Yeah, because they keep [pumping the water out](http://bigstory.ap.org/article/7f5b6433943644288ade95a1972eee5d/report-groundwater-pumping-california-has-land-sinking) from underneath it.
Many of the jokes are contributions from our users. If you find anything offensive and against our policy please report it here with a link to the page. We will do everything to make this an enjoyable platform for everyone.