OSU Study: Rivers recover natural conditions quickly following dam removal

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CORVALLIS, Ore. – A study of the removal of two dams in Oregon suggests that rivers can return surprisingly fast to a condition close to their natural state, both physically and biologically, and that the biological recovery might outpace the physical recovery.

The analysis, published by researchers from Oregon State University in the journal PLOS One, examined portions of two rivers – the Calapooia River and Rogue River. It illustrated how rapidly rivers can recover, both from the long-term impact of the dam and from the short-term impact of releasing stored sediment when the dam is removed.

Most dams have decades of accumulated sediment behind them, and a primary concern has been whether the sudden release of all that sediment could cause significant damage to river ecology or infrastructure.

However, this study concluded that the continued presence of a dam on the river constituted more of a sustained and significant alteration of river status than did the sediment pulse caused by dam removal.

“The processes of ecological and physical recovery of river systems following dam removal are important, because thousands of dams are being removed all over the world,” said Desirée Tullos, an associate professor in the OSU Department of Biological and Ecological Engineering.

“Dams are a significant element in our nation’s aging infrastructure,” she said. “In many cases, the dams haven’t been adequately maintained and they are literally falling apart. Depending on the benefits provided by the dam, it’s often cheaper to remove them than to repair them.”

According to the American Society of Civil Engineers, the United States has 84,000 dams with an average age of 52 years. Almost 2,000 are now considered both deficient and “high hazard,” and it would take $21 billion to repair them. Rehabilitating all dams would cost $57 billion. Thus, the removal of older dams that generate only modest benefits is happening at an increasing rate.

In this study, the scientists examined the two rivers both before and after removal of the Brownsville Dam on the Calapooia River and the Savage Rapids Dam on the Rogue River. Within about one year after dam removal, the river ecology at both sites, as assessed by aquatic insect populations, was similar to the conditions upstream where there had been no dam impact.

Recovery of the physical structure of the river took a little longer. Following dam removal, some river pools downstream weren’t as deep as they used to be, some bars became thicker and larger, and the grain size of river beds changed. But those geomorphic changes diminished quickly as periodic floods flushed the river system, scientists said.

Within about two years, surveys indicated that the river was returning to the pre-removal structure, indicating that the impacts of the sediment released with dam removal were temporary and didn’t appear to do any long-term damage.

Instead, it was the presence of the dam that appeared to have the most persistent impact on the river biology and structure – what scientists call a “press” disturbance that will remain in place so long as the dam is there.

This press disturbance of dams can increase water temperatures, change sediment flow, and alter the types of fish, plants and insects that live in portions of rivers.  But the river also recovered rapidly from those impacts once the dam was gone.

It’s likely, the researchers said, that the rapid recovery found at these sites will mirror recovery on rivers with much larger dams, but more studies are needed.

For example, large scale and rapid changes are now taking place on the Elwha River in Washington state, following the largest dam removal project in the world. The ecological recovery there appears to be occurring rapidly as well. In 2014, Chinook salmon were observed in the area formerly occupied by one of the reservoirs, the first salmon to see that spot in 102 years.

“Disturbance is a natural river process,” Tullos said. “In the end, most of these large pulses of sediment aren’t that big of a deal, and there’s often no need to panic. The most surprising finding to us was that indicators of the biological recovery appeared to happen faster than our indicators of the physical recovery.”

The rates of recovery will vary across sites, though. Rivers with steeper gradients, more energetic flow patterns, and non-cohesive sediments will recover more quickly than flatter rivers with cohesive sediments, researchers said.

This research was supported by the Oregon Watershed Enhancement Board, the National Oceanic and Atmospheric Association and the National Marine Fisheries Service. It was a collaboration of researchers from the OSU College of Agricultural Sciences, College of Engineering, and College of Science.

The study this story is based on is available online: http://bit.ly/1rdQ4wL

 

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Mirror Pond levels to drop next week for dam inspection

Bend, Ore. — PacifiCorp will lower the Mirror Pond water levels next week to facilitate another inspection of the dam.

The inspection will be conducted by Gannett Fleming, an engineering firm from Phoenix, for the Bend Parks and Recreation District as part of deliberations around the potential acquisition of the dam from PacifiCorp to maintain Mirror Pond after the facility is no longer used to generate electricity.

The drawdown will begin Tuesday morning and will continue gradually until about midday on Friday. The pond will be allowed to refill starting Friday afternoon and should be full again by the Sunday morning. The inspection itself is scheduled to occur on Thursday and Friday. According to BPRD employee Jim Figurski, for safety and security reasons, access to the inspection will be limited to BPRD personnel, the inspectors and PacifiCorp.

Because of increased flows compared to last October when the Mirror Pond was drawn down to facilitate a PacifiCorp inspection, water levels are not expected to drop as dramatically this time, although it will likely be noticeable.

As was the case during the October drawdown and refilling of Mirror Pond, PacifiCorp will monitor water quality and conduct fish surveys consistent with state regulatory requirements.

PacifiCorp inspected the dam on October 31 after a leak developed in one of the structure’s wooden panels. The inspection concluded that while the facility was safe, it would not be cost effective to rebuild the entire facility to generate power for current and future generations of customers across PacifiCorp’s six-state territory. Since then, the company and representatives of the Bend Parks and Recreation and the City of Bend have been in discussions around potentially transferring the dam to a local entity so the community can realize its vision for the future of Mirror Pond.

PacifiCorp has announced plans to install sheet pile reinforcement in front of the leaking panel. The reinforcement work is planned to take place in April, or earlier if permitting is complete and a contractor is in place. The company does not anticipate needing to lower Mirror Pond levels again for that procedure.

Potential flooding for Tumalo

The Deschutes County Sheriff’s Office is continuing to monitor the situation regarding potential flooding along the Deschutes River in the Tumalo area. In coordination with the Deschutes Basin Watermaster, we have been assessing the potential risk of flooding that could involve homes in Tumalo. At this time, stream gauges are continuing to rise along the Deschutes River.

Due to the potential risk, we are asking those recreating on the river such as kayakers to use caution and avoid accessing the river below Mirror Pond. Hazardous river conditions could exist. We also ask that people avoid low lying areas such as river trails along the Deschutes River.

The potential for flooding exists in the Tumalo community. Residents that live along the Deschutes River in Tumalo should be prepared for a flood event. The Deschutes County Sheriff’s Office and Water Master have been contacting residents in areas of highest risk to offer information.

Preparations include:

· Move valuables to higher ground, or higher floors
· Prepare a disaster kit. For more information see: www.ready.gov
· Prepare for evacuation as necessary
· Avoid walking or driving through high water

Deschutes County Sheriff’s Office Emergency Management is coordinating with the Deschutes Basin Watermaster and their partners to monitor and respond to this event. Deschutes County Sheriff’s Deputies and Search and Rescue Volunteers are preparing to offer assistance in the event it becomes necessary.

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Flooding Expected Along Little Deschutes and Deschutes Rivers

On 02-16-14, the Deschutes County Sheriff’s Office became aware of high water flows along the Little Deschutes River in the La Pine area. Based on information from the Deschutes Basin Water Master, we expect flooding to increase that could affect homes over the next few days.

Residents of La Pine along the Little Deschutes River to the confluence with the Deschutes River should begin making preparations for high water that will likely affect homes. The water will continue to rise peaking over the next few hours.

Residents in the Tumalo area along the Deschutes River will likely see high water peaking sometime on Monday night through Tuesday morning. Tumalo residents along the Deschutes River should begin making preparations for high water that could affect homes.

Preparations include:

Move valuables to higher ground, or higher floors
Prepare a disaster kit. For more information see: www.ready.gov
Prepare for evacuation as necessary
Avoid walking or driving through high water

Other areas may see high water, but the primary watch locations are mentioned above.

Deschutes County Sheriff’s Office Emergency Management is coordinating with the Deschutes Basin Water Master and their partners to monitor and respond to this event. Deschutes County Sheriff’s Deputies and Search and Rescue Volunteers are preparing to offer assistance.

The Deschutes County Sheriff’s Office requests unneeded sandbags distributed on Friday, February 14th be returned to the Riverwoods Country Store to be used other parts of the county.

BY: Sgt. Nathan Garibay, Emergency Services Manager

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Mirror Pond Dam Fix Planned for April

BEND, Ore. – PacifiCorp will reinforce a section of the company’s dam in downtown Bend to address a leak in one of the structure’s wooden panels that developed in October of 2013. The installation of steel sheet pile upstream of a leaking panel is planned to begin in April.

The company stopped generating power at the dam following the leak, and announced in November that it is not cost-effective to rebuild the entire facility to generate power for current and future generations of customers across its six-state territory. PacifiCorp has since been in formal discussions with Bend Parks and Recreation and the City of Bend regarding a potential transfer of the dam to a local entity for the purpose of maintaining the Mirror Pond impoundment.

“Though the dam remains safe, we fully understand the community’s concern about the potential for low water levels during summer recreation months,” said Mark Tallman, PacifiCorp’s vice president for renewable resources. “It’s possible Mirror Pond would have remained full this summer without this fix, but in our view this is the right action to take at this time.” Tallman said. “This reinforcement is also anticipated to restore hydro generation for the year, and should provide the community with more certainty about the structure and Mirror Pond during the summer season and going forward.”

The company used the sheet pile technique previously to address similar leaks in other wooden panels, known as bays. The work involves driving long pieces of interlocking steel sheets into the river bed to create steel facing on the upstream side of the leaking panel.

“This action will also facilitate further discussions with community leaders to determine if an agreement can be reached that enables PacifiCorp to clearly demonstrate that placing the dam under local control is better for all our customers than dam removal or other alternatives,” Tallman said.

“The company is very committed to trying to find the best possible outcome regarding this facility that balances the community’s priorities for Mirror Pond and our regulatory obligations” said Scott Bolton, PacifiCorp’s vice president for community and government relations. “That includes taking steps like this reinforcement as part of our community commitment, and our support of efforts by community leaders to preserve Mirror Pond’s future.” Bolton added, “We are hopeful an agreement can be reached that allows this to happen and also protects the interest of our rate-paying customers in Bend and throughout our six-state service area.”

Bend Senior High School Lockdown Release Information

Bend Police and Emergency Responders were called to Bend Senior High School shortly after a noon 9-1-1 call that a student had allegedly committed suicide on campus. The school is in lockdown at this hour as police investigate the situation. There is no further threat to students or staff and the building is secure. A crisis team has arrived on campus and is meeting with those affected.

Staff will begin escorting students out of the building, by wing, to their vehicles, buses, and off campus – for pedestrians and bike riders – at approximately 2:35pm. Student pedestrians and drivers will exit campus via the 6th Street and Clay campus exit. Parents can pick up their students at the Presbyterian Church on 9th Street. Campus will remain closed to visitors through the weekend.

Students, staff or community members who would like to meet with counselors, at no cost, can drop in to Bear Creek Elementary School between 9am – 2pm tomorrow.

All evening activities are canceled at Bend Senior High.

Our hearts go out to the students, staff and our community at Bend Senior High School.

Normally, the District and law enforcement would not share public information regarding a suicide, but due to the circumstances, the District felt it important to share this sad information with families and the community.

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First SuperForum Welcomes Gov. Kitzhaber to Bend

BEND, OREGON-The first SuperForum-Shaping the Future of Central Oregon, presented by Bend 2030 and programming sponsor the City Club of Central Oregon, welcomes Oregon Governor John Kitzhaber and First Lady Cylvia Hayes as the keynote speakers to discuss how Central Oregon can attain “prosperity with a view” and balance growth with livability in an exciting, interactive and informative evening.

This event will take place on Tuesday, Jan. 21, 2014 at 7 p.m. at the Tower Theatre, with doors opening at 6:15 p.m.

An unprecedented third-term Oregon Governor, Kitzhaber is motivated by his commitment to provide equity and opportunity for all, to secure jobs with upward income mobility, and to ensure safe communities where people have a sense of common purpose. He and First Lady Cylvia Hayes (a part-time Bend resident) will discuss their insights for Central Oregon in this SuperForum.

The SuperForum will also offer a snapshot of Bend 2030 Vision Accelerator Projects that are making a difference in our community, real-time audience electronic polling, and an opportunity to continue the conversation post-event.

General admission is $20 and tickets are available through the Tower Theatre box office at 835 NW Wall St., by phone at 541-317-0700, or online at towertheatre.org. A limited number of scholarships is available for students and those on a fixed income.

For more information about the event, please visit SuperForumCO.com or contact Marika Yuma, SuperForum Project Manager, at SuperForumCO@gmail.com.

For more information about bend 2030 visit facebook.com/Bend2030. For more information about City Club of Central Oregon visit cityclubco.org.

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PacifiCorp Looking to Divest the Mirror Pond Dam

BEND, Ore. — PacifiCorp has determined that it would not be cost-effective for its customers to make the investments needed to continue long-term operations at the company’s Bend hydroelectric generating project.

The decision follows a thorough engineering inspection of the project dam after a leak in the dam developed in early October, the third such leak in approximately five years, which also prompted a broader analysis of the facility.

“First and foremost, the inspection confirmed what we expected; the dam remains safe and is in overall good condition for a 100-year old facility, but further investment would be required for the hydro project to operate long term,” said Mark Tallman, PacifiCorp’s vice president for renewable resources.

“After a century of producing clean, emission-free and affordable power for customers, it’s time to divest or retire our Bend hydroelectric plant,” Tallman said. “It simply isn’t cost-effective or in the best interests of all our customers throughout six western states for PacifiCorp to rebuild the facility and generate power to serve current and future generations of customers.”

The project is located near the Newport Avenue Bridge. In addition to diverting water for the company’s hydroelectric project, the dam creates Mirror Pond on a section of the Deschutes River in downtown Bend. The Bend community has been engaged in extensive public discussions of its desires and priorities for the future of Mirror Pond.

“We’ve known and have been candid with the community that the facility was reaching the end of its useful life as a generating facility for PacifiCorp’s customers. That time is now here, accelerated by the recent new leak. This converges with public conversations and comparison of options the public has participated in,” said Pat Egan, PacifiCorp’s vice president for customer and community affairs.

The company will pursue discussions with the Bend Parks and Recreation District and the City of Bend to determine if an agreement can be reached that places the dam under local control in a way that PacifiCorp can also demonstrate to regulators that the outcome is in the best interest of PacifiCorp’s customers.

“The company wants to be supportive of community efforts to preserve its vision for the future of Mirror Pond as long as PacifiCorp can also meet its regulatory obligations,” said Egan. “Among the various options we must responsibly explore, we are hopeful an agreement can be reached that allows this to happen and also protects the interest of our rate-paying customers in Bend and throughout our multi-state service area.”

Pacific Amateur Golf Classic returns Sept 21-26

Entering its 17th year of competition, the Lithia Pacific Amateur Golf Classic is the longest running net-amateur tournament of its kind in the west.

With over 600 golfers competing on the finest golf courses in Central Oregon, the “PacAm” provides a professional golf tournament experience for the average golfer.

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