The Bureau of Land Management Uncompahgre Field Office has successfully utilized a low-tech, natural technique to restore East Paradox Creek near Bedrock, which had blown out of its natural channel during a 2013 flash flood.
BLM ecologists and volunteers installed a unique picket baffle system made up of more than 300 cedar posts that trapped sediment and debris.
The structure hardened and restored the blown out bank. It encouraged water from East Paradox Creek to turn and flow back to its native channel.
The ephemeral creek, a tributary of the Dolores River, provides essential water for a cutoff oxbow that includes one of the largest cottonwood galleries on the river, said BLM ecologist Ken Holsinger.
Oxbows, usually in the shape of a “C” or “U,” are abandoned meanders of rivers.
The oxbow fed by East Paradox Creek provides habitat for cottonwoods and wildlife, including a variety of bird species, deer and elk.
When monsoonal storms caused the creek blow out of its channel, it not only starved the cottonwoods of water, but its new course also damaged a road and threatened nearby injection wells of the Bureau of Reclamation’s Paradox Valley Salinity Control Project.
“You could see cottonwood die off because the oxbow had been cut off from water,” Holsinger said. “Another problem was the new course was flooding the injection wells.”
He and staff saw an opportunity to test the picket baffle system that uses natural materials to reharden the blown-out bank to get the water flowing back into its channel and on to the oxbow.
The technique was first designed by hydrologist Bill Zeedyk, a so-called “river-recreator” and author of “Let the Water Do the Work: Induced Meandering.” He promotes the use of low-tech natural materials and processes.
“We were not sure how well it would work, but it was successful and we were able to document it redirecting the creek back into its native channel,” Holsinger said. “The concept is to roughen the corner, which allowed the water to take the path of least resistance.”
BLM staff and 12 volunteers with the Dolores River Boating Advocates and Rivers Edge West installed cedar posts in staggered rows at the point of the blown out bank. Woody debris was also woven in between the posts to capture the sediment.
“It was a fun and different project,” said volunteer organizer Rico Fulton, stewardship director for DRBA. “The picket baffle is based on the philosophy of letting the natural system of sediment reinforce the bank structure.”
The posts slowed water flow, causing a natural barrier of sediments to form, and prevented the stream from flowing straight ahead to the newly eroded flood area.
“The sediment filled in between the posts and almost buried them in places,” Holsinger said.
The initial group of cedar posts were installed in 2019. A flash flood in October 2021 showed 85% of the stream was being successful so directed, so 175 more posts were installed, according to a BLM report.
The creek channel restoration filled the oxbow with 2 to 3 feet of water, providing a much needed drink for the cottonwoods.
“Cottonwoods are looking more vigorous, there are reports a new heron rookery has been established,” Holsinger said.
The additional posts extended the original picket baffle to make the restoration more effective for future storms.
A storm in late July and a much bigger storm in early October flooded the creek and tested the system, which showed fully restored flow into the historic East Paradox creek channel.
“It was amazing how well it worked,” Fulton said. “The oxbow has greened up and doing a lot better. The cottonwoods are over 100 years old and are a key part of that habitat. It feels important to keep them alive.”
She said project participants were thrilled to witness the restored habitat and see blue herons return. The area, which is on private property, is also relied on by elk during the winter months.
Using low-tech is also lower priced, Holsinger said. The project supplies and labor cost were less than $20,000.
“We’ve documented this low-tech restoration works, and the hope is that it will be used in other places,” he said.
jmimiaga@the-journal.com
