Marmot Dam, Oregon’s largest dam, is being removed: salmon and wildlife habitat and public recreation to benefit


A blast of explosives cracked the concrete face of Marmot Dam on the Sandy River on July 24, 2007, beginning its demolition and ushering in a new era for Oregon’s Sandy River Basin.


Marmot Dam, 50 feet in height, was built in 1913 to help supply needs as part of the larger Bull Run hydro project begun in 1906 by the Mt. Hood Company.


A blast of explosives cracked the concrete face of Marmot Dam on the Sandy River on July 24, 2007, beginning its demolition and ushering in a new era for Oregon’s Sandy River Basin.


The Dam Explodes.

Following the detonation, heavy equipment began taking apart the concrete structure. Demolition of the Marmot Dam should take about two months.


Demolition Shovels: Crews continue the work of demolition after the explosion.

 The concrete chunks will be recycled for road surfacing. 

The removal will improve salmon and wildlife habitat and public recreation. The Sandy River is home to winter steelhead, spring Chinook and Coho salmon, all listed as threatened under the federal Endangered Species Act. The State of Oregon lists coho as an endangered species.

 The Marmot Dam demolition will be the largest dam removal in the Pacific Northwest in 40 years and the largest ever in Oregon. It is the first phase in Portland General Electric’s $17 million Bull Run Hydroelectric Project “decommissioning” plan, developed in consensus with 23 diverse organizations (see list below).  They committed to a collaborative agreement, rejecting the expensive and exhaustive adversarial proceedings that characterize many major environmental decisions.

The plan also provides for the removal of PGE’s Little Sandy Dam, on its namesake river next summer, followed by the removal of most other project components. The plan has been approved by the Federal Energy Regulatory Commission (FERC). During that work, the river bypasses Marmot Dam, diverted by earthen coffer dams. The coffer dams will be washed away in late autumn by natural stream flows.


Salmon: Fish will have access to about 100 miles of stream habitat above the dam.


This partnership took a great step toward restoring a breathtaking river for fish, wildlife and people,” said Peggy Fowler, PGE Chief Executive Officer (CEO) and President. “We celebrate the future of a watershed that will provide unimpeded salmon and steelhead passage from the slopes of Mt. Hood to the Pacific Ocean.”


Marmot Dam and its diversion canal, 1987. PGE will maintain fish passage on the Sandy during dam removal, assisting fish if necessary.



Worker standing beside the No.2 unit, 1912. In 1912, the Bull Run Project was taken over by the Portland Railway Light & Power Company.

Located about 40 miles east of Portland, the structure was built in 1913 to power a trolley that carried city dwellers out to the countryside and was rebuilt in 1989 after a flood.


Bull Run Power House with Crew


At 22 megawatts, Bull Run is one of PGE’s smallest generating facilities, and its power has already been replaced with environmentally friendly wind power and other sources.

PGE is surrendering its rights to the water “in stream,” meaning no one can remove that amount of water in the future.

PGE, headquartered in Portland, also will donate 1,500 acres of its Sandy River Basin land to the Western Rivers Conservancy, which will convey most of the property to the U.S. Bureau of Land Management for permanent protection. The land will form the foundation of a planned 9,000-acre conservation and recreation area. The Sandy will remain one of the top Chinook salmon and steelhead fishing destinations in Oregon, while Marmot Dam removal will enhance whitewater rafting and kayaking on the river.

PGE announced that it would remove the Bull Run Hydroelectric Project in 1999 after the company determined that demolition would be more economical for its customers than maintaining the facility and upgrading it to modern fish protection standards. PGE remains committed to hydropower and is in the process of upgrading fish protection at its remaining hydro projects.


The elevated wood box flume at Bull Run will be removed in 2008.

  Next summer’s demolition of the 16-foot-high Little Sandy Dam will allow fish passage at that location for the first time in almost a century. The structure currently diverts almost all of the water out of the lower Little Sandy River for power production. More than 10 miles of habitat will be restored when the natural flows are restored to the Little Sandy River.

For more information, photos, video and updates, visit the Marmot Dam Web site.

The information for this article was provided by PGE.

Photographs: Portland General Electric

Note: Portland General Electric, headquartered in Portland, Ore., is a fully integrated electric utility that serves more than 796,000 residential, commercial and industrial customers in Oregon.

For more information contact Mark Fryburg, PGE, (1) 503-464-8481.

Partner organizations:

Alder Creek Kayak Supply, Inc.

American Rivers

American Whitewater

City of Sandy, Oregon

Northwest Sportfishing Industry Assoc.

Northwest Steelheaders

National Marine Fisheries Service

Native Fish Society

Oregon Council of Trout Unlimited

Oregon Dept. of Environmental Quality

Oregon Dept. of Fish and Wildlife

Oregon Dept. of State Lands

Oregon Trout Assoc.

Oregon Water Resources Dept.

Sandy River Basin Watershed Council

State of Oregon

Trout Unlimited Assoc.

U.S. Bureau of Land Management

U.S. Fish & Wildlife Service

U.S. Forest Service

WaterWatch of Oregon

Western Rivers Conservancy




Overview of the Coffer dam construction

Time lapse - Coffer dam construction removal project

Overview of the dam removal project

Latest articles


Air Pollution



Endangered Species




Global Climate Change

Global Health


Natural Disaster Relief

News and Special Reports

Oceans, Coral Reefs



Public Health



Toxic Chemicals


Waste Management


Water and Sanitation

Yale Himalaya Initiative