The declining water level of Lake Powell, shown in April 2014, is evidenced by the white bathtub ring on rock walls that were once underwater. Photo by Mike Jones

By Greg Trainor

As Colorado’s Water Plan moves forward through a year of revisions, there remains in the background a larger, most-worrisome issue of diminishing supply across the wider Colorado River Basin. This is evident from the dropping water levels of lakes Powell and Mead during the last 13 years. In 2014, these two major water storage reservoirs for the arid West reached all-time lows.

Colorado’s Water Plan is partially made up of eight individual river basin plans that hope to settle water supply allocations among themselves for various uses. However, like the interstate compacts that govern the use of Colorado’s rivers crossing state lines (there are nine such compacts between Colorado and adjacent states), the Colorado River Compact, on a larger, river-basin scale, already divided the waters of the Colorado River in 1922 among seven states that share the Colorado River Basin, and, in doing so, set the limits of water usage that those states have to live with in times of drought and short supply.

The Colorado River Compact of 1922 is an agreement among the states whose boundaries lie within the Colorado River Basin in the western United States. The idea for the compact was to insure water would be available for states experiencing slow economic growth even as other states were experiencing strong economic development. The water of the Colorado River, less a portion of water for Mexico, was divided in half—half going to the upper basin states of Colorado, Utah, Wyoming, New Mexico and parts of Arizona, and half to the lower basin states of California, Arizona and Nevada.

The 1922 Colorado River Compact divides the flows of the Colorado River Basin between the four upper and three lower basin states. The upper basin can not cause the annual flow measured at Lee Ferry, Ariz., to fall below 7.5 million acre-feet or 75 million acre-feet over a 10-year running average. 

Failure of the upper basin states to maintain the required volume of water to the lower basin could result in the lower basin states “calling” for their half of the water, with the upper basin being required to temporarily forego diversions. The volume required to reach the midpoint between the upper and lower basins at Lee Ferry, Arizona, is 7,500,000 acre-feet per year or 75,000,000 acre-feet over a 10-year rolling average.

To be more specific about the magnitude of the threat of little water, Colorado depletes about 2.5 million acre-feet annually from the Colorado River system, which equates to just under half the water used across the entire state. Of this amount, 1.1 million acre-feet is pre-1922 Compact water, while 1.4 million acre-feet, or 56 percent, is post-1922 Compact water. Post-1922 water would be the portion of Colorado’s water usage that would be most vulnerable in the event of a “call.” Ceasing those diversions would amount to a large reduction in use, not only on Colorado’s West Slope, but also along its Front Range, as water for transmountain diversions moving from west to east of the Continental Divide make up 43 percent of those post-1922 depletions.

It is certain that suspension of use would be mitigated or avoided if at all possible. However, long-term avoidance would have to be predicated on a rising supply and measurable reduction in demand across the entire upper Colorado River Basin, providing evidence that shortages would not be permanent.

In years of drought, the Compact minimum flow obligation poses a problem. A diminishing supply would have to be shared among not only upper basin users but also the lower basin users making the “call.” To thwart the contingency of the upper basin states having to cease or seriously curtail their water use, Lake Powell was constructed to store water in years of abundance and, then, in times of want, to supplement the 75,000,000 acre-foot requirement.

In the late 1990s, Colorado Basin water planners discussed the issue of how water surpluses could be shared and allocated. Then came the drought of 2002, and discussions changed focus to shortages. In 2005, the Secretary of the Interior directed the U.S. Bureau of Reclamation to develop additional strategies for improving coordinated management of the reservoirs of the Colorado River system. In response, Reclamation initiated a process to develop operational guidelines that can be used to address the operations of Lake Powell and Lake Mead during drought and low reservoir conditions.

Signed by the Secretary of the Interior and representatives of the seven basin states, the agreements were designated as “Interim Operational Guidelines” and included water level targets in lakes Mead and Powell to insure that various activities could continue unabated, such as the production of hydroelectric power. The parties recognized that as time marched on, the guidelines and their underlying hydrologic assumptions would have to be re-examined to account for changing climate, supply and demand conditions, and shortages.

Lake Mead, created by Hoover Dam, is a major storage supply on the Colorado River for the lower basin states. Shown in Feb. 2014, it was on its way toward reaching a historically low water level.

Simple observation of water levels in lakes Powell and Mead show us that lake levels are not “filling or spilling” but continue to drop. A conclusion? Current supply to the lower basin, and therefore the upper basin, is at risk. To date, the winter of 2014-2015 has produced snowpack at below-average levels. Additionally, as one attempts to look into the future by using past evidentiary data (paleohydrology), the conclusion is that future water supplies could be at risk as well. The evidence shows that it was common for drought to extend for decades.

Further complications arise. Colorado’s Water Plan is being developed today, in 2015. Review and modification of the Interim Operational Guidelines for Powell and Mead, affecting the Compact, are targeted for 2026-2030, 11 years hence. So how does one plan the wedding when the guest list isn’t drawn up until right before the ceremony? Or said another way, the review of the guidelines will include discussion of how to handle shortages of water, water that Colorado’s Water Plan may have already divided up. Envision the state policy makers and the guideline negotiators with their fingers in the same pie, each at their own party.

Ironically, the lower Colorado River Basin is the most vexing part of Colorado’s state water plan. Discussion of Colorado’s Interbasin Compact Committee (IBCC) and its conceptual criteria for the development of additional transmountain diversions from the state’s wetter West Slope to its urbanized East Slope addresses the Colorado River Compact in this way: “continued conversations and negotiations among the Basin States…are sensitive “ and “Colorado does not want to pre-judge the outcome of these discussions.” The developers of Colorado’s Water Plan know there could be sensitive interbasin outcomes in 2026 that are at cross purposes to the state water plan of 2015. The solution for now, it seems, is to kick the can down the road and hope that things “work out”—more water, less demand.

At least one basin roundtable has recognized the problem and is wrestling with the numbers, many numbers. This is a good sign that others are working on the problem. The 1922 Compact is not the only constraint on the Colorado River System. There are others that could restrict Colorado’s water usage. For example, how does Colorado measure up against the state’s percentage allocated in the Upper Colorado River Basin Compact of 1948, which divides the upper basin’s share between the four upper basin states? How does Colorado reconcile the Bureau of Reclamation’s determination of a 6-million acre-foot limit for the upper basin (compared with what was once assumed to be 7.5 million acre-feet)? What about depletion caps for recovery of endangered fish?

If we believe the data that reveals a future gap in Colorado’s municipal water supply of up to 538,000 acre-feet, should we not be including in Colorado’s Water Plan the most aggressive solutions to closing the gap? These could include the talked-about “insurance policy” to avoid the risk of Lake Powell dropping below minimum levels that would trigger a “call,” moving up re-negotiations of the Interim Operational Guidelines to gain more clarity of future requirements, serious discussion of importation of Mississippi River Basin water from beyond the state, desalination for fulfilling the U.S. Colorado River water obligation to Mexico, and land use mandates to decrease domestic water consumption to a certain maximum gallons per capita per day. Even legislative integration of a water component in local land use planning and development codes ought not to be dismissed as we look for solutions.

Until we see Powell and Mead water levels increase, the success of Colorado’s Water Plan rests on reduced demand. Decisive action is needed to solidify this policy. Increasing supply only works when climate favors us and water is available. Decreasing demand works both ways. In times of increased supply, decreased demand is a dividend and maintains water in storage. The rest of the time, decreased demand is the only way of staying within our ever-decreasing water supply.

Greg Trainor retired as the public works/utility director for the City of Grand Junction in March 2014. He was actively engaged in many water issues relative to his work: utility construction, endangered species, parks and trail development, storm water and sanitary sewage discharges, use of compressed natural gas as an alternative fuel for public works vehicles, water rights development, kayak park development, and active engagement in Colorado’s State Water Plan (2015). Greg has also been a member of the River Management Society for 15 years. He is the vice-president of the SW Chapter and has edited and authored submissions for the RMS Journal, organized and participated in the RMS Ranger Rendezvous, planned Chapter floats, and volunteered for the BLM in Desolation Canyon during the 2013 and 2014 river seasons. Greg served as town manager of the Town of Rangely in the late 1970s, worked on the development plans for the Battlement Mesa New Town with ARCO Coal Company’s community development group, and was project manager with the Colorado River Water Conservation District for the Taylor Draw Dam and Hydroelectric Plant, located on the White River in western Rio Blanco County.

Check out the Colorado Foundation for Water Education’s newest issue of Headwaters magazine, covering the development of Colorado’s Water Plan, a roadmap for managing the state’s limited water resources in the face of drought, climate change and rapid population growth. And read up on the Colorado River Compact and the state’s other water-sharing agreements in CFWE’s Citizen’s Guide to Colorado’s Interstate Compacts.