Ken Ransford: Guest opinion
December 8, 2012
Rocky Mountain PBS aired “Water Woes” on Nov. 30 to discuss water in Colorado. Cynthia Hessin asked the right questions about how Colorado will obtain enough water for its next population doubling, but the answers she received were biased toward the need for new supplies rather than toward increased conservation and riparian health. Consider the following:
• The Roaring Fork River flow through Aspen was only 5.2 cubic feet per second on July 25. A major cause for these low flows is the tunnel network beneath Independence Pass, which diverts the Roaring Fork River to the Front Range.
• The Crystal River flow through Carbondale was only 4 cubic feet per second Sept. 4 and 5. The Colorado Water Conservation Board holds an in-streamflow right on this river of 100 cubic feet per second, but it is so junior to senior agricultural water rights that it is ineffective to keep water in the river during droughts when it is needed most.
• The Front Range takes 73 percent of the average annual flow in the Upper Colorado River measured at Hot Sulphur Springs. Denver Water and the Northern Water Conservancy District are both pursuing “firming” projects that will cumulatively divert as much as 80 percent of the average annual flow to the East Slope. Brian Richter, a Nature Conservancy scientist, reports that once 10 to 20 percent of a river’s annual flow is diverted, riparian health starts declining.
• Farmers and cities regularly dry up rivers because their water lawyers say they’re at risk of abandoning their water rights if they do not continue to divert the maximum amount they have historically diverted. That 19th-century thinking is likely the major (or sole!) cause of the low flows in the Crystal River this year. Ranchers on the river who have installed water-wise sprinkler-irrigation systems still divert excess amounts from the river, which dries it up to avoid the risk of abandonment.
• Colorado lacks a statewide water plan, and land-use decisions are regularly made without concern for their impact on river flows. The conservation board claims it is not in the business of land use, and cities chafe at the thought that statewide laws could mandate that they consider water supplies in land-use decisions. The result is a system that encourages the tragedy of the commons.
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• Per-capita water use is 202 gallons per day – each of Colorado’s 5.15 million residents uses 202 gallons on average each day all year long. If that sounds high, it is, especially in a state that receives only 15 inches a year of precipitation. I calculate that break-even use is 120 gallons per person per day, where break-even means we can accommodate Colorado’s next population doubling without diverting any additional water from rivers and the only irrigated agricultural land lost is the acreage that growing cities encroach onto. Officials from the Colorado Water Conservation Board and Denver Water believe we can only reduce our use to 175 gallons per day, which means we could lose 20 to 25 percent of our irrigated agriculture to future sprawl.
• The Bureau of Reclamation estimates that Lee Ferry flows could decline 12.5 percent by 2080. If so, I calculate that Colorado is already diverting about 100,000 acre-feet more from the Colorado River than we are entitled to. If the predicted low flows in fact occur – it has happened many times before based on tree-ring analyses dating back to the time of Christ – there is no additional water available to Colorado from the Colorado River unless we renegotiate the 1922 Colorado River Compact. You can guess how sympathetic California, Arizona and Nevada will be to that idea.
Rocky Mountain PBS aired the most important issue facing Colorado. New supplies are a chimera and a euphemism for taking additional water from rivers that are already way overappropriated. We should be discussing how to get more water into rivers rather than how to take more out. There are ready solutions to the problems described above, and the problems are political rather than technical in nature.