| Reshaping history - Revitalization of Trout Creek in the Middle Deschutes Basin |
 |
|
 |
|
|
|
|
Part of the restored channel along Martin Nye's property
|
Written by Weisha Mize, Oregon Department of Agriculture
Lots of snow. Lots of rain. Big flood. Big problem? The Army Corps of Engineers (Corps) thought so. Forty years later, the local Soil and Water Conservation District (SWCD) and resource managers are working to “fix the fix.”
A large accumulation of snow, over frozen ground in some areas, followed by rapid warming and heavy rains caused widespread flooding through eastern Oregon in December 1964. Trout Creek completely inundated the Willowdale valley and dropped the streambed over 10 feet in places due to headcutting and channel widening. Many of these cut banks are still visible today.
Major channelization in Trout Creek by the Corps followed the 1964 flood, on the theory that a straighter stream gets water off the landscape faster and reduces flood stage. While true, it also squares the stream’s erosive capability. Additionally, the resultant berms have interfered with stream function by disconnecting streams from their floodplain. On a normal stream, the stream will get into flood plain and spread out, losing velocity and force, but with a berm holding the stream in place, the water just gets higher and higher.
“This had major deleterious effects on land use, water availability, riparian health and fish habitat,” Adam Haarberg of the Jefferson County SWCD notes, “not to mention actually increasing the amount of erosion with a corresponding decline in water quality.” Trout Creek had poor fish habitat with little instream habitat complexity. In places where it was really degraded, the hardwoods were not returning, the channel continued to incise and the water table was lowering. Farmers were losing the water table to their fields and fish were losing habitat.
Beginning in 1998, a project spearheaded by Adam Haarberg and Tom Nelson of the Oregon Department of Fish and Wildlife (ODFW) to modify the berms on a site-specific basis has greatly improved stream channel morphology within an 8-mile reach, getting rid of the berms and recreating meanders on a large scale, reconnecting the river to its floodplain and reducing erosion.
Adam explains that the Corps wanted to do a project on Annan Priday’s ranch to remove old berms and stabilize the eroding streambanks. “After Tom and I saw what the Corps proposed, we felt that there was a better solution that would benefit both fish and wildlife and the landowner. The Corps’s trapezoidal channel design would handle a 100-year flood but would result in poor habitat during normal and low flows. Designing a channel to accommodate the 1.5 year event (bankfull) and constructing/connecting to a floodplain for the higher flows would result in much better habitat for fish and improve the riparian vegetation for the wildlife.” The costs for the Corps design and construction were also a big factor for Adam and Tom. “We knew that if we could design a functioning natural channel and floodplain and then have the landowners enroll it into CREP (Conservation Reserve Enhancement Program), we could address twice as much stream length for a quarter of the cost.”
Adam and Tom’s actual design and on-the-ground work began in 2002. “We went to all four levels of Rosgen training, we gathered more data, and made our plan. It’s been an amazing and rewarding experience,” says Tom.
The funding partners for the Trout Creek project are the Bonneville Power Administration (BPA), Oregon Watershed Enhancement Board (OWEB), the Deschutes River Conservancy (DRC), and Natural Resource Conservation Service (NRCS)/Farm Services Agency. BPA funded most of the project, including the initial permitting, surveying and design, and Tom and Adam’s time. OWEB provided DRC funds, and Wildlife Habitat Incentive Program (WHIP) funds came from NRCS. Through CREP enrollment, the project area is fenced and protected from grazing for 14 years, through 2021.
Praises for District’s landowner partners
From the start, Annan Priday has been remarkably supportive and helpful. “He let us do tours, surveys, worked with the Corps, and hosted or allowed many meetings on his place. He was extremely patient through the entire process, he’s a great landowner to work with,” Tom reports. “The other landowner, Martin Nye, wanted to enroll in CREP. He agreed to wait to enroll until we finished our instream work removing the berms. That made it a win-win situation for everyone.” While most of the funding came from the BPA, these two landowners contributed rock, some equipment, and a ton of patience.
Priday Ranch reach - before
| Removing a berm is not an easy task
Each reach had its own unique problems. In two reaches on Martin Nye’s property, the streambed was deeply incised down to bedrock. There was no way to restore it and get the sinuosity back to have a flood plain the creek could access. In these reaches, Adam and Tom did a full channel reconstruction, pulling the creek up into its old original floodplain elevation in an unused field, and creating ponds in the abandoned channel. | 
Priday Ranch reach- after |
On Annan Priday’s land, there were several reaches where healthy riparian vegetation had established in front of five to six foot tall berms, leaving the creek disassociated from the flood plain. Adam and Tom pulled the berms back with an excavator and used a bulldozer to feather the spoils back into flood plain. “It looked like the moon in places after we got done!” Tom exclaims. “Now when Trout Creek rises to bank full, it can start spreading out and dissipate its energy over the flood plain instead of being blocked by the berms,” adds Adam.
The science of recreating meanders
At bankfull stage, there is a bedload (sediment, rocks, gravel, etc.) that moves through the system. For each stream reach, the first thing is to determine what size rock was moving through the system at that reach, then calculate the sinuosity and slope of the creek, making sure there is sufficient velocity at bankfull to move the bedload through the system. Tom explains that the trick is to match the channel configuration and pattern: “You don’t want it so straight that it mobilizes the bedload and the existing substrate (usually the larger stationary rocks in the streambed), but not so sinuous that it deposits the bedload and forms an unstable channel.” Throughout the project reach, Adam and Tom tried to incorporate the original stream beds and recreate meanders in their original general location and configuration wherever possible, using this methodology.
Bonus benefits
In addition to habitat modification as a result of the enhanced channel morphology and improved riparian vegetation, the project has also reduced sediment by significantly reducing streambank erosion in the project area and creating a riparian buffer to filter soil-laden runoff (irrigation or storm) from reaching the stream. Because of the riparian buffers now in place, bacteria entering the creek from livestock waste have been reduced. And while it is too early to tell, Adam believes that once the newly planted riparian vegetation (especially the hardwoods) grows and the canopy forms and starts to close, the temperature of Trout Creek will be maintained if not reduced through the project area.
Measurable results
When asked, Tom proudly describes the real impacts of the project: “Well, it’s raised the water table and improved storage capability of soil, which improves growing capacity, added more topsoil, and of course improved riparian areas and fish habitat. Since 2007, steelhead are spawning in the project area, with 43 redds in Annan Priday’s reach and 46 in Martin Nyes’ reach. Riparian vegetation is well on its way to coming back, starting from nothing.”
And what a lot of planting that ‘nothing’ needed! With help from a tree crew, a fence crew, and some hired labor and equipment, Adam and Tom planted 64,680 trees (two species of alders, red osier, mock orange, service berry, chokecherry, wood rose, elderberry, cottonwood, two species of willows, aspen, and a few pines), and 3,800 pounds native grass seed.
In addition to the new vegetation, the CREP buffer totals 244 acres, 8.7 surface acres of wetland and 97 pool complexes (riffle-run-pool-glide) were created, and 1.14 miles of stream sinuosity were added in the three years of construction.
As proof of the effectiveness of the Trout creek project, the first high water in 2005, a year after the first phase of the project, was a 35-year flood event. “It held up pretty good,” say Adam and Tom. Way to go, guys. Way to go.
Adam Haarberg can be reached at the Jefferson County SWCD at 541-923-4358 ext. 129, or by e-mail at adam.haarberg@oacd.org . Tom Nelson number at ODWF’s Madras office is 541- 475 2183 x 22, or you can e-mail him at Tom.Nelson@state.or.us . |
|
|
| |
|
|
