Condit Hydroelectric Project

From Wikipedia, the free encyclopedia

Condit Hydroelectric Project is a development on the White Salmon River in the U.S. state of Washington. It was completed in 1913 to provide electrical power for local industry and is listed in the National Register of Historic Places as an engineering and architecture landmark.

PacifiCorp has announced its intention to decommission the project due to rising environmental costs. If approved by FERC, Condit Dam will be the largest dam ever removed for environmental reasons and the largest dam ever removed in the United States.

Contents 1 Overview and history 2 Plant operations and specifications 2.1 River flow 2.2 Power production 2.3 Licensing 3 Decommissioning 3.1 FERC Proposals 3.2 PacifiCorp proposal 3.3 Controversy 4 References 5 External links

[edit] Overview and history

The White Salmon is a glacier fed river originating on the slopes of Mount Adams. Condit Dam is about 3.3 miles upstream of its confluence with the Columbia. The area below the dam is part of the Columbia River Gorge National Scenic Area, while parts of the river upstream belong to the National Wild and Scenic Rivers system. The area is famous for its natural beauty and recreational activities, include whitewater rafting and fishing. Impoundment of the river in 1911 removed 33 miles of steelhead habitat and 14 miles of salmon habitat.

The Condit Hydroelectric project, named after its lead engineer B.C. Condit, was built by Northwestern Electric Company in 1913 to supply electrical power for the Crown Willamette Paper Company in Camas, Wa. Surplus power was sold to Portland customers via a powerline across the Columbia River. The project was acquired in 1947 by its current owner, PacifiCorp.^[1]

The facility consists of Condit Dam and its impoundment, Northwestern Lake; a wood stave pipeline that transports water to a surge tank and auxiliary spillway; two penstocks and the powerhouse. Two horizontally mounted francis turbines and generators produce power and water rejoins the river about a mile downstream of the dam.

The original design had fish ladders which where twice destroyed by floods shortly after the dam's completion. The Washington State Fisheries Department then required Northwestern Electric to participate in a fish hatchery instead of rebuilding the fish ladders. This ended natural salmonid migration on the river.

In 1996, the federal government required that PacifiCorp make significant alterations to the dam to meet environmental codes, which included the addition fish ladders. PacifiCorp deemed the modifications too expensive and applied for decommissioning. Currently, the project is operating under annual license extensions, pending approval from FERC of the decommissioning plan. Dam removal is expected to begin in 2008.

[edit] Plant operations and specifications

[edit] River flow

Condit dam is required to discharge at least 15 cfs to keep the river channel viable. Surplus water is used by the turbines for electrical power generation and returned to the river about a mile downstream. Additional flow beyond what the turbines can use is discharged through five tainter gates and two sluice gates. The dam crest has a pneumatically actuated hinged crestgate which is designed to fail catastrophically as a safety relief when flow exceeds 18000cfs. The river averages 1125cfs, with flows up to 3500cfs fairly common.

[edit] Power production

The two turbines can use a maximum of 1,400 cfs and operate efficiently with as little as 1,100 cfs. In this flow range the plant operates as run-of-river; inflow equals outflow, and both turbines operate continuously to supply base load electricity.

When river flow isn't quite enough for two turbines, operation is cycled between running one and both turbines, based on a daily reservoir draw-down and refill cycle. The cycling is timed to meet peak electrical demands; that is, both turbines operate during hours of high electrical demand and the reservoir is drawn down; a single turbine operates during low electrical demand hours while the reservoir refills. A similar cycle is used when inflow is less than enough for a single turbine. A weekly cycle is superimposed on the daily cycle that tends to draw down the reservoir during the week and allowing refill during the weekend. In these cases, known as load factoring, the plant operates as a peaking plant. This mode of operation has been greatly reduced since the '80s and '90s to appease lakefront cabin owners.

[edit] Licensing

According to Federal Power Act of 1920, hydropower producers are periodically required to apply for license renewal from FERC. Condit's license was last reviewed in 1991, when it failed approval, and expired in 1993. Since then PacifiCorp has operated the plant under annual license extensions while it seeks approval from FERC for decommissioning.^[2]

In December, 2005 PacifiCorp filed an appeal of FERC's 1991 license rejection under the Bush administration's 2005 energy bill, which allows power producers to challenge licensing requirements retroactively. PacifiCorp explains the appeal as a backup plan in case decommissioning falls through.^[3]

Specifications^[4][5]

FERC number	2342
Dam type	Gravity dam, 471 feet long, 125 feet high
Location (river mile)	3.3
Concrete used for construction	30,000 cubic yards
Floodgates	Five Tainter, two sluice, one hinged crest gate
Pipeline	13.5 ft dia, 5100 ft long, wood stave
Penstocks	2 x 9 ft dia x 650 ft, steel and wood stave
Turbines	2 x Francis
Tailrace	concrete lined, 350 ft
Maximum generating capacity	14.7 MW
Maximum turbine hydraulic capacity	1400 ft³/s (40 m³/s)
Hydraulic head	167.8 ft (51 m)
Operation modes	peaking or baseload, depending on available flow
Normal lake maximum elevation above SL	295
Reservoir capacity	1,300 acre-feet (1,600,000 m³)
Useful reservoir storage capacity	665 acre-feet (820,000 m³)
Surface area	92 acres (370,000 m²)
Average annual Energy Production (1936 - 1989)	79,700 MWh
Annual operating costs	$400,000
Annual power benefits	$2,896,000
Annual value of power at consumer rates	$4.8 Million ($0.06/KWh)

[edit] Decommissioning

[edit] FERC Proposals

After Pacificorp's license application failed in 1993, FERC prepared an environmental impact statement that proposed installation of a state of the art fish passage system as conditions for license renewal. The enhancements were to include fish ladders to allow upstream migrations of spawning salmon, and other modifications of the dam and operating procedures to allow a 95% survival rate of down stream migrating salmon. These conditions were based on National Marine Fisheries Service requirements. FERC's report also reviewed options to decommissioning the project, which it estimated would cost twice as much as the fish passage system.^[6]

The investment needed to comply with the new requirements was estimated at $30 to $50 million, while at the same time reducing the amount of water available for power production.^[7] PacifiCorp decided the project was no longer economically viable and began negotiations for decommissioning. In 1999 PacifiCorp announced an agreement had been reached, at which point they applied to FERC for approval. The plan called for dam removal to begin in 2006 and capped PacifiCorp's liability at $17.5 million. In 2005 they applied for an operating extension to 2008, to earn another $3.3 million to help offset the cost of dam removal. The main parties involved in negotiations were federal regulatory bodies such as the National Marine Fisheries Service, Native American Tribal governments with interests in the area, and a number of local and national environmental groups.^[8]

[edit] PacifiCorp proposal

PacifiCorp's decommissioning plan differs from FERC's decommissioning proposal in how the sediment behind the dam is treated. FERC's plan was to dredge or bypass the sediment. While PacifiCorp's plan uses the demolition of the dam to quickly flush as much sediment as possible, thereby minimizing the amount of time the sediment plume harms downstream aquatic life.

Breeching the dam involves cutting a 12 x 18 x 100 foot tunnel in the its base; the final 15 feet will be drilled and blasted. A dredge will remove woody sediment from the dam's inside face and, when breached, the reservoir will drain within six hours. The rest of the dam will be cut into blocks and removed for disposal or recycling on-site. If decommissioning is approved, Condit dam will be the largest dam ever removed for environmental reasons and the largest dam ever removed in the United States^[9]

The quick drainage of the reservoir will flush a large amount of sediment quickly, helping to creating a new river channel above the dam. The remaining sediment will continue to erode until vegetation takes root. The sediment plume will harm the aquatic ecosystem temporarily; in the case of bull trout it will be a negative influence for two years, after which it will be a positive influence due to improved ecosystem nutrition.^[5] Also, a new sand bar is expected to form at the mouth of the White Salmon River, interfering with Native American fishing rights, for which PacifiCorp will pay a settlement.

[edit] Controversy

There is opposition to the dam removal from Klickitat and Skamania county governments. Objections revolve around the loss of lake front property and water recreation, loss of wetlands and water habitat, and a perception that PacifiCorp is choosing the cheapest way to abandon the project, rather than paying for FERC's preferred solution (a state of the art fish passage system), which some believe is the best solution for all parties.^[10]

The Klickitat Public Utility District Board of Commissioners investigated acquiring the project from Pacificorp to continue its operation as a power plant. A 2002 study commissioned from CH2M Hill calculated that purchasing and upgrading as required by FERC would lead to power production at $64 per MWh, and that for the project to be economically viable it would have to produce power at $45 to $50 per MWh. The report further stated that power produced at Condit would be more expensive than a Gas fired plant for more than 20 years after its acquisition.^[11]

In July, 2006, KPUD and Skamania County announced a new effort to acquire the project from Pacificorp and preserve the dam. Their plan relies on trucking spawning salmon around the dam as a less expensive alternative to fish ladders. This type of proposal was previously rejected by FERC. KPUD and Skamania County have retained lawyers and announced their intention to acquire the project under eminent domain should Pacificorp refuse to negotiate a sale.^[12]

The sediment plume is expected to kill some aquatic life below the dam and displace fish as far downstream as Bonneville dam. It could also harm several generations of an endangered chum population.^[13]

Most environmental groups involved with the decommissioning plan, as well as the national forest service, believe that the long term benefits of removing the dam far outweigh the short term damage done by flushed sedimentation.^[5] And fish and environmental advocates see this case as an important precedent for dam removals to restore free flowing rivers.^[13]

[edit] References

[edit] External links

• USGS map of the area
• Pacificorp map
• Links to official Documents hosted by PacifiCorp
• Terraserver imagery
• Restoring the White Salmon River