For many dams currently being removed in the U.S., the primary reason behind this work is the need to protect fish and restore their habitat. This article provides case studies of the removals under way and the context under which these decisions were made.
By Elizabeth A. Ingram
For people working in the hydroelectric industry, the idea of dam removal may seem counterintuitive. After all, the goal is to use dams to generate electricity, and removing them certainly prevents that from happening. But, the fact is that dam removal has been and is happening and appears certain to continue in the future.
The question is, Why are owners and other agencies removing dams? I'm sure it is challenging to accept the series of circumstances that leads to removal of a dam as the best available option for all parties, especially when so many developers throughout the U.S. and Canada are in the process of building new projects, expanding existing facilities or exploring potential future locations for hydroelectric powerhouses.
Hydro Review presents several dams recently removed or in the process of being removed to showcase the reasons for this work. The overarching common denominator? Fish protection and restoration. In all of the cases mentioned below, the ultimate decision to remove the dam(s) was made with an eye toward improving or restoring fish runs, particularly of species listed as endangered or threatened under the Endangered Species Act.
With installation of the fish passage structures required to earn a new Federal Energy Regulatory Commission operating license for the 13.7-MW Condit project estimated to cost $100 million, project owner PacifiCorp made the decision to decommission and remove this facility in 1997. A settlement agreement with federal and state agencies, as well as tribal and local conservation and recreation organizations, was finalized in 1999.
And in October 2011, after a dozen years of studies and permitting, PacifiCorp blasted a tunnel through the base of Condit Dam, on the White Salmon River in south central Washington. The entire dam structure is scheduled to be removed by August 31, 2012. Removal of this dam and hydroelectric facility, which had operated for nearly a century, opened 33 miles of the river for steelhead and salmon migration.
Condit Dam is 3.3 miles upstream from the confluence of the White Salmon and Columbia rivers. The dam created a reservoir, Northwestern Lake, that extended 1.8 miles upstream of the dam and covered about 92 acres. 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 woodstave flow line, then through two penstocks and into a powerhouse containing two double horizontal Francis turbines.
Condit Dam was built in 1912 and 1913 but wasn't under license requirements until the 1960s. It was originally licensed by FERC in 1968, with a May 1, 1965, effective date. PacifiCorp began work to relicense the project in 1991. Several resource agencies and groups, including American Rivers, pushed for decommissioning and removal of the dam because it cut off salmon and steelhead from the upper White Salmon River.
|PacifiCorp blasted a tunnel through the base of Condit Dam, on the White Salmon River in south central Washington, in October 2011. The entire dam structure is scheduled to be removed by August 31, 2012, to open 33 miles of the river for salmon and steelhead migration.|
In November 1996, FERC issued a final environmental impact statement that would have required PacifiCorp to install fish ladders and screens for fish passage. Fish ladders were part of Condit's original design, but they washed out twice during floods in the early years of the dam's operation. FERC also required higher instream flows, which would reduce capacity of the project by an undetermined amount. PacifiCorp determined that these requirements would render the dam uneconomical for its customers.
In a settlement signed in 1999, after two years of negotiation with resource agencies and stakeholder groups, PacifiCorp agreed to remove Condit Dam and to decommission the project. The cost of decommissioning and removing Condit is estimated at $35 million, including funds already spent during the planning process over the 12 years since the settlement was announced.
Micheal Dunn, president of PacifiCorp Energy, says the choice to remove Condit Dam was a result of a decision to work with "settlement partners to come to the most reasonable solution for everyone involved, especially the cost to our customers."
In October 2010, the Washington Department of Ecology approved a Section 401 Water Quality Certification for the project. FERC then accepted PacifiCorp's surrender of its license for Condit Dam and approved the utility's plan to remove the dam. In December 2010, PacifiCorp received a surrender order from FERC providing for dam decommissioning.
The commission made minor modifications to the surrender order in April 2011, including timing issues and sediment management details. In conjunction with a section 404 permit received from the U.S. Army Corps of Engineers in May 2011, this provided the regulatory certainty PacifiCorp needed to proceed to remove the high dam. In June 2011, the commission completed review and approval of project removal design and resource management plans.
Crews worked throughout the summer of 2011, preparing to blast a 13-foot-wide hole near the base of the dam. During August and September, crews excavated a 90-foot-long drain tunnel through the dam. Other work included dredging the upstream side of the dam at the drain tunnel, strengthening a bridge that crossed Northwestern Lake, relocating a water pipeline that crossed the reservoir and shutting down the powerhouse (just minutes before the breach).
PacifiCorp, prime contractor JR Merit of Vancouver, Wash., and detonation contractor Kiewit Infrastructure West of Vancouver, Wash., surveyed the area after the October 2011 blast, took readings from sensing devices, and flew over the area in a helicopter before declaring the breach a success and the remaining structure to be safe.
Demolition of the remaining portion of the dam is in progress and is to be completed by August 31, 2012. Restoration work throughout the former reservoir area is slated for completion by the end of 2012.
PacifiCorp says there are no plans to dismantle the powerhouse, and the generating equipment was not removed.
Elwha and Glines Canyon dams
The three-year process to remove the Elwha and Glines Canyon dams began in September 2011. The Elwha River flows through Olympic National Park in Washington, and restoration will open up more than 70 miles of salmon and steelhead habitat. At 210 feet, Glines Canyon will be the largest dam ever removed.
Elwha Dam construction was completed in 1913 and Glines Canyon Dam in 1927. Neither dam included a fish ladder, thus preventing native anadromous salmon and trout from advancing past the lower 5 miles of the river.
Congress passed the Elwha River Ecosystem and Fisheries Restoration Act in 1992, requiring the Secretary of Interior to restore the Elwha River ecosystem and native anadromous fisheries. Interior determined dam removal is the only option that would accomplish full restoration. The proposed project also is to protect and restore treaty fishing rights for affected Indian tribes. The act requires the National Park Service, which acquired the dams in 2000 from Daishowa America, to maintain the existing level of flood protection for developments along the Elwha River and to protect industrial and municipal water users from adverse water quality effects of dam removal.
NPS said restoration of natural sediment flow in the lower river would allow sediment to accumulate in areas that have eroded since the dams were built. That is expected to increase river elevations from 1 to 4 feet in some areas, with an average increase of 2 feet. Since the dams were built, about 18 million cubic yards of rock, gravel, sand and sediment have been trapped behind them.
In 2004, representatives of the service, city of Port Angeles and Lower Elwha Klallam Tribe signed a memorandum of understanding to advance the dam removal plan.
In January 2007, NPS sought a 10-year construction permit to remove the structures. Agencies reviewing this application were the U.S. Army Corps of Engineers (in accordance with the Rivers and Harbors Act and Clean Water Act), U.S. Environmental Protection Agency (aspects that could affect the aquatic environment pursuant to the Clean water Act) and Washington Department of Ecology (for consistency with the Coastal Zone Management Act).
In June 2009, NOAA allotted $2 million to Elwha River floodplain restoration in Washington, with a goal of restoring 82 acres of floodplain in conjunction with plans to remove these two dams.
The work, including removal of the dams, power plants, power lines and associated facilities, is expected to cost $40 million to $60 million.
In late August 2010, researchers with the Northwest Fisheries Science Center and Washington Department of Fish and Wildlife installed a temporary fish weir 5 miles downstream from Elwha Dam. The goal was to learn about salmon populations before the dam removal. Data collected from captured fish includes species, sex, spawn condition, fork length, presence of a coded wire tag or passive integrated transponder tag, fin mark, scale samples and DNA samples.
And in September 2010, NPS awarded a $26.9 million contract to Montana-based Barnard Construction Company Inc. to remove the two dams. In February 2012, workers were notching Glines Canyon Dam to lower the dam and reservoir to elevation 530 feet. Once that level is achieved, a 14-day hold will begin to allow the river to erode across the newly exposed sediments. At the same time, at Elwha Dam, contractors were excavating the river's channel in preparation for removing the remainder of the dam.
Deconstruction of the two dams is expected to be complete by 2014.
Veazie and Great Works dams
In December 2010, the Penobscot River Restoration Trust in Old Town, Maine, struck a $24 million deal with PPL Corporation to buy three dams on the Penobscot River: 8.4-MW Veazie, 7.9-MW Great Works and 1.9-MW Howland. Of these, Veazie and Great Works are to be removed.
This sale culminates an agreement reached in June 2004 by PPL and a coalition of governmental agencies and private groups to facilitate the removal or bypassing of the three generating facilities to restore runs of migratory fish to the Penobscot River in Maine. The coalition includes the U.S. Department of Interior, U.S. Bureau of Indian Affairs, U.S. Fish and Wildlife Service, Maine Department of Inland Fisheries and Wildlife, Maine Department of Marine Resources, Maine Atlantic Salmon Commission, Penobscot Indian Nation, American Rivers, Atlantic Salmon Federation, Trout Unlimited, Maine Audubon Society and Natural Resources Council of Maine. The group plans to decommission Howland Dam and leave it in place but install a bypass channel for fish passage. This work will open up nearly 1,000 miles of river habitat to 11 species of sea-run fish, including endangered Atlantic salmon, sturgeon and river herring. The Penobscot River once supported one of the largest runs of Atlantic salmon in the U.S.
|Two excavator-mounted hydraulic hammers were chipping away at the 210-foot-tall Glines Canyon Dam in February 2012. Once this and the Elwha Dam on the Elwha River are removed, more than 70 miles of salmon and steelhead habitat will be restored.|
In return for this removal, the settlement included agreement for improvements at its remaining hydro developments in Maine, enabling PPL to retain more than 90% of its original generation. For example, in May 2006, PPL announced it had increased generation at its 1.95-MW Stillwater project and planned to complete work the following month to increase generation at its 3.44-MW Medway and 13-MW West Enfield projects. The work involved adding flashboards at the top of each dam, raising the water level by 1 foot and increasing the pressure of water flowing through the turbines. This increased annual generation by 965 MWh at Stillwater, 2,303 MWh at Medway and 5,800 MWh at West Enfield.
"This landmark partnership has proven that business, government and interested citizens can reach mutually agreeable solutions that benefit the community, the economy and the environment," says Dennis J. Murphy, vice president and chief operating officer of PPL's eastern fossil and hydro generation unit, which sold its remaining dams in Maine to Black Bear Hydro Partners LLC in 2009.
In late 2007, the trust reached its fundraising goal of $25 million to purchase the three dams.
In addition, in April 2008, PPL announced plans to spend $4.7 million to renovate and recommission the 2.33-MW Orono project, increasing capacity to 3 MW. Work involved building a 20-foot-wide, 12-foot-tall concrete penstock to replace three 10-foot-diameter woodstave penstocks, the failure of which had idled the project since 1996. PPL also refurbished the four turbine-generator units in the powerhouse. Work on the Orono project was completed in March 2009. Capacity was increased to 2.78 MW, and it generates 20,000 MWh annually.
The trust exercised its option to move forward on the dam purchases in June 2008. And in November 2008, the trust filed for federal and state permits required to purchase the dams.
When PPL sold its Maine holdings, it retained the Veazie, Great Works and Howland dams, subject to the agreement. The agreement was completed in January 2009 when FERC approved transfer of those three projects to the Penobscot River Restoration Trust.
In 2009, NOAA awarded $6.1 million in economic stimulus money to Penobscot River Restoration Trust to help fund removal of the Great Works project. The allotment was part of $167 million in NOAA awards announced June 2009.
In the summer of 2009, scientists began collecting baseline monitoring data around the three dams that can be compared with data that will be collected after dam removal work begins. Monitoring will be conducted in 2012 and 2013 (during dam removal) and in 2014 and 2015 (to measure the early effects of dam removal on the restoration of fisheries and on changes in geomorphology, water quality, wetlands and marine nutrients).
And in June 2010, FERC accepted the surrender of these three hydro project licenses, clearing the way for the trust to remove Great Works and Veazie.
Great Works will be the first dam removed, and final engineering designs for this work are complete. The work is scheduled to take place from June to November 2012. Removal of Veazie Dam is anticipated to occur in 2013 and 2014.
In June 2010, FERC issued a draft EIS endorsing the surrender and decommissioning of the 4.6-MW Kilarc-Cow Creek project on Old Cow and South Cow creeks in Shasta County, Calif.
Pacific Gas and Electric Co. began the process to relicense the project in 2002 but concluded in 2004 that the cost of the protection, mitigation and enhancement measures for the resources affected by the project would outweigh the economic benefit of generation over the life of a new license, resulting in an uneconomic source of power for its customers.
Consequently, in March 2005, PG&E entered into the Kilarc-Cow Creek Project Agreement signed by eight other parties, including resource agencies and nongovernmental organizations. PG&E agreed not to file an application for a new license by the statutory deadline of March 27, 2005, and instead support project decommissioning. In exchange, the other signatories agreed to support a scope of decommissioning that would address specified subjects but provide PG&E with the flexibility to address those subjects in a cost-effective manner.
Once the deadline passed for PG&E to file an application for a new license, FERC invited other entities to file a notice of intent to obtain a new license to operate the project. One entity filed an NOI but failed to file an application within the 18-month timeframe. Thus, in March 2009, the company filed an application to surrender its license for Kilarc-Cow Creek.
The project consists of two forebays and five diversion dams, 20 canal sections, flumes, tunnels, spillways, one siphon, two penstocks and two powerhouses. The project generates 31,300 MWh annually.
In its 2009 license surrender application, PG&E proposed to remove the diversion dams and allow for free passage of fish. The utility proposed to leave in place some abutments and foundations to protect stream banks and provide grade control. PG&E also proposed leaving in place the historic powerhouse structures, with an option of their preservation. The utility would remove turbine-generators and other equipment.
In the 2011 final EIS, FERC estimates the cost of decommissioning the project at $9 million. Benefits include restoring natural flows and improving water quality in the Old Cow and South Cow creeks and tributaries, enhancing aquatic habitat in the current bypassed reaches for resident and anadromous species. Adverse impacts identified in the final EIS include the socioeconomic effects to a group that uses water discharged from the Cow Creek powerhouse for irrigation and loss of aquatic habitat in the 4.5-acre Kilarc and 1-acre Cow Creek forebays.
In August 2011, FERC issued a final EIS supporting, with staff modifications, the proposed decommissioning. The California Water Resources Control Board is reviewing potential environmental impacts of the project, which is required before FERC can issue an order to decommission.
Attend HydroVision International for more on civil structures and dam safety
The HydroVision International event, being held July 17-20 in Louisville, Ky., features an entire seven-session track of panel presentations dedicated to the topic of civil works and dam safety.
The topics of these seven sessions are:
- Best Practices for Emergency Action Plans: Is Your Notification Process Adequate?
- Dam Hazard Classifications - A Discussion of Regulations and Risks
- When Does it Make Sense to Consider a Dam Removal?
- Uncovering Weaknesses, Improving Reliability - Learning from Recent Dam Failures or Potential Failures
- Outcomes and Impacts of the PFMA Process
- New Trends in Dam Safety Surveillance and Monitoring
- Dam Safety Training, Tools and Resources for Dam Owners and Operators
In addition, the event features three concurrent seven-session tracks of technical paper presentations on such related topics as Dam Safety and Construction and Gates and Dams. For more information or to register, visit www.hydroevent.com.
Elizabeth Ingram is senior editor of Hydro Review.
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