The earth drops away, and the twisting, turbulent Animas River suddenly comes into full view as LightHawk pilot Jim Grady guides his 1953 Cessna 180 into the faded blue sky near Durango.
But this flight is focused on the Lower Dolores River at high flows, so Grady makes a beeline west for McPhee Reservoir Dam, where water managers released record flows of 4,000 cubic feet per second last weekend.
Celene Hawkins of The Nature Conservancy is part of a team of private and government researchers studying the ecological benefits of the rare flushing flows on the sometimes water-starved river that feeds Southwest Colorado.
The day before, she was rafting the river to monitor effects, but seeing it from the air provides a bigger picture.
“From here, you can really see the river braiding, overflowing its banks and filling backwaters relied on by native fish,” she said. “Yesterday on the river was a celebration at Snaggletooth Rapid.”
Down on the river, Jeff Christenson, a Bureau of Land Management recreation planner, watched as Grady dipped toward the BLM’s Gypsum Valley boat ramp where brightly colored rafts embark on the Slick Rock Canyon run, one of the most scenic and wild sections of the Dolores.
The river has been very busy, and there have been no reports of injuries, major accidents or rescues.
“Boaters are looking out for each other,” Christenson said. “There have been some swimmers at Snaggletooth Rapid. A lot of Dove Creek residents traditionally come down to sit on the bank and watch the excitement.”
On May 6, he counted 89 vehicles at the Bradfield Bridge put-in, and 75 on May 7. During a boater count May 6, 130 people floated by between 8 a.m. and 1 p.m.
“But when we compared that to the boating register, only 34 had registered, so we want to remind boaters to register because our funding for managing river recreation is tied to visitation numbers,” he said. “It is also important to know where people are in case of emergencies.”
At 4,000 cfs, boaters cruise along at 20 mph, and rapids normally raucous at lesser flows become washed out.
“Snags are being swept away, the river corridor is much wider and is breaching its banks,” he observed.
Seven miles downstream of Bradfield Bridge, boaters reported a large herd of elk swimming across the river in front of them. Desert bighorn sheep watch from the cliffs, river otters swim alongside boaters and flurries of butterflies fly by.
The BLM hired Sam Carter as a seasonal river ranger in partnership with the San Jun Mountains Association. He has been helping boaters and directing traffic at the crowded Bradfield and Pumphouse put-ins.
Five monitoring sites are recording the ecological benefits of this year’s release, Hawkins said. The research is in partnership with Colorado Parks and Wildlife, the BLM, the Dolores Water Conservancy District, Dolores River Boating Advocates and American Whitewater.
Flying over the Disappointment Creek confluence, she explains that the creek dumps high volumes of sediment into the Dolores, which builds up without regular flushing flows.
“When the fine sediment is cleared, the cobble habitat improves for native fish,” she said. “High flows scour out pools, making them deeper for fish during low-water conditions.”
The release also recharges groundwater aquifers, and the flooding allows native seeds to be dispersed beyond the river corridor. It also reduces the effect of “channel armoring,” a result of consistent low flows, which creates a ditch effect and blocks the river from flowing over the banks and into back channels.
“It is behaving more naturally with a lot of river channel diversity, and that improves fish habitat,” Hawkins said.
This year’s above-average snowpack allowed reservoir managers to easily fill the reservoir for farmers and to collaborate with environmentalists on implementing a release plan that mimics a natural spring hydrograph for ecological benefits.
“We have 10 years of science on the river on how to best utilize high flows, and now we get to see the benefits at different flow levels,” Hawkins said. “We’re seeing that without peak flows, the river channel loses its complexity.”
A series of weak winters between 2011 and 2015 prevented any release below the dam, and the chronic low flows hurt river ecology. But two years of average to above-average snowpack has brought it back to life.
“Low flows are a tough issue,” Hawkins said. “We understand water supplies are tight and depended on by local economies. We have a good collaborative approach between the different water users to determine the best system, and we are improving every year.”
jmimiaga@the-journal.com
