Dam Near Done

The Newport Avenue dam is at the end of its life cycle. Everyone knows it—even PacifiCorp, the utility company that owns the 102-year-old dam, which creates the pond at Drake Park near downtown Bend.

What many don’t know, however, is that the dam cannot remain if it ceases to function as a hydroelectric facility. Those are the rules: According to water-right certificate No. 29581, Pacific Power & Light Co. (now PacifiCorp, which owns Pacific Power) has the right only to use the water for power generation and ice and debris removal. There’s no built-in right for storing water.

So, the idea that PacifiCorp can simply retire the crumbling dam from service as a power-generating tool, but leave the structure in place to retain a pond, is a thought that should no longer be considered.

“By no means could it stay there just to keep Mirror Pond,” said Deschutes Basin Watermaster Jeremy Giffin, who also put to rest talk of transferring those water rights for recreational purposes. All of the water rights on the Upper Deschutes River, said Giffin, have already been allocated.

PacifiCorp officials hope, however, the case isn’t as cut and dried as it seems. Company spokesman Bob Gravely said, although, “it’s not really an issue we’ve looked at closely,” he’s optimistic a solution could be found that would allow the dam to remain in place.

But the water-right news puts PacifiCorp in a tight spot. Company representatives have admitted that, from a hydroelectric standpoint, the dam provides negligible electricity. According to company stats, the dam only generates enough power for 300 to 400 homes. Angela Price, PafiCorp rep and Mirror Pond Steering Committee member, recently called the structure “a small asset.”

Moreover, altering the Newport Avenue dam is also an unlikely course. Adding fish ladders and other such necessary updates or repairs would be expensive and would trigger action from the Federal Energy Regulatory Commission. FERC licensing would be a costly route that could take years to navigate—an unappealing scenario for PacifiCorp.

Jim Figurski, the project manager who’s been hired by the city and Bend Park & Recreation District to find a fix for a pond that is clogging with silt, has already thought about all this.

“My understanding is that the water right is solely associated with the generation of power,” said Figurski, echoing Watermaster Jeremy Giffin’s words. Figurski added that, while he can’t speak for the city, he thought a handoff or sale of the dam from PacifiCorp to the city highly unlikely.

To account for this, Figurski, who also sits on the Mirror Pond Steering Committee, the decision-making body overseeing the project, said at least three of the four possible solutions being drafted by his consultant team will include a Deschutes River with no dam in place at Newport Avenue. Figurski expects to have four designs, ones created by Portland’s Greenworks, a landscape architecture and environmental design firm, ready for public viewing and input by early June.

Fellow Steering Committee member Ryan Houston, Upper Deschutes Water Council executive director, is enthusiastic about Figurski’s approach but wants to make one thing clear: “Whether you want a pond or not is irrelevant—that dam is old,” Houston said. “The writing is on the wall.”

Going forward, Houston said he hopes the community can understand that the issues swirling about the silt-filled pond aren’t either/or.

“It’s either going to benefit recreationalists or homeowners; water quality versus not—when I hear someone playing these things off of each other as if they’re-black and-white solutions, I say ‘no,’ ” Houston said. “They’re false choices.”

Some would like to see the pond stay, no matter the cost, as they see it as an iconic Bend fixture. Other residents, who value the river’s health, would rather see the Deschutes return to a more natural state. River enthusiasts hope the solution allows for more recreating on the river. Others still ask that the area around Drake Park remain aesthetically pleasing.

The solution, Houston said, should be clever enough so that it pleases environmentalists, neighbors and recreationalists alike.

Figurski agrees, and said he’s trying to help his design team think outside of the box.

“The potential to retain pond-like characteristics,” Figurski said, is there, even without a dam.

But, at this point, one eventuality is clear—the dam’s days are numbered. SW

Source: The Source Weekly ©2013

How much water is flowing through Mirror Pond?

mirror-pond-spillway

The flow of the Deschutes River through Mirror Pond depends highly on the type of winter we are having. During dry years the winter flow through Mirror Pond is around 450 CFS and during wet years (when the Watermaster is passing live flow out of the upper basin reservoirs) it can be as high as 1600 CFS. In the summer it ranges from 1400-1600 CFS, depending upon irrigation demand.

Dam Inspection for Mirror Pond Dam 2012

Oregon-Header-KitzOctober 16, 2012

Roger L. Raeburn, Manager Dam Safety
PacificCorp Energy
P.O. Box 3040
Portland, OR 97208

Re: Bend Hydro (Mirror Pond) Dam (B-99)- Inspection Summary

This dam was inspected on July 12, 2012. I performed the inspection with District 11 Watermaster Jeremy Giffin. You were there, as were Tom Becker and Nathan Higa from Pacific Corp. and provided very helpful dam history and safety information. The Water Resources Department conducts these routine inspections to identify safety, maintenance or operational issues that may affect dam integrity. Dams are assigned a hazard rating based on downstream hazard to people and property, not on the condition of the dam. Bend Hydro (Mirror Pond) dam is classified as a significant hazard dam. Significant hazard dams are inspected every 2-3 years.

The results of this inspection are illustrated and described in the following photos and text. This inspection includes recommendations to keep the dam safe

Results of Inspection:

The spillway is often the most important safety feature of a dam. The spillway is needle type structure, with multiple bays to wood stop and end timbers, and a more recent concrete cap.

Reservoir , log boom, and old needle style spillway section
Reservoir , log boom, and old needle style spillway section

A walkway constructed on top of the cap that allowed detailed inspection of top of the spillway section. The walkway was sound.

Old section, with old timbers on downstream face
Old section, with old timbers on downstream face

The rest of the spillway received visual inspection only. Some of the timbers show signs of significant decay. The concrete sections that support the bays, and their foundations near original, and a more thorough inspection at very low water would be prudent.

Leak controlled by sheet piling
Leak controlled by sheet piling

A leak through the spillway section was discovered by Watermaster Jeremy Giffin a couple of years ago. The leak was controlled by installation of sheet pi ling as shown above. The leak is an indicator that this part of the dam is showing its age, and in need of a thorough inspection to evaluate the base and the condition of the large timbers, and the overall needle structure.

New emergency gate control valve
New emergency gate control valve

The Emergency gate for this dam was just replaced with a new motor and controls. It was operated during the inspection (for a small part of its cycle, as the gate is not in the same condition as its control). The gate and control functioned well for this limited operation.

Release of water from gate during inspection
Release of water from gate during inspection

The gate structure is also old, but appears to be operational, and was opened for limited flow as described above. When closed, there is moderate leakage, mostly through gaps between the old timbers.

Concrete buttressed wall section
Concrete buttressed wall section

The concrete buttress wall forms the middle section of the dam. It is mostly the original section, so is also 100 years old. There are areas of minor to moderate spall, and some fairly minor cracking. Overall, the section appears sound. The area below the dam is well maintained grass, with no wet areas, and was maintained for easy inspections.

Minor seepage and old concrete deterioration
Minor seepage and old concrete deterioration

The location above shows the maximum deterioration seen in the buttressed wall section. Seepage loss was low, around one gallon a minute. This is not a concern at this time.

bend-hydro-power-house-2012
Powerhouse Section

The powerhouse wall is also one of the dam sections. This was inspected from the inside, and is in the best condition of any of the dam sections, with no leaks or significant cracks.

Access to and security at the dam was very good. It is, fenced with appropriate signage. This is a run of the river reservoir, and there are no signs of erosion around the dam site.

Recommendation(s):

  1. Continue with good maintenance and operations, including security, vegetation control, and security.
  2. Evaluate Deschutes River flow, and accompany me on an inspection of the base of the spillway structure at very low water. I will coordinate with you and Watermaster Jeremy Giffin on the timing of such an inspection.

We use a standard inspection form for all dams, and a copy of the field inspection sheet for this dam is attached. The next regular inspection is planned for 2015. Thanks for sending me the drawings of the dam, and please let me know if you have any questions about this inspection.

Sincerely,

Keith Mills, P.E., Dam Safety Engineer

Document: Bend Hydro Inspection 2012-1

Related: Dam Inspection Summary 2009Mirror Pond dam passes inspection

Dam Inspection for Mirror Pond Dam 2009

Dam-Inspect-Letter-B-99-Jul-21-09-1-HeaderJuly 21, 2009

Gregg Sheerer
Pacific Power
201 SW Columbia Ave
Bend, OR 97702

Re. Dam Inspection for Mirror Pond Dam (Bend Hydro Project, File B-99)

On April 27th, Jeremy Giffin (Watermaster) and I inspected Mirror Pond Dam. A field form is attached. It was great having someone there to discuss issues with and ask questions. These complementary dam inspections are done as part the State of Oregon’s Dam Safety Program. This dam has similar issues to what was observed in a 2005 inspection (Letter dated Octobler 10, 2005) which included the following key issues:

  • There was considerable seepage and some spalling along the downstream slope of the dam along the spillway area along the center part of the dam (upstream of island area)(Figure 1).
  • The sluice gates in the turbine bays had considerable leakage (Figure 2).
  • The stop logs were in generally poor condition.
  • Some of the cribs were really pushing a great deal of water out along the left side (spillway portion of the dam and make shift repairs had been done to some) (Figure 3).

I would suggest having the damaged concrete examined in greater detail by a concrete expert considering the seepage that is forming there. Some of the cribs along the spillway section are nearing the end of their functional life and should be prioritized and repaired over time. Please keep us in the loop on the current repairs that are going to be done.

Please let me know if you have any questions. We look forward to continued mutual cooperation to insure the safety and stability of this dam.

Sincerely;

E. George Robison, PhD
Dam Safety Coordinator
george.robison@state.or.us
Ph. 503-986-0840
Fax. 503-986-0902

c. Jeremy Giffin – Watermaster OWRD, Barry Norris – State Engineer OWRD

 

Figure 1. Concrete damage upstream of island (note seepage in places).
Figure 1. Concrete damage upstream of island (note seepage in places).
Figure 2. Leakage near turbine area on far right side of dam.
Figure 2. Leakage near turbine area on far right side of dam.
Figure 3. Excessive water moving thru one of the cribs.
Figure 3. Excessive water moving thru one of the cribs.

Source: Dam Inspect Letter B-99 Jul 21-09

Related: Dam Inspection Summary 2012

 

FERC to OWRD: “FERC no longer has jurisdiction”

Mr. Barry F. Norris
Dam Safety Section
Oregon Water Resources Department
158 12th Street NE
Salem, Oregon 97310-0210

Dear Mr. Norris:

By a March 4, 1996 Order (copy enclosed), the Federal Energy Regulatory commission approved the withdrawal of license application for the Bend Hydroelectric Project No. 2643, filed by PacifiCorp Electric Operations on January 16, 1996. Upon withdrawal of this license application, the FERC no longer has jurisdiction for this project. Jurisdiction is now under the State or Oregon.

The project is located on the Deschutes River in the city of Bend, Oregon. It is classified as a “Low” hazard potential structure based on criteria established in the FERC Guidelines for the Evaluation of Hydropower Projects. Our last operational report dated August 26, 1994, identified some broken wooden planks on the downstream face of the 14-foot-high rockfill timber crib dam. It is our understanding that the required repairs have been made, and the vertical timber planks controlling the low level slots or sluices were replaced when needed. We are not aware of any conditions that indicate immediate hazard to the project. PacifiCorp continues to operate this project.

If you have any questions or require any additional information, please contact me or Mr. Chin Lee of this office at (503) 326-5858, ext. 228.

Walter S. Boyle
Acting Regional Director

Document: ferc-to-owrd (PDF)