Some 10,000 years ago, present-day New Mexico was just beginning to thaw out from the planet’s most recent ice age. The Rio Grande that currently cuts Albuquerque in half didn’t spill into the Gulf of Mexico back then. Instead, in was part of a big inland sea.

And that’s precisely when big, salty, mineral-rich water deposits — today know as brackish water — were forming deep underground.

That lovely, shorthand history came to me last week from the Albuquerque Journal’s science writer, John Fleck, as I was getting his take on the many issues these controversial new water discoveries raise. I spoke with Fleck for KNME’s weekly program New Mexico In Foucs.

Alas, that ancient bit of water history didn’t make it into KNME’s broadcast this past weekend. I interviewed Fleck just off of Paseo del Volcan smack dab in the middle of Albuquerque’s far west mesa — beautiful, wide open country — that several private developers see as the city’s new western frontier.

Overlooking California-based SunCal Companies’ large track of land, Fleck and I talked about the new push to give State Engineer John D’Antonio jurisdiction over an estimated 15 billion acre-feet of brackish water believed to be deep under New Mexicans’ feet. That’s a ton of water, but it won’t last. Once it’s pumped, it’s done — no recharge from snowpack melt or other precipitation can get that far down.

Meanwhile, test wells have concluded that one of the biggest deposits may lie underneath the Rio Puerco basin in Sandoval County.

Currently, the state engineer only has authority to manage water wells that are no deeper than 2,500 feet deep. That may change. A bill sponsored by state Rep. Mimi Stewart, an Albuquerque Democrat, would give D’Antonio’s office authority to permit wells that go deeper still. The Rio Puerco basin brackish water deposits are estimated to be approximately 3,800 feet deep.

Stewart’s House Bill 19 passed the full House of Representatives last week with unanimous support.

Check out that interview with Fleck above.

Since he and I spoke, Fleck has elaborated on one of the juicier aspects to this brackish water conondrum on his blog – that is, should we think of the water policy in New Mexico as a proxy for a sensible growth policy? Fleck’s says no. He argues we run the risk of doing both poorly if we conflate the two. In his own words:

… it also is the case that we could get the water management piece right here — proper pricing to account for the scarcity of the resource, for example, and careful consideration of the effect of pumping on surface water and shallow aquifers. Done right, it could ensure a long term sustainable supply for whatever ends up built out there — and still leave us with a sprawling city that is auto-dependent, with poor transit and long commutes and the rest of the problems that we really need to figure out how to avoid as we envision a greater Albuquerque metro area of the 21st century.

This is why water policy, while offering tempting leverage for those interested in managing growth correctly, should not be mistaken for growth management policy.

Then again, many would probably argue that water availability should act as a natural barrier to Albuquerque’s westward growth. I might even count myself among that group.

Better yet, New Mexico’s towns and cities might take a cue from Santa Fe’s local ordinance that requires private developers to purchase sufficent water rights for planned develpment prior to allowing projects to go forward. Currently, not all municipal governments do this.

That’s actually one of the issues I raised in my subsequent interview with D’Antonio, which was also part of the In Focus broadcast this past weekend. I also asked him about how he’d like to tame what he calls an ongoing water “free for all,” current federal settlements of Native American water claims, acequias, and even a bit about his decision to turn down a big water job offer from ex-President George W. Bush a couple years ago. That bit had not been reported previously, and the question clearly took D’Antonio by surprise.

The upshot of all this, seems to me, is the nitty gritty of water policy looms very large over New Mexico’s foreseeable future. It may not seem that way when your water bill is likely one of the smallest bills you pay each month. But that will probably be changing too.

Here’s my interview with D’Antonio.