Colorado-Big Thompson Project update: Reclamation is moving water from Grand Lake to Shadow Mountain Reservoir to test the effects on Grand Lake clarity


From email from Reclamation (Kara Lamb):

Even though we finally have the snow melt run-off behind us, we are still releasing water from Granby Dam to the Colorado River. Currently, we are releasing about 500 cubic feet per second. The reservoir is still pretty full, dropping slowly. Today, it is at a water level elevation of 8278 feet above sea level–about two feet below full.

The current release of 500 cfs will continue most likely through September and possibly into October.

The reason for the longer-than-most-years release is two-fold. First, we just have a lot of water this year. The heavy snow pack is still melting out from the highest mountain elevations, albeit much more slowly than in June and July.

Second, and most significantly, with all the snow melt and then the rain we had this summer, there just is not a lot of demand for water from the east slope. Plus, east slope storage is close to full. Without a call for or a place to store C-BT water, we cannot import it from the west to the east slope.

Additionally, this is the time of year we adjust how we run the C-BT west slope system as part of our on-going work to improve clarity in Grand Lake. For the past four years we have experimented with different operations. This year, we are attempting to maintain a steady flow from Grand Lake to Shadow Mountain Reservoir. Usually, the flow is in the opposite direction because we are diverting more water to the east slope.

I have received several questions over the past few days regarding the west slope collection system. Please feel free to contact me directly with any additional questions. More C-BT information is also available by visiting Northern Water on-line, or by visiting Reclamation’s website.

From email from Reclamation (Kara Lamb):

Most of you have probably noticed that Pinewood has not gotten as high this summer as it has in previous years. I’ve had a couple inquiries so I thought it was a good time to send out an e-mail update.

The reason for Pinewood’s elevation fluctuation is because it is a forebay for the Flatiron hydro-electric power plant ; it’s the water storage above a power plant. Water is stored in the reservoir to build up “head,” or energy, then run downhill to produce that energy at the plant below . Because we are only generating with one of the two units and because we have had so much water move through the system this year, Pinewood’s fluctuations this summer have been slightly different than in other summers: it isn’t getting as high as most are used to seeing.

We’re going to try and get the water elevation at Pinewood back up for this weekend, however. Right now, Pinewood’s water surface elevation is on the decline. Its current elevation is about 6567 feet–about 13 feet below full–and it will probably go down another three feet or so. The good news is the decline will stop later today and the reservoir will begin to rise again. The elevation climb will continue well into the coming weekend…

If you’d like more information on the Colorado-Big Thompson Project of which Pinewood is a part, please visit us on-line.

From email from Reclamation (Kara Lamb):

As snow melt run-off has declined in the Blue River basin, we’ve been cutting back our releases from Green Mountain Dam to the lower Blue River. Releases have dropping over the last week.

The most recent change was this morning, calling for another reduction. By early evening, releases from the dam should be around 950 cfs. Additional changes will depend on weather and water demands.

The reservoir elevation has remained very close to full. It is currently at about 7948 feet, two feet down from full.

More Colorado-Big Thompson Project coverage here.

More Grand Lake clarity coverage here. Check out this article from November, 2007 written by Tonya Bina for the Sky-Hi Daily News. I think it’s cool that the deep link still works.

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