Water officials see grim scenario

Climate change may shrink supply, hike demand in Denver

Jerd Smith, Rocky Mountain News

Published April 27, 2006 at midnight

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Denver Water could see its customers' thirst for water rise dramatically and its supplies shrink if Colorado's temperatures rise an average of 2 degrees, a scenario that is possible as climate change occurs, the agency says.

"The combination of lost supply and higher demand is a worst-case scenario worth worrying about," said Tom Gougeon, a Denver Water Board member.

Gougeon's comments came during a board briefing Wednesday on the agency's long-term water supply plans.

As part of that work, the agency analyzed the effect of various climate-change scenarios, both on its water supply and on how much water customers would need to maintain healthy landscapes in a warmer environment.

According to Denver Water's analysis, its supplies, derived largely from mountain snowmelt, could drop 12 percent or 45,000 acre feet, as customer demand rises 6 percent, or 23,000 acre feet each year.

That would be under a "moderate" climate change scenario in which temperatures rose 2 degrees.

An acre foot equals nearly 326,000 gallons, or about enough water to serve up to two urban households annually.

Denver Water, which serves about 1.2 million metro-area customers, is Colorado's largest municipal water utility.

The agency derives about half of its annual water supply from the headwaters of the Colorado River and the rest from the South Platte River.

A study by the United States Geological Survey published late last year indicates that higher temperatures could reduce the Colorado River's flows 10 percent or more and that could jeopardize Denver's share of the river.

One of the key issues the board is examining is how large a water reserve it should maintain.

The agency's system generates just over 325,000 acre feet of water annually. It maintains a reserve of 30,000 acre feet.

The reserve is designed to help the agency survive a multi-year drought or to cope with a major breakdown in its water supply system.

Now, climate change is being factored into the agency's reserve calculations.

"We don't know what's going to happen," said George Beardsley, another board member.

"But we don't have the luxury of waiting to find out."

smithj@RockyMountainNews.com or 303-892-5474

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