City Council
Report
City Council Meeting: September 8, 2026
Agenda Item: 4.D
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To: Mayor and City Council
From: Oliver Chi, City Manager, Office of Sustainability & the Environment Subject: Authorization to Enter Into Second Modification to Agreement #11181 with ES Engineering Services, dba Onterris, for Operation, Maintenance, and Monitoring of the Landfill Gas Management System
Recommended Action
Staff recommends that the City Council:
1. Adopt a finding of Categorical Exemption pursuant to Section 15301 (Existing Facilities), and Section 15330 Minor Actions to Prevent, Minimize, Stabilize, Mitigate or Eliminate the Release or Threat of Release of Hazardous Waste or Hazardous Substances) of the California Environmental Quality Act (CEQA) Guidelines, and exempt pursuant to Section 15061(b)(3) (Common Sense Exemption) of the CEQA Guidelines.
2. Authorize the City Manager to execute a second modification to agreement #11181 in the amount of $306,076 with ES Engineering Services, dba Onterris, for the operation, maintenance, and monitoring of the Landfill Gas Management System for the City Manager’s Office. This will result in a six-year amended agreement with a new total amount not to exceed $1,321,287, with future year funding contingent on Council budget approval.
Summary
The City of Santa Monica (City) has continuously operated a landfill gas extraction (LFG) and treatment system since 1998 to monitor methane levels and to maintain safe environmental conditions for the nearby Pico Neighborhood residents, Gandara Park users, and City staff who work at the City Yards. Oversight of the LFG is performed by a licensed independent contractor, ES Engineering Services, dba Onterris Environmental (Onterris), who maintains, operates, and manages the LFG system in strict accordance with permits from the County of Los Angeles’ Department of Health Services (DHS) and the South Coast Air Quality Management District (SCAQMD). The permits require 2 of 5
continuous and routine monitoring and maintenance of a perimeter probe network, ambient air quality above the landfill, and control system operation. Compliance reports are submitted to the DHS and SCAQMD on a quarterly basis. In June of 2021, the City conducted a competitive solicitation process via RFP #289 and entered into agreement #11181 with ES Engineering Services, at the time dba Montrose Environmental, for routine maintenance and operation of the LFG system. The current agreement will expire in September of 2026. Staff is currently working through a new competitive solicitation process to select a consultant to continue the same oversight services for the landfill, which has taken longer than anticipated. To maintain continuous and ongoing oversight of the landfill system, staff is recommending amending the existing agreement with Onterris for an additional one-year term, which will allow sufficient time to complete the solicitation process and negotiate and execute a new agreement, which will ultimately require council authorization.
Discussion
The City has been actively monitoring methane levels at the former landfill site since 1996. California Title 27 regulations for control of LFG adopted in 1997 required an LFG Control System to be installed to control gases generated by the decomposition of the landfill material. An interim LFG Control System was installed in 1998 and construction of a permanent LFG Control System was completed in the fourth quarter of 2000.
The objectives of the LFG Control System are:
• Reduce methane concentrations within the landfill;
• Reduce methane concentrations in native soils surrounding the landfill; • Reduce methane concentrations in identified utility trenches; and • Maintain methane concentrations in perimeter subsurface detection probes outside the landfill below the regulatory action level of five percent methane by volume or 50,000 parts per million.
Over the past 24 years, the LFG has observed predominantly safe methane levels in all of the system’s 37 sub-surface probe monitors, including a network of monitoring probes and gas extraction wells that specifically monitor methane levels adjacent to the Mountain View Mobile Home Park. This record demonstrates that methane levels - both 3 of 5
underground and in the ambient air environment - are generally below the regulatory compliance threshold of 5%, with a few isolated exceptions. Overall, the site generates a low volume of methane. This can be attributed to the landfill being over 50 years old and to the composition of the waste landfilled, which was predominantly construction debris, such as concrete blocks, bricks, and wood. Based on the volume and type of waste in place and the known time the landfill was in operation, landfill modelling indicates that the landfill’s current ability to generate methane is very low and will continue to decrease over time due to the low levels of organic materials buried in the landfill.
Today, landfill gas levels remain relatively stable at the former landfill site; however, some anomalies were recorded in the past at a handful of locations within the Municipal Yards that exhibit temporary increases in methane levels and momentarily exceed the regulatory threshold. These anomalies were attributed to excess moisture in the landfill due to above average rainfall, a main water line that leaked into the subsurface soil, and site construction activities over the past year. Increased moisture and saturation of organic materials increases the production of methane via methanogenesis (anaerobic digestion). As a result the City returned to council with a first modification to the agreement with a request for an additional $306,076 in funding to make improvements to the methane extraction system by installing two additional methane extraction wells along with general improvements to the extraction system. These improvements were successful in bringing the methane levels back down within compliance levels. In order to maintain ongoing compliance with the DHS and SCAQMD monitoring workplans the City is recommending extending the current agreement with Onterris to perform regular oversight of landfill system while staff completes the RFP process for ongoing maintenance, monitoring, and reporting of the landfill system.
Environmental Review
The contract for services related to the operation, maintenance, and compliance sampling and reporting for the LFG system is categorically exempt from CEQA pursuant to Section 15301 (Existing Facilities), 15330 (Minor Actions to Prevent, Minimize, Stabilize, Mitigate or Eliminate the Release or Threat of Release of Hazardous Waste or 4 of 5
Hazardous Substances) of the CEQA Guidelines and exempt pursuant to Section 15061(b)(3) (Common Sense Exemption) of the CEQA Guidelines. Section 15301 (Existing Facilities) provides an exemption for the operation, repair, maintenance, permitting, or minor alteration of existing public or private structures, facilities, mechanical equipment, or topographical features, involving negligible or no expansion of use beyond that existing at the time of the lead agency’s determination. The contract would continue the operation and maintenance of the existing system and would not expand or materially change existing facilities or operations. Furthermore, Section 15330 (Minor Actions to Prevent, Minimize, Stabilize, Mitigate or Eliminate the Release or Threat of Release of Hazardous Waste or Hazardous Substances) exempts any minor cleanup actions taken to prevent, minimize, stabilize, mitigate, or eliminate the release or threat of release of a hazardous waste or substance which are small or medium removal actions costing $1 million or less. This includes small scale in situ soil vapor extraction and treatment systems which have been permitted by the local Air Pollution Control District or Air Quality Management District. Additionally, the contract is exempt from CEQA pursuant to Section 15061(b)(3) (Common Sense Exemption) of the CEQA Guidelines, which states that CEQA does not apply “where it can be seen with certainty that there is no possibility that the activity in question may have a significant effect on the environment.” The contract will ensure landfill gas levels remain at stable and compliant levels. Therefore, the contract is exempt pursuant to Section 15301, 15330, and Section 15061(b)(3) of the CEQA Guidelines.
Past Council Actions
Meeting Date Description
07/12/2022
(attachment A)
First Modification to agreement with ES Environmental
Services, dba Montrose Environmental, for the operation, maintenance, and monitoring of the Landfill Gas
Management System.
10/26/2021
(attachment B)
Landfill Gas Study Session
07/27/2021
(attachment C)
Original RFP bid and award of agreement with ES
Engineering Services, dba Montrose Environmental, for
services related to the operation, maintenance, and
compliance sampling and reporting for the City’s Landfill Gas Control System.
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Financial Impacts and Budget Actions
Staff seeks authority to approve available funding from the General Fund to increase the amount of contract with Onterris, for services related to the operation, maintenance, and compliance sampling and reporting for the City’s Landfill Gas (LFG) Control System.
Contract Modification Request
Agreement Current
Authorized
Amount
FY 2026-27
Modification
Request
Amount
Dept Account # Total Revised Contract
Amount
11181 $ 715,211 $ 306,076 01500020.550010 $1,021,287
$ 300,000 C0104580.689000 $ 300,000
Total $1,015,211 $ 306,076 $1,321,287
Prepared By: James Velez-Conway, Senior Sustainability Analyst Approved Forwarded to Council
Attachments:
A. First Mod to ES Engineering July 12, 2022 (attachment A) B. 4576 LFG Study Session (attachment B)
C. ES Engineering Original_Contract_2_2021 (attachment C) D. OAKS INITIATIVE FORM Onterris USA (attachment D)
E. Levine Act Disclosure Form 2025 Onterris Signed