Hannah Holm

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December 13, 2012
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WATER LINES: Colorado Basin Study; Make changes or face water shortages

Looking at the Colorado River as it flows through Grand Junction, it's hard to believe the scale of the demands placed upon this modest stream, where rubber rafts scrape gravel bars in summer. According to the US Bureau of Reclamation, the Colorado River and its tributaries provide water to nearly 40 million people and irrigate nearly 5.5 million acres of land across seven states plus Mexico.

The Colorado River Basin Water Supply and Demand Study, released by the Bureau Wednesday, Dec. 12, projects that these demands will continue to grow, even as climate change models indicate that average annual inflows to the basin from rain and snow are likely to diminish. The fact that water use has already exceeded inflows into the basin for nearly a decade, while the region has been in drought, shows just how close to the margin we are already. The giant reservoirs of Lake Powell and Lake Mead can only enable overuse of the river for a limited amount of time.

The Bureau's study, conducted with input from numerous water managers and interest groups and drawing on historical observations, studies of ancient tree rings and global climate change models, began by defining four plausible future water supply scenarios and six demand scenarios. Interim reports on these scenarios have been out for months, and they don't paint a pretty picture.

Comparing the median of water supply projections against the median of demand projections (without any action to change how water is managed) yields a projected imbalance of 3.2 million acre feet/year by 2060. That's 3.2 million football fields covered with water one foot deep. An acre foot is about enough to supply two average families of four for a year, under current use patterns. 3.2 million acre feet is a lot of water to want but not get.

The new parts of the Bureau's study focus on what can be done to avoid that bleak future. For this, the Bureau asked for input from all interested parties. They got about 150 suggestions, ranging from towing icebergs to California to conservation and reuse strategies.

The study evaluated a representative range of all the suggestions it received based on their feasibility, viability, how much water they could generate or save, environmental impacts and other factors. These were then grouped into portfolios reflecting different strategies (try everything, maximize reliability, minimize environmental impacts, etc.), and the portfolios were evaluated to see how well they would work to resolve future supply and demand imbalances.

The results of these evaluations show that all of the portfolios significantly reduce the number of years in which the basin would be vulnerable to hitting key indicators of supply and demand imbalances, such as critically low water levels in Lake Mead, low flows below Lake Powell, and failure to maintain target flows for healthy rivers and recreational boating. However, the study points out that even if every measure studied is taken, "plausible futures still exist in which the system is vulnerable." Put more directly, "complete elimination of Basin vulnerability is not likely attainable."

To review the study for yourself, and find out how to submit comments, go to the study website at http://www.usbr.gov/lc/region/programs/crbstudy.html

Reactions to the study have been mostly positive, although some critics claim that states "cooked the books" to inflate their demand figures. The organization American Rivers lauded the study as "a critical step towards bringing water management into the 21st century," although it cautioned that "some of the options (evaluated by the study), like a pipeline from the drought-stricken Missouri River, are economically unfeasible, controversial and environmentally harmful."

The Colorado River District, the primary water policy and planning agency for the Colorado River Basin within Colorado, released a statement praising the study as a "call to action." River District General Manager Eric Kuhn said that, "in order to meet the needs of people and aquatic-dependent species and habitats, new ways of thinking and doing business will be essential."

Greg Trainor, public works and utilities director for the City of Grand Junction, suggested some practical responses. He said the study points to the need for "new incentives for conservation and requirements that new housing developments bring to the table new water supplies or aggressive conservation techniques such as low-water-use landscaping, increased densities, rainwater harvesting and greywater re-use." Policy changes at the state level would be required to enable some of these measures, such as rainwater harvesting.

Water users that rely on the Colorado River and its tributaries might be forced to try some of these tactics sooner, rather than later, if the current drought continues. Latest figures show the snowpack for the Upper Colorado River Basin at a mere 49% of average for this time of year, despite recent storms.

This is part of a series of articles coordinated by the Water Center at Colorado Mesa University in cooperation with the Colorado and Gunnison Basin Roundtables to raise awareness about water needs, uses and policies in our region. To learn more about the basin roundtables and statewide water planning, and to let the roundtables know what you think, go to www.coloradomesa.edu/WaterCenter.

Hannah Holm is coordinator of the Water Center at Colorado Mesa University.

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The Post Independent Updated Dec 13, 2012 03:49PM Published Dec 13, 2012 03:48PM Copyright 2012 The Post Independent. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.