Mexico sinking how many inches a year

At best, previous attempts to re-inject groundwater elsewhere around the world have found that they only gained back an inch or so of elevation. Think of those stacked dishes—and particles—again. Or how hard it is to re-wet your dried clay mask to scrub it off. And these kinds of plates, or kinds of sheets, rearrange and don't allow the water to go back into its structure. Indeed, these researchers are finding parts of Mexico City that have kept on sinking after water extraction there has ceased.

It might make you wonder how much this will cost the city in the long run. These researchers are actually currently working on that calculation. Mexico City is square miles of roads, pipes, public transportation, cables, and buildings. After a big earthquake, the city will calculate the cost to repair the infrastructure and get to it.

Some areas have already sunk below the original lake bed, while others remain on slightly higher ground. While this lack of uniform sinking might sound like a good thing, it ultimately leads to a higher risk of intense surface fracturing, which can damage infrastructure and cause contamination of water supplies.

Rain and spring water running off the mountains surrounding Mexico City have left the sunken city especially prone to flooding. As the clay underneath it further sinks and cracks, the authors worry this strong downward flow of water will ultimately percolate through to the groundwater, introducing pollutants or sewerage.

Currently, 70 percent of the city's drinking water comes from groundwater extraction wells, which continues to deplete the region's aquifers. If this water becomes contaminated it would "eventually set the stage for a water pollution crisis", the authors say. Iddris et al. Skip to content Water flow in Mexico City in Before decades of heavy groundwater extraction, water flowed upward, artesian fashion, to the aquifer through basement and volcanic rock.

By the groundwater was lowered to a potentiometric level mostly deeper than the base of the Quaternary alluvial sediments Qal and upper aquitard. In the s, the city was sinking at a rate of 9 centimeters 3. Since the late s, when that rose to 29 centimeters While that helped to slow down the sinking for a while, it did not stop or reverse the process.

For while it went back to 9 centimeters, but in the last two decades it rose to a sinking rate of 50 centimeters in some parts of the city. Now, the team believes that the amount of water removed no longer affects the level of subsidence.