From email from Reclamation (Kara Lamb):
Now that it is fall, we are into our annual maintenance schedule on the east slope of the Colorado-Big Thompson Project. That means there will be some changes across our reservoirs and canals.
The first update is actually a schedule change at Pinewood Reservoir. Previously, I had let you all know that Pinewood was going to be drawn down considerably in November. That is no longer the case. With the changes in place, Pinewood will now be full by October 28 and stay relatively high until the week of Thanksgiving. During that week, testing at the Flatiron power plant below will begin and the water level at Pinewood will slowly drop for about three weeks. At this time, we are anticipating the water level at Pinewood will start going back up in the middle of December.
While the test is going on at Flatiron, the contractor will be busy on the Pole Hill Canal box culvert project. With Pole Hill, Pinewood, and Flatiron under maintenance, it is very likely we will wind up running some water down the Big Thompson Canyon, releasing from Olympus Dam on Lake Estes. After October 28, flows in the canyon could be as high as 350 cfs. They could stay at that level into November.
Meanwhile, pumping to Carter Lake is scheduled to end on October 28. Currently the reservoir water level is slowly rising at a rate of about a tenth of a foot a day.
When pumping to Carter stops, delivery of water to Horsetooth will come back on. Water released from Lake Estes and sent down the Big Thompson Canyon will be recaptured at the Dille Diversion (just upstream of the Dam Store) and sent north to Horsetooth. That means that Horsetooth Reservoir’s water elevation will likely stay above 5400 feet–a very unusual situation. All boat ramps will be in the water all year.
We will likely keep water going to Horsetooth until mid-November.
The second update has to do with C-BT facilities in Estes Park. Annual maintenance at the Marys Lake Power Plant, dikes and related system will draw Marys Lake down to dead storage in the middle of November. While Marys is down, the water level at Lake Estes will fluctuate very little. Marys Lake will start going up again the middle of December, once maintenance work concludes.
More Colorado-Big Thompson Project coverage here.