Its hues rivaling the vermillion canyon walls, the Colorado River ran red this week, startling travelers and delighting the scientists who dyed it.
The U.S. Geological Survey sprayed 2,200 pounds of the nontoxic, red dye Rhodamine WT into the river channel at Lee's Ferry at noon on Wednesday. Researchers will use the brilliant dye to measure the river's velocity during the controlled flood this week and, with that data, calibrate computer models of the Colorado River.Ultimately, the information will be used in determining how to manage sediment along the river corridor.
"By the time it actually goes downstream about 30 miles, (the dye) actually picks up the color of the red rock up here and looks metallic, so you don't really even notice it unless you're looking for it," said Dave Wegner, Glen Canyon Environmental Studies manager. "We'll be measuring the effects of this experiment for the next six days."
More than 100 scientists are set up along the Colorado River and within the Grand Canyon to study the impact of a series of test-flood experiments that continues through next week.
Running a controlled flow of 45,000 cubic feet per second from the Glen Canyon Dam, the USGS, Bureau of Reclamation, National Park Service and others are hopeful the high water will stir up sediment along the river channel and deposit it in the forms of beaches and sandbars as the level drops next week.
Initially, the first stages of the project already appear successful as flood waters coursed through the river corridor, turning the previously clear, green-colored water a dirty brown as the current dug up sediment from the bottom.
In the moments after the dye was dumped at Lee's Ferry Wednesday, Mark T. Anderson, chief of hydrologic investigations and research for the USGS Arizona District, raced downstream to await its arrival at the Navajo Bridge.
"You can see what's happening. The main flow is coming down the center of the river," said an almost-giddy Anderson, pointing out the vivid stain as it first approached the bridge about 12:50 p.m. On its edges, the dye revealed the water's spiraling course outside the main channel.
"As the eddies and the backwaters begin to swirl around, that creates a lower velocity . . . and some of the sand begins to drop out," he said. "Right now, if you could see on the bottom of the river, you would see a sandbar being built under there.
"It would be very slow, maybe a couple centimeters a half-day," Anderson said. "But down the river, what you have is on a much larger scale . . . that's how we build beaches."
Construction of beaches and restoring habitat along the Colorado River is the impetus behind such projects as the dye experiment. Altogether, the seven-day test-flow marks the culmination of some 14 years of study and countless government meetings and public hearings.
Formal research of the river was manifested in the Glen Canyon Environmental Studies project that started in 1982 after scientists realized the Glen Canyon Dam had drastically changed the characteristics of the Colorado River and was impacting the entire river ecosystem.
Lake Powell, the growing reservoir of water behind the dam, effectively absorbed the seasonal rhythms of runoff and drought, spewing forth a consistent flow of cold, clear water. In the years since, scientists have seen the river beaches erode from a lack of new sediment and the backwaters fill in without the necessary flushing action of a seasonal flood.
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ADDITIONAL INFORMATION
Online sites track dye project, river flow
Going online and using satellite telemetry, researchers and the general public can find information about this week's dye project and the Beach/Habitat Building Test Flow as it happens.
Along with real-time streamflow data provided by four gauging stations set up below the Glen Canyon Dam, the online sites also include fact sheets about the study.
- (http://wwwdaztcn.wr.usgs.gov)
- (http://www.usgs.gov)