T.O. Ranch Mixed-Use and Multi-Family Residential Redevelopment Project Response Plan
5 Documents in Project
Summary
SCH Number
2021120559
Lead Agency
City of Thousand Oaks
Document Title
T.O. Ranch Mixed-Use and Multi-Family Residential Redevelopment Project Response Plan
Document Type
NOD - Notice of Determination
Received
Posted
2/10/2025
Document Description
The Department of Toxic Substances Control (DTSC) has approved a Response Plan associated with the T.O. Ranch Mixed-Use and Multi-Family Residential Redevelopment Project located at 325 and 391 Hampshire Road in Thousand Oaks, CA (Site). The Response Plan has been prepared to address and mitigate potential effects from contaminants present in soils and soil vapor at the Site. The Response Plan entails excavation and off-Site disposal of contaminated soils, installation of a soil vapor extraction (SVE) system, installation of a passive vapor intrusion mitigation system (VIMS), and implementation of institutional controls (Land Use Covenant, Soil Management Plan, and Operations & Maintenance Plan).
Targeted excavations at depths ranging from 5 to 10 feet below ground surface (bgs) will be performed to remove approximately 200 cubic yards (300 tons, assuming 1.5 tons per cubic yard) of impacted soils present at the Site. The targeted excavations will be performed in three areas of the Site prior to the start of grading activities in these vicinities. The impacted soils, once excavated, will be loaded into trucks and taken offsite for reuse or disposal.
Two SVE systems will be installed at the Site to remove VOCs from soil vapor. The SVE systems consist of vacuum system equipment, vapor treatment equipment consisting of vessels filled with granular activated carbon (GAC), soil vapor monitoring equipment, and noise control measures. One SVE system (including seven SVE wells to a maximum depth of 20 ft bgs) will be installed in the southern portion of the Site, and another SVE system (including eight SVE wells to a maximum depth of 20 ft bgs) will be installed in the northern portion of the Site. The SVE systems will be installed in a phased approach. Initially the southern SVE system will be installed and an SVE Pilot Study would be performed. After completion of the pilot study a full-scale design for both the southern and northern SVE systems will be prepared and the systems installed.
The VIMS will be incorporated into the design of the building foundations of future Site development to provide an additional physical barrier to further inhibit the migration of VOCs into indoor air of the future buildings at the Site. The VIMS will consist of an impervious membrane installed beneath each building along with a passive venting system consisting of perforated horizontal pipes, gravel surrounding the perforated pipes, and vent risers.
The Response Plan includes adoption of a Land Use Covenant (LUC) and Operations and Maintenance (O&M) Plan as institutional controls. The proposed LUC would place restrictions on the current and future site uses due to the residual contamination present on site. The LUC may require that any engineering controls on site be maintained until such time as DTSC deems they are no longer required. The LUC is attached to the property title, and its requirements will pass on to future owners if the property changes ownership. The LUC will be reviewed and approved by DTSC and recorded with the Ventura County Recorder’s Office. The O&M Plan will detail the VIMS and SVE components installed at the Site and provides a plan for how these systems will be operated, maintained, and monitored to ensure the system is operating as intended to protect indoor air against the potential exposure to VOCs in the subsurface. The O&M Plan will be referenced in the LUC.
Contact Information
Name
Shawna Couplin
Agency Name
Department of Toxic Substances Control
Job Title
Project Manager
Contact Types
Responsible Agency
Phone
Name
David Tedesco
Agency Name
IMT Capital V Hampshire LLC
Job Title
Principal/Managing Director
Contact Types
Project Applicant / Parties Undertaking Project
Phone
Email
Name
Carlos Contreras
Agency Name
City of Thousand Oaks
Job Title
Senior Planner
Contact Types
Lead/Public Agency
Phone
Email
Location
Coordinates
Cities
Thousand Oaks
Counties
Ventura
Regions
Citywide, Southern California
Cross Streets
Hampshire Road and Foothill Road
Zip
91362
Total Acres
10.97
Parcel #
676-0-150-375; 676-0-150-285; 676-0-150-365
State Highways
US-101, CA-23
Township
1N
Range
18W
Base
SBPM
Notice of Determination
Approving Agency
Department of Toxic Substances Control
Approving Agency Role
Responsible Agency
Approved On
County Clerk
Ventura
Final Environmental Document Available at
9211 Oakdale Avenue, Chatsworth, CA 91311
https://www.envirostor.dtsc.ca.gov/public/profile_report.asp?global_id=60003460
Determinations
(1) The project will have a significant impact on the environment
No
(2a) An Environmental Impact Report was prepared for this project pursuant to the provisions of CEQA
No
(2b) A Mitigated or a Negative Declaration was prepared for this project pursuant to the provisions of CEQA
No
(2c) An other document type was prepared for this project pursuant to the provisions of CEQA
Yes (EIR Addendum)
(3) Mitigated measures were made a condition of the approval of the project
Yes
(4) A mitigation reporting or monitoring plan was adopted for this project
Yes
(5) A Statement of Overriding Considerations was adopted for this project
No
(6) Findings were made pursuant to the provisions of CEQA
Yes
Attachments
Final Document(s) [Approved_Certified draft environmental documents]
Notice of Determination
Disclaimer: The Governor’s Office of Land Use and Climate Innovation (LCI) accepts no responsibility for the content or accessibility of these documents. To obtain an attachment in a different format, please contact the lead agency at the contact information listed above. For more information, please visit LCI’s Accessibility Site.