On the scale of Colorado River water diversions yet unbuilt, the possibility of taking water out of the Gila River in southwestern New Mexico is small stuff – 14,000 acre feet per year, or maybe less if the water’s simply not there. But the current debate in New Mexico illustrates a common refrain as western water’s dam-building era winds down – the cheap stuff has already been built:

As New Mexico’s Interstate Stream Commission heads into the final stretch of a decision a decade in the making – whether to partially dam the Gila River – the federal agency best known for building dams says the costs far outweigh the benefits.

That’s my colleague Lauren Villagran (story behind Google survey wall) in one of a couple of good stories this weekend in the New Mexico press about the Gila project, for which decisions loom. In the Santa Fe Reporter, Laura Paskus takes a deep dive:

As water supplies dry up and demand increases across the western United States, it seems natural that New Mexico would jump at the chance to nail down new water supplies. Already, officials have spent millions of federal dollars on studies, staffers and meetings. But with the clock ticking toward an irreversible decision, important questions remain. Neither project proponents nor the state know how much the three proposed diversion projects will actually cost or how they’ll be funded.

Uncertainty in the climate, as well as within the engineering plans, has people scratching their heads over how much water the Gila could even yield. And no one is promising they’ll actually buy the water once it’s for sale.

The decision-making meetings before the New Mexico Interstate Stream Commission begin Aug. 26, though both Laura and Lauren suggest the action could drag on into fall.