by groundwater (63% or 53 m³ /s), imported water (27% or 23 m³ /s) and recycled water (10% or 8 m³ /s). The natural recharge of the MCMA aquifer is approximately 23 m³ /s, indicating an overexploitation of groundwater resources of approximately 25 m³ /s (800 Mm³ annually), a reasonable future goal for recharge in the MCMA. Hydrologic analysis indicates two main opportunities currently to increase water supply in the MCMA: indirect water reuse with recycled water and managed aquifer recharge (MAR) with storm water. An inventory of MAR project case studies in the MCMA summarizes methods for recharge, water sources, geographical distribution, and the main results obtained in each project for the last 80 years. The inventory consists of 21 MCMA area MAR case studies including (1) conceptual, (2) design level, and (3) pilot- to full-scale facilities, only some of which have operated for relatively short periods of time, with one remaining MAR project currently operational. The review found that beyond the technical and economic issues that MAR project design normally address, the existing regulatory framework and the continuous change in water district chairs in charge of the operation and supply of water are significant barriers to increasing MAR in the MCMA.