City Council
Report
City Council Meeting: June 23, 2026
Agenda Item: 4.F
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To: Mayor and City Council
From: Christopher Dishlip, Director of Public Works, Water Resources Division Subject: Approval of the Second Modification to Agreement #10779 (CCS) with Ramboll America's Engineering Solutions, Inc. for Charnock Groundwater Management Program
Recommended Action
Staff recommends that the City Council:
1. Adopt a finding of categorical exemption pursuant to Section 15301 (Existing Facilities) of the California Environmental Quality Act (CEQA) Guidelines; and
2. Authorize the City Manager to execute a second modification to Agreement #10779 (CCS) in the amount of $350,000 with Ramboll America’s Engineering Solutions, Inc. to provide Charnock Well Field (Charnock) groundwater management program services for the Public Works Department. This will result in an amended agreement with a new total amount not to exceed $2,175,000, with future year funding contingent on Council budget approval.
Summary
The City of Santa Monica (City) is responsible for conducting the cleanup of polluted ground water supplies as part of a settlement agreement with the responsible parties and for restoring groundwater supplies in the local groundwater aquifer. The City’s Charnock Groundwater Management Program supports pollution remediation efforts and ensures compliance with federal, state and local permitting, water quality and reporting requirements related to the City’s largest drinking water aquifer, the Charnock Well Field. The City requires use of a contractor for services including groundwater monitoring, sampling, modeling to aid in remediation efforts in compliance with requirements established by the Regional Water Quality Control Board (RWQCB) and the Division of Drinking Water (DDW). Staff recommends increasing agreement #10779 (CCS) issued to Ramboll America’s Engineering Services, Inc. (Ramboll) by $350,000 2 of 5
to support monitoring well work and other requirements outlined in the recently issued No Further Action from the RWQCB, as well as the ongoing well rehabilitation and replacement process with DDW. This first modification would result in a new total amount not to exceed $2,175,000.
Discussion
The Charnock Well Field is the City’s largest drinking water aquifer. Over the past five (5) years, the aquifer has produced between 7,500 and 8,400 acre-feet per year (AFY) of groundwater from five production wells. This represents approximately 80% of the City’s groundwater production. Since December 2010, the City has operated the Charnock Treatment Unit, located at 11375 Westminster Ave. in Los Angeles to restore the Charnock Well Field to full production. The purpose of the treatment system is to remove methyl tertiary-butyl ether (MTBE) and tertiary-butyl alcohol (TBA) from the groundwater prior to distribution. This provides the City with a reliable supply of clean drinking water and aids in the cleanup of MTBE and TBA contamination in the Charnock aquifer.
To monitor the subsurface contamination, the City oversees a groundwater monitoring network that comprises 52 regional monitoring wells. Water quality data obtained from the most recent groundwater monitoring activities show that concentrations of MTBE and TBA in the subsurface have declined significantly over time. Given the positive status of the restoration of the Charnock aquifer, the City commissioned a technical memorandum in February 2018 to determine the path to achieve a No Further Action (NFA) letter from the Los Angeles Regional Water Quality Control Board (RWQCB) for the Charnock Well Field. The technical memorandum, prepared by Advisian, concluded that achieving NFA closure would be feasible within five years at a cost of approximately $2,483,000. The NFA was issued by the RWQCB on November 22, 2023, and the City has been working toward meeting the requirements outlined in the NFA, which are expected to be completed by the end of 2026.
The monitoring work provided by Ramboll is essential to continue without interruption, not only to meet the requirements of the NFA but also to continue the monitoring of the 3 of 5
Charnock Wells required by DDW. The original contract term was extended to December 31, 2026, with Modification #1 to allow sufficient time to bid these services out for a new award starting January 1, 2027. RFB #482 will be posted during this period for a new contract award starting January 1, 2027. The request of additional contract authority is to support the additional term extended in Modification #1.
Since 2007, the City has conducted a voluntary regional groundwater monitoring program in the Charnock aquifer. The RWQCB is the lead groundwater regulatory agency that oversees enforcement within the region. In May 2018, the RWQCB approved a modified sampling program based on the positive status of the restoration of the Charnock aquifer. With the significant reduction in contaminant levels within the Charnock aquifer, the City plans to request approval from the RWQCB for closure of the Charnock monitoring programs, which would result in a significant annual savings for the City. In order to achieve closure, additional groundwater transport modeling would be required to document that the remaining MTBE and TBA mass present in the aquifer no longer poses a risk to the Charnock Well Field.
The modification is to continue the work that Ramboll would perform, conducting groundwater well sampling, water quality analysis and regulatory reporting for the 52 groundwater wells until the conditions outlined in the RWQCB’s NFA have been met.
This includes five semiannual, four annual and one single three-year monitoring event.
The second-largest task involves the abandonment and closure of 40 groundwater monitoring wells. Both of these major efforts require expertise that City staff does not have.
Environmental Review
The contract amendment for groundwater well sampling, water quality analysis, and regulatory reporting is categorically exempt pursuant to Section 15301 (Existing Facilities) of the California Environmental Quality Act (CEQA) Guidelines. Section 15301 “exempts the operation, repair, maintenance, permitting, leasing, licensing, or minor alteration of existing public or private structures, facilities, mechanical equipment, or topographical features, involving negligible or no expansion of existing or former 4 of 5
use.” The contract amendment would allow for the continuance of day-to-day water operations at water treatment facilities and would not expand or materially change existing facilities or operations. Therefore, the contract amendment is categorically exempt as set forth in Section 15301 of the CEQA Guidelines.
Past Council Actions
Meeting Date Description
11/27/2018 Original bid and award of agreement with Ramboll US Corporation Inc for Charnock Well Field groundwater
management
Financial Impacts and Budget Actions
Staff seeks authority to approve available funding from the Water Fund to increase the amount of CT#10779 (CCS) with Ramboll America’s Engineering Solutions, Inc. for Charnock Well Field groundwater management. Funds are included in the FY 2026-27 Proposed Operating Budget. Future year funding is contingent on Council budget approval.
Agreement #
Current
Authorized
Amount
FY 2026/27
Request
Amount Account #
Total Revised
Contract Amount
10779 (CCS) $1,825,000 $350,000 50500001.552010 $2,175,000 Prepared By: Thomas Poon, Engineering Support Services Administrator Approved Forwarded to Council
Attachments:
A. Nov 27, 2018 Staff Report (web link)
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B. FY 25-26 Oaks Initaitve (Ramboll)
C. FY 25-26 Levine Act (Ramboll)
D. CT 10779 (CCS) - Ramboll (Original)
E. CT 10779 (CCS) - Ramboll (Mod 1)