Environmental Oversight For Construction Of S. Milpitas Blvd Extension and Tango Park

The City of Milpitas ("City") is seeking proposals from qualified vendors ("Proposer") in response to this Request for Proposals ("RFP") to perform environmental oversight during construction of S. Milpitas Blvd Extension and Tango Park projects.

The South Milpitas Boulevard Road Extension, Project No. 2016 (“SMB Project”), and Metro Tango Subdistrict Park, Project No. 2023 (“Tango Park”) are included in the adopted FY 2026-2030 Capital Improvement Program. The SMB Project provides for the design and construction of a bridge over Penitencia Creek and extension of S. Milpitas Blvd. to Sango Court road extension. Following the completion of the bridge and road extension, construction of Tango Park will begin. Tango Park will be developed across two adjacent sites at 1831-1841 Tarob Court and 1700 Sango Court. The park features will include a playground, sports courts, dog park, community garden, picnic and BBQ area, walking loop, restrooms, and open space lawn.

The 1831-1841 Tarob Court property was developed with the existing commercial building in 1979 and was used for circuit board manufacturing until facility closure in 2016. Volatile organic compounds (VOCs) including trichloroethene (TCE) and benzene were detected in soil, groundwater, and soil vapor at the Site. A risk assessment approved by the California Regional Water Quality Control Board (“Water Board”) in June 2019 concluded that the cancer risk to future street and park use, potential restroom users and custodians, and construction workers is less than significant, but that TCE in soil vapor may present a significant hazard of noncancer adverse effects for construction workers performing trenching or excavation at the site. To reduce this risk, the previous owners of the property (Geomax) agreed to excavate contaminated soil near the sampling location where highest TCE concentrations were detected. Soil removal was performed in October 2019. Post-excavation sampling still found elevated concentrations of residual TCE. Additional excavation was performed in December 2019, and the Water Board received post excavation sampling results in February 2020.

In October 2020, the Water Board implemented a Covenant and Environmental Restriction (“Covenant”) on the property that included provisions to prohibit residential land use, prohibit well drilling, regulate earthwork, and require notifications to the Water Board. As part of the covenant, a Risk Management Plan (RMP) and Soil and Groundwater Management Plan (SGMP) were developed to provide guidance on all future construction activities that would disturb the existing soil and groundwater at 1831-1841 Tarob Court.

Tango Park will span two properties: 1831–1841 Tarob Court and 1700 Sango Court. While 1700 Sango Court does not have a Covenant and Environmental Restriction Document, environmental testing identified trace levels of contaminants due to its proximity to 1831–1841 Tarob Court. As a result, a separate Soil and Groundwater Management Plan has been prepared for 1700 Sango Court, along with a Health and Safety Plan for Tango Park construction.