New Mexico water law is a tangle in many ways, not least of which is our inability to adjudicate water rights and therefore implement priority calls to restrict usage when there is not enough water to go around.

But in one area, we’re ahead of a number of other western states: the regulation of groundwater. New Mexico law recognizes the connection between surface water and groundwater. If you pump groundwater, eventually surface water will find its way down to fill the depression created in the aquifer, so in New Mexico groundwater pumpers* are ultimately required to replace the surface water they deplete. Sorta.

In California, not so much, as Mike Eaton explained recently in the Sacramento Bee:

Under state law, groundwater, unlike surface water, can be pumped virtually at will, unless limited by local governments or the courts.

This legal delusion dates to California’s early days, when water resources seemed inexhaustible, and salmon were abundant in our rivers and streams. It remains in effect today despite what science and common sense tell us: Water moves constantly from the surface of the land, pulled by gravity out of our rivers and streams to fill the dry space created below ground when water is pumped out.

The results are predictable:

The remaining wet spots in the Cosumnes River channel in southern Sacramento County faded away earlier this month. Most of the river corridor from the foothills to the Delta will be bone-dry until the rains return.

It wasn’t always so. Historically, the river helped replenish groundwater during the wet season, and in the summer, enough groundwater seeped into the river to sustain a rich corridor of life from the Delta to the Sierra.

* Well, some of them, anyway, it’s complicated.