An interpretive sign overlooking the Colorado River near Windy Gap Reservoir heralds “The Mighty Colorado.”
It’s a long-time moniker for the artery that drains nearly a quarter-million square miles through seven states before terminating at the Gulf of California in Mexico. Yet the vista below the sign is of a river that is dammed and diverted, harnessed and held back.
Last year, the Upper Colorado was designated one of America’s Most Endangered Rivers, earning the number-six spot on American Rivers’ 2010 list. Potential new water diversion projects could sap the life from the Upper Colorado, the conservation group noted, threatening already-challenged trout fisheries, boating and long-term sustainable water supply.
“We are currently at the point of an ecological collapse on portions of the upper part of the river,” says Ken Neubecker, executive director of the Western Rivers Institute and past-president of Colorado Trout Unlimited. “We’re losing a tremendous resource here that’s going to be hard to get back.”
A survey of stonefly and fish populations on the Upper Colorado from 1980-2009 conducted by the Colorado Division of Wildlife confirms a basis for concern. The 2010 report notes the virtual disappearance of the large stonefly P. californica, which it refers to as “one of the single most important species of the Windy Gap Reach of the Colorado River,” in the six miles below Windy Gap Dam. The mottled sculpin, another indicator species that is reliant on cobbles and riffles to reproduce, is also vanishing from stretches directly below dams in the Upper Colorado River. Loss of biodiversity in the river may have major ecological impacts for the future, especially if more water is removed from the Colorado via additional diversions, according to the report.
“At some point, if you’re losing a lot of water during runoff, you don’t have flushing flows, which can result in incremental degradation of the habitat quality,” says Barry Nehring, a biologist with the division’s Aquatic Wildlife Research Group and one of the report’s authors.
Back in 1890, water from the Colorado headwaters began flowing over La Poudre Pass via the hand-dug Grand Ditch, bringing water to farmers and settlers on the arid, eastern plains. More than a century later, 10 transbasin diversions move water from the state’s wettest basin—the Colorado River mainstem and its tributaries—to the drier South Platte and Arkansas river basins, where most of the state’s usage occurs. The reservoir at Windy Gap, built in 1985, is but one component in that eastward transportation process in which nearly two-thirds of the Colorado River headwaters in Grand and Summit counties is now diverted to the Front Range.
The ability to obtain pristine, mountain snowmelt is a tremendous asset to historic agricultural areas and growing cities, but Tim O’Keefe, education director for the Roaring Fork Conservancy, a watershed group based in Basalt, believes it can result in people seeing the river as nothing more than a system of buckets and pipes. “Just looking at a river and seeing that it’s clean, clear and relatively full-flowing does not necessarily mean it’s a healthy river,” says O’Keefe. Rather, it’s essential, he says, “to understand and appreciate the importance of fluctuations and flows in a river over the course of a year or even a day.”
A drive along the Colorado River Headwaters Scenic Byway between Granby and Kremmling offers a case in point. In this iconic western landscape, a blue ribbon of river snakes through tawny gorges and sage-dotted hills, its banks edged with green willows and cottonwoods. You’ll almost certainly see some fly fishermen, as this is designated Gold Medal trout country. By all appearances, the river and its environs look healthy enough. But looks can be deceiving.
With so much water taken out of the headwaters, the temperature in this stretch regularly exceeds state-designated levels necessary to protect trout health. Shallow flows, sun-warmed rocks and less oxygen in the water cause stress that can be lethal to insects and detrimental to the fish that feed upon them. “If the base of the food chain, in this case the insects, disappears, the fish that eat them will soon follow,” says Neubecker. “They’ll either die off themselves or migrate out of the area in search of food.”
Nehring’s research group has been monitoring stonefly populations on the Colorado River below Windy Gap since 1980, before construction of Windy Gap Reservoir began. The big flies, a favored food of trout, were abundant in the early 1980s at a monitoring site about two miles below the present dam. “We have a very good baseline of what was there then,” says Nehring. “Now there are hardly any there at all.”
Nehring and other researchers think alterations in the river’s flows are likely to blame. Windy Gap’s original permit required minimum bypass flows ranging from 90 to 150 cubic feet per second (cfs) be maintained below the dam with flushing flows of 450 cfs once every three years, but, based on data the Colorado Division of Wildlife has collected, those minimums may not have been enough—not that Windy Gap is the only project diverting water in the region.
Not only are historical flow levels down—by 65 percent, according to U.S. Geological Survey data, at Kremmling, where the last of the upper headwaters tributaries, the Blue, joins the Colorado—but the whole flow regime has been altered.
Peak Flows Matter
The Colorado River’s natural hydrograph was dynamic. Fed by melting snowpack, the river roared down the West Slope in late spring, topping its banks into the meadows that line its course, flushing its bed and moving sediment downstream while rejuvenating the riparian zone. By late summer, flows would be low and the river would meander into new channels, establishing more riparian vegetation.
When spring floodwaters are diverted and dams regulate flows, the river’s seasonal fluctuations become less pronounced. In extreme cases, on certain river reaches, the river’s hydrograph, or charted rise and fall, can become nearly flat. With high water no longer spilling over the river’s banks, the protected pools and eddies that nurture small fish fry and insects vanish. Another casualty may be cottonwoods, the classic marker of a West Slope riparian zone. Normally, peak flows support a finely synchronized process in which flooding and the germination of new cottonwoods go hand in hand, especially on the lower river.
Again, appearances can be deceiving. “While you may look at what seems to be a healthy, dense grove of cottonwoods, you get into it and don’t see any young trees,” says John Sanderson, a biologist and co-director of The Nature Conservancy of Colorado’s Center for Conservation Science and Strategy. “Where are we going to be in 40 or 50 years when all those trees have died?”
According to Dee Malone, an ecologist with the Colorado Natural Heritage Program who conducts habitat assessments in the Roaring Fork watershed, an important feeder to the Colorado, cottonwoods provide a multitude of functions. They hold onto riverbanks, prevent erosion and stave off aggressive non-native vegetation such as tamarisk and Russian olive. They also provide homes for mammals and birds.
When rivers don’t overbank and riparian areas don’t form, the river also loses its own flood control system. “Riparian areas act like a huge sponge that soaks up excess water,” says Malone. Not only does this mitigate floods, but the water that is absorbed slowly percolates back into the river, supplying late-summer flows for agriculture and recreation.
Sanderson further explains that the flushing of sediment by high water volumes keeps the river open to carry big flows and reduce flooding. “If you limit those flows, over time you get more sediment deposition, more vegetation filling the channel, and the channel becomes smaller.” That smaller channel is more likely to flood.
Sanderson says the probability of flooding this year is high, given that Granby Reservoir, upstream of Windy Gap, is expected to spill for the first time in 11 years thanks to this year’s exceptional snowpack. The spill could have positive ecological effects, he says, if reservoir operators coordinate their releases during the big spring flows for greater impact. Fortunately, such coordination is already happening.
As part of the Upper Colorado River Endangered Fish Recovery Program, a group called CROS, short for Coordinated Reservoir Operations, works to enhance the river’s peak flows. These operators are already required to release a certain amount of water for endangered fish downstream under an agreement with the U.S. Fish and Wildlife Service, and can create even bigger flushing flows by working together rather than independently. Such complementary releases could help achieve the USFWS goal of running 23,500 cfs through part of the fishes’ critical habitat near Grand Junction in June once every fourth year. That kind of flow will go a long way toward improving the river’s overall ecology, says Sanderson.
CROS has successfully coordinated peaks topping 23,500 cfs in 1997, the group’s first year, and again in 2008 and 2010, but they release water to augment lesser peaks much more often than that. This year, CROS does not plan to contribute any additional water to the peak as the USFWS predicts a 50 percent chance that the river on its own will reach 36,000 cfs, well above the 25,400 cfs that is considered flood level at Grand Junction.
Potential Flow Reductions
The challenge of supplying sufficient peak flows will be compounded if two new diversion proposals currently in the permitting process are approved. While some 65 percent of the Upper Colorado’s historical flows are now diverted to the Front Range, that figure could jump to 80 percent by 2030 with the Moffat Collection System and Windy Gap firming projects fully in place. Respective projects of Denver Water and the Northern Colorado Water Conservancy District, both are designed to improve the reliability of diversions, via existing projects, by building or expanding storage reservoirs on the East Slope. While both entities already hold the necessary water rights, their proposed actions would increase the volume of water currently diverted and reduce flows during peak runoff season and therefore need a number of state and federal permits and approvals to proceed.
“Our goal is that if we build the projects and follow through with mitigation and the enhancements, conditions in the river will be better than they are today.” – Jeff Drager
Under state law, the Colorado Wildlife Commission is asked to review plans to mitigate impacts to fish and wildlife developed by proponents of new water projects that require a federal permit. While Northern and Denver Water have proposed mitigation plans, some fear they will be inadequate to compensate for the new diversions. The current proposals, for example, “are offering a flushing flow of up to 600 cfs, but there has been a lot more in the river than that, and sedimentation is still a problem,” says Fritz Holleman, a water attorney representing ranchers in the Upper Colorado watershed.
The flushing flows are an issue, acknowledges Windy Gap Firming Project’s project manager Jeff Drager, that has been repeatedly raised at public hearings held by the commission. But, he points out that 600 cfs is the flow the Grand County Streamflow Management Plan recommended and would be an improvement over flushing flows required under the original Windy Gap Dam’s Environmental Impact Statement (EIS), which stipulated that 450 cfs be maintained for a period of 50 hours once every three years.
Holleman and others argue, on a more fundamental level, that the data used to estimate the river’s baseline flows, and therefore determine appropriate mitigation, was flawed. Drager, however, believes such arguments are based on the expectation that the EIS examine historical river conditions—as in, what existed prior to today’s diversions—as a baseline. But, while the EIS compares three different conditions to help the federal agencies make their decisions, historical flows are not one of them. Rather, the two agencies currently involved, the U.S. Bureau of Reclamation and U.S. Army Corps of Engineers, consider how the proposed action will affect existing conditions on the river today and require mitigation to offset those impacts.
Going beyond that, to improve the river beyond existing conditions, is not required under the National Environmental Policy Act, which governs the federal permitting process. Such improvement is, however, the goal of voluntary, cooperative enhancement plans that have been submitted by both project proponents, which attempt to address concerns about the river’s current health status. “Our goal is that if we build the projects and follow through with mitigation and the enhancements, conditions in the river will be better than they are today,” says Drager.
The final EIS for each project is expected this summer, at which point the public will have opportunity to provide further input.
Toward a Healthy River
In the meantime, a range of local efforts are underway to rejuvenate the health of the Colorado and its tributaries. The Grand County Water Information Network, established in 2004, has developed a system of monitors to test water quality and temperature and supplies data to Grand County water stakeholders and the public to inform decision-making. Both Denver Water and Northern Water help finance the network’s efforts as part of their ongoing work to keep tabs on what is happening in the ecosystems they divert from.
GCWIN director Jane Tollett says that while her organization is concerned with water quality, quantity matters, too. “There is a need to add in other efforts to provide water for the environment in the headwaters. The Grand County Streamflow Management Plan is being used to inform some of the conversations and to determine what segments could be helped with more water.”
The Roaring Fork Conservancy, which also does extensive monitoring, is completing a watershed planning effort, says Sharon Clarke, the organization’s land and water conservation specialist. The plan, sponsored by the Ruedi Water and Power Authority, calls for urgent action on several items, including the addition of environmental and recreational needs in water availability studies, quantifying site-specific nonconsumptive flow needs, and restoring crucial riparian areas through invasive species removal and stream channel restoration.
The Eagle River Watershed Council likewise is monitoring water quality and fish and insect health in its region and beginning to restore sections of rivers and creeks such as a 1.6-mile stretch of the Eagle as it flows through Edwards. Melissa Macdonald, executive director of the Eagle River group, says they will turn their attention to the Colorado mainstem in August with an inventory and assessment of the river in Eagle County. They will examine water quality, quantity, wildlife, riparian values and recreation aspects, with stakeholder input, to form action plans to protect the river’s health. The group is currently seeking grants to fund the project from Eagle County, the Colorado Water Conservation Board and the “Save the Colorado River” campaign.
The Colorado Basin Roundtable has also performed an extensive assessment of similar environmental water needs throughout the entire river basin. Phase I of this nonconsumptive needs study included a comprehensive stakeholder-driven mapping effort of environmental and recreational focus areas. It identified 65 sites where additional flows are warranted. Many of these sites are in the headwaters and Roaring Fork watersheds, both regions with extensive existing diversions.
Figuring out exactly how much water to leave in the river is a challenge. “We don’t know what the breakpoints are in terms of flows,” says Clarke. Trying to factor in enough water for climatic variability and predictions of more intense drought makes it difficult for stakeholders to even start talking, let alone reach consensus, she says. The river itself is also a stakeholder. “We have to recognize what the river needs as a river,” says Neubecker. “We must incorporate the biology into our management as much as the engineering. We have to treat the river as more than a conduit to deliver water.”