Ray Grass, for the Deseret News
Lake Powell visitors enjoy a houseboat in August of 2009. The $1.2 billion Lake Powell Pipeline as envisioned would run 139 miles from Lake Powell to St. George, and deliver water to some communities in Southern Utah.

The largest, most expensive water slide in the world.

That's what Utah will be able to claim if the "Lake Powell Pipeline" is ever built. The Washington County Water Conservancy District, or WCWCD, wants to build a 139-mile pipeline to bring water from Lake Powell to Southwest Utah, and they want everyone in Utah to pay for it with a 15 percent earmark on future growth in sales tax.

Here's the kicker: It's not needed.

Back in 2008, the state projected a big population growth for Washington County. By the year 2060, they said, there will be 860,400 thirsty residents in places like St. George, a considerable jump from the 138,800 people who populated the county as of the 2010 Census. Then this summer the Governor's Office of Planning and Budget did a revised population estimate, and it turned out they were off by a few hundred thousand people. In 2060, they now project Washington County will have roughly 498,200 residents — about 42 percent less than originally projected.

It's true that more people are going to need water in the coming decades, but WCWCD will have plenty to go around without asking taxpayers to find the $1.2 to $2 billion it would cost to build a giant pipeline. Washington County doesn't have a supply problem. They have a consumption problem. On average, Washington County residents use more water than just about every residential area in the West. Phoenix, Albuquerque, Denver and even Las Vegas residents use less water than Washington County.

It is common in the West for water providers to conserve 1 percent of their water each year, but WCWCD conserves only a small fraction of a percent today. If they did nothing else but increase water conservation to 1 percent per year, WCWCD could meet the needs of most of the projected population in 2060. If they also follow through with their projected agricultural conversions, WCWCD would not only meet, but exceed projected water demands for decades to come.

Some state legislators have expressed concerns about earmarking money that could be used instead for critical needs, like education. The Lake Powell Pipeline doesn't yet exist and isn't really needed anyway. So why are Utah elected officials even considering the idea?

State Rep. Patrick Painter, the chief proponent of potential legislation, doesn't like the idea that Utah isn't using every last available drop that it is legally entitled to take from the Colorado River. As Painter told KSL television recently (Oct. 16), "I think we're derelict in our duty if we don't put that water into use."

OK, but if Washington County doesn't need that water, then what would it do with it? How do you "use" hundreds of thousands of gallons of excess water?

Building a 139-mile pipeline is a lot more expensive, a lot more controversial and a lot more complicated than designing a conservation plan for water users. In fact, WCWCD wouldn't even need to make drastic reductions in water use in order to meet future demand. Basic changes to outdoor landscaping (think native plants, not bluegrass) and irrigation practices will go a long way in Washington County. Couple that with effective water rate structures, and we're nearly there.

Utah should scrap the pipeline idea. What Washington County needs is a real conservation plan for the future, because that's a plan everyone can afford.

Amelia Nuding is water-energy analyst at Western Resource Advocates, an environmental nonprofit with offices throughout the West — including Salt Lake City.