SALT LAKE CITY — The U.S. Bureau of Reclamation is continuing to sift through 150 proposals designed to reduce demand, boost water supplies or invoke new management strategies for the Colorado River, with a final report now delayed until September.

One of the most comprehensive studies of what the future holds for the Southwest's premier river comes in the midst of the nation's most widespread drought since 1956 — with more than half the continental United States imperiled because of dry conditions.

How water supplies may be boosted or at least protected along the 1,400-mile river serving seven Western states and Mexico is a key component of the bureau's exhaustive study, launched in January and now in its final phases.

The report was originally expected to be released in July. But an update on the report's progress and what comes next was detailed Tuesday in a teleconference hosted by the agency, drawing more than 100 listeners.

Carly Jerla, the study co-manager, said what's clear so far is there is great uncertainty when it comes to projecting supply and demand on the Colorado River system over the next 50 years.

The objective of the study is to define and provide options to projected imbalances that could range from 3.8 million acre-feet to 6 million acre-feet over the next 50 years, depending on what scenarios unfold. The long-term average flow of the river that serves an estimated 30 million people is 15 million acre-feet, Jerla said.

Over time — even in the face of slowed growth in the region or enhanced environmental stewardship — the biggest draw on the system will be municipal and industrial users, said Jim Prairie, the bureau's lead architect of the study's demand assessment.

The bureau has come up with six scenarios of how the water story could play out in the coming five decades, from rapid growth and economic resurgence to slowed growth and expanded environmental stewardship that curtails water deletions from the Colorado River.

Those story lines involve uses divided up by each state and attempts to quantify how much demand may escalate or be restrained given what may be happening in Utah and the other six basin states.

Each story line plots consumptive use, but those stories about water being used from the Colorado River decades from now need to be subject to review and revision, the bureau cautioned, because the future will demand flexible decision-making.

"We understand that we just can't plan for a single future," Prairie said.

In its review of suggestions for bolstering or preserving water resources in the Colorado River Basin, the bureau is grading those proposals where possible based on 16 different criteria such as:

• Cost
• Technical feasibility
• Legal and public policy considerations
• Potential yield of water

Each criteria in the analysis will receive a score, ranging from A to E.

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<p>For a complete look at the water issues surrounding the west and the possible solutions, see Amy Joi O'Donoghue's exhaustive series, "The fight for water: Here's why the West's oldest battle could hit you at the tap."

Although many of the proposals were region- or city-specific — such as prohibiting private residential pools in places like Phoenix — Prairie said any individual score being assigned to a strategy will happen on a basin-wide scale.

Those suggestions or proposals which can't be ranked quantitatively will be addressed in papers or memos that explore potential pitfalls such as regulatory or legal constraints that would have to be overcome.

More information on the study is available at www.usbr.gov/lc/region/programs/crbstudy.html.

Email:aodonoghue@ksl.com

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