The federal government added another piece of evidence this week in the argument over regulating California's underground water -- the San Joaquin Valley's famous sinking landscape is still dropping.
It happened this fast mostly because of new permanent crops, such as almond orchards, in areas of Madera County that do not have access to river water, say many water experts.
The study has some people quietly buzzing again about California passing its first law over groundwater supplies. States, such as Colorado, have had such regulation for years. There is no such law here.
Even among some farmers, there is talk of the regulation, though nobody has stepped up yet to openly suggest it. This political hot potato will burn most anyone, even in a state as environmentally minded as California.
The USGS study is important. Two feet of subsidence in two years over a broad landscape is telling. But it is hardly new.
Between 1926 and 1970, the ground sank nearly 29 feet on the Valley's west side. It slowed after farmers started buying Northern California river water to irrigate.
But farmers have complained to me that drought and environmental regulation at the Sacramento-San Joaquin River Delta would force them to use more underground water. It defeats the purpose of the projects to deliver water from the north, they say.
Does that move the state closer to underground water regulation? That's the question floating around right now.