Then, in 2002, she closed her tab. The brutal drought that still grips the valley began that year, when the Rio Grande shriveled to a quarter of its average flow. Because the state still hadn't finalized regulations to cut off wells before river users, fields with old river rights withered while wells went on a bender. The Closed Basin Project could no longer keep peace between well and river users, or help Colorado meet its downstream commitments without further limiting river diversions.

The drought also made it obvious that agriculture here was overgrown: Water demand far outstripped supply. The valley had become an anti-gravity sieve with some 6,000 holes sucking it dry. In 2002 alone, the shallow aquifer north of the river lost 400,000 acre-feet -- more than Nevada siphons from the Colorado River annually. In the decade since, it's hemorrhaged double that. At a 2003 Alamosa confab, Steve Vandiver, then a state water engineer, didn't mince words: "Without some significant moisture, the entire system is now in a death spiral."

Around the same time, another agricultural water crisis further convinced a few key valley leaders that business as usual could not be sustained.

Along the South Platte River northeast of Denver, pitiful snowpacks and two court decisions abruptly idled thousands of wells. A few years into the drought, Tom Cech, then-manager of the Central Colorado Water Conservancy District, which helps develop and administer water supplies along the South Platte, stood before 700 people in Greeley to deliver sober news. Well owners wanted to know what it would take to resume pumping as usual. Cech did the math: "The cost would pretty much be equal to purchasing all of your farms again," he recalls saying. "You could see 700 sets of shoulders drop. It was like going through a death -- shock, anger, depression. Some folks were going to lose their farms."

Before the South Platte crisis, whenever there was a "call" on that river -- meaning that those with junior rights had to wait with empty buckets until senior users got their share -- well owners could keep pumping if they submitted annual plans to the State Engineer to balance what they extracted by increasing supplies for senior-right holders. (They might lease reservoir water that could be sent downriver, for instance.) But the court revoked the state's authority to approve those temporary plans. Well owners had to come up with permanent "augmentation" plans and man-euver them through water court -- an expensive, lengthy and litigious process that required them to find more water to protect senior water rights.

Worse, calls on the South Platte that used to last a couple months now lingered nearly year-round. Well users had to come up with a lot more "replacement" water, and many couldn't find or afford it.

In the San Luis Valley, until the big drought, the Closed Basin Project had excused well owners from supplying replacement water when a call was made on the Rio Grande. Due to the valley's complex geology, its wells generally don't have as clear a linkage to surface flows as many South Platte wells do. Still, people here saw a specter looming: If the Rio Grande did follow the South Platte's rules, easily half the valley's wells could be shut off. And because so much of the local economy depends on agriculture, the ripple effects would be prolific.

But a fiercely intelligent San Luis Valley potato farmer and out-of-the-box thinker named Ray Wright imagined a different future, one in which people solved their groundwater problems out of court. Before he was killed in a freak accident three years ago, Wright was president of the taxpayer-funded Rio Grande Water Conservation District, charged with developing and protecting the valley's water supplies. He believed it was inevitable that irrigated agriculture would be downscaled, whether by regulators, courts or climate. So why shouldn't the community experiment with self-governance? "Ray's view," says David Robbins, the water district's lawyer, "was, 'Why don't we try to do this cooperatively?' "

Wright's business card asserted that he "speaks farmer fluently," and he was equally well-versed in water politics and policy. He, Robbins and a few comrades hatched a plan to rebalance the water budget through a system of shared sacrifice, where every pumper helped pay down the groundwater debt. They proposed dividing the water district into "sub-districts" composed of folks united by geography, who already managed ditches together and talked shop over coffee every morning. Computer models would determine the collective impact of each sub-district's wells to figure out how much the group needed to trim its pumping to rebuild the aquifer, and import new water to mitigate effects on rivers and streams. And water would no longer be free: Irrigators would pay for every drop pumped that couldn't be offset. That money would buy new water and pay farmers to fallow marginal land. In effect, those whose operations remained viable would help soften the landing for everyone else.

In 2004, state Sen. Lewis Entz, R, another local potato farmer, pushed a bill through the Legislature mandating the aquifer's restoration. It authorized sub-districts to charge for pumping, and create court-approved groundwater management plans and state-endorsed annual plans to bolster rivers. It also directed the state to finally develop well regulations for the valley. Once those rules are in place, well owners here will have three choices: Enroll in a sub-district, get an augmentation plan through court, or close their valves.

Lax regulation in many intensively farmed places has allowed pumpers to deplete Western aquifers, harming rivers and everything that depends on them. As supplies run increasingly short, conflicts between well and river users -- including people and fish -- are intensifying, from Idaho's Snake River Plain to California's Central Valley. Idaho irrigators have been engaged in an epic battle for most of the decade over the decline of the Eastern Snake River Plain Aquifer, with river users begging the state to turn off junior wells, and well users arguing that it's obligated to let them exploit groundwater for human gain. Some progress has been made: The federal Conservation Reserve Enhancement Program (CREP) has paid farmers to fallow just under 20,000 groundwater-irrigated acres, and a plan to rebuild that aquifer is in the early stages of implementation. But it remains underfunded, and efforts to cut water demand have proved difficult.