Condit Dam above the White Salmon River was breached a little after Noon on Wednesday, October 26, 2011. During the event approximately 750 acre feet of water was drained into the White Salmon River downstream of the dam and into the Columbia River. Flows from the breach of the dam are anticipated to transport a plume of accumulated sediment from the reservoir causing turbid water.
Over the course of the next 10 months, dam removal will be conducted and restoration of the former reservoir area completed.
The Condit Hydroelectric Project is located 3.3 miles upstream from the confluence of the White Salmon and Columbia Rivers. Constructed between 1911 and 1913 by Northwestern Electric Company it has been operated by PacifiCorp since 1947. PacifiCorp has chosen to remove the dam rather than seek fish passage required under a new federal dam license.
The Washington Department of Ecology (Ecology) conducted necessary environmental reviews and issued regulatory approvals associated with the project, including granting a Section 401 Water Quality Certification. The 401 certification under the federal Clean Water Act certifies that water quality standards and other water-protection regulations are met during dam removal and subsequent restoration. The 401 outlines the steps PacifiCorp must take to protect water quality during dam removal.
A muffled roar and a puff of pulverized concrete preceded a rush of water at the dam, about three miles upstream from the White Salmon’s confluence with the Columbia River. Immediately after today’s 12:11 p.m. detonation, the waters of Northwestern Lake immediately began pouring through a tunnel created in the dam’s 90-foot wide base during August and September. PacifiCorp and prime contractor JR Merit of Vancouver, Wash., along with the detonation crew from Kiewit Infrastructure West, also of Vancouver, surveyed the blast zone, took readings from sensing devices on the dam and flew over the area in a helicopter before declaring the breach event a success and the remaining structure safe.
“Condit has served our customers very well for nearly a century,” said Micheal Dunn, president and chief executive officer of PacifiCorp Energy, which operates 46 hydroelectric facilities in the West. “We are sad to lose this emission-free source of power. But we made a decision to work with our settlement partners to come to the most reasonable solution for everyone involved, especially the cost to our customers. For the next 11 months, we will proceed with the safe dismantling of the dam structure and work toward restoring the natural streambed of the area.”
Dam removal was determined to be less costly to PacifiCorp customers than the fish passage that would be required for dam operation to be granted under a new federal hydroelectric power license. The cost of decommissioning and removing Condit is currently estimated at about $33 million, including funds already spent during the planning process over the 12 years since the settlement was originally announced.
About 150 representatives of the settlement parties, contractors and local leaders gathered a safe distance away from the dam to watch a live webcast of the final blast. The gathering also was used to acknowledge the efforts of all parties to the decommissioning settlement agreement. “Getting to this point took a long time and a focused work effort,” said Todd Olson, program manager for PacifiCorp Energy. “Many people have worked to get the project to this point and PacifiCorp recognizes their contribution.”
Demolition of the remaining portion of the dam is scheduled to begin in spring 2012 and be completed by August 31, 2012. Restoration work throughout the former reservoir area is planned to be completed by the end of 2012.
Throughout this restoration, the former reservoir area and project area will remain closed to the public. PacifiCorp will continue to work closely with county officials and local residents on access restrictions and other safety measures as the project progresses.
PacifiCorp is one of the lowest-cost electricity producers in the United States, serving more than 1.7 million customers in the West. PacifiCorp operates as Pacific Power in Oregon, Washington and California, and as Rocky Mountain Power in Utah, Wyoming and Idaho. With a generating capability of more than 10,620 megawatts from coal, hydro, gas-fired combustion turbines and renewable wind and geothermal power, the company works to meet growing energy demand while protecting and enhancing the environment.
The project is located approximately 3.3 miles upstream from the confluence of the White Salmon and Columbia Rivers. Project facilities consist of a 125-foot high, 471-foot long concrete gravity diversion dam, and an intake structure that directs water into a 13.5-foot diameter by 5,100-foot long wood stave flow line.
Removal will open approximately 33 miles of new spawning and rearing grounds for steelhead and 15 miles for salmon in the White Salmon River basin. Before the breach, fish biologists moved more than 500 salmon above the dam, which are already spawning in new habitat. The juveniles from these eggs will descend the White Salmon unimpeded by the dam.
The powerhouse, which was permanently turned off just before the blast, contains two double horizontal Francis turbines with an installed capacity of 13.7 megawatts (enough to power about 7,000 average homes for a year). There are no plans to dismantle the powerhouse.
The project created a reservoir, Northwestern Lake, which extended 1.8 miles upstream of the dam and covered approximately 92 acres. It is expected to drain in roughly six hours.
In 1999, the Condit Settlement Agreement was signed by PacifiCorp and project stakeholders. The settlement agreement was amended in 2005 to extend the dates for project removal.
Settlement parties include: American Rivers, American Whitewater, Columbia Gorge Audubon Society, Columbia Gorge Coalition, Columbia River United, Federation of Fly Fishers, Friends of the Columbia Gorge, Friends of the Earth, Friends of the White Salmon, The Mountaineers, Rivers Council of Washington, The Sierra Club, Trout Unlimited, Washington Trout, Washington Wilderness Coalition, the Columbia River Inter-Tribal Fish Commission , the Yakama Nation, the U.S. Forest Service, the U.S. Department of the Interior, the National Marine Fisheries Service, the Washington Department of Ecology, the Washington Department of Fish and Wildlife and PacifiCorp.