"What PGE learned while removing Marmot Dam
Some of those lessons could be applied to other projects; including no two dam removals are alike.
By TIM KELLER
Portland General Electric
October 28, 2010
What PGE learned while removing Marmot Dam
Some of those lessons could be applied to other projects; including no two dam removals are alike.
By TIM KELLER
Portland General Electric
With the Elwha and Glines Canyon dams set for removal next year in Washington, attention is turning to how such massive structures are actually taken down. One of the most recent dams removed
in the Northwest was Marmot Dam on Oregon’s Sandy River.
Portland General Electric in 2007 removed Marmot Dam, which was part of the Bull Run Hydroelectric Project.
In November of 1999, PGE filed a notice not to seek a new federal license for the Bull Run project near the city of Sandy. PGE decided that it would not make sense to upgrade the nearly
century-old facility to meet current standards for protection, mitigation and enhancement of the natural resources affected by the project — especially salmon and steelhead runs on the Sandy
River. The likely cost would outweigh the economic benefit to PGE customers from power generation at the project.
The Bull Run project was located about 30 miles east of Portland on the western slopes of Mount Hood, and consisted of:
• Marmot Dam, a 47-foot-high, 345-foot-long roller-compacted concrete dam that was built in 1989 to replace an earlier timber structure.
Photos courtesy of Portland General Electric [enlarge]
Marmot Dam was a 345-foot-long roller-compacted concrete dam built in 1989 on the Sandy River.
• Little Sandy Dam, a small concrete diversion dam on the Little Sandy River.
• A complex system of connecting canals and flumes.
• A 22-megawatt powerhouse.
• Roslyn Lake, a 160-acre forebay located 320 feet above the powerhouse.
Water was diverted from the Sandy and Little Sandy rivers to Roslyn Lake. From there, flow was delivered to the powerhouse and then discharged to the Bull Run River after passing through
Approximately 980,000 cubic yards of sediment — silt, gravel, cobbles and boulders — had accumulated behind Marmot Dam during its lifetime.
After convening a group to develop a decommissioning and removal plan — a process involving 23 governmental and nonprofit organizations and literally years of collaborative effort — PGE
committed to removing the dam within one construction season in 2007, extracting only as much sediment as was required for the demolition. The remaining sediment would be allowed to disperse
with natural stream flow.
PGE and stakeholders hoped that this approach would minimize the impact of excavation and truck traffic on the riverbed and surrounding landscape. It would also minimize transportation costs
that would ultimately be borne by PGE customers.
The dam was fractured by drilling, and then controlled blasting.
PGE solicited bids for Marmot Dam removal in March of 2007, requiring bidders to follow a predetermined format with information on pricing, labor and equipment rates, a hazardous material
plan, a demolition plan, project schedule, risk analysis and qualifications.
PGE then evaluated bids and awarded the contract to Natt McDougall Co. Work began almost immediately.
To allow demolition of the instream structures, workers placed a cofferdam upstream and another downstream of the dam. Project engineers designed the cofferdams to fail during normally high
stream flows expected to occur in the fall after the dam was scheduled to be removed.
After work was completed on the cofferdams and the river water diverted around the work area, excavators removed the sediments behind the dam. Then, the dam was fractured by drilling and
controlled blasting operations and removed by excavators as well.
When forecasts called for river flows above 1,500 cubic feet per second on Oct. 19, 2007, PGE and McDougall prepared to initiate the cofferdam breach. Using a forklift, McDougall workers
removed dewatering pumps that had been installed to assure the integrity of the upstream cofferdam and started scraping a notch in the cofferdam down to water level with the machine. As flow
through the notch increased it quickly cut away sediment, taking less than 30 minutes to reach full flow diversion.
This flow was also enough to breach the downstream cofferdam, allowing maximum sediment transport and timely creation of a passable channel though the sediment for salmon.
Since the breach, the movement of the sediments and fish migration has been monitored by PGE, research groups, federal and state agencies. The consensus is that the recuperative power of the
Sandy River proved to be much greater than expected in such a short time.
Here are the lessons learned:
1. Form a strong project team. The project team managed by PGE consisted of engineering design and research firms, biologists, hydrologists and fisheries experts. Coordinated by PGE’s hydro
licensing staff, there were several sessions during the design process to inform, gather consensus and work through the more difficult issues, which usually were fish passage details.
2. Get early feedback and involvement from all permitting agencies. Even with biological opinions in place from the state and federal fish management agencies, the joint permit application to
the Oregon Department of State Lands and the Army Corps of Engineers required PGE to perform a more stringent sedimentation analysis and resulted in a one-year delay to the start of
decommissioning. Getting early feedback and involvement is essential to ensure a timely and cost-effective result.
3. Contractor selection is critical. The selection of a trustworthy contractor who will work closely with the owner to develop efficient work strategies is a key element of any project’s
success and was especially important for the Marmot Dam removal. McDougall provided valuable insight and worked with PGE to minimize the overall project cost and impacts while fulfilling
4. Plan ahead. Planning for the Marmot Dam removal incorporated all concerns introduced by federal and state agencies as well as the project team. This included contingency planning in case
events did not unfold as expected.
5. Demolition is not an exact science. Engineers design a structure like Marmot Dam conservatively; it takes knowledge, experience and good judgment to determine how best to apply enough but
not too much force to demolish it.
6. Be ready to adapt quickly. The Sandy River has more than 90 years of historical river flow data and PGE had access to state-of-the-art flow predictions and forecasts. Even so, flows could
not be accurately predicted more than 12 hours in advance. The contractor had to be able to respond with short notice to initiate the breach procedure.
7. Prepare for the impact of news media and researchers. There was a concern that the news media and researchers would slow the project. Careful planning and centralized communications with
the media alleviated any problems. There was a small impact on productivity as PGE responded to news media and stakeholder interest in viewing the first blast event.
8. Work early and cooperatively with the ultimate land owner. In this case the land owner was the federal Bureau of Land Management. BLM explained its plans to PGE, helping to avoid
unnecessary work through site visits and design coordination.
Another, more general lesson illustrated by the decommissioning process at the Bull Run Hydroelectric Project is that no two projects are alike.
Decommissioning and removal of Marmot Dam was a success for both PGE’s customers and the environment, and PGE worked closely with government agencies, advocacy groups and technical experts to
assure that the plan was executed smoothly. The results exceeded expectations and provide a model for other dam removal projects.
PGE has faced relicensing at other hydroelectric projects in recent years, however, and found that the same kind of cost and benefit analysis can yield very different results at different
At PGE’s T.W. Sullivan Plant on the Willamette River, the company opted to make significant investments in upgraded fish passage facilities, because analysis showed that the improvements
would benefit customers even though the hydroelectric plant was actually older than Bull Run’s.
The view downstream after the dam was removed.
And at the Pelton Round Butte Hydroelectric Project on the Deschutes River in Central Oregon, PGE completed a one-of-a-kind fish passage and water temperature management facility last year.
PGE is also committed to a comprehensive strategy of helping to improve habitat and reintroduce fish runs that were blocked when the project was constructed in the 1960s.
Improvements at the Sullivan Plant and Pelton Round Butte have earned both projects Low Impact Hydro certification.
In each case, the goal has been to produce the same win-win result for PGE customers and the environment, but the strategy chosen to get there was developed to fit the specific circumstances.
The common element is that PGE has conducted extensive outreach and engaged stakeholder groups and government agencies to assure that all perspectives are taken into account and every effort
is made to address potential questions, concerns and problems as the process unfolds.
That’s true for the planning stages, and — as demonstrated by the Marmot Dam decommissioning — carries through to implementation of the resulting plan.
Tim Keller is a construction manager with Portland General Electric’s Power Supply Engineering Services group. He has 30 years of construction and project management experience at
Studying the Elwha River, Washington, in Preparation for Dam Removal
By Amy Draut
Nov. / Dec. 2006 in this issue:
previous story | next story
Above: Elwha Dam, the lower of two dams on the Elwha River in northwestern Washington scheduled for removal. Spillway on right side of photograph has eroded substantially, and rounded pieces
of concrete from dam are a common component of sediment in recent study's first survey reach downstream of dam. [larger version]
Above: Schematic map of northwestern Washington, showing locations of Elwha and Glines Canyon Dams on the Elwha River. (Modified from map by Bureau of Reclamation, posted online.) [larger
Above: Josh Logan surveying part of Elwha River channel, in the intertidal zone. [larger version]
Above: Tom Reiss surveying a section of the lower Elwha River and coastal zone. [larger version]
In a few years, the Federal Government will begin the biggest dam removal in U.S. history, restoring a major coastal watershed and its prized salmon river on the Olympic Peninsula, Wash. U.S.
Geological Survey (USGS) scientists are already working on the Elwha River Restoration Project, which has been in the works for many years, being planned by organizations that include the
National Park Service (NPS), the Bureau of Reclamation, and the Lower Elwha Klallam Tribe. The project will involve removing two large dams on the Elwha River to help restore this stream and
the associated coastal zone to a more natural state and to improve ecosystem health (see related Sound Waves article, "Dam Removal on the Elwha River in Washington—Nearshore Impacts of
Elwha and Glines Canyon Dams were completed on the Elwha River in 1913 and 1927 at heights of 32 and 64 m, respectively, to provide hydropower for local timber companies. The dams blocked the
natural supply of sediment to the lower river and coast, causing changes on the flood plain and erosion of beaches downdrift (east) of the river mouth. Because the dams were built without
fish passage, their presence has greatly limited the available spawning run for salmon and steelhead, fish that spend most of their lives in the ocean but return to the stream where they
hatched in order to reproduce. These native fish populations have declined severely in the Elwha watershed and around the Pacific Northwest, owing partly to the dam-related loss of their
river spawning habitat. At present, salmon and steelhead have only 7.8 km of the river to use as spawning habitat (the distance from the river mouth to Elwha Dam). After dam removal, more
than 70 km of the river should eventually become usable habitat for these fish.
In 2000, the Federal Government purchased Elwha and Glines Canyon Dams from the timber companies that formerly owned them. It was agreed that because both dams were aging and needed costly
repairs, a better alternative to repairing them would be to remove them and thereby restore the river habitat. Dam removal will take place in stages over 2 years and is scheduled to begin in
2009. This will be the first watershed-restoration project in which dams this large will be removed, and so it presents a unique opportunity to study how a river and coastal system respond to
the changes that will follow dam removal, especially the reintroduction of sediment as the river erodes much of the sediment now trapped in the two reservoirs. More than 80 percent of the
Elwha watershed lies within the boundary of Olympic National Park and has never been developed. It is hoped that dam removal will improve not only the native fish populations but also the
general condition of the ecosystem in this largely pristine area.
Scientists from the USGS Western Coastal and Marine Geology (WCMG) team are part of a large, interdisciplinary group of researchers studying the Elwha watershed as agencies gear up for dam
removal. In September 2006, Amy Draut, Tom Reiss, and Josh Logan conducted the first of numerous planned USGS surveys of the river channel. They documented channel topography and sediment
grain size in three study areas between Elwha Dam and the river mouth. They also surveyed part of the river channel upstream of both dams, at a site in Olympic National Park, to use as a
"control" area to monitor changes in channel form and sediment unrelated to the dams or dam removal. These four sites will be revisited twice a year, in spring and fall, to document the
magnitude of changes that occur seasonally in the dammed system. After dam removal begins, the scientists will continue to monitor these areas to evaluate how the river and intertidal zone
change when the reservoir sediment begins to move downstream.
In addition to the research in the river channel and intertidal zone, WCMG scientists Guy Gelfenbaum, Guy Cochrane, Jon Warrick, and Dave Rubin are leading mapping and oceanographic profiling
in the nearshore zone and farther offshore along the coast. USGS specialists in biology, hydrology, and geography are also conducting studies related to dam removal. USGS scientists are
working closely with the Lower Elwha Klallam Tribe, the National Oceanic and Atmospheric Administration (NOAA), and the NPS to learn as much as they can from this first-of-its-kind
comprehensive watershed-restoration experiment.
For more information, visit Elwha River Restoration and Elwha River Restoration Project or contact Amy Draut at email@example.com or
Grandes represas serán destruidas para la Restauración del Río Elwha y el retorno de los salmones
Dams Removal on the Elwha River in Washington.
Estados Unidos está expectante a poco del inicio de la eliminación de represas más grande del país, en el Valle Elwha.
La Restauración del Río Elwha devolverá al río su estado natural, permitiendo que fluya libremente, permitiendo que las cinco especies de salmón del
Pacífico y otros peces, llegen nuevamente a sus ancestrales hábitats y zonas de desove.
Restoring the Elwha
A new video about the Elwha River includes computer-generated animations created by American Rivers that show the Elwha Valley before, during and after dam removal. The video,
produced by Earth Tribe TV, provides a good summary of the river and its people and discusses the dam removal scheduled to begin in 2009. American Rivers staff used special computer
modeling software to create the 3-D photo-realistic visualizations that appear in the video.
22-3-2011- PORT ANGELES — The National Park Service has reduced the cost estimate for the mammoth Elwha River Restoration Project, which includes the removal of the streams’ two dams. The
project is estimated to cost $324.7 million, said Dave Reynolds, Olympic National Park spokesman. That’s down from the previous estimate of $351 million.
DESTRUCCIÓN DE LA REPRESA “RÁPIDOS SALVAJES” EN EL RÍO ROUGUE
ANNIMATION _ Elwha River Restoration Project: Elwha Dam Removal – Courtesy of Olympic National Park.
La cuenca Elwha es la más grande en la reserva Olympic National Park; el restablecimiento de las rutas del salmón, en más de 70 millas de ríos y
afluentes, devolverá los nutrientes vitales para la cuenca y restaurará el ecosistema. Para la tribu Klallam del bajo Elwha, este proyecto traerá salud cultural, espiritual y económica
con el retorno del salmón después de una ausencia de un siglo, cuando sus sitios sagrados desgraciadamente inundados, se restauren.
El río Elwha drena las escarpadas Olympic Mountains de Washington, que fluyen hacia el norte por el Estrecho de Juan de Fuca. La construcción de dos
represas hidroeléctricas en el año 1900 dio lugar a la pérdida del 95% del hábitat de desove en el río de los salmones anádromos (salmones que viven en el mar pero
regresan a desovar en lo alto de los ríos donde nacieron). En 1992, COMPRENDIENDO EL GARRAFAL ERROR EN QUE SE HABÍA INCURRIDO AL CONSTRUIR LOS FARAÓNICOS EMBALSES, se promulgó la ley
“Elwha River Ecosystem and Fisheries Restoration Act” aprobada en el Congreso, una Ley de Pesca para autorizar la demolición de las represas a fin de restablecer el salmón, en otro tiempo
abundante en el río Elwha.
La eliminación de las represas en el río Elwha hará regresar al salmón, pero liberará más de 14 millones de m3 de sedimentos depositados en los dos
embalses. La estrategia de gestión de los sedimentos es permitir que el material se vaya naturalmente, que sea erosionado y transportado hasta el Estrecho de Juan de Fuca, favoreciendo
que parte de los sedimentos se mantengan en su lugar y se depositen en el cauce del río y en las llanuras de inundación aledañas. Los aportes de sedimentos al estrecho puede terminar con
la actual erosión costera o incluso invertir la tendencia de erosión actual cerca de la desembocadura del río Elwha. Los aportes de sedimentos también puede enterrar o alterar los
hábitats cercanos a la costa (incluidos los lechos de algas marinas y bancos de almejas geoduck), mar adentro, en la desembocadura del río.
Los científicos del Servicio Geológico de EE.UU. (USGS), han comenzado la investigación para caracterizar los impactos cerca de la costa de la
voladura de las represas, como parte del Proyecto de Manejo de Hábitats Costeros en la bahía Puget Sound (USGS Coastal Habitats in Puget Sound Project) . Los científicos
del proyecto han estado trabajando estrechamente con las organizaciones locales, tribales, estatales y federales para desarrollar, coordinar, monitorear y modelar planes. Dentro de
la USGS, los científicos del Programa Geológico Costero y Marino, que están financiando el proyecto, están trabajando con el hidrólogo Chris Konrad, el biólogo Jeff Duda, y el geógrafo
Harvey Case para desarrollar un plan científico coordinado del río Elwha que lige la investigación fluvial, ecológica y costera.
Dam Removal on the Elwha River in Washington—Nearshore Impacts of Released Sediment
The Elwha River drains the rugged Olympic Mountains of Washington, flowing northward to the Strait of Juan de Fuca. Construction of two hydroelectric dams in the early 1900s resulted in
the loss of approximately 95 percent of the anadromous salmon spawning habitat on the river. In 1992, the Elwha River Ecosystem and Fisheries Restoration Act was enacted by Congress to
authorize removal of the dams in order to restore the once-plentiful salmon runs in the river. Dam removal is currently slated to begin in early 2008.
As well as restoring salmon runs, dam removal on the Elwha River will expose more than 14 million m3 of sediment deposited in the deltas within the two reservoirs. The
sediment-management strategy is to allow the material to be naturally eroded and transported to the Strait of Juan de Fuca, acknowledging that some sediment will remain in place and be
deposited in the river channel and flood plain. Contributions of sediment to the strait may end or even reverse the current trend of coastal erosion near the river mouth. Sediment
contributions may also bury or alter nearshore habitats (including kelp beds and geoduck clam burrows) offshore of the river mouth.
U.S. Geological Survey (USGS) scientists have begun research to characterize the nearshore impacts of the Elwha River dam removals as part of the USGS Coastal Habitats in Puget Sound project. Project scientists have been working closely with local, tribal, State,
and Federal parties to develop coordinated monitoring and modeling plans. Within the USGS, scientists
from the Coastal and Marine Geology Program, which is funding the project, are working with hydrologist Chris Konrad, biologist Jeff Duda, and geographer
Harvey Case to develop a coordinated Elwha River science plan that links fluvial, ecological, and coastal research.
As part of this coordination, USGS geologist Jon Warrick participated in the “Technical
Workshop on Nearshore Restoration in the Central Strait of Juan de Fuca” held March 2004 in Port Angeles, WA, where
ecologists, fishery scientists, engineers, and geomorphologists agreed on the high-priority need for a conceptual model of sediment transport and deposition off the Elwha River. Since
this workshop was held, the USGS has led efforts to develop both a simple conceptual model of sediment
transport and a research plan for quantifying sediment-transport rates and pathways.
Above Left: The Elwha River (mouth in foreground) flows into the Strait of Juan de Fuca from Washington’s Olympic Mountains (background). [larger version]Above Right: Simple conceptual model of sediment
transport offshore of the Elwha River. Potential pathways of sediment (arrows) may be along the shore or cross-shore down the submarine delta.
The USGS Coastal Habitats in Puget Sound Project will employ three major techniques to evaluate
dam-removal impacts: mapping, monitoring, and modeling. The mapping work will focus on collecting baseline bathymetric and seabed information from which changes can be tracked through the
dam-removal process. Two mapping techniques are being used. In March 2004, Guy Cochrane, Jon Warrick, Jodi Harney, Andy
Stevenson, Larry Kooker, Mike Boyle (all of the USGS), and
Tina Blewett (Washington Department of Fish and Wildlife) used combined swath-sonar, seabed video, and seabed grain-size sampling techniques from the research vessel
Karluk to map the nearshore region off the Elwha River mouth. Preliminary results show that the substrate from the river mouth out to approximately 30-m water depth consists of mixed sand and gravel, with areas of large sand waves (approx 10 m high) and some boulder fields.
In September 2004, Guy Gelfenbaum, Peter Ruggiero, Jodi Eshleman (all USGS), and Etienne Kingsley (Washington Department of Ecology) conducted bathymetric and topographic mapping, using a second mapping
technique that relies on satellite-based global-positioning-system (GPS) units on land and in watercraft. More than 100 shoreline cross sections were obtained in the September mapping
exercises, which will be repeated twice per year through the dam removal. These measurements—along with beach surveys by the Lower Elwha Klallam Tribe at seven sites and aerial
photography by the Surfrider Foundation—will be the primary method of tracking changes offshore of the Elwha River mouth.
Above Left: Preliminary results of the swath-sonar backscatter mapping (which records the intensity of sound energy reflected from features on the sea floor),
showing large sand waves (dark color) over a region of mixed gravel and sand (bright colors). Water depth of observations is approximately 5 m. [larger version]Above
Right: Combined bathymetric and topographic data for the area of the Elwha River mouth. Bathymetry of the delta is from swath-sonar and GPS measurements. Topography of the land surface is from lidar (light detection and ranging) measurements
provided by the Lower Elwha Klallam Tribe. View southeastward. Image created by Peter Dartnell (USGS). [larger version]
Because oceanographic information about the strait is very limited, the USGS research project will also
monitor and numerically model waves and currents in the region offshore of the river mouth. Oceanographic monitoring will begin during spring 2005 with deployments of acoustic Doppler
current profilers (ADCPs) and directional wave gauges, which will be used to develop an understanding of waves, tides, and currents that may affect the sediment released by dam removal.
Observations of physical conditions off the river mouth will be used to calibrate and validate a three-dimensional hydrodynamic model of the Elwha River area of the strait currently being
developed by Guy Gelfenbaum and Giles Lesser with Delft3D modeling software. Modeling is an important part of the research plan because wave and current
conditions along the river-mouth delta are expected to vary widely, owing to the complex bathymetry of the submarine delta offshore of the present river mouth. Preliminary results of the
circulation modeling show strong eddies offshore of the river mouth, features that are commonly encountered by local fishermen.
The planned mapping, monitoring, and modeling will help characterize the pathways and fate of sediment released from behind the dams of the Elwha River. This information will be crucial
in evaluating the impacts of dam removal on the substrate and habitats of the beaches and the nearshore.
Datos batimétricos y topográficos combinados del área del delta del río Elwha. La batimetría del delta empleó sonar de franja y mediciones GPS. La topografía de la superficie terrestre es
LIDAR y las mediciones fueron realizadas por la tribu Klallam del bajo Elwha
Checking on fish produced by the captive brood program of the Lower Elwha Klallam Tribe.
Acuarela de James Gilchrist Swan (1818-1900) de la nación Klallam comandada por el jefe Chetzemoka (apodado el Duque de York), con una de sus esposas (apodada Jenny Lind)
distribuyendo potlatch en Port Townsend, Washington, EE.UU., (colección de Yale de la cultura americana occidental, Libros Raros y Manuscritos Beinecke, Universidad de Yale
Watercolour by James Gilchrist Swan (1818-1900) of the Klallam people of chief Chetzemoka (nicknamed ‘the Duke of York’), with one of
Chetzemoka’s wives (nicknamed ‘Jenny Lind’) distributing potlatch at Port Townsend, Washington, USA, now in the Yale
Collection of Western Americana, Beinecke Rare Book and Manuscript Library, Yale
Klallam Indians pose with canoe near Chimacum Creek, Washington, ca. 1914
The Tse-whit-zen story comes to life in this moving slideshow.
Flash 6+ required
Klallam people village
The Tse-whit-zen story comes to life in this moving slideshow.
Flash 6+ required
Klallam people village
“This depicts the 1750 Indian Klallam Village, I-enn-nus. The name Klallam means ‘strong people’ in their language. They were primarily a hunting / gathering culture but also practiced
forms of agriculture.”
“Today many Klallum cultural and traditional practices continue among Native people here on the Peninsula.”
Escribió Biologo Malcolm Allison