The Cienega de Santa Clara, the one remaining major wetland in the Colorado River Delta, is not being drained as a result of Mexico’s 7.2 magnitude earthquake, according to Karl Flessa, the University of Arizona researcher who is part of a team monitoring the ecosystem.
The area was hit hard by the earthquake. The San Diego Union-Tribune’s Sandra Dibble reported Monday on displaced communities adjacent to the wetland. Area soils apparently suffered liquefaction, and irrigation works on which the local farmers depend were damaged.
There were reports, based on NASA’s MODIS satellite data, that a substantial area of the Cienega had lost its water. (The Cienega is a wetland created inadvertently with water from “MODE”, the Main Outlet Drain Extension, which dumps saline ag runoff into what was once barren delta flats.) But in an email sent to the Cienega monitoring community (quoted here with permission), Flessa reports that field team measurements show no change in water levels:
I’ve just returned from the Cienega de Santa Clara and can report that it has not, and is not, draining. The recent earthquake has not caused the Cienega to drain….
The field crew is downloading data on water levels (among other things) at all our sites. While we may yet see some evidence of earthquake effects in these data, major changes in water level in the Cienega do not seem to have occurred.
The MODE/Bypass Drain appears in good shape and continues to deliver water to the Cienega.
There has, indeed, been some flooding in the area. Some has likely resulted from liquefaction (groundwater coming to the surface) and some from breaks in levees and irrigation canals….
Other, non-earthquake-related sources of water in the vicinity include recent rains and high tides. Sorting out the effects of the earthquake from “normal” variability will take some time.