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): Countywide
Title:
Title
Agreement for Environmental Review for the Potential Expansion of the Sonoma County Central Disposal Site
End
Recommended Action:
Recommended action
A) Receive an update on the potential expansion of the Sonoma County Central Disposal Site
B) Authorize the Director of Public Infrastructure to execute an agreement with RCH Group to manage and prepare an Environmental Impact Report (EIR) pursuant to the California Environmental Quality Act (CEQA) for the proposed expansion of the Sonoma County Central Disposal Site, for a period of three years ending April 28, 2029, with two (2) optional one (1) year extensions, and a total amount not to exceed $1,423,000.
end
Executive Summary:
The Sonoma County Central Disposal Site (CDS) is a critical component of the County’s solid waste system, providing daily disposal capacity and supporting debris management during emergencies. A 2022 regional capacity study found that, due in part to wildfire-related debris, the remaining permitted capacity at CDS is approximately 15 years. The study also concluded that reliance on out-of-county landfills would increase costs, greenhouse gas emissions, and operational risks, while development of a new landfill within Sonoma County is impractical.
On September 12, 2023, the Board accepted these findings and directed staff to evaluate expansion of CDS as the most viable option to maintain in-County disposal capacity. The Board identified land west of the existing site as the preferred expansion area and directed staff to proceed with environmental review under the California Environmental Quality Act (CEQA), including evaluation of alternatives and a no-project scenario that would involve exporting waste to regional landfills. The Board also authorized negotiations with Republic Services for potential development and operation of the expansion area.
To support CEQA review, the County retained GeoSyntec Consultants to prepare conceptual (30%) designs for potential expansion scenarios, providing sufficient detail to define the project for environmental analysis.
Following a competitive RFP process, staff recommend award of a contract to RCH Group in an amount not to exceed $1,423,000 to prepare an Environmental Impact Report (EIR), anticipated to take approximately 24 months. Staff will provide periodic updates to the Board and public throughout the process to ensure policy direction and stakeholder input.
Discussion:
Site Overview
The Sonoma County Central Disposal Site (CDS) has operated as the County’s primary municipal solid waste landfill since approximately 1972. Over the past five decades, the facility has served as a core public infrastructure asset, providing daily disposal capacity for County residents and businesses, and functioning as a critical resource during emergency events requiring debris management, including floods and fires. The facility also plays an important role in supporting Sonoma County’s agricultural community by providing disposal capacity for materials generated by farms and ranches, including during disease-control responses such as the disposal of poultry and other materials associated with avian influenza containment efforts.
The CDS encompasses approximately 398 acres, with roughly 173 acres currently permitted for waste disposal. Each year the facility receives approximately 300,000-325,000 tons of municipal solid waste for disposal, along with additional materials that are recovered or diverted through recycling and resource recovery programs. In addition to waste disposal, the site supports several public services relied upon by the community, including household hazardous waste collection, construction and demolition material recovery, disaster debris management, and public recycling drop-off opportunities.
The site is currently operated by Republic Services of Sonoma County under a Master Operations Agreement (MOA), which became effective in 2015 after flow commitments were secured from most cities. The MOA established a 25-year initial operations term and transferred closure, post-closure, and environmental liabilities for the existing landfill to Republic Services, significantly reducing the County’s long-term financial exposure while maintaining County oversight.
1998 EIR and Early Expansion Planning
Long-term planning for additional landfill capacity at CDS is not new. The 1998 Central Disposal Site Improvement Program Environmental Impact Report (EIR) contemplated expansion into the West Canyon area as part of the long-range development of the site.
To further evaluate that opportunity, the County commissioned technical feasibility studies in 2003 and 2004 to assess the potential development of what was referred to at the time as the West Area Expansion (WEA) within the West Canyon area. Those studies included geologic and seismic hazard investigations, groundwater investigations, geotechnical and civil engineering analyses, conceptual master planning, containment system and liner design concepts, refuse fill planning and capacity estimates, and construction cost estimates. Thus, the groundwork for future expansion has existed for more than two decades, even though implementation was deferred.
Master Operations Agreement (MOA) - 2013 and 2015
On April 23, 2013, the Board approved the Master Operations Agreement (MOA) for operation of the CDS and County transfer stations. The MOA became effective in 2015 following fulfillment of various conditions, including the issuance of permits, and securing of flow commitments from eight of the County’s nine cities, along with an associated settlement agreement with those cities.
The MOA established a 25-year initial term and included rate-setting provisions allowing modest annual adjustments tied to CPI. Importantly, the MOA transferred closure, post-closure, and environmental liabilities associated with the existing landfill to Republic Services. The liability transfer under the MOA is a foundational element of the County’s solid waste strategy, significantly reducing long-term financial exposure to the County, while preserving the County’s oversight of the facility.
The County’s goals in entering into the MOA were as follows:
• Increased diversion - decreased landfill disposal
• Public ownership for "local control" - Private operations for "economic efficiencies"
• No pre-set volume (put-or-pay) disposal commitments - Supports increased diversion and local flexibility
• Long term liability relief for closure, post-closure, and unforeseen environmental liabilities at the Central Landfill site
• A sustainable rate model that works with high levels of waste diversion
• In-county landfill to end reliance on outhaul export of Sonoma County trash
• Quantifiable greenhouse gas (GHG) reductions
• Ongoing funding for education, household hazardous waste, and other programs
• Ongoing funding source for closed county landfill sites
Post-2017 Wildfire Impacts and Regional Capacity Concerns
Beginning in 2017, Sonoma County experienced a series of catastrophic wildfire events including the Tubbs, Nuns, and Pocket Fires in 2017, the Kincade Fire in 2019, and the LNU Lightning Complex fires in 2020, which significantly increased disposal demands at CDS.
The large volume of disaster debris generated by these events materially reduced projected site life and demonstrated the critical role the CDS plays in regional disaster response and recovery. During the five-year period following 2017, disaster debris accounted for a substantial share of landfill disposal, totaling more than 1 million tons between 2017 and 2023 and representing roughly 31 percent of all material disposed at the site during that period, significantly accelerating consumption of the site’s remaining permitted airspace.
Recognizing the strain on remaining landfill capacity and the variability introduced by disaster events, the Integrated Waste Division commissioned the Sonoma County Preliminary Regional Disposal Capacity Analysis in 2022. The study evaluated two primary pathways: (1) expansion of permitted capacity at CDS; and (2) outhaul of Sonoma County waste to regional landfills.
The 2022 study concluded that while out-of-county regional facilities may have theoretical capacity to accept Sonoma County waste, reliance on outhaul would substantially increase vehicle miles traveled, as waste would need to be transported long distances to regional landfills in other counties, resulting in increased greenhouse gas emissions, higher transportation and fuel costs, greater exposure to future fuel price volatility, and increased long-term ratepayer risk associated with reliance on third-party disposal infrastructure outside the County’s control. The study also identified the impending closure of certain regional facilities, which will limit the availability of long-term disposal alternatives for the entire region. The uncertainty created by these region-wide capacity pressures adds urgency to the County’s solid waste planning efforts.
The 2022 Regional Disposal Capacity Analysis emphasized that establishing an entirely new landfill site in Sonoma County would be impractical within the existing planning horizon, given that the Central Disposal Site is projected to reach permitted capacity in approximately 15 years. The 2022 study noted due to permitting timelines, environmental review requirements, infrastructure costs, and siting constraints, development of a new disposal facility is unlikely to be completed before existing capacity is exhausted. In contrast, expansion of the existing CDS would leverage existing infrastructure and access routes, environmental controls, and operational systems.
September 12, 2023 Board Direction
On September 12, 2023, the Board of Supervisors accepted the findings and recommendations of the 2022 Solid Waste Regional Capacity Study and designated the land immediately to the west of the CDS permitted boundary as the preferred site for future landfill expansion. The Board also directed staff to undertake further analysis in accordance with the California Environmental Quality Act (CEQA).
Concurrently, the Board adopted Resolution No. 23-0456, authorizing initiation of negotiations with Republic Services on a sole-source basis for development and operation of the potential expansion project and setting forth goals and objectives for such negotiations, including:
i. The Expansion Project, consisting of potentially both vertical and lateral expansions to the CDS, will be operational before the existing CDS capacity limit is reached;
ii. Republic will be responsible for the permitting (to the extent permitted by applicable law) and development of all vertical and/or lateral expansion of the CDS in accordance with all required permits;
iii. As with the existing CDS operational area, Republic will assume all liabilities associated with the Expansion Project, including, but not limited, to operational liability, and closure, post-closure, and third-party liability, and the Expansion Project shall not alter, waive, release or discharge Republic from its existing liabilities associated with the CDS;
iv. The amendment will reduce gate rates, if possible, and support a sustainable funding source for the County and Cities;
v. The amendment will ensure that all waste and other materials delivered for disposition at CDS are accounted for economically;
vi. The MOA term will be extended to account for the Expansion Project, while providing the County with rights to protect the public interest given the significant additional timeline associated with the Expansion Project; and
vii. The amendment will recognize Republic’s investment and liability assumption while ensuring the revenue potential of the Expansion Project is equitably shared among the parties.
Importantly, the Board’s direction expressly maintained that any potential expansion project would remain subject to full CEQA review, including evaluation of alternatives and the no-project alternative.
Following the Board’s September 12, 2023, direction, staff initiated preliminary engineering efforts to better define the potential expansion footprint, operational configuration, and sequencing assumptions necessary to support environmental analysis. In 2025, the County engaged GeoSyntec Consultants to prepare approximately 30 percent conceptual design drawings and phased development sequencing plans for potential vertical and lateral expansion scenarios at the Central Disposal Site.
This engineering work is ongoing and is being developed concurrently with the initiation of formal CEQA documentation. The purpose of the 30 percent design effort is not to advance construction, but to establish a project description and operational framework that will be the subject of environmental analyses. The conceptual design will include grading limits, fill elevations, infrastructure modifications, stormwater controls, landfill gas systems, access improvements, development sequencing, and key operational parameters to support evaluation of potential environmental impacts and alternatives within the Environmental Impact Report.
The CEQA consultant selected through this process will rely upon and coordinate with the ongoing GeoSyntec work to ensure that the project description, impact analyses, and mitigation measures are grounded in current engineering assumptions.
CEQA Consultant Selection
On October 29, 2025, SPI issued a Request for Proposals to solicit competitive proposals from qualified consulting firms to conduct environmental impact studies and prepare an Environmental Impact Report (EIR) pursuant to the California Environmental Quality Act (CEQA). Proposals were received from the following firms on or before the due date of December 17, 2025:
1. RCH Group
2. David J. Powers Associates, Inc.
3. Kimley-Horn and Associates, Inc.
4. Nichols Consulting Engineers, Chtd
In January 2026, proposals were reviewed and scored by partnered staff of SPI, County Counsel and Permit Sonoma, based on the following criteria:
• Project Understanding and Approach;
• Qualifications and Experience, understanding of landfill expansions;
• Costs relative to the scope of services;
• Quality of Work and References;
• Willingness to accept the County’s contract terms;
• Responsiveness and clarity of Written Proposal;
• Locality of the proposer.
While all four proposing firms were qualified to perform this work, RCH Group was selected due to the strength of their team and their experience with similar complex projects that distinguished the firm from the other proposers. The total proposed contract amount is $1,423,000.
Staff recommend Board approval of the attached agreement with RCH Group to provide specialized CEQA program management to coordinate technical studies and public review processes, and to prepare the Environmental Impact Report (EIR) for the proposed expansion. Work to prepare the EIR for the project is anticipated to take 24 months. During that time, staff will periodically provide updates to the Board and the public as appropriate to ensure policy direction and stakeholder input on this important process.
Strategic Plan:
N/A
Racial Equity:
Was this item identified as an opportunity to apply the Racial Equity Toolkit?
No
Prior Board Actions:
09/12/23: Board accepted the findings and recommendations of the Solid Waste Regional Capacity Study; Designated the land to the west of the Sonoma County Central Disposal Site as the preferred site for future landfill expansion; Adopted a resolution finding that an MOA amendment was exempt from competitive bidding and directed staff to initiate negotiations with Republic; Directed staff to begin engaging partners in project outreach.
03/15/22: Board approved the First Amendment to the Amended and Restated MOA
08/04/20: Board approved the Amended and Restated MOA
03/01/16: Board approved the Second Amendment to the MOA
03/03/15: Board approved the First Amendment to the MOA
4/23/13: Board approved the MOA with Republic
Fiscal Summary
|
Expenditures |
FY 25-26 Adopted |
FY 26-27 Projected |
FY 27-28 Projected |
|
Budgeted Expenses |
$200,000 |
$823,000 |
$400,000 |
|
Additional Appropriation Requested |
|
|
|
|
Total Expenditures |
$200,000 |
$823,000 |
$400,000 |
|
Funding Sources |
|
|
|
|
General Fund/WA GF |
|
|
|
|
State/Federal |
|
|
|
|
Fees/Other |
$200,000 |
$823,000 |
$400,000 |
|
Use of Fund Balance |
|
|
|
|
Contingencies |
|
|
|
|
Total Sources |
$200,000 |
$823,000 |
$400,000 |
Narrative Explanation of Fiscal Impacts:
Appropriations for this agreement are available in the FY 25/26 Integrated Waste Former Urban Landfill (41123-34050300) Adopted Budget and will be included in future Integrated Waste Former Urban Landfill Recommended Budgets. The Formal Urban Landfill Fund receives operating income from Concession Fees collected by Republic Services through fees collected at the Central Disposal Site and transfer stations located throughout the County. Fees are based on volume (weight) and type of material being disposed of.
Narrative Explanation of Staffing Impacts (If Required):
None
Attachments:
Professional Services Agreement
Related Items “On File” with the Clerk of the Board:
Amendment to Master Operator Agreement
Master Operator Agreement