Colorado River-Big Thompson Project Update
Kara Lamb (970) 962-4326, Eastern Colorado Area Office, Reclamation 11056 W. CR 18E,
Loveland, CO 80537 United States
It has been an interesting week with the weather this past week. On and off rain and
fluctuating temperatures have made the snowmelt runoff difficult to anticipate.
That, combined with some regular work around the Colorado-Big Thompson Project, has
had an effect on how we move water through the project.
This week, due to cooler temperatures, melting snow down the Big Thompson River into
Lake Estes dropped off considerably. While Lake Estes is filled primarily by C-BT
water coming from the west slope and delivered through the Estes Power Plant, we
have been moving that water on down through the project and into Horsetooth
Reservoir. When the natural inflow from Big Thompson dropped off, that dropped the
water level of Lake Estes down a full foot to around 7470--about five feet below
full. We anticipate that over the weekend, we will be able to store a little more
behind Olympus Dam and raise the water level of Lake Estes back up that foot to
around 7471 or maybe even 7472.
Downstream of Lake Estes, the Big Thompson River through the canyon has been
fluctuating, reflecting the inflows we have been seeing from the upper Big Thompson
River to the reservoir. We have been passing matching inflows through Olympus Dam on
down through the canyon. The changing temperatures play the largest role: when it is
warmer, more snow melts during the day, causing flows in the Big Thompson to rise at
night. We adjust the gate at Olympus Dam to reflect those flows and pass them on
down to the canyon. But, when it cools off, the inverse happens, less snow melts,
and flows in the river drop off. That is why the Big Thompson below Olympus Dam
started at around 175 on Monday, bumped up to near 300 cfs on Tuesday, dropped to
just under 200 cfs on Wednesday, and is now flowing around 125 cfs. Depending on
what the weather does, we will adjust the release from Olympus Dam at night to match
the snowmelt coming down the river.
"Down canal" from Lake Estes is Pinewood Reservoir. Pinewood stores water above
Flatiron Power Plant before we drop the water down the penstocks to generate
hydro-electric power at the plant. We have been doing some upgrades at Flatiron for
several months--and that will continue through the summer. Because of that, we are
generating with one unit instead of two. This means, we cannot run as much water
through the plant. So, we are not filling Pinewood as full as it typically has been
this time of year in other years. As a result, Pinewood has been holding a fairly
steady water elevation of around 6567 most of the spring. On Wednesday, the change
in inflow at Lake Estes also effected Pinewood and the water elevation dropped three
feet to about 6564--about 16 feet down from full. As we move through the weekend,
the elevation at Pinewood will climb back a little bit, but we do not anticipate it
getting much higher than 6570--ten feet down from full.
Carter Lake has remained steady at an elevation of 5753--about six feet down from
full. Once warmer weather hits, we anticipate water users will begin to pull their
water from Carter Lake. But, the rain has staved that off a bit. We anticipate
Carter will maintain this water elevation through the weekend.
Similarly, Horsetooth Reservoir has been holding at a steady elevation of about
5416, almost 5417. Like Carter, we have not seen much water go out of Horsetooth,
yet, for water users. Again, the rain is probably holding that off. We have been
bringing only a little water into Horsetooth Reservoir over the past week because
water users downstream on the Big Thompson River are taking some of their C-BT
water. If that demand drops off and the cool weather continues, Horsetooth will rise
slightly. Otherwise, it is likely to maintain the same water elevation through the
weekend, as well.