To: Board of Supervisors
Department or Agency Name(s): Sonoma County Public Infrastructure
Staff Name and Phone Number: Johannes J. Hoevertsz, 707-565-2550
Vote Requirement: Majority
Supervisorial District(s): First
Title:
Title
Fifth Amendment to the Contract with Moffatt & Nichol for Design and Construction Support of the Watmaugh Road Bridge over Sonoma Creek Replacement Project.
End
Recommended Action:
Recommended action
Approve and authorize the Director of Sonoma County Public Infrastructure (SPI) to execute a Fifth Amendment to the Professional Services Agreement with Moffatt & Nichol for the Watmaugh Road Bridge over Sonoma Creek Replacement Project (C08001), extending the term by five years and increasing the agreement by $158,147, for a new total not-to-exceed contract amount of $1,323,456, including contingency, and a new term ending December 31, 2031.
end
Executive Summary:
Sonoma County Public Infrastructure (SPI) is requesting that the Board approve a Fifth Amendment to the Professional Services Agreement with Moffatt & Nichol for the Watmaugh Road Bridge over Sonoma Creek Replacement Project (C08001) and authorize the Director of SPI to execute the amendment.
The proposed amendment will provide additional design and construction support services, including updates to the bridge design to meet current engineering and seismic design standards and other applicable requirements and specifications, as well as continued support during construction.
The proposed amendment will increase the base agreement amount by $158,147, for a new total not-to-exceed agreement amount of $1,323,456, including contingency. Additionally, the proposed amendment will extend the term of the agreement by five years, through December 31, 2031.
Discussion:
The Watmaugh Bridge over Sonoma Creek was constructed in 1929. The bridge is a steel truss bridge with a concrete deck. The bridge is listed as seismically deficient and does not meet current road and bridge standards. Although the bridge was included on the Sonoma County list of historic structures, evaluations conducted in 1986 and 2003 by consultants on behalf of Caltrans determined that it did not qualify for listing on the National Register of Historic Places. Based on those findings, SPI received Highway and Bridge Program (HBP) funding in 2012 to design and construct a replacement bridge that would meet current standards. With HBP funding secured, on July 12, 2012, the County awarded an engineering and design contract to Moffatt & Nichol for a not-to-exceed amount of $471,756 and a term ending December 31, 2015.
On December 11, 2012, by Resolution No. 12-0586, the Board certified the Final Environmental Impact Report for the Project. By Resolution No. 12-0587, the Board adopted a statement of overriding considerations and a mitigation monitoring program and approved the Project.
In 2014, the State of California determined that the prior finding regarding the bridge’s eligibility for listing on the National Register of Historic Places was incorrect and reversed the determination. This resulted in substantial additional work to evaluate alternatives for mitigating impacts to the historic structure and to address associated regulatory and community concerns. Based on these additional design and engineering requirements, the Board approved the First Amendment to the agreement on May 12, 2015, increasing the not-to-exceed amount by $103,400, to $575,156, and extending the term through December 31, 2018.
On December 4, 2018, the Board approved a Second Amendment, extending the term of the Agreement to December 31, 2021, and updating required federal language in the Agreement, with no change to the contract amount. A Third Amendment was approved by the Director of Transportation and Public Works (TPW) on December 7, 2021, extending the term through June 30, 2023, with no change to the contract amount.
As the project progressed, the bridge’s historic status, together with revisions to engineering, seismic design, and other applicable standards and requirements since the project began in 2012, required additional design work and updates to the project plans and specifications. To address these changes and provide for continued design and construction support services, on April 18, 2023, the Board approved a Fourth Amendment increasing the not-to-exceed amount, including contingency, to $1,165,309 and extending the agreement through December 31, 2026.
On April 14, 2026, following a competitive bidding process, the Board awarded a construction contract to Viking Construction Company, Inc., in the amount of $7,112,953. The project is currently under active construction, with Moffatt & Nichol providing construction support services, including review of construction submittals and reports.
Due to additional design requirements resulting from the bridge’s historic status, revisions to applicable engineering standards, and a delayed construction start that extended the project into a second construction season, additional design and construction support services are needed beyond those originally anticipated.
SPI is therefore requesting that the Board approve the Fifth Amendment and authorize the Director of SPI to execute the amendment. The proposed Fifth Amendment will increase the base contract amount by $143,770 and provide an additional 10% contingency of $14,377, for a total increase of $158,147 and a new total not-to-exceed contract amount of $1,323,456, including contingency. The amendment will also extend the agreement term by five years, through December 31, 2031, to provide sufficient time for continued design and construction support through project completion and post construction audit support. The construction contract will likely be complete with punchlist items in early 2028, with the designer required for final acceptance at that point. Based on past experience with recent audits, it has greatly assisted staff to have the engineer of record available for the following three years after project close out with Caltrans.
Strategic Plan:
This item directly supports the County’s Five-year Strategic Plan and is aligned with the following pillar, goal, and objective.
Pillar: Resilient Infrastructure
Goal: Goal 3: Continue to invest in critical road, bridge, bicycle, and pedestrian infrastructure.
Objective: Objective 4: Identify and retrofit bridges in County that are at high risk for damage during earthquakes.
Racial Equity:
Was this item identified as an opportunity to apply the Racial Equity Toolkit?
No
Prior Board Actions:
4/14/2026, Item # 17 - Board awarded construction contract with Viking Construction Company, Inc.
4/18/2023, Item # 37 - Board approved a Fourth Amendment to the Agreement with Moffatt & Nichol for the design if the Watmaugh Bridge over Sonoma Creek Replacement Project.
12/4/2018, Item # 19 - Board approved a Second Amendment to the Agreement with Moffatt & Nichol for the design if the Watmaugh Bridge over Sonoma Creek Replacement Project.
5/12/2015, Item # 25 - Board approved a First Amendment to the Agreement with Moffatt & Nichol for the design if the Watmaugh Bridge over Sonoma Creek Replacement Project.
12/11/2012 - Board Adopted a Resolution certifying the Watmaugh Bridge Final Environmental Impact Report, Statement of Overriding Considerations, and a Mitigation Monitoring and Reporting Program, and approving the Watmaugh Bridge Replacement Project.
7/31/2012, Item # 63 - Board awarded a Professional Services Agreement for the design of the Watmaugh Bridge over Sonoma Creek Replacement Project to Moffatt & Nichols Engineers.
Fiscal Summary
|
Expenditures |
FY26-27 Adopted |
FY27-28 Projected |
FY28-29 Projected |
|
Budgeted Expenses |
$158,147 |
|
|
|
Additional Appropriation Requested |
|
|
|
|
Total Expenditures |
$158,147 |
|
|
|
Funding Sources |
|
|
|
|
General Fund/WA GF |
|
|
|
|
State/Federal |
$140,007.54 |
|
|
|
Fees/Other (SB1) |
$18,139.46 |
|
|
|
Use of Fund Balance |
|
|
|
|
General Fund Contingencies |
|
|
|
|
Total Sources |
$158,147 |
|
|
Narrative Explanation of Fiscal Impacts:
Appropriations for the proposed amendment are included in the FY 2026-27 Roads Capital (11051-34010103) Adopted Budget. Eligible expenses associated with this amendment are 88.53% ($140,007.54) reimbursable through the Federal Highway Bridge Program (HBP). The Roads Division is responsible for the remaining 11.47% (18,139.46) local match which will be funded using traditional Roads funding sources such as the Senate Bill 1 Road Maintenance and Rehabilitation Program (SB1).
Narrative Explanation of Staffing Impacts (If Required):
N/A
Attachments:
Amendment 5
Scope and Cost proposal
Related Items “On File” with the Clerk of the Board:
Original Contract Agreement
1st Amendment to the Agreement
2nd Amendment to the Agreement
3rd Amendment to the Agreement
4th Amendment to the Agreement
Construction Contract