This is an archived article that was published on sltrib.com in 2012, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.

The reason given for the $1.5 billion Lake Powell Pipeline is that rapid population growth in St. George will soon outrun the water supply. But what if population growth turns out to be much slower than pipeline proponents have projected?

Preliminary population projections from the Governor's Office of Planning and Budget have raised that possibility. Growth in St. George has slowed dramatically in the wake of the Great Recession and the bursting of the real estate bubble. Fewer new homes means fewer new customers to pay off the pipeline. That could leave taxpayers statewide holding the bag for an expensive project. It's reason enough to scrap the pipeline, at least for now.

The more important reason is that global climate change could easily reduce the available water in the Colorado River to the point that there would not be enough to supply the pipeline. Last time we checked, a water pipeline without water isn't very useful.

In 2008, a study predicted that Washington County's population would grow to nearly 560,000 by 2040. But new preliminary projections, adjusted after the 2010 census, now forecast a 2040 population of 314,000, or 56 percent of the 2008 prediction.

Pipeline proponents are trying to convince the Legislature that the state should loan the water districts in southwest Utah the money to build the pipeline. The retail customers then would repay that loan over 20 years, mostly through onetime impact fees that are $5,800 for a new house now and gradually would rise to $20,000 for a new home built in 2040. However, those fees would have to be dramatically higher if the growth rate were only half of what was predicted when the project was originally envisioned.

The proposed pipeline would bring fresh water from Lake Powell to St. George, a distance of about 120 miles. It would travel from the lake, through northern Arizona, into Kane County, and on to Washington County. It would supply about 70,000 acre-feet of water annually to St. George. An acre-foot is roughly the amount necessary to supply a single-family home and yard for a year.

However, according to the U.S. Climate Change Science Program, the Colorado River Basin is likely to face a decrease in runoff of 10-25 percent by mid-century. The Bureau of Reclamation projects a 9 percent decline. In short, the river may not be able to supply all the folks who have claims on it.

A cheaper alternative would be radical water conservation, based on the realization that Utahns are pushing the environmental limits of population growth.