The U.S. Army Corps of Engineers announced Thursday that it has begun implementing its 2014 “Spring Fish Operations Plan” at its four lower Snake River and four lower Columbia River dams.
The 2014 Spring FOP includes fish passage operations such as spill for the timely and safe migration of juvenile salmon and steelhead at dams, and the Corps’ schedule for transporting juvenile salmon and steelhead aboard barges from the lower Snake’s Lower Granite, Little Goose and Lower Monumental dams.
As specified in NOAA Fisheries’ 2014 Supplemental Biological Opinion, the Spring FOP calls for spill to begin at the lower Snake River dams April 3, and lower Columbia River dams April 10. The annual plan, prepared by the Corps, is coordinated with states, tribes, and other federal agencies in the region.
The Corps is planning to conduct performance standard fish survival tests at McNary Dam this spring. The Corps conducted similar testing at two of the eight dams during summer 2013.
“We’ve experienced many successes in recent years, and remain committed to continuing to meet the performance standards in the BiOp, as well as engaging in ongoing collaboration with the region to do what’s best for the fish,” says Rock Peters, senior fishery program manager for the Corps’ Northwestern Division.
The most recent water supply forecast issued by the Northwest River Forecast Center for the Columbia River Basin (April-August) is 106 percent of normal, as measured at The Dalles Dam, and 114 percent of normal for the Snake River basin (April-July), as measured at Lower Granite Dam.
For more information on the federal salmon and steelhead recovery efforts in the region, visit www.salmonrecovery.gov
Meanwhile, the navigation lock at the lower Snake River’s Little Goose Lock and Dam will remain closed to all river traffic to allow workers to replace key gate components that were examined during annual maintenance and determined to be in critical condition and requiring immediate replacement, according to Corps navigation officials at the Walla Walla District.
The Corps owns and operates four dams, including Little Goose, on the Snake in southeastern Washington. Locks at the lower Snake dams and at four dams downstream on the Columbia River allow commercial barges and other boat traffic to steer inland from the Pacific Ocean as far as the ports of Clarkston, Wash., and Lewiston, Idaho. Both are located at the Idaho-Washington border. The four lower Columbia River dams are also operated by the Corps.
Little Goose Lock & Dam is located 70.3 river miles upstream from the Snake’s confluence with the Columbia.
The locks also allow the transport of juvenile salmon and steelhead downstream through the federal Columbia-Snake hydro system.
Walla Walla District planners estimate the Little Goose lock may be returned to service by May 1. With the Little Goose lock out of service, NOAA Fisheries’ 2014 Federal Columbia River Power System supplemental biological opinion fish transportation scheduled to begin sometime in late April may be delayed, according to the Corps.
Coordination of fish transportation operations and related research will be addressed through BiOp adaptive management processes. The BiOp was developed to assess whether FCRPS operations jeopardize the survival of salmon and steelhead stocks that are protected under the Endangered Species Act. The BiOp outlines measures, such as the timing and extent of fish transportation, that are intended to improve fish survival and thus mitigate for the existence and operation of FCRPS projects. The eight lower Snake and Columbia dams are among the 31 federal projects in the Snake and Columbia river basins that make up the FCRPS.
During a June 13, 2013, routine inspection of the downstream navigation lock gate, engineers first detected a problem with a gudgeon, where small cracks appeared to be forming. A gudgeon is the metal arm at the top of the south gate leaf that hinges and holds the gate leaf to the lock wall.
Phased-array ultrasonic testing was performed on July 25 to determine the extent of the cracking. Conditions at that time indicated the gate could continue to be used with increased monitoring on the gudgeon assembly. On March 12, additional ultrasonic testing was performed to assess whether cracking had worsened, followed by load-testing of the gudgeon on March 24 to determine if the gate was safe to operate.
According to the Corps, results obtained Monday evening indicated that cracks were propagating in the 50-year-old gudgeon component of a depth and rate of growth that metal fracture might occur if it the 334-ton gate leaf was put back into regular operation. For safety, the lock will remain closed until repairs are completed.
The Corps placed the lock out of service until replacement parts could be installed. Spare gudgeon assemblies for both gate leafs were ordered Sept. 26, 2013, after the cracks were originally identified.
"We are doing everything we can to minimize this emergency outage period -- all work has been expedited," said Steve Hartman, repair team project manager. "The Corps is committed to meeting our obligations under the BiOp, and to providing safe commercial and recreational navigation services at our locks -- this delay in reopening is necessary to provide safe locking."
Contractors accelerated production of one of the ordered gudgeon assemblies, rescheduling machining and fitting tests to allow shipment of expedited parts to the dam by the first week of April. Repair-project team members are preparing an emergency contract solicitation and have already identified several contractors that have the capability and schedule to perform the necessary installation work.
The Corps anticipates it will take several weeks to complete the installation work, and are estimating reopening by May 1. To reduce the time needed for staging and set-up, Corps staff at Little Goose are preparing the lock for immediate access by whichever contractor receives the award to conduct installation work.
A miter gate looks like a giant set of French doors. One gate leaf at Little Goose lock is about 118 feet tall, 43 feet wide and weighs 334 tons -- from 1986 through 2013, the gate performed 35,713 lockages.
A gate gudgeon linkage is a key component of this style of gate, holding the gate into position at the top while the gate pivots to open and close (a hinge-like assembly). The steel gudgeon assembly is an original component of the lock and has not been removed since installation in the late-1960s.
The Corps has notified commercial navigators, fish managers and other stakeholders, and will continue to provide updates as they become available. Public Notices and other navigation lock information are available on the Walla Walla District website at www.nww.usace.army.mil/Missions/Navigation.aspx.