As you follow the South Platte River out of Denver, you travel north and east. Warehouses and meat packing plants along the river banks give way to crops.
Agriculture is productive out here. It also uses a lot of water. That’s led to calls for farmers to become more efficient. This is happening, but it doesn’t always mean there’s more water to go around. In fact, it may mean there’s actually less.
Until about 10 years ago, rancher Jim Yahn would water his hilly hayfield near Sterling by flooding the land. But as Yahn, who heads North Sterling Irrigation District, points out, about half of that water didn’t even stay on his field.
“A lot of it just ran quickly to the bottom, and then ran back to the creek, and ran back to the river.”
Flooding is how most farmers out here used to water their fields -- some still do. Yahn, however, has changed watering strategies. He, and about three-quarters of the farmers around him, have installed center pivot sprinklers. Think of them as long arms that sit in the middle of the field and rotate in a giant circle, like the second hand of a clock, sprinkling the crops underneath. This has made Yahn a lot more efficient.
“I just apply a little bit of water, really nothing runs off,” he says.
To be more precise, only about 15 percent runs off. Compared to the 50 percent he was losing before, that’s a big savings. It’s certainly increased his hay yields. And that’s the catch: Yahn is using more water.
Remember, half the water Yahn was entitled to used to run off his field and back to the river. Now, only a trickle runs back off. So by changing how he irrigates, Yahn is actually using more. In the arid West, that means someone else is getting less.
That someone is Larry Frame, and the farmers he represents as head of the Julesberg Irrigation District, just downstream of North Sterling and Jim Yahn.
Driving out down a grassy path between farm fields, Frame pointed to a creek that runs into one of his irrigation ditches.
Before most farmers upstream switched to sprinkler irrigation, said Frame, the creek would have twice that amount. That’s because runoff from those fields isn’t just waste. It flows slowly back to the river and back to little creeks and drainages. Those, in turn, flow to Frame and the farmers in the Julesburg Irrigation District.
Now that three-quarters of North Sterling’s farmers use sprinklers, Frame says farmers where he lives, downstream of North Sterling, get about 20 percent less water.
This unexpected downside of efficiency isn’t unique to the Colorado plains. Experts like Reagan Waskom, director of the Colorado Water Institute at Colorado State University, say it can happen anywhere upstream farmers change their irrigation so less runs off, and more is used on site.
“One farmers waste, if you will, or unused water, inefficient water, is a downstream farmers water right,” said Waskom.
That means when farms become more efficient, there’s actually less water to go around. In fact, Waskom says if enough farmers change from flood to sprinkler irrigation there’s the potential for the whole basin to use more water.
“And that can cause concern for downstream water rights,” he added.
At this point, no one, not even Larry Frame, whose district is getting less water -- is saying farmers should go back to flooding their fields. Sprinkler irrigation improves water quality, increases yields, and saves farmers on labor. He has nothing against the farmers in North Sterling, and that farmers in his district will gladly switch to sprinklers when they have the chance, and are doing so now.
“Guys are doing the best they can with the water they have available,” said Frame.
Up in North Sterling, Jim Yahn agrees.
“It's like pushing a balloon,where it goes in on one side but goes out on the other side so there's always a consequence.”
And that’s kind of the lesson here. With water in Colorado, when becoming more efficient can actually mean there’s less to go around -- there just aren’t any easy solutions. That’s something water planners will have to grapple with as the state’s population is forecast to double by 2050.