Roaring Fork River running high after Twin Lakes diversion ends
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ASPEN — The roar was put back in the upper Roaring Fork River this week, as the Twin Lake Reservoir and Canal Co. curtailed its diversions near the top of Independence Pass and let more water flow in the river through Aspen and down to the Colorado River.
The water returned to the river first makes its presence felt in terms of volume, as the Roaring Fork River above Difficult Creek east of Aspen climbed from about 200 cfs Tuesday to about 600 cfs by Thursday morning, swelling the slow-moving section of river through North Star to the upper limit of its banks.
The higher flows in the river as a result of Wednesday’s curtailments had not caused any problems in the valley as of midday Thursday, Pitkin County emergency manger Valerie MacDonald said.
“We still urge caution for people recreating in and around the river,” MacDonald said. “While many in the local community may appreciate the restoration of the natural flows in the river, the swift current, the cold temperature of the water and the now-slippery banks and rocks can catch visitors unaware.”
This is the third consecutive year the company curtailed its transmountain diversions from Lost Man Creek, Lincoln Creek and the Roaring Fork due to legal and physical constraints.
It is not clear how long it will be before Twin Lakes Co. starts diverting again, lowering flows in the Roaring Fork.
“Once flows in the Arkansas (River) start to drop, which they will eventually, that will create more demand for Twin Lakes water and then we’ll start taking some more,” Twin Lakes Co. President Kevin Lusk said. “But in terms of how much and when, it’s really up to the weather and the different shareholders, in how they are managing their supplies.”
Last year, the tunnel was closed from June 14 to 28.
At dawn Wednesday, 598 cfs of water coursed out of the Twin Lakes-Independence Tunnel on the eastern slope after having entered the tunnel at Grizzly Reservoir on Lincoln Creek on the west slope. But by midnight, there was just 5 cfs flowing through the tunnel.
Correspondingly, the flow in Lincoln Creek below Grizzly Reservoir went from a trickle of 2.8 cfs at the start of Wednesday, and ended the day at 319 cfs, which is enough water to make it hard to wade across.
And the rest of the water was being released down Lost Man Creek, the main stem of the Roaring Fork, and three creeks that run into lower Lincoln Creek.
At 10:30 a.m. Wednesday, the tunnel under Independence Pass was fully closed and water was then collected and instead slowly released out of Grizzly Reservoir, with all of the water fully turned out by 9:30 p.m. Wednesday.
Lincoln Creek and the Roaring Fork come together just below Lincoln Gulch Campground and just above the Cascades at the Grottos area on Independence Pass.
At 8:25 p.m. Wednesday, the front edge of the flow of water released in Lincoln Creek reached the confluence with the Fork and quickly changed the character of the creek from walkable to swimmable.
And around the corner from the confluence of the Lincoln Creek and the Fork are the Cascades, which went from mild on Wednesday afternoon to wild by Thursday afternoon when whitewater poured over the rocks in a renewed frenzy of foam and spray.
In addition to adding volume to the river and creeks, the return of natural flows brings the Roaring Fork headwaters back to life, adding an urgency and vibrancy to the flow that’s been missing since the Twin Lakes diversion system was built in the 1930s.
The system originally sent water to sugar beet fields in the Arkansas River basin, but most of the water today goes to Colorado Springs, Pueblo, Pueblo West and Aurora.
The water rights held by Twin Lakes Co. have limitations that can cause it to stop diverting, including a junior diversion right on the Colorado Canal, which takes water from the Arkansas River near Ordway, and the amount of water in Twin Lakes Reservoir, which is owned and operated by the Bureau of Reclamation.