COMMANDERS PANELPNWA ANNUAL MEETING

LTC Rick ChildersAlan FeistnerWalla Walla District6 Oct 2020

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WALLA WALLA DISTRICT BOUNDARIES

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Mill Creek Dam(Bennington Lake)

McNary Lock & DamIce Harbor Lock & Dam

Lower Monumental Lock & Dam

Little Goose Lock & DamLower Granite

Lock & Dam

Dworshak DamLucky Peak Dam Jackson Hole Levees

• Civil Works Boundary focused on the Snake River Basin

• Covers 107,000 square miles

• Includes parts of 6 States• Regulatory Boundary is

Idaho border

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AGENDA

District OverviewLower Monumental Guidewall

Channel Maintenance

2020 Fish Passage Improvement

2021 March NavLock Maintenance

McNary Update

Long Term Outage Planning

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Broken Lower Monumental floating guidewall cables removed by divers in September 2020.

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Above: The deadman anchor cable for the floating guidewall at Lower Monumental Lock and after being removed from the riverbed.

Top: Slack in the service cable connected to the guidewall was found on June 13, an indicator of broken cable.Above left: The anchor chain that replaced the anchor cable. The chain is twice as strong and not susceptible to damage by abrasion.Above right: A towboat held the floating guidewall in place from Aug. 1 to Sept. 22, even through the days were air quality was hazardous dues to fires and dust storms.

Above: A contractor was brought in to dredge the area around the cables and replace the damaged cables.

LOWER MONUMENTAL FLOATING GUIDEWALLEMERGENCY REPAIR

Anchor cable holding the floating guidewall in place separated in June 2020, requiring an emergency repair that was completed in September

5CHANNEL MAINTENANCE

• Channel Maintenance – Two primary concurrent actions post CRSO EIS

Accomplish Programmatic Sediment Management Study (2-year effort)- Complete hydraulic study - Begin NEPA- Complete Study; propose permanent federal navigation channel location

Interim Dredging Action - Coordinating scope and funding needs

- Value engineering dredging alternatives to reduce cost of dredging

• Lower Snake River Sediment Management Forum (Virtual, Wednesday 28 October, 9AM-2PM)

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2020 FISH PASSAGE UPDATE

• Adult returns well below 10-year average; poor ocean conditions (BC, WA, OR); Fall Chinook and Sockeye showed promise, B-run Steelhead returns improved over 2019

• Fish Facility improvements– Lower Granite spillway PIT system successfully detecting fish – Automated water temperature monitoring in fish ladders– New transport trucks for Lower Granite

• 2020 Spill program changes– Spring (Apr-Jun ) increased spill volume to reach 125% gas cap at all projects– Additional spill in fall (Oct 1- Nov 15) and late winter (March 1-30) to assist

migrating adults in reaching natal tributaries • Evaluated early juvenile fish facilities startup

– 2020 – Lower Granite and McNary dams

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MARCH 2021 MAINTENANCE PLANNING

Start: 6 am, Saturday, 6 March 2021

End: 11:59 pm Sunday, 21 March 2021 (2 weeks)• McNary• Ice Harbor• Lower Monumental • Little Goose

End: 11:59 pm Sunday, 28 March 2021 (3 weeks)• Lower Granite

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MCNARY DOWNSTREAM MITER GATE MAINTENANCE HISTORY

File Name

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The 65-year old D/S gate is a two-leafed, arched miter gate - 106 feet tall by 86 feet wide. Each gate leaf weighs 400 tons.

• 2011 Inspection - Steel/weld cracks of concern• 2014 major crack repairs• 2015 Inspection - Cracks increased in length• 2016 Welded and bolted repairs• 2018/2019 No significant crack repairs required• Embedded gudgeon anchor frames determined to be highest risk element

Crack growth indicates the D/S miter gate is past its fatigue life

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MCNARY DOWNSTREAM MITER GATEMONITORING AND NEAR-TERM ACTIONS

File Name

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o Semi-annual inspectionso Real-time stress monitoring of miter

gate and gudgeon anchorso Structural analysis of gate

• Update with new data• Advanced fatigue analysis

o Gudgeon anchor inspection• Will require minor concrete

removal in first quarter FY21• Weld inspection/analysis

o Crack repairs as needed• Minor crack repairs are completed

annually by maintenance staff each outage

Typical Weld Repair

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MCNARY DOWNSTREAM MITER GATEFUTURE ACTIONS

File Name

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Replace the D/S miter gate, gudgeon anchors and operating machineryInterim: Extend the life of the D/S miter gate• Monitor and repairs

• Real time monitoring – to determine if significant change occurred

• Gudgeon anchor replacement in Spring 2024 to eliminate highest risk element leading to catastrophic failure

• Quoins and miter required along with gudgeon anchor replacement • Emergency repairs as needed

The D/S Miter Gate is at or past it’s service life.

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MCNARY NAVIGATION LOCKIN SERVICE SINCE 1954

File Name

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Nav Lock Needs/Issues• Gudgeon Anchor Replacement• U/S & D/S Derrick Cranes Replacement• D/S Miter Gate Replacement• Power and Controls Upgrade• U/S & D/S Drainage and unwatering pumps• Tainter Valve Replacement

Strategy• Perform instrumentation monitoring and repairs

of gate until replaced• Incremental/Level Funding• Minimize extended outages• Early acquisition (longer lead items)• Replace highest risk assets first• Reduce schedule risk during extended outages

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OTHER ITEMS

Long Term Outage PlanningWalla Walla is striving to extend the interval to the next extended outage by:

o Prioritizing replacement/refurbishment of highest identified riskso Replace McNary Navlock derrick cranes to reduce schedule risk during outageo Coordinating for early McNary gate prefabrication/delivery to mitigate risko 8-12 week outage Spring 2024 for McNary gate gudgeon anchor replacement to

mitigate risks prior to FY30 extended outage

Other Required Worko Little Goose upstream gate and machinery replacement o McNary navlock power and controls replacemento Lower Monumental navlock power and controls replacement

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QUESTIONS

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BACKUP SLIDES

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MCNARY LOCK & DAM (2 WEEKS)

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• Annual navigation lock maintenance • Inspect new tainter valves (1 & 3) to

establish baseline and monitor• Inspect original tainter valves (2 & 4)

to monitor known cracks and lifting eye issues

• Downstream miter gate crack mapping and monitoring

• Inspect gudgeon anchors for cracks• Install piping for new upstream

tainter valve unwatering systemMcNary’s NavLock

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ICE HARBOR LOCK & DAM (2 WEEKS)

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• Annual navigation lock maintenance

• Five-year Dam Safety culvert inspection requires complete dewatering of navlock

• Repair concrete spalling at Tainter Valve #3

• Complete replacement of remaining service & safety cables on floating guide wallFloating Guide wall cable broken

strands

Dewatered Navlock Chamber

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LOWER MONUMENTAL LOCK & DAM (2 WEEKS)

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• Annual navigation lock maintenance

• Replace tainter valve #2 lift cylinder

New Tainter Valve Cylinder and Piping Installed in 2020

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LITTLE GOOSE LOCK & DAM (2 WEEKS)

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• Annual navigation lock maintenance

• Gudgeon anchor instrumentation work

• Drain valve inspection & repairs, possibly fill valve repairs if needed and time allows

Navigation Lock Downstream Sill Inspection April 2020

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LOWER GRANITE LOCK & DAM (3 WEEKS)

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• Annual navigation lock maintenance• Tainter valves inspection• Remove bird netting from miter

gates• Complete miter gate cleaning and

inspection

Miter Gate – Failed Bird Netting and Required Cleaning

Failed Bird Netting