WNDSMP_Pre-Bid Site Visit_Brochure_v4.pdf

WNDSMP Site Visit

Solicitation No. W912BV23R0039 q0rmctjf Text Box

Site Visit Meeting Location:

Pico Rivera Golf Club 3260 Fairway Dr. Pico Rivera, CA. 90660

Sign-in begins at 8:30 Project Presentation begins at 9:00 q0rmctjf Text Box

1. Refreshments and snacks will be available inside the pro-shop.

2. A guided site tour will follow the project presentation.

3. PPE is not required.

4. Photographs of the site are allowed.

5. Public restrooms are located at Pico Rivera Golf Club.

q0rmctjf Callout Meeting Location

Pico Rivera Golf Club 3260 Fairway Dr. Pico Rivera, CA. 90660 q0rmctjf Cloud+ q0rmctjf Cloud+ Parking for project presentation

WHITTER NARROWS

DAM SAFETY

MODIFICATION

PROJECT

SITE VISIT

FEBRUARY 28, 2024

SAN GABRIEL SPILLWAY (STA 117+80 to STA 124+50)

Limits San Gabriel Spillway Width: 1,300 ft

Summary of

Modification

Embankment and Bridge-founded Parapet wall (5ft high) Foundation Existing bridge, embankment

Utilities – Proposed

Modification

Power, water, and communication service lines, leach line

Two City of Whittier Pipes (modified in Contract 1)

- PiP

Quantities (CY) Limited

Options Surface filter drainage blankets

Site access Dam crest

Considerations or

Restrictions

Must maintain access, power, and communications to spillway at all times.

EAST EMBANKMENT (STA 124+50 to STA 179+00)

Limits Station 126+00 (east of spillway to Station 179+00

(end of dam)

Length: 5,300 ft

Summary of

Modification

Overtopping section

Blanket drain

Parapet Walls

Remove road (Sports Arena Dr)

Foundation Alluvium

Groundwater (baseline) Wet Season: 10’ to 12’

Dry Season: 18’ to 19’ Utilities – Proposed

Modification

SCE Transmission Tower - PiP

LACSD sewer pipe – PiP

Quantities (CY) Excavation: ~140,000

Hardfill: ~75,000

Gravel: ~25,000

Sand: ~30,000 Options N/A

Site access Upstream side of dam, limited access from south

Considerations or

Restrictions

N/A

EAST EMBANKMENT: . The main features are the downstream hardfill, training walls on both sides of the spillway, stilling basin, and trench drain.

IMPACTED UTILTIES: A chlorination testing building and meter vault are also part of the SWS system. A 25-inch wastewater line runs through the same gallery owned by LACSD. There is an SCE distribution line that runs over the dam that from the downstream embankment toe. Frontier communication lines hang below the SCE distribution lines for which SCE will be coordinating their relocation plans for Frontier relocation to follow the new SCE alignment.

There are communication lines that serve the USACE facility. A 60-inch

LACSD sewer parallels the east embankment 6 feet behind the curb line of

Sports Arena Drive. LADWP has high voltage transmission towers that parallel the Sports Arena Drive. A 3-inch gas line runs up and over the embankment near Station 150+00. Several water lines shown on original as-builts for the

East Embankment listed as Rincon and Pellissier are believed to be abandoned. An active owner has not been identified. It is anticipated that these will be removed during construction. Relocation of the San Gabriel Bike trails are an option.

San Gabriel Spillway &

East Embankment

(STOP 1 & 2)

SAN GABRIEL SPILLWAY: Construct adjacent parapet walls which will be placed to elevation 243.3 ft NAV29. The proposed cross section for the wall over the existing bridge and on the existing embankment are shown in structural sheets. There will be no modifications to the spillway gates or operating system. Stream crossings are planned for at the control structures and the crossover channel. These crossings must allow movement of materials or equipment without violating water pollution control standards.

During the previous contract, a vertical diaphragm was installed around the

City of Whitter pipes which cross the dam at the gallery at Station 126+60.

Under this contract, the inclined trench drain will need to transition to vertical to maintain the continuity of the gravel drain and filter zones.

For general illustration purposes only, not a bid document.

See solicitation number W912BV23R0039 for bid information.

NORTH ABUTMENT (STA 6+70 to STA 11+00)

Limits High ground to north, Lincoln to the south

Length: 400 ft Summary of

Modification

300’ of low embankment (5’ to 6’)

100’ of parapet wall Foundation Alluvium and artificial fill

Utilities – Proposed

Modification

Numerous abandoned service lines associated with dam tender’s house

18” abandoned sewer line that parallels Lincoln

Quantities (CY) Undetermined but low

Options None

Site access Lincoln

Considerations or

Restrictions

Adjacency to homes

Threatened/endangered species habitat adjacent

Bird nesting restriction

LINCOLN AVE (STA 11+00 to STA 15+00)

Limits Road modification extends 1,000 ft to west (south) and

1,400 ft to east (north) Summary of

Modification

Raise/relocate Lincoln 70’ to the southeast

Build parapet across the existing roadway

Relocate/protect in place numerous utilities

Add a shallow slurry cutoff trench (including around utilities)

Foundation Road and embankment fill

Utilities –

Proposed

Modification

78” Storm drain crossing - PiP

30” high pressure gas line - Relocation by SoCalGas in coordination with Contractor

SCE transmission lines. PiP; guy wires to be relocated by SCE in coordination with Contractor

32” SGVWC water line. PiP

Several 5” to 8” lines, mostly fuel and oil. PiP

Quantities (CY) ~200,000 of fill

Options Bike/hiking trail Surface filter blanket

Site access Lincoln

Considerations or

Restrictions

Adjacency to homes

Reservoir

Minimize closure of road

Bird nesting restriction

CENTRAL EMBANKMENT(STA 66+40 to STA 117+80)

Limits Station 66+40 (east of Rosemead to Station ~

115+00 (spillway)

Length: 5,000 ft

Summary of

Modification

• Overtopping section

• Blanket drain

• Trench drain

• Relief Wells

• Parapet Walls

Foundation Alluvium

Groundwater (baseline) Wet Season: 10’ to 12’

Dry Season: 15’ to 17’ Utilities – Proposed

Modification

LACSD 63” sewer – PiP and encase

Quantities (CY) Excavation: ~250,000

Hardfill: ~125,000

Gravel: ~65,000

Sand: ~65,000

Options N/A

Site access Rosemead, upstream side of dam

Considerations or

Restrictions0

Limited Construction Access

Lincoln Ave Relocation

(STOP 4)

Streamland Park &

Central Embankment

(STOP 3)

LINCOLN AVE MODIFICATION: To minimize impacts to the existing utilities in the existing utility corridor, Lincoln Avenue will be shifted approximately 70 feet to the south and the minimum elevation at the centerline of the dam will be raised to 243.3. A parapet wall will extend from the north side of the relocated road across the existing road to approximate Station 9+60. To the south, fill will be extended to Station 15+00. These modifications were designed by AECOM consistent with USACE dam safety criteria.

IMPACTED UTILTIES: The following major utilities are impacted by the proposed raising of Lincoln Avenue: SCG’s 30-inch HP gas line; SCE’s above ground power and AT&T communications; SGVWC’s 32-inch water main; and

LACDPW’s 72-inch flood control pipe. Minor utilities include small diameter oil lines that run under the pavement parallel to the roadway. The design and relocation of SCG’s HP gas line, SCE’s above ground power, ATT communications, and SGVWC 32-inch water line are to be done by the utility owners in close coordination the USACE contractor. Relocation of the Rio

Hondo Bike and Equestrian trails are an option.

CENTRAL EMBANKMENT: The main features are the downstream hardfill, stilling basin, trench drain, training walls (Stations 66+40 and 114+00), a splitter wall (to prevent the need for a stilling basin at the Mission Creek

Gallery), hardfill, stilling basins, filter/drainage blankets (which varies in length across the embankment) and the existing relief wells. A trench drain will be used in two reaches.

IMPACTED UTILTIES: Streamland Park and the Pico Rivera Golf Course have irrigation, power, water, and sewer utilities that will be abandoned by the

City of Pico Rivera and removed as encountered by the dam modification contractor. Four LADWP transmission towers are located at the toe of the dam within this reach but will not be physically impacted by filter/drainage blanket construction.

A 63-inch LACSD sewer trunk line, to be protected in place with an encasement, passes through the dam at the Mission Creek gallery (Station

69+50), turns to the west then roughly parallels the dam and Rosemead

Boulevard until well beyond the project.

For general illustration purposes only, not a bid document.

See solicitation number W912BV23R0039 for bid information.

NORTH ABUTMENT: A parapet wall will extend between station 9+60 and the relocated Lincoln Avenue fill (approximately 250 feet). The wall will be approximately 5 feet high and be on the upstream side of the crest. A significant portion of the embankment extension will be excavated to remove the existing 18-inch wastewater pipe. The previously removed dam tender house has underground features that were left in place, including a septic tank, septic field, a one-inch water line, and gas line which will be removed.

North Abutment & West

Embankment

(STOP 4)

WEST EMBANKMENT: The main features are the downstream hardfill, stilling basin, and trench drain.

IMPACTED UTILTIES: The construction of the West Embankment will have to be done in close coordination with the impacted utilities with significant consideration to sequencing. A 30-inch high pressure gas (transmission) line crosses the dam in Lincoln Avenue, turns south and parallels, roughly 100 feet downstream, of the dam toe. A 78-inch reinforced concrete pipe (RCP) storm drain owned by LACDPW crosses underneath Lincoln and will be modified

(reference plan package 4). The storm drain continues to the Rio Hondo. The current design package shows the pipe as being protected in place between

Stations 15+00 and the Rio Hondo. Manholes will be raised to match grade.

AT&T is evaluating an alignment that skirts the edge of USACE proposed work so that it can be done prior to the USACE dam mods. SCE service to

USACE dam. USACE will install the new service pole and lines around the proposed footprint of the dam mods. SCE will be preparing the relocation design and perform the relocation work. This schedule will be integrated with the USACE dam mods. SCE anticipated 12 months lead time starting from our

95% design to be provided to SCE.

West Embankment &

Rosemead Blvd.

(STOP 6)

OUTLET WORKS TO ROSEMEAD BLVD (STA 30+00 to STA 46+00)

Limits From Rio Hondo Channel to west of Rosemead (training wall at Station 46+00)

Length: 1500 ft Summary of Modification Overtopping section

Trench drain Foundation Alluvium, artificial fill Groundwater (baseline) Wet Season: 9’ to 13’

Dry Season: 15’ to 20’ Utilities – Proposed

Modification

SCE transmission lines – PiP

Whittier well – PiP

EPA observation wells – raise

Multiple HDPE collector pipes (24” to 36”) – PiP

Drainage blanket – PiP, Modify

Quantities (CY) Excavation: ~100,000

Hardfill: ~50,000

Gravel: ~30,000

Sand: ~25,000 Options 1,500 ft of trench drain Site access Rosemead, upstream side of dam Considerations or

Restrictions

Proximity to homes downstream

RIO HONDO OUTLET WORKS (STA 28+00 to STA 30+00)

Limits Rio Hondo Bridge

Length: 225 ft

Summary of

Modification

Parapet wall (5ft high)

Slabs at parking areas

Foundation Existing bridge, embankment

Utilities – Proposed

Modification

Power, water, com service lines, leach line

Quantities (CY) Limited

Options None

Site access Dam crest

Considerations or

Restrictions

Must maintain access, power, and communications to Outlet Works

RIO HONDO OUTLET WORKS: For the Rio Hondo Outlet Works, parapet walls will be constructed along the upstream edge of the bridge from Station

28+08 to Station 30+22 at elevation 243.3. As the outlet works have settled approximately one foot since original construction, the embankment road (at elevation 239) will ramp down to the bridge. A short, reinforced concrete curb will be added on the downstream side of the ramp to maintain the elevation at which embankment overtopping initiates. The existing asphalt surface at the control house parking areas will be replaced with a reinforced slab, underlain by filter and drain material. At the west parking area, the existing septic tank and leach line will be replaced with a 1000-gallon holding tank.

WEST EMBANKMENT: The main features for the West Embankment are the downstream hardfill, stilling basin, and trench drain. The width of the project right of way at the toe is roughly 130 feet. Homes (single family residences and condominiums) abut the right of way. A maintenance road extends from the crest at Station 32+00 to the toe at Station 37+00. Stream crossings are planned for at the control structures and the crossover channel. These crossings must allow movement of materials or equipment without violating water pollution control standards.

West Embankment &

Rio Hondo Outlet Works

(STOP 5)

ROSEMEAD BOULEVARD: . Rosemead Boulevard is under the jurisdiction of the County of Los Angeles. The proposed Rosemead Boulevard alignments will be directly above the existing Rosemead Boulevard center median. The road will be raised approximately 6 feet above the existing elevation near the dam crest and gradually converge back to the existing vertical road elevation

(350’ to the northeast of Gallatin Road at the south tie in and at the existing flood flow channel bridge at the north tie in).

The proposed cross section for Rosemead Boulevard was approved by the

Los Angeles County Department of Public Works. The cross section consists of a 14-foot center median, and in each direction, one 12-foot travel lane, one

14-foot travel lane, and one 8-foot outside shoulder. The 14-foot median will be continuous along Rosemead Boulevard without an opening or break at the dam crest for USACE operations staff to access the dam from the opposite roadway direction - i.e., there will be no access to the east side of the dam crest from the southbound roadway and vice versa. The typical roadway section was approved by Los Angeles County Department of Public Works.

The 14-foot center median will begin tapering down at Sta. 68+79.66 (NB) to a

4-foot center median at Sta. 79+12.63 (NB) to tie into the existing flood flow channel bridge at the north tie in. The roadway improvements begin at the south end at Sta. 50+00 (NB) and Sta. 10+00 (SB) respectively. The roadway improvements end at the north end at Sta 81+55.90 (NB) and Sta. 41+57.02

(SB) respectively.

IMPACTED UTILITIES: At the Rio Hondo Side Diversion Channel, the proposed modification is to temporarily remove the existing diversion conduit and install a diaphragm and drainage system. Between the outlet and the weir, where the channel invert is approximately 6 feet deeper than adjacent ground, proposed modification is to remove the riprap, geotextile, and overlying fine materials (estimated to be 5 feet). The base of the sand filter would match the elevation of the existing trench drain. The bedding, and riprap would be restored. Filter, bedding, and confining riprap would be added to the channel slopes. A row of SCE power poles are approximately 120 feet from the toe and will be protected in place by the USACE Dam Modifications contractor.

WEST EMBANKMENT (STA 15+00 to STA 28+00)

Limits From east of Lincoln (training wall at Station 15+00) to Rio Hondo Channel

Length: 1300 ft

Summary of

Modification

Overtopping section Trench drain

Foundation Alluvium

Groundwater (baseline) Wet Season: 9’ to 14’ Dry Season: 17’ to 22’

Utilities – Proposed

Modification

78” Storm drain - PiP

30” gas – PiP

SCE transmission lines – PiP

Power, water, and com service lines – relocate

Wells – abandon

Leach line – PiP

24” HDPE collector pipe - PiP

Quantities (CY) Excavation: ~70,000

Hardfill: ~40,000

Gravel: ~25,000

Sand: ~20,000

Options 500 ft of trench drain

Modifications to small 400’ long trap. channel Site access Lincoln

Considerations or

Restrictions

Adjacency to homes

Excavation limitations during wet season

Santa Fe Dam Borrow Area

Site Map

SANTA FE BORROW AREA: The designated borrow areas are the two sources at Santa Fe Dam approximately 9 miles north of the site (the SFD

Basin Borrow Area and the SFD Stockpile Borrow Area). Soils from the borrow areas are primarily sands, gravels, cobbles, and boulders, but there are some silts and clays in the upper portion of the SFD Stockpile Borrow

Area.

2, 6, 16, EXAMPLE OF ADDITIONAL UTILTIES IMPACT AT LINCOLN

SCG’s 2 inch distribution line. This buried line is along the northerly side of the road and is no longer in service and will be removed.

SCE utility poles carrying electrical lines. These compensable lines border the north side of Lincoln Avenue and have guy poles on the south side of the road.

The north lines contain transmission and distribution lines and include communication lines from various owners. These poles and lines require relocation based on the original roadway alignment, however, with the proposed shift 60 feet toward the basin, only the southerly guy poles and attached AT&T communication lines are impacted. The design will be developed by SCE and the relocations done by SCE.

AT&T communication lines. These lines are above ground hanging from the

SCE pole listed above. AT&T is preparing the design. These also service the

USACE office at the Rio Hondo outlet of Whittier Dam. The construction will be sequenced with the USACE construction and will be called out as “by others” on the plans and coordination explained in the specs with POC and phone numbers.

Abandoned Oil lines - Crimson, Chevron, Texaco, Standard Oil, and Union.

These lines generally all parallel each other below the paved shoulder of the southerly side of Lincoln and many have connections or older pipe alignments that were relocated during the original dam construction. Crimson and

Chevron are both taking their lines out of service and are cleaning them for abandonment. The other abandoned lines are no longer owned by Texaco, STD or Union and will be cleaned by USACE. Approximately 100 feet of each pipeline will be removed where they cross over the crest of the dam to prevent seepage. Since these lines are all close to each other crossing over the

USACE dam core, they will all be removed by USACE to maintain quality control and avoid having 3 contractors being responsible for removal of potential contaminated soil. Where these lines cross under the roadway fill the removal limits will be defined by AECOM and designated as such in the plans and specs.

Other abandoned pipes (no ownership) – There are several other pipes of varying sizes that traverse the embankment centerline at varying depths.

These will be removed during construction.

For general illustration purposes only, not a bid document.

See solicitation number W912BV23R0039 for bid information.

Special Considerations

SECURITY: The project site has experience frequent security issues associated to vandalism, theft, and unhoused population.

CONSTRUCTION: The project is in a highly urbanized environment, and in close proximity to residential dwellings.

WORK HOURS: The project work hours are set as Monday through Friday

6:00 a.m. to 6:00 p.m.; however, the contractor must comply with the relevant local ordinances (noise, vibration, dust, light, etc.). Other than routine equipment maintenance or aggregate deliveries, no work will be permitted on

Saturdays, Sundays, or federal holidays without prior written approval.

WORK RESTRICTIONS: All vegetation clearing must occur from August 15 through March 15, outside of the bird nesting season, to avoid and minimize unauthorized injury or death of federally endangered least Bell's vireo (Vireo bellii pusillus) and federally threatened coastal California gnatcatcher

(Polioptila californica californica).

EXCAVATION LIMITATIONS DURING CONSTRUCTION: The size of excavations on the dam crest during the wet season will be limited, such that existing crest elevation can be completely restored within 72 hours in the event of a dam safety emergency. No trench drain excavation will be allowed in Reach 3 during the wet season. All other excavations during the wet season will be limited to what can be backfilled to original grade within 24 hours.

DEWATERING: The depth to groundwater at Whittier Narrows Dam varies seasonally sometimes as much as 40 feet or more. The groundwater table has ranged typically between 15 to 40 feet below natural grade, but historically has been as shallow as at the ground surface (0 feet below natural grade) and deeper than 60 feet below grade. Due to the high seasonal variability of groundwater conditions at the site, it is expected that the contractor will be able to schedule the work in such a way to avoid construction dewatering. It will be up to the contractor to incorporate the risk and cost of possible dewatering on the project. If construction dewatering becomes necessary, the groundwater table would be drawn down to at least two feet below the bottom of excavation (at least 17 feet below grade). Seasonal restrictions for excavation are in the specifications.

ROSEMEAD ROADWAY RELOCATION: During construction, four lanes of travel will be provided except for brief durations where short-term full closures are required and other periods where lanes will be reduced to one lane in each direction to construct pavement near the tie-in locations at each end of the project. Single lane operations will be limited to one week per closure assuming the use of rapid strength concrete (RSC) pavement for the tie-ins is permitted. This is an important assumption since the placement of lean concrete base and JPCP takes several weeks to place and cure. RSC allows for reduced construction durations due to shortened cure times of the JPCP and lean concrete base.

LINCOLN ROADWAY RELOCATION: One lane in each direction will be provided to motorists in the permanent condition. During construction, one lane in each direction will also be provided except for brief durations where short-term full closures are required to complete the construction and shift traffic from the existing road to the proposed road.

1. AT&T

2. Chevron

3. City of LA Dept of Water and

Power

4. City of Montebello

5. City of Whittier

6. Crimson

7. Frontier

8. LA County Dept of Public

Works

9. LA County Flood Control

District

10. LA County Parks and

Recreation

11. LA County Sanitation District

12. Pellissier/Rincon

13. San Gabriel Valley Water

Company

14. Santa Fe Springs

15. Southern California Edison

16. Southern California Gas

Company

17. Standard Oil

18. Suburban Water Systems

19. Texaco

20. Union

21. USACE Utilities

22. Unknown Utilities

IMPACTED KNOWN UTILITIES FOR THE ENTIRE PROJECT