Attachment_11_-_Virtual_Presentation_Slides_0001.pptx

Folsom Right Wing Dam - North Fork Ditch Bypass Modification Pre-Site Visit Meeting American River Division, Folsom Unit, Central Valley Project, Central California Area Office

January 23, 2025

Presentation Outline Introduction – Carlos Lopez (Contracting Officer) Solicitation Summary – Carlos Lopez Location & Background – Sean Frische (COR) Work Locations, Site Security & Coordination – Sean Frische Purpose – Mehdi Khan (Design Team Lead) Modification Features / Components – Mehdi Khan Schedule & Physical Site Visit – Carlos Lopez Contracting Officer’s Closing Remarks and Q & A – Carlos Lopez

Solicitation Summary and Site Visit Guidelines Solicitation: January 13, 2025

NAICS Code 237990 - Other Heavy and Civil Engineering Construction, Firm Fixed Price Total Small Business set aside procurement.

Refer to Section L of the solicitation for the estimated notice to proceed date for development of the schedule and proposal analysis purposed only.

Refer to Section M for Quality Predominance Evaluation and Factors and Subfactors and information on how proposals will be evaluated.

Contractors are required to monitor SAM.gov for any updates to dates related to the acquisition approach and timeline.

The complete set of specifications are provided as Attachment 1 of Section J and are available under the separate cover via Kiteworks. To obtain this file, please send an email to request the Kiteworks link to Ron Gamo at rgamo@usbr.gov and cc: Abelardo (Carlos) Lopez at aclopez@usbr.gov.

Solicitation Summary and Site Visit Guidelines Site Visit Guidelines

No questions will be addressed during the site visit.

All questions shall be formally submitted to the Contracting Officer and Contract Specialist as stated in Section L of the solicitation.

Government responses at the site visit are not to be construed as solicitation supplements.

An amendment will be issued by the government to address industry questions.

The attendees of this virtual site visit, in person site visit sign in sheet, this PowerPoint, and the site visit agenda will be posted as an amendment in SAM.gov.

Location

This is a map of California showing the location of Folsom Dam. It’s about 25 miles northeast of Sacramento and. You will notice in the site map that three counties, Placer, Sacramento, and El Dorado converge within the footprint of Folsom Reservior, and work in this contract will be performed in two of those counties, Placer and Sacramento.

Background Folsom Dam Constructed between 1951 and 1956 Provides water for the Federal Central Valley Project Consists of:

Main concrete gravity dam flanked by two earthen wing dams Eight earthen dikes and an earthen auxiliary dam Impounds Folsom Reservoir Confluence of the north and south forks of the American River Provides nearly 1 million acre-feet of storage Crest Length Main concrete dam: 1,400 feet Right Wing Dam (RWD): 6,700 feet Left Wing Dam (LWD): 2,700 feet

Three 66-inch diameter CMPs were used as a temporary bypass for the North Fork Ditch during construction of Folsom Dam. According to construction records, the CMPs were plugged and left in place during original construction of the RWD. The CMPs are approximately 400 ft long, running parallel to the abandoned North Fork Ditch at the foundation of the RWD.

Background (continued)

North Fork Ditch Construction Area Conduit work

(2) inspection wells

Toe Drain Cleanout

Inspection Well

Right Wing Dam Work Locations

Inspection Well Toe Drain Cleanout Access to Existing Toe Drain Outfall

Left Wing Dam Work Locations

Review Specification Section 01 35 50 – Site Security and WBR 1452.237 – Site Security Requirements (Section I).

Access at the toe of the RWD and LWD is considered Zone 2, however, the toe of the RWD will be treated as Zone 3 until the USACE contractor no longer requires access to the RWD crest from the toe access road and reestablishes the required security features.

Site Security

Coordination with Folsom Dam Raise Work USACE is constructing a concrete floodwall for additional freeboard.

Floodwall is being constructed on the entire length of the RWD and LWD crest along the upstream slope. Crest access will need to be maintained via the RWD toe access road until USACE work is complete.

Coordination with Folsom Dam Raise Work (continued) The USACE contractor is expected to complete work on the crest of the RWD in Fall of 2025. Work on the crest of the LWD will continue into 2026.

Additional coordination will be required at both the RWD and LWD toe drain modification work areas.

USBR & USACE will coordinate joint use of the site.

NFD Construction Area USACE Contractor travel path

LWD toe drain Construction Areas

RWD toe drain Construction Area RWD toe drain Construction Area

Now I will turn this over to Mehdi Khan, Design Lead from Reclamation Technical Service Center.

Why Are We Constructing This Safety of Dams Modification?

The modification will add a filter, drain, and berm to protect the Right Wing Dam from seepage induced internal erosion at the North Fork Ditch Culverts, and Toe drain inspection well manholes and cleanouts will be installed at the Right Wing Dam and Left Wing Dam to improve seepage monitoring and to enable the ability to detect adverse seepage behavior at both wing dam embankments.

Current Condition of NFD Conduits

The three 66-in dia. CMPs & concrete headwall are on bedrock and are backfilled with grout and/or concrete.

Based on visual inspection of the interior and exterior surfaces, the metal of the CMP cutout pieces appears to be in good condition. There are minimal to no signs of pitting on the surface, even where the coating or lining has peeled and bare metal is exposed. This could be due to the galvanization which creates a passive layer at the surface of the metal. There is some corrosion product present on the exterior of the CMP, which could indicate that corrosion is occurring.

Summary of Work Areas NFD Construction Area – dewater, install temp bypass, excavate, cut conduits, install filter and berm, restore site.

RWD Toe Drain Construction Area – excavate and install toe drain cleanout.

RWD Toe Drain Construction Area – excavate and install toe drain inspection well manhole.

LWD Toe Drain Construction Area – excavate and locate toe drain, install toe drain cleanout and inspection well manhole.

Onsite work at toe of RWD and LWD cannot begin before August 1st, and excavation shall not begin after November 1 without approval from the COR (01 14 12).

Optical Fiber There is an existing optical fiber line that will need to be cut and relocated.

Specification section 33 82 23 calls for temporary and permanent fiber lines.

North Fork Ditch Area – Dewatering Wells

Point out all 8 dewatering well locations and mention that a temporary bench must be constructed to install wells DW-1, DW-2,DW-3, and DW-4.

North Fork Ditch Area – Dewatering Bench

20’ temporary dewatering bench Slide rail system takes out most of this temporary bench as shown.

For slide rail construction, some existing embankment will also need to be excavated.

Temporary access ramp to the bench for drill rig access.

Excavation beyond the limits shown on the drawings is not allowed.

The dewatering system(s) shall operate for a minimum of 24 days continuously prior to excavation, unless otherwise approved by the COR (31 03 33).

North Fork Ditch Conduit Excavation Braced excavation

Slide Rail system

Will require tighter closure than this example which shows space between sheetpiles and the conduit

Materials are cohesionless

Prevent movement of surrounding soil into excavation.

NFD Conduit Excavation (continued) Details on how to brace excavation around conduit to be provided by contractor (31 23 23).

Remove pipes to the limits shown on drawings using methods described in 33 11 19.

Excavation shall be backfilled with zoned materials to existing grade prior to December 31, unless otherwise approved by the COR (01 14 12).

The downstream 15 feet of the three conduits and concrete headwall will be cut and removed in a manner that avoids disturbing or moving the portion of the culverts to remain.

NFD Stability Berm Details Filter diaphragm and drain

Berm includes a chimney filter

Stability Berm

When backfill rises to elevation of the base of the toe drain, a new toe drain pipe will be installed across the area and the temporary toe drain diversion is removed.

A stability berm will be constructed above the new toe drain segment to overcome the potential for excessive hydrostatic pressure.

Soil fill will be placed in horizontal lifts and be compacted.

Erosion control materials will be placed over the stability berm.

Section 31 23 02 describes compaction and laboratory testing requirements. Requirements for selecting the testing agency can be found in 01 46 20.

Notify the independent testing laboratory and Government:

Left Wing Dam Toe Drain Modification Location of toe drain is approximate as shown on drawing 485-D-1290.

“Contractor shall perform exploratory excavation to confirm location of toe drain.” (33 46 36 3.01)

State that a work restriction will be added to the specifications to require exploratory excavation prior to initiation of excavation at the North Fork Ditch to expose the North Fork Ditch conduits. We need the North Wing Dam toe drain to be located early in the project.

Toe Drain Video Inspection Video inspection will be required once installation of inspection wells and new toe drain is complete in accordance with Specification Section 33 46 46. Inspect entire length of LWD & RWD toe drain systems.

(check spec, fill in spec section and determine if we require video of Left Wing Toe Drain or just the new segment at the Right Wing Dam toe drain?)

Site Visit: Friday, January 24 @ 10:00 AM PST

Questions Due: Tuesday, January 28 @ 5:00 PM PST

Proposals Due: Wednesday, February 12 @ 5:00 PM PST

Estimated Award: Mid April 2025

Contract Duration: 372 calendar days

Schedule

Site Visit Agenda Meet at the designated meeting location (to be provided) …...... 9:30am – 10:00am Review agenda and JHA ………………………………………………….…… 10:00am – 10:15am Site Visit to Right and Left Wing Dam work and use areas …...… 10:15am – 12:00pm

Required PPE: hard hat, safety vest, and appropriate clothing for an active construction site (i.e. closed-toe work boots, long-sleeved shirts, pants) Sign-in sheet will be shared on Sam.gov.

Contracting Officer’s Virtual Site Visit Closing Remarks and Q & A image2.png image5.png image3.png image6.png image7.png image8.png image9.png image15.png image16.svg image90.png image10.png image11.png image12.svg image13.png image14.svg image17.png image18.png image19.jpeg image20.png image21.jpg image4.png image22.emf image23.emf image24.png image25.png image26.png image27.png image28.jpeg image29.jpeg image30.png image31.png image32.png image33.png image34.jpeg