Lower Blue and Green Mountain
After thinking we'd have to bump up flows for inflow bypasses a few weeks ago, we've wound up doing the opposite. Yesterday at noon, we decreased releases by 250 cfs. We are now releasing only about 100 cfs to the Lower Blue below the dam.
The reason for this change is storage. It's time for us to fill up Green Mountain Reservoir. We have to get it full to the brim in order to support the remainder of the gate work we are hoping to complete this summer.
Once the reservoir is full, a dive team will come in and place a bulkhead in the outlet works near the dam, on the bottom of the reservoir. By blocking the water from entering the outlet and the penstocks (the large pipes that carry the water to the power plant), we will dewater them. Once they are void of water, the crew can go in there and place the gate in the penstocks we pulled out and had fixed a few years ago, the last time we had a good water year. While this work is being done, we will release water over the spillway to the Lower Blue. That's why we have to have the reservoir "brimming" full--to get the water over the spillway.
Previously, our forecast had shown a peak on the Colorado River a little later in spring than is now being anticipated. With a shorter time frame to work with, we had to begin our storing and filling program right away. Because we are starting that sooner, we will not be bypassing some of the run-off this month as we originally thought.
For those of you who are hoping for a higher flow on the Lower Blue this season: don't lose hope, yet. We also have enough snowmelt to help augment peaking flows in the Colorado River for the endangered fish program this year. When that time comes, we might have an opportunity to bump up releases from Green Mountain as part of that program towards the end of May or early June. I'll keep you posted.
That's it for now. Enjoy the glorious weather and have a great weekend!
Eastern Colorado Office
Bureau of Reclamation