Colby ? A few hundred yards off a blacktop road, down a dirt path that runs through the stubble of last year’s corn field, Brownie Wilson uses a GPS locator on his laptop to steer his four-wheel-drive SUV to the site of the next well.

Once there, he gets out and drops a tape measure into the head of the well, sending the weighted end down exactly 155 feet, submersing it into a pool of water known as the Ogallala Aquifer that has been buried below the dusty plains for millions of years.

Based on previous records, that should be more than enough to hit the top of the water table. Then he reels the tape measure back into its spool like a fisherman pulling in his line.

The end of the tape measure is covered in chalk, so when it comes back above the surface, he can see exactly how far into the water it went. He reads that number, subtracts it from 155, and that tells him exactly how far down the water is.

It’s about 18 inches further down than it was this time last year — not as sharp of a drop as he’s seen the last couple of years, but a noticeable drop all the same, and typical of the other wells around Thomas County he’s been measuring.

Brownie Wilson of the Kansas Geological Survey documents data about well depths in the Ogallala Aquifer and uploads information into a database at Kansas University. The information helps farmers estimate the usable life remaining in their groundwater supplies.

Wilson, a researcher for the Kansas Geological Survey at Kansas University, punches those numbers into an app installed on his Android cell phone. Almost instantly, a web page KGS is developing is updated to show the latest reading from that well, almost in real time.

Over the next several days, teams from KGS and the Department of Agriculture’s Division of Water Resources will measure some 1,400 wells in the Ogallala region, documenting as closely as they can exactly how rapidly the aquifer is being depleted.

Those measurements will be critical to farmers in the region, many of whom have relied on the aquifer as a source of irrigation water for generations.

But they’re also important to state officials in Topeka, and to water users in all parts of Kansas. That’s because it’s usually just a matter of time before economic problems in the west half of the state trickle down to become concerns of the entire state.

A disappearing resource

It’s really been since the mid-1970’s that irrigation farming has exploded on the High Plains. That’s when the much of the beef-packing industry moved here from the old stockyards in Kansas City, Chicago and Omaha to take advantage of the area’s drier climate, which is healthier for the cattle, and its access to cheaper, mostly immigrant, non-union labor.

Lon Frahm, who owns large farming operations in northwest Kansas, depends on the Ogallala Aquifer for much of his grain production. He says finding more efficient ways to irrigate will help extend the life of the aquifer.

That, in turn, has put pressure on the aquifer, which was once thought to be a virtually limitless natural resource. While cattle thrive on the dry climate because it exposes them to fewer pathogens, they are typically fed a diet that is not native to the area — high-moisture feed made up of corn, milo and soybeans that fattens them out and gives their meat the lean, marbled texture that consumers enjoy.

Today, local officials say, even though only about 15 to 20 percent of the farm acres in western Kansas are irrigated, that irrigation accounts for 90 to 95 percent of the water that’s pumped out of the ground.

And that pumping has led to a steady — and in some people’s eyes, alarming — decline in groundwater supplies, what farmers and geologists call the “usable life” of each well.

“Depending on the decline rates we saw happening in the 2000s, when it’s been near drought conditions or below normal precipitation, some of those lifetimes might be between 25 and 50 years,” Wilson said. “But there are other areas where it might be more like 50, 75 or 100 years. It really kind of depends on where you’re at.”

In search of options

Sitting in his office in downtown Colby, Lon Frahm, who owns one of the biggest farming operations in northwest Kansas, says he’s less alarmed about the aquifer decline than others. In fact, he says it often seems like people in eastern Kansas are more concerned about it than people in western Kansas.

That’s because he knows that reaching the end of the “usable life” of the aquifer wells doesn’t necessarily mean the end of life or farming on the High Plains.

“Will we run out of water?” he asked. “We’ll run out of large amounts of water that make some types of projects more feasible. Before energy prices came back down, it was a popular concept, and I probably said it, too, that it’s going to get too expensive to pump this water out of the ground before the water runs out.”

In recent years, though, Frahm says, farmers have shifted to newer, more efficient practices that require less water, such as no-till farming, more high-tech irrigation systems, and even dry-land farming using new plant hybrids.

“I use a rough statement that says we’re raising twice the corn on half the water as we were when I was in high school,” Frahm said. “I’m 56 years old. So we’re being up to four times more efficient with our water than we ever were.”

Not far from Frahm’s office, Freddie Lamm of Kansas State University’s Northwest Research Extension Center has spent the past 25 years developing Subsurface Drip Irrigation – a kind of large-scale version of garden soaker hoses – that could virtually eliminate water from evaporation and runoff that often occurs with traditional above-ground, center pivot systems.

And some irrigators who are members of the local groundwater management district have formed a Local Enhanced Management Area, a voluntary program that gives them flexibility for how to reduce water use over a five-year period.

Meanwhile, in southwest Kansas, local officials are studying a more ambitious plan that is raising eyebrows throughout the state – building a 350-mile aqueduct to pump water from the Missouri River in northeast Kansas to storage wells on the High Plains.

But most people in northwest Kansas seem skeptical about that idea.

“Those guys have always been cowboys and dreamers,” Frahm said of the southwest farmers. “You know, there have been other plans to send canal water through pipes or open canals up north. They’d be the largest public project in history, except for maybe that dam over in China.”

In the end, KSU’s Lamm believes something fundamental will have to change in western Kansas agriculture.

“Irrigated agriculture will decline because the economics just won’t be able to justify the pumping,” he said. “The saturated thickness will be so thin, you just won’t be able to pump the large amounts of water that’s required.”