Over a Century of Sinking in Mexico City: No Hope for Significant Elevation and Storage Capacity Recovery
Por:
Chaussard, E., Havazli, E., Fattahi, H., Cabral-Cano, E., Solano-Rojas, D.
Publicada:
1 abr 2021
Resumen:
Many areas worldwide are known to experience land subsidence due to
groundwater extraction. It is traditionally assumed that subsidence
extent and rates are controlled by groundwater extraction locations and
volumes. Here, we reevaluate this assumption in the Mexico City
metropolitan area by combining stratigraphic, hydrologic, geodetic, and
demographic datasets. Integration of 115 years of leveling with 24 years
of Interferometric Synthetic Aperture Radar (InSAR) and 14 years of GPS
data reveals that subsidence rates have been mostly constant in Mexico
City since at least 1950 and reach 50 cm/year. Analysis of InSAR and GPS
data shows that no significant elastic deformation exists, demonstrating
that the subsidence is almost fully irreversible. In Mexico City, no
direct relationships exist between groundwater level fluctuations and
subsidence rates or between pumping rates and subsidence rates. In
contrast, a strong positive linear relationship is isolated between
subsidence rates and the thickness of the upper aquitard. Through the
integration of these long-term datasets, we forecast that it will take
similar to 150 years to reach total compaction of the upper aquitard,
which may lead to additional subsidence up to 30 m. With the
potentiometric surface now deeper than most of the aquitard, clay's
porewater rich in salts, chemical constituents, and pollutants is now
flowing downward into the productive aquifer, hence decreasing water
quality. Finally, our work shows that the consequences of land
subsidence greatly influence the socioeconomic landscape in the Mexico
City metropolitan area.
Filiaciones:
Chaussard, E.:
(Corresponding Author), Univ Oregon, Dept Earth Sci, Eugene, OR 97403 USA
Univ Oregon, Dept Earth Sci, Eugene, OR 97403 USA
Havazli, E.:
CALTECH, Jet Prop Lab, Pasadena, CA USA
Fattahi, H.:
CALTECH, Jet Prop Lab, Pasadena, CA USA
Cabral-Cano, E.:
Univ Nacl Autonoma Mexico, Inst Geofis, Mexico Cdmx, Mexico
Solano-Rojas, D.:
Univ Nacl Autonoma Mexico, Fac Ingn, Div Ingn Ciencias Tierra, Mexico Cdmx, Mexico
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