Title
a. Approve Change Order No. 3 to the contract with Graniterock Company for Nacimiento Dam spillway repair work to: (1) increase the contract amount by $123,000 ($76,000 to come from original contract amount; $65,000 from San Antonio spillway repair work and $11,000 remaining contract balance) to a total of $412,000, and (2)
extend the contract term to September 30, 2019; and
b. Approve Change Order No. 3 to the contract with Graniterock Company for San Antonio Dam spillway repair work to: (1) decrease the contract amount by $65,000 (moved to the Nacimiento Dam spillway repair work) to a total of $135,000, and (2) extend the contract term to September 30, 2019; and
c. Authorize the General Manager to execute both Change Orders.
Report
RECOMMENDATION:
It is recommended that the Monterey County Water Resources Agency Board of Directors:
a. Approve Change Order No. 3 to the contract with Graniterock Company for Nacimiento Dam spillway repair work to: (1) increase the contract amount by $123,000 ($76,000 to come from original contract amount; $65,000 from San Antonio spillway repair work and
$11,000 remaining contract balance) to a total of $412,000, and (2) extend the contract time to September 30, 2019; and
b. Approve Change Order No. 3 to the contract with Graniterock Company for San Antonio Dam spillway repair work to: (1) decrease the contract amount by $65,000 (moved to the Nacimiento Dam spillway repair work) to a total of $135,000, and (2) extend the contract term to September 30, 2019; and
c. Authorize the General Manager to execute both Change Orders.
SUMMARY/DISCUSSION:
Nacimiento and San Antonio Dams are regulated with regard to dam safety matters by the California Department of Water Resources, Division of Safety of Dams (DSOD). Nacimiento Dam is also regulated by the Federal Energy Regulatory Commission (FERC) due to the hydroelectric plant at the dam.
After the 2017 Oroville dam spillway incident, DSOD and FERC directed the Agency (and all high hazard dam owners) to submit Work Plans for spillway work needed before the 2017-18 winter, conduct a focused spillway inspection, and submit a Spillway Condition Assessment Report. Graniterock Company was hired in late 2017 to compete the Work Plans for Nacimiento and San Antonio spillways under Agency Board of Director’s recommendation (September 18, 2017), and Agency Board of Supervisor’s authorization of the General Manager to enter into a construction contract on an emergency basis for immediate repairs to the spillways (September 26, 2017).
Both spillways were inspected in July 2017. The San Antonio Dam Spillway Condition
Assessment Report was submitted to DSOD in May 2018, and the Nacimiento Dam Spillway Condition Assessment Report was submitted to DSOD and FERC in July 2018. The reports recommend additional work to both spillways. A scope of work addressing report recommendations for Nacimiento Dam spillway was submitted to DSOD and FERC in July 2018. DSOD has provided approval to proceed, but FERC approval has not yet been received.
Change Order No. 3 at Nacimiento allows Graniterock Company to proceed with spillway work contained in the July 2018 Nacimiento Dam spillway scope of work when approved by FERC. The July 2018 Nacimiento Dam spillway scope of work includes:
1. Borescope exploration (drill ¾” diameter hole and insert camera) into and below spillway concrete chute slabs to indicate concrete condition and search for voids, and fill hole with grout;
2. Seal moving, non-moving cracks, and fine cracks in spillway concrete chute;
3. Repair delaminated spillway chute concrete;
4. Repair concrete spalls; and
5. Quality control and inspection program.
Change Order No. 3 at San Antonio allows Graniterock Company to proceed with underdrain exploration work, while the scope of work addressing Spillway Condition Assessment Report recommendations for San Antonio Dam spillway is in preparation. The remaining funding will be moved to the Nacimiento Dam spillway repair project.
OTHER AGENCY INVOLVEMENT:
DSOD and FERC must approve construction work plans for the Nacimiento dam, and DSOD must approve construction work plans for the San Antonio dam.
FINANCING:
Monies for Change Order No. 3 are available from FY 2018-19 Fund 116 - Nacimiento Dam Operation and Maintenance.
Prepared by: Chris Moss, Senior Water Resources Engineer (831) 755-4860
Approved by: ___________________________________________________
David E. Chardavoyne, General Manager, (831) 755-4860
Attachments:
1. Change Order No. 3 for Nacimiento
2. Change Order No. 3 for San Antonio
3. Change Order Nos. 1 and 2 for Nacimiento
4. 2017 Nacimiento Dam Spillway Emergency Repairs Project Time and Materials
Contract
5. Change Order Nos. 1 and 2 for San Antonio
6. 2017 San Antonio Dam Spillway Emergency Repairs Project Time and Materials
Contract
7. Board Order