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Remodel of Lower Granite Dam Juvenile
Salmon Facility Expected to Improve Fish Survival

by Staff
Columbia Basin Bulletin, April 18, 2014

Lower Granite Dam impounds Snake River waters nearly forty miles to the Idaho border. An extensive reworking of the juvenile salmon facility expected to begin this year at the lower Snake River's Lower Granite Dam should help reduce stress, injury and delay during the fishes' first encounter with the federal Snake-Columbia river hydro system.

Such results would answer demands of NOAA Fisheries' Federal Columbia River Power System biological opinion. The Lower Granite upgrades should increase both dam and system performance.

The Endangered Species Act BiOp's primary goal is to encourage actions that improve the survival of listed salmon and steelhead migrating through the hydrosystem. Those listed fish include Snake River spring/summer and fall chinook and sockeye salmon and steelhead.

Plans and specifications for Phase 1A of the "Juvenile Fish Facility Upgrade" project will be completed in the spring of 2014, with a construction contract slated for a bid award in the summer of 2014, according to the U.S. Army Corps of Engineers. Construction is currently planned to take place over two construction seasons with the expectation that the new facilities will be in operation for the spring 2016 juvenile out-migration season without impacting the 2015 passage season.

And while the Corps declines to publicly offer project construction cost estimates prior to completion of the bidding process, the Lower Granite upgrade is the big ticket item on this year's Columbia River Fish Mitigation program budget, which totals about $100 million. Spreadsheets provided to the System Configuration Team early this year had 2014 costs ballparked at $35 million.

The hydro and federal, state and tribal fish managers on SCT help prioritize construction and research projects for potential funding through the Corps' CRFM program, which is funded by annual congressional appropriations. The appropriations are reimbursed to the U.S. Treasury by the Bonneville Power Administration, which markets power generated at federal Columbia River basin dams and funds fish and wildlife projects as mitigation for dam impacts.

An initial 2014 work plan developed by the Corps and made public in March has spending estimates of:

The Lower Granite project is within the Columbia River portion of the program.

Construction of JFF upgrades is divided across two phases. Total "construction magnitude" for both phases is estimated between $25,000,000 and $100,000,000, according to the Corps.

Modifications and additions would also benefit passage of adult salmonids, particularly steelhead kelts -- fish that, unlike salmon, can spawn and then head downstream before potentially taking another run upstream to spawn again.

The upgrade of the juvenile fish facilities at Lower Granite has been identified in various Corps and regional documents as a potential near-term improvement in the hydropower system to meet the needs of ESA-listed fish species.

Lower Granite Lock and Dam was placed into service in 1975 and is located in southeast Washington 107 river miles upstream from the Snake's confluence with the Columbia River. Lower Granite is the first dam juvenile salmon and steelhead must negotiate on their way to Pacific, and the eighth dam in the Columbia-Snake system that the fish must clear on their return trip as adult spawners to hatcheries and spawning grounds in, for the most part, Idaho and northeast Oregon.

The fish passage systems at Lower Granite project provide a means of allowing juvenile fish to bypass the dams during downstream migration, as well as the means for allowing adult fish to pass over the dams during upstream migration.

Existing juvenile fish passage facilities at Lower Granite consist of bypass and transportation facilities and a removable spillway weir, the latter providing a surface oriented route.

The existing juvenile fish sorting and holding facilities are located downstream of the dam on the south shore.

Juvenile fish enter the bypass system through bulkhead slot orifices located in the upstream powerhouse intake bulkhead slots. Fish that are guided away from the turbines into the bulkhead slot pass through the orifices and into a collection channel.

Downstream of the collection channel, flows enter a downwell that connects to a pressurized transportation pipe that carries transportation water and fish approximately 1,700 feet downstream to the holding and loading facilities.

At the holding and loading facilities, the fish upwell into a head tank and pass through a fish separator. The juvenile fish are separated from the larger adult salmonids, non-salmonids, and debris. From the separator, the fish can be directed to raceways for holding, to a barge for transportation down through the hydro system, to a sample tank for counting and/or marking or back to the river, etc.

From the raceways, the fish can be loaded into trucks or barges or released to the river through the barge loading boom.

The upgrade is a piece of the BiOp puzzle. Future hydro system performance, including hoped for survival improvements for fish passing Granite, will be tracked and evaluated through adult reach survival and juvenile dam survival performance standards, and through a juvenile system performance target (bluefish: but what is this target really? From "The performance targets represent long-term goals, which are not necessarily achievable by this Proposed RPA/BiOp alone.").

Even minor improvements, particularly related to indirect project survival, transport, and delayed mortality, may dramatically increase smolt to-adult returns (SAR), according to the Corps.

New features being added to this facility also have the potential to significantly increase kelt returns.

Reasons for Phase IA improvements include:

  1. Locate the best juvenile bypass and collection system at the most upstream dam that ESA-listed fish experience on downstream migration. This project handles the most fish and is the critical link in the Snake River fish transportation system.

  2. Support the adaptive management strategy by making significant improvements in bypass features so that the best operations/facility features can be utilized when it would be most advantageous to the fish.

  3. Support an action item identified in the NMFS 2008 BiOp.

  4. Replace an aging facility incorporating design improvements utilizing the latest fish passage criteria that have been developed and proven over the past 30-plus years. Make improvements before major problems occur (i.e., maintenance and reliability issues).
Improvements include:
  1. Larger LED lighted collection channel orifices, in possible combination with overflow weirs, will provide more attraction flow with improved debris passage.

    That, in turn, will reduce delay, injury, and stress for juveniles and adults/kelts.

  2. A new primary dewaterer with an automated cleaning system will meet NMFS screen criteria, significantly improve debris management issues, and reduce fish injury and stress

  3. Open channel flow from the collection channel to the main facility/normal bypass with light access over the entire route (and with no turbulent flow upwell and downwell, and pressurized conditions) will reduce stress and lower potential for injury and delay.

  4. PIT-tag detection on the improved full flow bypass/outfall will improve fish operations and research efforts. It will also allow late season PIT-tag detection without having to water up the full facility.

  5. Re-use of excess water to augment both the adult fishway and the adult fish trap will facilitate meeting criteria for the adult fishway system and help reduce wear on the pumps. In addition, it will allow the adult trap to run at full capacity without impacting the adult fish ladder system.
A separate contract for Phase IB, which will relocate the primary bypass outfall to reduce tailrace egress delay and potential predation, is planned to be awarded in FY15. Construction of the new outfall is planned to occur during the winter of 2015-2016 and the relocated outfall is planned to be placed in service in conjunction with the Phase IA upgrades in the spring of 2016.

Pending completion of a pre-design feasibility report, Phase 1B includes:

Additional improvements to address elements of the current system that are specific to transportation such as size separation, fish handling, barge and truck loading facilities, and raceway improvements will be evaluated to determine potential biological benefits, the Corps says. If determined to be warranted, these will be prioritized for potential future contracts if funding is available. The potential benefits for additional collection channel weirs is also under evaluation.

Remodel of Lower Granite Dam Juvenile Salmon Facility Expected to Improve Fish Survival
Columbia Basin Bulletin, April 18, 2014

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