Annual Dam Safety Inspection Report_Willow Creek_2024.pdf

RECOMMENDATIONS

New recommendations or revised language is italic

Recommendations are date‐coded by the year the recommendation was initially made

Maintenance / Repair

ID DESCRIPTION STATUS

WC‐16‐01

Service and repair the guard gate operator. See 3.E.2 and 3.E.6, the 2/13/2020

Gate Operator Inspection and Maintenance letter, and photos 50 through 53 .

Repair the operator so the high speed pinion cannot be pulled out from the gearcase.

WC‐18‐01

The bottom of the tower is dirty, see photo 68 . Clean the bottom of the tower, gate operator, gate bonnets, and conduit transitions.

WC‐18‐02

Remove soil, debris, and vegetation from the low level outlet structure walls and wall tops. Continue with killing vegetation and removing debris. See photos 136 and 142 .

WC‐18‐04

Kill or remove the few remaining shrubs and willows from the embankment faces. The few remaining live shrubs and willows are small . See photos 16, 17, 22 and 28 .

WC‐18‐05

At the bottom of the tower, remove the operating gate air vent blind flange and / or the check valve. The blind flange and check valve are still on the check valve body. See photos 72 and 73 .

WC‐22‐01

Modify the gatehouse window vent covers to be removable, or add additional vents which would be more resistant to vandalism, such as roof vents.

WC‐24‐01

Remove the two remaining trees at the intersection of the downstream groins, downstream face, and toe fill area. See photo 40.

WC‐24‐02

Repair the two spalling and exposed reinforcement locations in the crown of the outlet conduit, 21 feet and 27.5 feet upstream of the portal. See Comment 3.C.4 and photos 130 through 132.

Annual Maintenance

ID DESCRIPTION STATUS

WC‐AM‐01

Operate the project so the reservoir pool elevation does not exceed elevation

4732.0 feet until the spillway is replaced. Continue to inspect the spillway annually and address any new damage.

WC‐AM‐02

Remove debris from the top of the walls of the outlet structure and spillway chutes.

WC‐AM‐03 Keep the tower clean from large dirt and debris.

WC‐AM‐04

Clean any buildup of the old grease, oil, and debris from the tops of the operating and guard gate pedestals and gate stems. Ensure the gear cases are lubricated.

WC‐AM‐05

Remove weeds, brush, and small trees from the dam embankment and groins as necessary.

WC‐AM‐06

Monitor the cavitation damage on the operating gate stem deflector Babbitt seat, and on the transition section.

Willow Creek Dam Inspection, 2024 Recommendations 1 of 1

INVENTORY NO.: OWNER:

HAZARD CATEGORY: OPERATOR:

TYPE OF DAM: STREAM(S):

YEAR BUILT: DRAINAGE AREA:

RESERVOIR STORAGE STATUS

At Time of Inspection (4/15/24):

At Time of Inspection (7/2/24):

At Restricted Pool:

At Spillway Crest:

At Min. Dam Crest Elevation:

*Storage per 2019 O&M

NAME OF DAM: WILLOW CREEK DAM

4/15/24 and 7/2/24

4736.0

4744.5

Storage*

(Acre‐Feet)

13,300

18,000

26,600

Zachariah Campbell (4/15)

DNRC SWP: Josh Gilstrap, PE Brent Zundel, PE

Troy Benn, PE (4/15)

High

MT 22

Willow Creek

WCWUA

DNRC

155 sq. mi

DATE OF INSPECTION:

Water Surface Elevation

(Feet)

Sam Johnson, PE (4/15)

WUA:

4730.1

DEPARTMENT OF NATURAL RESOURCES AND CONSERVATION

DAM SAFETY INSPECTION REPORT

4732.0 14,813

Lezlie Kinne (4/15)

Brian Dyk (4/15)

WEATHER: 4/15: 40's and 50's, light rain

DNRC DSP:

7/2: 55°, light breeze, partly cloudy

4730.4 13,539

Zoned Earth and Rock Fill

Willow Creek Dam Inspection, 2024 Checklist 1 of 8

1. EMBANKMENT

A. Crest

B. Upstream Face

*For 8 vertical feet below crest

C. Downstream Face

Width: 28 FT Length:

Erosion

YES NO

X Minor two‐track rutting

Animal damage

2H:1V

Other X See comments

X

REMARKSITEM

Traffic or roadway damage

Settlement X

See comments

Nuisance vegetation X

Riprap deterioration X

ITEM YES REMARKS

Erosion

Surface Gravel

See comments

X

Misalignment

Transverse cracking

Longitudinal cracks X

X

Lower Slope Ratio: 3H:1V

Transverse cracks X

Longitudinal cracking X

X

Nuisance vegetation

453 FT

X

Upper Slope Ratio:*

Adequate vegetation cover X Coarse, rocky soil, boulders near toe

Seepage X

Debris X

Slumps / Sloughs

X

Debris X

Other

Minor (a few) pieces of small driftwood

Animal damage ‐

A few dormant & dead willows / shrubs

X

Longitudinal cracks X

Slumps / Sloughs X

Adequate riprap protection

Settlement / Depressions X

X

X

Transverse cracks X

ITEM YES NO REMARKS

Slope Ratio: 1.5H:1V

Erosion X

Other X

NO

Settlement / Depressions X

Nuisance vegetation X A few small shrubs & sagebrush

Animal damage X See comments

Height: 105 FT

Willow Creek Dam Inspection, 2024 Checklist 2 of 8

2. ABUTMENT AND TOE

A. Downstream Toe

B. Upstream Abutment

C. Downstream Abutment

3. OUTLET WORKS

* 390 CFS used in 2010 drawdown analysis, 350 CFS used in 2018 spillway performance review

A. Intake Structure

At Res. El.: 4,744.5

Left Abutment

NO REMARKS

Seepage X See comments

See comments

Other X

Animal damage X See comments

Depressions / Bulges X

Boils X

ITEM YES

Erosion X

See comments

ITEM YES NO REMARKS

Animal damage X

Debris X

Nuisance vegetation X

Cracking X

ITEM YES NO REMARKS

Nuisance vegetation X

Animal damage X

X Date Last Inspected:

Type:

NA

Slides / Depressions X

Erosion X

Slides / Depressions X

Erosion X

Cracking X

Other X

Not Visible During Inspection:

Visible During Inspection:

Settlement ‐ ‐

‐ As aboveConcrete spalling ‐

Maximum Discharge: 700 CFS*

ITEM YES NO REMARKS

Seepage X See comments (2.C.4.a, b, c)

Location:

Debris X

Other X

Nuisance vegetation X See 2.A.6

Concrete erosion

Concrete w/Steel Trash Racks

Concrete cracking ‐ ‐ As above

Underwater, not inspected

Tilting ‐ ‐ As above

‐ ‐ As above

Sinkholes X

Willow Creek Dam Inspection, 2024 Checklist 3 of 8

3. OUTLET WORKS (Continued)

A. Intake Structure (Continued)

B. Upstream Conduit

C. Downstream Conduit

60‐inch

Open joints or holes X

Leakage X See comments

Calcium deposits

X

Exposed reinforcement X See comments

Concrete cracking

Size:

See 3.C.8

Concrete spalling X See 3.C.4

Concrete erosion

Type: Reinforced Concrete Horseshoe

Size: 60‐inch

Corrosion of metal appurtenances ‐ ‐ As above

Breakage of metal appurtenances ‐ ‐ As above

Open joints

Joint displacement ‐ ‐ As above

Exposed reinforcement ‐ ‐

Erosion around intake ‐ ‐

As above

Concrete spalling ‐ ‐ As above

As above

Deposition around intake ‐ ‐ As above

Trash rack in good condition ‐ ‐ As above

Anchor systems secure ‐ ‐ As above

Concrete cracking ‐ ‐ Underwater, not inspected

As above

ITEM YES NO REMARKS

Not Visible During Inspection: X

Other X

Wear of protective coatings ‐ ‐ As above

Joint displacement ‐ ‐ As above

Loss of joint material ‐ ‐ As above

Concrete erosion ‐ ‐ As above

Exposed reinforcement ‐ ‐ As above

Visible During Inspection:

Open joints or holes in the wall ‐ ‐ As above

Calcium deposits ‐

Leakage ‐ ‐ As above

Material deposition ‐

Misalignment of conduit ‐ ‐ As above

Appears minor

X

‐ As above

Not Visible During Inspection: Type: Reinforced Concrete Horseshoe

X

Right side drain, see 3.C.8

NO REMARKS

Joint displacement X

‐ As above

Other X

Flow from drains X

At cracks, see 3.C.8

Corrosion of metal liner / transition X

Visible During Inspection: X

ITEM YES

Loss of joint material X

Willow Creek Dam Inspection, 2024 Checklist 4 of 8

C. Downstream Conduit (Continued)

D. Gatehouse and Tower

E. Guard Gate

F. Operating Gate

Type: Butterfly Gate / Pivot Valve

Not Inspected current year: Size, in: 54

See comments

NO REMARKS

Seepage from tower walls X

Safety problems X See comments and 3.D.5

‐ ‐ See comments

Life line in good condition X

Ladder in good condition X

Jet pump piping in good condition

Inspected current year: X

Bonnet and housing in good condition

Leakage from stem packing

X

X

Operated during inspection

Gears lubricated

X

Leakage from flanges

See comments

See comments

See comments

Other X

X

ITEM YES

Material deposition

‐ See comments

Wear of protective coatings X Gate transition section

Misalignment of conduit

Grating in good condition

Stem, pre‐inspection, in: 3‐1/2 26‐3/4

Stem, during guard gate operation, in: 3‐1/8

Stem, during inspection, in:

Stem, post‐inspection, in:3‐1/2

X

Other X See comments (3.D.13.a, c)

X

Pedestal dirty

Stem lubricated X See comments and 3.E.6

X

Pooling water in bottom of tower

Operator operational X See comments

Vandalism Nothing noted since previous inspection

O&M and EAP in gatehouse X

See comments and 3.E.6

X

X

Debris in bottom of the tower X Debris and oil residue

Jet pump operational X See comments

Jet pump leaking

Other

Stem, pre‐operation, in: 65‐1/8 Type: Circular Wedge / Gate Valve

Stem, closed/during inspection, in: 9‐1/16 Size, in:

Stem, post‐operation, in: 65‐1/8

REMARKS

X See comments

ITEM YES NO

Leakage from gate

Gate leaf in good condition X Only downstream side observed

Air vent & valve in good condition

See comments

X See comments

Stem Dia., in: ‐ Threads per Inch: ‐

12:02Time when seated: 14:17Time when unseated:

X

X

X

Stem in good condition

Willow Creek Dam Inspection, 2024 Checklist 5 of 8

F. Operating Gate (Continued)

G. Outlet and Chute

H. Downstream Channel

4. SPILLWAY

A. Approach Area

X

ITEM

Other X

Pedestal dirty

Gate seals in good condition X See comments

Restricted grade X

Bonnet and housing in good condition X

Operator lubricated

X See comment

YES NO REMARKS

Stem in good condition

X See comment

Operator operational X

NO REMARKS

Concrete cracking X

Other

See comments (3.F.13.a….b, c)

Gate leaf in good condition X

Leakage from gate ‐ ‐ See comments

Leakage from flanges X

Leakage though crosshead guide X

See comments

Crosshead guide clean X Dead mouse and other minor debris

YDewatered for Inspection:

See comments

Seepage X See 3.G.1

Debris X Top of walls, most on left

X

Air vent in good condition X

Cavitation damage X

Type: Reinforced Concrete

Exposed reinforcement X

Concrete spalling X Freeze‐thaw spalling ‐ See 3.G.1

Concrete erosion X

ITEM YES

ITEM YES NO REMARKS

Not Visible During Inspection:

Visible During Inspection: X

Seepage X

Erosion

X

Debris X

X

X

Boils

Max. Discharge: 8091 CFS

Type:

Number of Chutes:Left Abutment 1

Concrete Chute At Res. El.: 4744.5

See comment

Location:

Nuisance vegetation

Nuisance vegetation X Above chute walls

XOther

Willow Creek Dam Inspection, 2024 Checklist 6 of 8

4. SPILLWAY (Continued)

A. Approach Area (Continued)

B. Weir

C. Chute

D. Downstream Channel

ITEM YES NO REMARKS

X

See comments

X

Exposed water stops

Nuisance vegetation

Deposition / debris / obstructions ‐ ‐ Soil access ramp on right end

Erosion of flip bucket ‐ ‐

Other X

Nuisance vegetation X See comments

Seepage from weep pipes X See comments 4.C.10

Other

See comments

See comments

Water, debris, & vegetation

Debris in flip bucket

XNuisance vegetation

ITEM

Material deposition above walls X No significant change

Weep pipes in good condition X

Deposition of material X

X

X Left wall joint C

Exposed reinforcement

Concrete erosion X

REMARKS

Rocks from left slope wasting

As above

YES NO REMARKS

See 4.C.15

Boom in good condition

Other

X

X See comments (4.C.16.a, b)

Exposed water stops ‐ ‐ As above

Spalling of weir concrete

NO REMARKS

‐ As above

Exposed reinforcement ‐

X

Nuisance vegetation ‐ ‐ As above

Debris ‐

Length:

‐ As above

ITEM YES NO

90 FT

ITEM YES

OgeeType of Weir:Not Visible During Inspection:

Visible During Inspection: X

Operating During Inspection: No Type: Uncontrolled Concrete Chute

Cracking of weir concrete

As above

See 4.C.16.a, b

Other X

Debris

‐ ‐ No spillway boom

Blockage of drains ‐ ‐

Surface paste erosion

Concrete cracking X

Seepage (not from weep pipes)

Displacement or offset of joints X See comments

See 4.C.15

Concrete spalling X

As above

Joint sealant in good condition ‐ ‐ See comments

XErosion

Willow Creek Dam Inspection, 2024 Checklist 7 of 8

5. RESERVOIR CONTROL

A. Development and Changes

6. INSTRUMENTATION

* Reservoir transducer is automated

A. Instrumentation

7. DOWNSTREAM CONDITION

A. Downstream Land Use

Report reviewed by: Brent Zundel, PE

Report reviewed by: Jillian Hendrix

Atypical piezometer data ‐ ‐ See comments

Report completed by: Josh Gilstrap, PE

Changes in basin hydrology ‐

Description X See comments

ITEM YES NO REMARKS

Recent downstream development ‐

See comments

Other X

Other X

Reservoir and Piezometers Monitored Manually: X

Cataract, Bell, Norwegian

Significant debris in reservoir X

Large impoundment upstream

Slope pins in good condition X

X

Data reviewed & attached X

Piezometers in good condition X X See comments

Reservoir Monitored Automatically:

Farm and ranch land, town of Willow Creek.

‐ See Feasibility Study deliverables

Change in reservoir operation X

Not closely reviewed for annual

Slides in reservoir area X

ITEM YES NO REMARKS

Recent upstream development ‐ ‐ Not closely reviewed for annual

Willow Creek Dam Inspection, 2024 Checklist 8 of 8

COMMENTS

1. EMBANKMENT PHOTOS

1.A.9

On the second visual inspection date an approximate 5' x 6' area of diesel contaminated soil was present at the left end of the crest towards the gatehouse and spillway approach. The contaminated soil was removed by DNRC on 7/24/24.

1.B.4

Overall the upstream face is in good condition. However, riprap is of varying sizes, with the right side generally having larger riprap. There are several areas of minor benching and riprap variability, where the face has an almost dish‐like shape and smaller riprap.

Less of the upstream face was visible with the reservoir being approximately 7 feet higher compared to the fall 2023 inspection, but no significant changes were noted during the 2024 inspection.

1, 2, 4, 5, 10‐12, 13

1.B.9

Near the shoulder of the upstream face proximal to piezometers DH‐4A and DH‐4B two bull snakes were observed entering interstitial pockets in the riprap. These are not considered to be problematic, compared to burrowing rodents, for example.

18, 19

1.C.9

Live rodents were not observed during the inspection but visual inspection field notes suggest a minor, non‐concerning presence of rodents in the boulders at the lower end of the downstream face.

2. ABUTMENT AND TOE

2.A.1

During the 2024 inspection (4/15/24) seepage was observed at the left bank of the original Willow Creek channel when the pool elevation was lower while the outlet was shut for the conduit entrance. On the second visual inspection day the bank just above the seepage area was damp, without active seepage.

31, 32

2.A.5

A rodent hole was observed on 7/2/24 located beyond the toe of the embankment, between the outlet and downstream of the left abutment bedrock in the downstream valley fill area. The hole measurement approximately 6" x 9" at the surface and was probed 7 feet with a tape measure. It did not appear to be fresh or active, and at this location is not considered a dam safety concern or in need or backfilling.

46, 47

2.A.6

There were a number of trees in the fill section downstream of the dam, not previously identified as problematic. Most of these were removed during the recent geotechnical investigation (test pits and a boring) as seen during the second visual inspection day.

Two trees remain at the intersection of the downstream groins and toe fill area, best practice is to remove these trees.

39‐41

2.B.8 The void at the spillway right headwall abutment has not exhibited any change.

2.C.4.a

Seepage is typically present in the bedrock above the conduit outlet. During the 2024 inspection seepage through the rock was typical of expected conditions: there were approximately 30 separate drips on each side of the outlet ‐ total flow would be low if combined. There is also seepage at the rock interface on the left end of the outlet structure.

2.C.4.b

Bedrock seepage also exits at a location approximately 100 feet to the right of the outlet (left of the toe of the dam), discharging into a swale, typically wet for only a short distance downstream (this seepage was not active on 4/15/24, but was active on

7/2/24.

42‐44

2.C.4.c The seepage location in the draw in the far right abutment was minimally active on

4/15/24 (visible water) but not active on 7/2/24 (noted as just damp).

45, 46

Willow Creek Dam Inspection, 2024 Comments 1 of 6

3. OUTLET WORKS PHOTOS

3.C.4

Corroded rebar reinforcement is exposed in two places in the conduit crown, centered approximately 21 feet from the outlet portal and another location approximately 6.5 feet upstream. There was no visual change between the 2024 and 2023 inspections, however, spalling at the location 21 feet from the portal has progressed over the last five years. Best practice for these small locations is to sawcut a rectangular shape, remove damaged concrete, remove corrosion from the reinforcement, and to patch the spalls. A non‐sag fast‐set patch such as EucoRepair V100 is recommended.

130‐132

3.C.8

Approximately 12 cracks and six construction joints were observed and documented in the outlet conduit during the 2019 5‐year inspection. Visual review during the 2024 5‐

Year inspection are generally consistent with this number, but several unique cracks from 87 to 93 feet upstream of the portal (record drawing stationing 2+09 to 2+015) could be considered one crack, as HDR documented in 2022 and as DNRC observed during this 5‐Year inspection, totaling 10 cracks instead of 12. The number of leaking locations depends upon the reservoir elevation, three locations were noted as seeping during the 2024 inspection. However, general conduit surface moisture near the pivot valve (from releases) could obscure other seep locations if they exist. One of the drains

(70.8 feet upstream of the portal) was flowing at approximately 1 GPM, which is normal. A comparison table of conduit notes is attached after the instrumentation plots

120‐135

3.C.15

2019 DNRC and 2022 HDR conduit inventories were reviewed during the 2024 conduit entrance; a full conduit inventory was not repeated. Review and comparison indicates variability in observation methods, which creates comparison difficulty. For example

HDR's stationing is slightly different than DNRC's, and a few observations may be erroneous. HDR observation 4 (O4) referenced at station 0+25 (a conduit crown spall) is centered at station 0+21 per DNRC; HDR notes appear to note this spall twice, as a spall is also referenced for observation O3 at station 0+22. Despite the inconsistency, conduit conditions are generally similar with the exception of progression of the spall at station 0+21. A comparison table of conduit notes is attached after the instrumentation plots.

120‐135

3.D.2

The gate tower grate platform has an opening immediately inside the access door which is used to lower items to the bottom of the tower. The grate should always be closed when not in use; when the grate is open the exterior door lock bar must be in place. Additionally, the lower grillage does not extend upstream of guard gate

3.D.4 The grating appears to be in good condition. The lower grating at the guard gate operator level is not continuous across the full section of the tower.

3.D.5

The lifeline is in good condition, but safety upgrades are recommended to the tower ladder system and safety devices. The main ladder does not extend above the upper tower grillage (there is an offset ladder and platform below the upper grillage) and there are no fall arrestors on the short upper ladder steel cable. Ideally, there would be one continuous ladder from the lower grillage to above the upper grillage. A self retracting lifeline can be used instead of the upper cable until an entrant is attached to the main ladder lifeline.

Willow Creek Dam Inspection, 2024 Comments 2 of 6

3. OUTLET WORKS (Continued) PHOTOS

3.D.6 There is a very minor leak at a construction joint at the bottom of the tower on the left hand side downstream wall. This was the same as with previous inspections.

3.D.9 Since the 2017 repair the jet pump has continued to work well. The main valve was cycled 10 times during the 2024 inspection.

65, 66

3.D.11 The original jet pump pipe remains in place upstream and downstream of the elbows;

the integrity of those sections is not known. Their exterior appearance shows corrosion.

3.D.13.a Structurally, the gatehouse could use improvements. A beam and pulley would be useful for lowering and lifting equipment.

3.D.13.b

The plastic covering the window vents should not be in place when making irrigation releases as the purpose of venting is to provide air to satisfy operating gate air demand and reduce cavitation potential. The plastic covers are screwed in place, but should be modular and easily removed. Alternatively, additional venting, possibly on the roof, should be installed. No visual change noted compared to previous inspections.

70, 71

3.E.2

Guard gate operation during the 2024 inspection was very good. Resistance increased from approximately 12" (which is normal), with the most resistance at final seating after approximately 10". From 11" to closure (in the seating range) operation difficulty increased (which is normal). The high speed pinion can be pulled out of the journal, likely because of a loose set screw from the high speed gear. This should be repaired when the guard gate operator is serviced as described in 3.E.6.

50‐53

3.E.3

Some fluid weeps from the low‐speed pinion journal during gate operation. Notes scribed on the tower wall indicate two gallons of gear oil were added in 2021. During the 2024 inspection the operator thrust bearings were greased via the Zerks fitting.

3.E.4

During the 2024 inspection the stem was manually lubricated with Valvoline Palladium grease over most of its range and Molykote G‐N in the upper seating/unseating range.

Unseating force causes shearing of lubrication on the thread faces within the unseating range.

3.E.6

Conditions during the 2024 inspection were similar to 2023 and previous inspections:

The guard gate operator is dirty. Servicing the guard gate operator the same as on guard gate operators at other DNRC dams includes: fully cleaning and relubricating the stem, greasing the Zerks fitting while operating the gear case, removing the gear case cover (and side case), drilling a new check / fill hole in the case cover, cleaning and flushing the gear case, resealing, and installing new oil (Sprinkler Lube 1200 recommended). Afterwards, drape a tarp / cover over the stem and guard gate operator to keep it clean. See the 2/13/2020 Gate Operator Inspection and

Maintenance letter.

50‐53

3.E.9

The packing around the stem of the guard gate leaks when the gate is being operated and in the closed position. Leakage is minimal (much less than 1 gpm), longstanding, and was typical during the 2024 inspection. If the leakage rate becomes more of a nuisance, bolts could be tightened around the stem packing.

54‐56

3.E.10

The guard gate air vent 8" gate valve and check valve appear to be in good condition.

Minor bright corrosion staining was noted near the check valve disc bronze seal. The 8" valve and check valve are always in the closed positions.

57‐59

Willow Creek Dam Inspection, 2024 Comments 3 of 6

3.E.11

The guard gate usually seals well, as was the case during the 2024 inspection. Portions of the bronze seal are visible at the edges of the gate disc. On rare occasion (such as in

2016) the gate hasn't sealed well, with several hundred gpm of leakage estimated;

experience indicates these occurrences are infrequent non‐concerning anomalies possibly related to the disc not fully reaching a seated position in the wedge.

60‐63

3.F.1

The operating gate is typically very stiff when closing any further than approximately 3‐

3/4" of stem opening. On 4/15/24 the stem setting was initially 3‐1/2"; the gate was opened to 26‐3/4" for the conduit entrance and gate inspection, and set to 3‐1/8' following the conduit entrance. The WUA operated the gate during the 2024 inspection.

70, 71

3.F.2

The WUA serviced the operating gate operator on May 7, 2020. The operating gate gear case should be checked yearly and filled with gear oil or Sprinkler Lube 1200 as needed.

Gear case, stem, and thrust bearing(s) lubrication is a WUA maintenance item. The gate operator components appeared lubricated during the 2024 inspection (grease on the stem and residual lubricant near the drive pinions).

70, 71

3.F.3

There may be a slight bend in the operating gate stem at the lower‐most stem coupler

(between the 2nd and 3rd stem guides) from the bottom, noted visually but not measured during HDR's outlet system inspection in 2022. Further investigation would be necessary to determine if deflection exists. Regardless, stem condition at this location has not produced evidence of negative effects on gate operation.

3.F.8

The gate is not inspected under head. Operationally the gate is not closed for sealing and leakage is inevitable even if the gate is fully closed. Since the reservoir is on‐stream this is of no operational consequence.

3.F.11

The Babbitt material (valve body sealing surface) is in good condition. The wear pattern on the gate stem at the lowest stem guide indicates the gate has been closed as far as

1.75" of stem exposed above the gate operator at some historical point. During the

2018 inspection, the operating gate was closed down to 2" of stem during the first closure (to close the guard gate) and then to 3‐3/4" of stem during the second closure

(to open the guard gate). On the lower half of the Babbitt there is a discernable higher surface for approximately half of the width of the seal, and it appeared during the first gate closure the gate traveled to that position. This may be related to the increased level of difficulty in operating the gate at small stem ranges. On the lower portion of the Babbitt seal below the pivots some of the seal is covered in film which roughly corresponds to normal closures and the aforementioned high spot. A full set of 2024 photos showing the seal is included in the photo log ‐ the seal was visually consistent with previous inspections.

77‐107

3.F.12

DNRC recommends removing the check valve and / or blind flange on the air vent.

DNRC has observed stuck check valves, and this would ensure air demand can always be met. This is maintenance recommendation WC‐18‐05.

72, 73

3.F.13.a

Minor, shallow cavitation damage is on both sides of the operating gate stem deflector, along the crown upstream of the operating gate Babbitt, and along the invert downstream of the gate body in the transition section.

101‐104, 109‐116, and see

2024 5‐YR

Willow Creek Dam Inspection, 2024 Comments 4 of 6

3.F.13.b

During the 2024 inspection the appearance of some of these areas were 'clean', but aggressive recent cavitation was not observed. A cavitation comparison photo log was included with the 2019 inspection report to establish a base line of measurements and visual condition assessment. A photo log of 2019 and 2024 photo comparisons is appended to the 2024 5‐YR. Basic depth measurements and visual comparisons do not indicate substantial change since 2019. Some areas appear 'cleaner' but shape and depths are essentially unchanged: consequential cavitation progression was not observed.

101‐104, 109‐116, and see

2024 5‐YR

3.F.13.c

If condition‐baselining cavitation repairs are performed, they may require bypass pumping or material which does not have restrictive prep and cure time, since cavitation repairs are usually staged when spillway flow satisfies downstream flow.

3.G.1

Both of the chute walls show cracking and freeze thaw damage. There is one continuous crack across both chute walls and floor. A crack on the downstream termination of the concrete chute on the right wall (above transition to riprap) fills with water when the outlet is flowing. Once the outlet is shut off, flow out of this crack reduces. Similarly, a crack on the wall of the chute does the same thing. No changes were noted during the 2024 inspection.

136‐142

4. SPILLWAY

4.C.6

Comparison of locations measured by WJE in 2018 indicates additional joint offset and concrete or repair material bulking since 2018. For example the faulting at Joint G just left of longitudinal Joint 3 increased from 3/4" to 1" from 2018 to 2024, and the repair downstream of Joint D left of longitudinal Joint 3 is bulked as much as 2". See Appendix

D of the 2024 5‐Year for specifics.

, 1 , 1

, an d see 2

‐YR

4.C.7 Transverse joint sealant is in place, condition is consistent with joint condition.

4.C.8

Information obtained during the first visual inspection led to replication of previous

(DNRC & WJE 2018) weep pipe depth measurements and basic notes during the second visual inspection on 7/2/24. The previous reporting missed the two lowest weep pipe rows, included a nonexistent weep pipe downstream of Joint D, etc. Six of the weep pipe depths are significantly different and 11 weep pipes are obstructed with concrete

(whereas only two were noted as obstructed by WJE). See Appendix D of the 2024 5‐

Year for specifics, including a map and weep probing depth table.

an d see 2

‐YR

4.C.10

On 4/15/24 seepage was present at many cracks on the lower chute floor; however, earlier in the day the entire chute was wet from precipitation which was a contributor to the seepage observed. On 7/2/24 with a similar reservoir elevation the only active seepage noted was at one of the weep pipes on chute floor panel L7; seepage through cracks in the chute floor was not present.

‐1 , 1

, 1 ‐1

4.C.13 There is significant vegetation in the flip bucket, accumulated organic / soil debris, and a few rocks.

146, 147, 181, 182

4.C.15

Minor small vegetation was present along some of the joints and cracks in the chute floor during the 2024 inspection. Most of the vegetation is constrained to the flip bucket.

146, 147, 159, 163, Willow Creek Dam Inspection, 2024 Comments 5 of 6

4. SPILLWAY (Continued) PHOTOS

4.C.16.a

DNRC personnel inspected the spillway thoroughly in 2017, and WJE Associates, Inc.

completed a final "Willow Creek Dam Investigation of Spillway Distress" report, dated

11/20/2018. Since the completion of these investigations there has been no hydraulic loading of the spillway (i.e. pool level restriction and the spillway has not operated) and inspections have been brief and primarily intended to check for new major damage rather than continued degradation. The WUA performed maintenance in 2018 consisting of replacing missing joint sealant, sealing of some cracks, and installation of two concrete patches (slabs L2 and L6). Annual reviews have been brief and have included replication of select standard photos to compare year‐to‐year changes at identical locations and perspectives. This year‐to‐year comparison is included as a separate photo log to this annual report. The 2024 comparisons document ongoing degradation of repair material at Photo ID Plan 03, which is at transverse joint D just right of longitudinal joint 3.

Se p arate A n n u ally R ep licated

P h o to s

4.C.16.b

On 7/2/24 during the second 2024 visual inspection date photos were taken to replicate many of those included in the 2018 WJE "Willow Creek Dam Investigation of

Spillway Distress" report. Comparison of these locations and photos indicates continued degradation of spillway chute concrete despite no hydraulic loading. See

Appendix C of the 2024 5‐Year for specific comparisons.

Se e 2

‐YR

5. RESERVOIR CONTROL

5.A.5 The maximum permissible reservoir level was lowered four feet to 4,732 feet in 2018.

6. INSTRUMENTATION

6.A.1

Instrumentation at this dam consists of nine piezometers located in five drill holes. Data from these piezometers, along with the reservoir elevation, has been plotted, reviewed, and is attached. Recently two standpipe piezometers were installed in the toe fill area test pits and have been measured during monthly monitoring.

6.A.2

A field piezometer inventory was completed on 6/5/24. The inventory included down‐ casing video, casing depth sounding, and various supporting measurements. The inventory indicates problems with several of the piezometers such as sediment or obstructions near the bottom of the casing, screen slot zones which are partially blocked, trapped water in the bottom of the casing, and completion log errors. This information is summarized in Appendix F of the 2024 5‐Year; conclusions and improvements in the understanding of piezometer condition have been added to the visual plots in this annual owner inspection report.

6.A.4

Piezometer DH‐2B water levels range between 4,700 feet to 4,705 feet. Piezometer DH‐

2B is completed in the Zone A embankment. Piezometer DH‐2A, completed in the same borehole in Zone A embankment but likely at or near the Zone B contact consistently has water levels 30 to 40 feet lower than DH‐2B, indicating DH‐2A may be controlled by

(functionally completed in) Zone B material. Piezometers DH‐3 and DH‐5B are dry, DH‐

4B is usually dry, and 5A is nearly always dry.

Willow Creek Dam Inspection, 2024 Comments 6 of 6

4,655

4,660

4,665

4,670

4,675

4,680

4,685

4,690

4,695

4,700

4,705

4,710

4,715

4,720

4,725

4,730

4,735

4,740

4,745

4,750

W at e r El e va ti o n

FT

M

SL

Date

Willow Creek ‐ All Piezometers

Dam Crest Spillway Crest Reservoir Elevation Manual Reservoir Elevation Automated DH‐1A

DH‐1B DH‐2A DH‐2B DH‐3 DH‐4A

DH‐4B DH‐5A DH‐5B

*DH‐3, DH‐4B, DH‐5A, and DH‐5B are dry or nearly always dry, shown as consistent flat elevations. Consistent / flat ranges in DH‐1B indicate dry readings.

4,704 4,709 4,714 4,719 4,724 4,729 4,734 4,739 4,744 4,749 4,754

D H A

W at er

El ft

Reservoir El., ft

DH 1A vs Reservoir El.

Left Crest Near Gatehouse and Outlet

Gneiss Bedrock

2005 to 2022 2023

2024 Sand Pack

1:1 Line Piezo Screen

Field Inventory Screen Slots 2023 and 2024 Trend

Log completion zone elevation (hole cave): 4681.5' to 4701.2' Log screen elevation: 4681.5' to 4686.5' Field inventory screen elevation: sounded bottom to 4691.6'

Ground elevation 4746.2'

4,715 4,720 4,725 4,730 4,735 4,740

D H 1B

W at er

El ft

Reservoir El., ft

DH 1B vs Reservoir El.

Left Crest Near Gatehouse and Outlet

Logged as Sandy Clay

2005 to 2022 2023 2024

Sand Pack Piezo Screen 1:1 Line

Trend 1 Trend 2 Field Inventory Screen Slots

Log sand pack elevation: 4705.2' to 4715.2' Log screen elevation: 4707.2' to 4712.2'

Field inventory screen slot elevation: sounded bottom to 4691.6' Ground elevation 4746.2'

Approximately 2' of screen casing is clear, and 3' is compromised. Discard field readings below el. ~4711.0' which do not represent embankment pore pressure.

4,712 4,717 4,722 4,727 4,732 4,737 4,742

H 2A

W at e r El ft

Reservoir El., ft

DH 2A vs Reservoir El.

Left End of DamUpstream Crest Shoulder

Zone A near or at Zone B Contact Sandy Clay Embankment

2005 to 2022 2023 2024

Sand Pack Piezo Screen 1:1 Line

2023 and 2024 Trend Field Inventory Screen Slots

Log Sand pack elevation: 4656.3' to 4666.3' Log Screen elevation: 4658.3' to 4663.3'

Field inventory screen slot elevation: 4658.4' to 4662.8' Ground elevation 4745.27'

4,710 4,715 4,720 4,725 4,730 4,735 4,740 4,745

D H 2B

W a te r El ft

Reservoir El., ft

DH 2B vs Reservoir El.

Left End of Dam Upstream Crest Shoulder

Zone A Sandy Clay Embankment

2005 to 2022 2023 2024

Sand Pack Piezo Screen 1:1 Line

Trend Field Inventory Screen Slots

Log sand pack elevation: 4696.3' to 4707.3' Log screen elevation: 4698.3' to 4703.3' Field inventory screen slot elevation: 4698.3' to 4702.7'

Ground elevation 4745.27'

4,712 4,717 4,722 4,727 4,732 4,737

H

W a te r El ft

Reservoir El., ft

DH 3 vs Reservoir El.

Left End of Dam Downstream Crest Shoulder

Zone B Gravelly Sand

2005 to 2022 2023 2024 Sand Pack Piezo Screen 1:1 Line Field Inventory Screen Slots

Log sand pack elevation: 4712.1' to 4721.5' Log screen elevation: 4713.1' to 4718.1'

Field inventory screen slot elevation: 4713.5' to 4718.0' Ground elevation 4745.14'

Piezometer is dry.

Discard water levels below el. ~4,713.7' reflecting water trapped in the bottom of the casing, rather than Zone B pore pressure.

4,708 4,713 4,718 4,723 4,728 4,733 4,738

D H A

W at e r El ft

Reservoir El., ft

DH 4A vs Reservoir El.

Right Side of Dam Upstream Crest Shoulder

Zone A / Foundation Contact Sandy Clay / Sandy Silt

2005 to 2022 2023 2024

Sand Pack Piezo Casing 1:1 Line

Trend Field Inventory Screen Slots

Log sand pack elevation: 4687.4' to 4697.4' Log screen elevation: 4689.4' to 4694.4' Field inventory screen slot elevation: sounded bottom to 4692.8' Ground elevation 4745.43'

Screen is 1.6' lower than logged Lower 3' of screen is compromised

4,711 4,716 4,721 4,726 4,731 4,736

H 4B

W at e r El ft

Reservoir El., ft

DH 4B vs Reservoir El.

Right Side of Dam Upstream Crest Shoulder

Zone A Sandy Clay / Sandy Silt Embankment

2005 to 2022 2023 2024 Sand Pack Piezo Casing 1:1 Line Field Inventory Screen Slots

Log sand pack elevation: 4717.4' to 4727.4' Log screen elevation: 4719.4' to 4724.4'

Field inventory screen slot elevation: 4719.0' to 4723.4' Ground elevation 4745.43'

Nearly always a dry piezometer Discard field readings below el. 4,719.2' which do not represent embankment pore pressure

Minor (~1') offset in screen location compared to log

4,711 4,716 4,721 4,726 4,731 4,736

D H 5A

W a te r El ft

Reservoir El., ft

DH 5A vs Reservoir El.

Right Side of Dam Downstream Crest Shoulder

Logged as Sandy Clay

2005 to 2022 2023 2024 Sand Pack Piezo Casing 1:1 Line Field Inventory Screen Slots

Log sand pack elevation: 4699.6' to 4708.6' Log screen elevation: 4700.6' to 4705.6' Field inventory screen slot elevation: 4701.0' to 4705.5'

Ground elevation 4745.62'

Nearly always a dry piezometer Discard field readings below el. 4,701.2' which do not refelect embankment pore pressure

4,711 4,716 4,721 4,726 4,731 4,736

H B

W at er

El ft

Reservoir El., ft

DH 5B vs Reservoir El.

Right Side of Dam Downstream Crest Shoulder

Zone B Gravelly Sand

2005 to 2022 2023 2024 Sand Pack Piezo Screen 1:1 Line Field Inventory Screen Slots

Log sand pack elevation: 4718.6' to 4726.6' Log screen elevation: 4719.6' to 4724.6' Field inventory screen slot elevation: 4719.9' to 4724.3'

Ground elevation 4745.62'

Nearly always a dry piezometer Discard field readings below el. 4,720.1' which do not indicate embankment pore pressure

WILLOW CREEK DAM ‐ OUTLET CONDUIT INVENTORY

From To From To

2019 Outlet Tunnel Portal

2019 Exudation ‐ rt. side wall

2022 O1 Pitting in conduit wall. Possibly voids from construction

2022 O2 Delaminated area noted (sounded) along right side of conduit

2019 Crack ‐ around entire horseshoe

2024 Seeping at left and right sides and crown. Photos …001‐...006

2019 HO3 Crack ‐ top portion only, exudation

2022 O3 Crack and delaminated area noted. 3x5" area of concrete spalling

2024 ‐ Spall, exposed reinforcement, essentially same as last fall, photos ...996‐...999

(0+21 is center)

2019 Crack (minor) ‐left side

2022 O4 Spalling resulting in exposed rebar. HDR error, this is the same as 0+22, not a unique spall

2022 O5 Delaminated area noted

2019 Crack (minor) ‐left side

2024 ``

Spalling resulting in exposed rebar at crown of conduit.

Seam with general calcium deposits at wall to rounded transition

2024 Photos ...993‐...994, no observable change

2019 Joint ‐ actively seeping lt. side, (<<1 gpm) rt. side

2024 Seeping from both sides, nail, photo ...991 and ...992 (left) ...995 (right)

2019 Crack ‐ rt. side above springline

Description

0+27.5

1+35.0

1+38.0

1+43.00+21.0

1+46.30+24.3

Inspection Station Record Dwg. Station*

0+28.0 1+50.0

0+13.0

0+16.0

0+25.0

0+26.0

Year HDR ID

NA

HO1

HO2

O6

0+28.7

HO4

HO5

HO6

HO7 1+57.30+35.3

0+00.0 1+22.0

0+07.9 1+29.9

0+16.6

0+22.0

1+38.6

1+44.0

1+47.0

1+48.0

0+26.3 1+48.3

1+49.5

1+50.7

From To From To Description

Inspection Station Record Dwg. Station* Year HDR ID

2019 Crack (longitudinal ‐ left side, exudation

2019 Exudation, left above springline

2022 O7 General calcium deposits on seam

2019 Crack (spiral) ‐ left

2024 Right side also

2022 O8 General calcium deposits on seam

2019 Joint? ‐ more calcification than others, all circumference

2024 Photos ...987‐…990, possibly crack instead of joint, dampness on left side to crown

2022 O9 General calcium deposits on seam

2019 Joint ‐ full circumference

2022 O10 Two plugged holes near crown. Grout injection from previous repairs?

2019 Drain ‐ rt. side, 2" ID flowing ~1gpm, probe 31"

2024 Flowing up to 1 GPM, photos ...985, …986

2019 Crack ‐ full circumference (possibly joint lower lt. side)

2019 Crack (small) ‐ rt. side, 2:30 position

2024 Not specifically observed as unique crack

2022 O11 0+87.0 0+93.0 2+09.0 2+15.0 Crack observed through entire conduit

2019 Joint ‐ full circumference, Lt. drain 2"ID (no flow), probe 16"

2024 Probed 15.5", no flow, photos ...981, ...983, ...984

2019 Crack (spiral) ‐ Lt. and rt. 2' up walls

2024 Crack photos ...981, ...982, spiral, floor and walls

1+62.0

1+59.30+37.3

0+36.8 0+40.4 1+58.8 1+62.4

0+40.0

0+89.0

0+64.5 1+86.5

1+92.0

0+70.8 1+92.8

0+76.7 1+98.7

0+44.3 0+45.3 1+66.3 1+67.3

HO13

HO14

HO15

HO16

HO17

HO8

HO9

HO10

0+45.0

0+70.0

1+67.0

0+64.0 1+86.0

HO11

HO12

0+93.0 2+11.0 2+15.0

0+86.7 2+08.7

0+88.7 2+10.7

0+52.5 1+74.5

From To From To Description

Inspection Station Record Dwg. Station* Year HDR ID

2019 Crack (diagonal floor) ‐ weep rt. side, no flow, probe 21.4"

2024 No flow, probed 21.5'', Photos ...979, ...980

2019 Joint ‐ less efflorescence

2019 Joint ‐ efflorescence decreasing moving upstream

2019 Crack (diagonal) ‐ Lt. side only

2019 Hole ‐ Crown, probe 3" (likely grout hole)

2024 Photos ….977, …..978

2019 Transition to circular

2019 NA DS End of Operating Gate

2022 O12 The pivot valve was observed in its near open condition

2024 NA

Stationing increases from outlet portal to tower

2019 & 2024 = DNRC

2022 = HDR, Feasibility Study Task 9c, Conduit Inspection and Evaluation Tech Memo

*Record Drawing Stationing From 5‐47‐13 (#11), equivalent stationing based on 1+22 (end of tunnel)

Italic text is from 2024 conduit entrance

1+13.8 2+35.8

1+21.8

1+09.5

0+89.0

1+20.8

HO22

HO21

HO18

HO19

2+43.8

2+14.02+11.00+92.0

2+31.5 2+33.71+11.7

2+42.8

HO23

HO20

1+20.8 2+42.8

1+00.9

1+03.8

1+09.8

2+22.9

2+25.8

2+31.8

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 1 of 46

Photo 1 Upstream face of dam from right abutment

Photo 2 Upstream face of dam and left abutment / spillway approach from left abutment

Photo 3 Downstream face from right abutment

Photo 4 Upstream face at waterline from near right upstream groin

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 2 of 46

Photo 5 Upstream face and shoulder view left from near right end of dam

Photo 6 Crest view left from near right end of dam

Photo 7 Downstream face and shoulder view left from near downstream right groin

Photo 8 Downstream face view left from near middle of embankment

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 3 of 46

Photo 9 Crest view left from near middle of embankment

Photo 10 Upstream face and shoulder view left from near middle of embankment

Photo 11 Upstream face near waterline view left from near

Photo 12 Upstream face near waterline view right from near

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 4 of 46

Photo 13 Upstream face and shoulder view right from near

Photo 14 Crest view right from near middle of embankment

Photo 15 Downstream face and shoulder view right from near middle of embankment

Photo 16 Dead or dormant willows on upstream face

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 5 of 46

Photo 17 Dead or dormant willows on upstream face

Photo 18 Bull snake on upstream face

Photo 19 Small pocket on upstream face where bull snake was entering rock / embankment

Photo 20 Diesel spill on crest, cleaned up after inspection

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 6 of 46

Photo 21 Example of rockier area near surface, upper part of downstream face

Photo 22 Example of small brush on downstream face

Photo 23 General area of transition to area of larger cobbles and boulders near toe of embankment

Photo 24 View down right downstream groin

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 7 of 46

Photo 25 View up right downstream groin

Photo 26 View up right downstream groin near toe

Photo 27 View up left downstream groin near toe

Photo 28 View up upper portion of left downstream groin & abutment

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 8 of 46

Photo 29 View down left downstream groin

Photo 30 View down left downstream groin, from crest

Photo 31 Original stream channel pool

Photo 32 Seepage area in original stream channel pool area, pool level lower while conduit was dewatered

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 9 of 46

Photo 33 View towards original stream channel from low level outlet confluence

Photo 34 View towards low level outlet portal

Photo 35 View downstream

Photo 36 View down downstream embankment and toe area

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 10 of 46

Photo 37 View from abutment to low level outlet, original stream channel pool and downstream channel

Photo 38 View from abutment to spillway and downstream stream channel

Photo 39 View up downstream face and left abutment from toe, after geotech field investigation

Photo 40 Toe fill area after geotech investigation, PVC casings installed in test pit backfill

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 11 of 46

Photo 41 View up downstream face and right abutment from toe, after geotech field investigation

Photo 42 April, bedrock seepage area not active

Photo 43 July, bedrock seepage area active

Photo 44 July, bedrock seepage area active - closeup

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 12 of 46

Photo 45 Downstream right abutment draw seepage area, active in April

Photo 46 Rodent hole in general toe area, right of outlet and downstream of left abutment bedrock

Photo 47 Rodent hole in general toe area, right of outlet and downstream of left abutment bedrock (background is location of bedrock seep)

Photo 48 Upstream right abutment, example of minor live brush

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 13 of 46

Photo 49 Instrumentation (reservoir transducer) telemetry panel

Photo 50 Guard gate operator, gate closed

Photo 51 Guard gate stem after reopening gate, lubrication partially sheared from lower side of threads from unseating gate

Photo 52 Guard gate operator high speed pinion can be pulled out from gear case; may be a set screw issue requiring gear case cover removal

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 14 of 46

Photo 53 Guard gate operator high speed pinion pushed pack in

Photo 54 Guard gate operator at top of stuffing box and stem packing follower, dirty

Photo 55 Guard gate stem, stem packing follower, grease, etc.

Photo 56 Guard gate stem packing following, minor seepage (drip) from stem packing

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 15 of 46

Photo 57 Guard gate bonnet and eight inch vent valve (closed)

Photo 58 Guard gate air vent check valve

Photo 59 Guard gate air vent check valve disc

Photo 60 Lower portion of guard gate and invert of conduit

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 16 of 46

Photo 61 Lower portion of guard gate and invert of conduit -closeup

Photo 62 Upper portion of guard gate

Photo 63 Upper portion of guard gate - closeup

Photo 64 Operating gate bonnet and cross head guide, stem, and gate air vent valves and check valves

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 17 of 46

Photo 65 Jet pump main valve handle extension (off position)

Photo 66 Right side of bottom of tower and jet pump

Photo 67 Jet pump outlet

Photo 68 Left side of bottom of tower, left of guard gate bonnet, oily debris

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 18 of 46

Photo 69 Minor seepage on left downstream tower wall

Photo 70 Operating gate operator after conduit entrance

Photo 71 Operating gate stem setting following inspection (April)

Photo 72 Operating gate eight inch valve and check valve for air vent

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 19 of 46

Photo 73 Operating gate air vent inlet and check valve (check valve disc still in place)

Photo 74 View down operating gate cross head guide (lining) to cross head

Photo 75 View up conduit to operating gate and guard gate in background

Photo 76 Lower edge of operating gate disc below left pivot

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 20 of 46

Photo 77 Lower edge of operating gate disc right of previous photo

Photo 78 Lower edge of operating gate disc right of previous

Photo 79 Lower edge of operating gate disc right of previous

Photo 80 Lower edge of operating gate disc right of previous

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 21 of 46

Photo 81 Lower edge of operating gate disc right of previous

Photo 82 Lower edge of operating gate disc below right pivot

Photo 83 Upper edge of operating gate disc above left pivot

Photo 84 Upper edge of operating gate disc right of previous

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 22 of 46

Photo 85 Upper edge of operating gate disc right of previous

Photo 86 Upper edge of operating gate disc right of previous

Photo 87 Upper edge of operating gate disc right of previous

Photo 88 Upper edge of operating gate disc right of previous

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 23 of 46

Photo 89 Upper edge of operating gate disc above right

Photo 90 Operating gate Babbitt seat near (below) left pivot

Photo 91 Operating gate Babbitt seat right of previous photo

Photo 92 Operating gate Babbitt seat right of previous photo

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 24 of 46

Photo 93 Operating gate Babbitt seat right of previous photo

Photo 94 Operating gate Babbitt seat right of previous photo

Photo 95 Operating gate Babbitt seat right of previous photo

Photo 96 Operating gate Babbitt seat near (below) right pivot

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 25 of 46

Photo 97 Operating gate Babbitt seat near (above) left pivot

Photo 98 Operating gate Babbitt seat right of previous photo

Photo 99 Operating gate Babbitt seat right of previous photo

Photo 100 Operating gate Babbitt seat right of previous

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 26 of 46

Photo 101 Operating gate Babbitt seat, slightly upstream of previous photo showing cavitation area

Photo 102 Operating gate Babbitt seat right of previous

Photo 103 Operating gate Babbitt seat, slightly upstream of previous photo showing cavitation area

Photo 104 Operating gate Babbitt seat right of previous

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 27 of 46

Photo 105 Operating gate Babbitt seat right of previous

Photo 106 Operating gate Babbitt seat right of previous

Photo 107 Operating gate Babbitt seat near (above) right

Photo 108 Operating gate stem deflector and crown, upstream side

Willow Creek Dam Inspection, 2024 Visual Inspection Photo Log 28 of 46

Photo 109 Operating gate stem deflector and crown, left and upstream side

Photo 110 Operating gate stem deflector and crown, right side

Photo 111 Cavitation / pitting area just downstream of operating gate body, approximately 4:30 o’clock position

Photo 112 Cavitation / pitting area just downstream of operating gate body, approximately 5 o’clock position

Willow Creek…