Colorado River Basin Water Supply & Demand Study Interim Report #1 is hot off the press

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Here’s the link to the webpage where you can download the report. Here’s a preview:

Spanning parts of the seven states of Arizona, California, Colorado, New Mexico, Nevada, Utah, and Wyoming (Basin States), the Colorado River Basin (Basin) is one of the most critical sources of water in the western United States (West). The Colorado River and its tributaries provide water to over 30 million people for municipal use, supply water used to irrigate nearly 4 million acres of land, and are also the lifeblood for at least 15 Native American tribes, 7 National Wildlife Refuges, 4 National Recreation Areas, and 11 National Parks. Hydropower facilities along the Colorado River provide more than 4,200 megawatts of generating capacity, helping meet the power needs of the West and offset use of fossil fuels. The Colorado River is vital to Mexico to meet both agricultural and municipal water needs. It is essential to understand that the natural water supply of the Basin is highly variable year to year. The ability to capture water Basin-wide during years in which supply is greater than demand has resulted in meeting most of the resource needs throughout the 20th- century, although localized shortages routinely occur, particularly in the headwaters areas during times of drought.

Throughout the 20th-century, the challenges and complexities of ensuring a sustainable water supply and meeting future demand in the over-allocated Colorado River system have been recognized. These challenges have been systematically documented in studies conducted by the Bureau of Reclamation and the Basin States over the past 60 years. Concerns regarding the reliability of the Colorado River system to meet the future needs of Basin resources1 in the 21st-century are heightened, given the likelihood of increasing demand for water throughout the Basin, coupled with projections of reduced supply due to climate change.

Funded through the Basin Study Program under the Department of the Interior’s WaterSMART Program, the Colorado River Basin Water Supply and Demand Study (Study) is being conducted by the Bureau of Reclamation’s Upper Colorado and Lower Colorado Regions and agencies representing the Basin States. The purpose of the Study is to define current and future imbalances in water supply and demand in the Basin and the adjacent areas of the Basin States that receive Colorado River water over the next 50 years (through 2060), and to develop and evaluate adaptation and mitigation strategies to resolve those imbalances. The Study contains four major phases to accomplish this goal: Water Supply Assessment, Water Demand Assessment, System Reliability Analysis, and Development and Evaluation of Opportunities for Balancing Supply and Demand.

The Study is being conducted in collaboration with stakeholders throughout the Basin whose participation and input are critical to the Study’s success. Interests are broad and include Native American tribes and communities, agricultural users, purveyors of municipal and industrial water, power users, and environmental groups. Through the Study’s outreach efforts, many interested parties have been involved and others are encouraged to do so. A variety of options for involvement exist and range from attending public meetings and informational webinars to participating directly in the development of work products through the Study’s technical sub-teams. Additional information is provided on the Study website at:

More coverage from The Grand Junction Daily Sentinel (Dennis Webb):

Drought frequency and duration are expected to increase under a climate-change model, one of four different water supply scenarios used by the agency in an ongoing study of supply and demand in the Colorado River Basin. The report says projected changes in the basin include continued warming in the basin, along with snowpack decreases as more precipitation falls as rain. “Droughts lasting five or more years are projected to occur 40 percent of the time over the next 50 years” under the climate change assumption, the report says.

More coverage from Gretchen Weber writing for From the article:

In a statement Monday, the Environmental Defense Fund (EDF) applauded the study’s focus on potential climate change impacts, but urged the agency to find ways to address the supply/demand imbalance while still maintaining “healthy” river flows.

“The economic well-being of rural communities and major cities in the basin are inextricably linked to the environmental health of the Colorado River itself,” said EDF’s Rocky Mountain regional director, Dan Grossman. “And just as human health depends on healthy blood flow, the Colorado River’s health depends upon healthy water flows that are being compromised by current management practices and policies, as well as a warming climate.”

The next interim report is expected in the Fall of 2011, and a final report is due in July of 2012.

More Colorado River basin coverage here.

Aspinall Unit update: 11,000 cfs in the Gunnison at Delta

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From email from Reclamation (Dan Crabtree):

Gunnison River flows in the Black Canyon and Gunnison Gorge are currently at 5,100 cfs and continuing to climb. We are still anticipating a peak flow of around 6,900 cfs in this reach tomorrow, June 7th or the following day. Flows at Delta are nearly 11,000 cfs and should peak at about 13,000 cfs late June 7th or early June 8th. We still anticipate slowly ramping down releases from the Aspinall Unit beginning June 9th and stabilizing at around 3,100 cfs in the Canyon and Gorge around June 14th.

More Aspinall Unit coverage here.

Fryingpan-Arkansas Project update: 1200 cfs in Lake Creek below Twin Lakes

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From email from Reclamation (Kara Lamb):

We are starting to see run-off pick up. As a result, we’re adjusting our releases from Turquoise and Twin Lakes to the Arkansas River.

Earlier today, we bumped releases from Twin Lakes to Lake Creek to about 1080 cfs. This evening, we will bump up about another 100 cfs. That will put just under 1200 cfs into Lake Creek to the Arkansas River.

The water released from Twin Lakes Dam is native inflow. East slope snow melt run-off that flows into Turquoise and Twin Lakes reservoirs, and a little bit of what comes down Half Moon Creek, is diverted via the Fryingpan-Arkansas Project. Those diversions are then released to Lake Creek.

However, additional native run-off is now flowing into Turquoise Reservoir. As a result, we will increase releases from Sugarloaf Dam to Lake Fork Creek by 50 cfs early this evening. We will increase our release another 50 cfs from Sugarloaf tomorrow. By tomorrow evening, about 100 cfs should be flowing from Sugarloaf to Lake Fork Creek.

More Fryingpan-Arkansas Project coverage here.

Colorado-Big Thompson Project update: 945 cfs in the Big Thompson below the Olympus dam

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From email from Reclamation (Kara Lamb):

As the warm weather continues, we went ahead and increased releases again from Olympus Dam on Lake Estes to the lower Big Thompson River. At 2 p.m. today, we added another 145 cfs to the release for a total flow at the top of the canyon of around 945 cfs.

If you are interested in tracking stream flow around the region and the state, I’ve posted some of those links at the bottom of our main webpage.

More coverage from the Loveland Reporter-Herald. From the article:

Monday afternoon, the amount of water released from two gates along Lake Estes’ Olympus Dam was increased to give those watching flow more “operational flexibility” as water levels rise, said Kara Lamb, spokeswoman for the Eastern Colorado Bureau of Reclamation office…

Last year, the rate climbed as high as 1,100 cfs, a rate Lamb thinks the dam will hit, if not exceed, this year. At that point, all five dam gates would open.

More Colorado-Big Thompson coverage here.

Runoff news: The National Weather Service has issued a flood advisory for parts of the Front Range

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From The Denver Post (Joey Bunch):

The runoff started to affect rivers in Larimer and Weld counties Sunday, prompting a flood advisory there until 3 p.m. Wednesday. Minor flooding was forecast for Larimer County, including the Laramie, Cache La Poudre and Big Thompson rivers. Flows are expected to increase through Tuesday. The Big Thompson River could spill over into parking lots and trails in Estes Park late today into early Tuesday, forecasters said. The Cache La Poudre could rise enough to close streets in Fort Collins and Greeley.

A flood advisory is in effect until at least 11:45 a.m. Wednesday for much of western Colorado, including Summit County. Among the areas of concern are Tenmile Creek near Frisco, the Blue River upstream and downstream of Dillon Reservoir and Hamilton Creek on the north side of Silverthorne. In Grand County, authorities are watching the Colorado River, Muddy Creek, Troublesome Creek and Willow Creek, which all were at or above their banks Sunday…

The Elk River at Milner was just short of its 7.5-foot flood stage Sunday afternoon, and the Yampa River has held steady at 6.5 feet since Thursday, about a foot below flood stage, according to U.S. Geological Survey river gauges.

From Denver Water (Stacy Chesney):

Recent Snotel measurements show record or near-record snowpack upstream of Dillon Reservoir. Forecasts call for peak inflows later this month to be in the range of 2,800–4,100 cubic feet per second, or cfs (average this time of year is about 1,700 cfs, and the record peak, set in 1995, is 3,408 cfs).

As in years past, Denver Water’s goal is to operate the reservoir so the peak outflow does not exceed 1,800 cfs, which is approximately the “bank full” condition for the Blue River downstream of the dam. Because of this year’s exceptionally high snowpack and the uncertainty of the amount, timing and rate of the melt, it may not be possible to keep the peak outflow below 1,800 cfs.

Denver Water is continually monitoring conditions and took a number of precautions — including lowering Dillon Reservoir levels — earlier this spring in anticipation of the coming snowmelt. The utility can only lower the reservoir so much, but intends to operate its system consistent with the outflow goal, while also fulfilling its legal and service-related obligations.

Denver Water will continue to monitor conditions and provide updates as they become available; however, residents and businesses along the Blue River downstream of Dillon Dam should be prepared for flows in excess of 1,800 cfs in the upcoming months. Currently, the outflow is 1,300 cfs and Denver Water likely will increase outflow to 1,400 cfs this afternoon and through the weekend. The current inflow to Dillon Reservoir is about 1,600 cfs.

From the Fort Collins Coloradoan (Trevor Hughes):

The “hydrologic advisory” applies to Larimer County and west-central Weld County, and warns that low-lying areas along rivers and streams will experience rising water levels in the early part of the week. The advisory runs to 3 p.m. Wednesday.

“Minor flooding of low-lying areas can be expected along the Laramie and Cache la Poudre rivers as snowmelt and stream flows increase through Tuesday,” the weather service said. “The Big Thompson River through Estes Park is also forecast to rise. By late Monday night into early Tuesday morning, flows may become high enough to produce minor flooding into parking lots and walkways along the Big Thompson River in Estes Park.”

The service says Weld County may see the Poudre River rise 6 to 12 inches, which would be high enough to close 71st Avenue over the Poudre on the northwest side of Greeley. The Poudre River Trail in Greeley has been closed between 47th Avenue and 83rd Avenue, due to high water…

Since June 1, the Poudre River in Fort Collins has risen from 900 cubic feet per second, or cfs, to about 2,500 cfs this morning.

Eagle River Valley ‘State of the River’ meeting tonight

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From email from the Eagle River Water and Sanitation District (Diane Johnson):

Please join us at Berry Creek Middle School in Edwards at 5:30 p.m. on Monday, June 6.

The Colorado River Cooperative Agreement is on the agenda.

More Eagle River watershed coverage here.

Colorado-Big Thompson Project update: 800 cfs in the Big Thompson below Olympus dam

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From email from Reclamation (Kara Lamb):

The warm (hot!) weather today [June 5] has melted some of that higher elevation snow. As a result, we are anticipating that inflows down the Big Thompson River into Lake Estes will bump up tonight, possibly higher than last night. We are adjusting the gates at Olympus Dam accordingly. Late tonight/early tomorrow morning (around 2 a.m.) we will bump releases from the dam to the river by about 150 cfs. The resulting flow from the dam will be about 800 cfs. On Friday, we cracked open two additional gates at Olympus, giving us a little more operational flexibility. The 800 cfs will be released through three of the five gates.

More Colorado-Big Thompson Project coverage here.

Runoff news: 2,410 cfs at the Cache la Poudre at Fort Collins gage, 38,200 cfs in the Colorado River near the state line

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Thing are really picking up all across the state. Here’s the link to the Colorado River near the state line gage. Here’s the Cache la Poudre at Fort Collins gage and here’s the Clear Creek at Golden gage. Runoff on the South Platte through Denver has not really started yet.

Researchers determine the mechanism for Didymo algae growth in relatively pristine streams

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From the Boulder Daily Camera (Laura Snider):

“Diatoms pretty much grow everywhere, whether it’s really clean water or waters that are relatively impacted,” said Sarah Spaulding, a researcher at the University of Colorado’s Institute of Arctic and Alpine Research. “Generally, the more nutrients you get in the water, the more biomass you get. “What’s different about this diatom is that we found it would make a large amount of biomass where there weren’t many nutrients in the water.”

This has allowed rock snot, an invasive species in North America, to explode in streams that have not historically supported large algae blooms. In a study published in the journal Geophysical Research Letters, the scientists explain how Didymo does it. The key is Didymo’s stalks, which keep the algae attached to the rocks. The stalks are able to collect the limited phosphorous nutrients available in the stream on their surfaces along with iron. Then, bacteria that live in the rock snot mats interact with the accumulated iron to make the phosphorous easier for the algae to use.