Regarding this article, I live close to Mendota, Calif., the site of the photo depicting ground subsidence due to overpumping of groundwater. Though I have only lived here for two summers, I am surprised at the amount of water wasted daily by agriculture and residential users in this area. A casual observer would not know that there is a drought in the western United States or even a pending worldwide water crisis.

Daniel O’Donnell
Hanford, Calif.

You mentioned California’s problem of the ground settling 9 meters in the San Joaquin Valley, due to overconsumption. Could this also be the problem Florida is having with all the sinkholes?

Frank Cichon
West Lafayette, Ohio

Overconsumption, plus droughts, contributes to Florida’s sinkhole problem. Ironically, wet periods cause sinkholes, too–all that rain dissolves underground limestone and forms massive caverns .–S. Perkins