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Department of Transportation recommending the Board approve and authorize the Chair to sign a Covenant and Agreement between the California Regional Water Quality Control Board, Central Valley Region, and the County of El Dorado to protect future health and safety and the environment as a result of potential risk related to the possible presence of hazardous materials as defined in Health and Safety Code §25260 pertaining to the Diamond Springs Parkway Phase 1B Project, Capital Improvement Program number 72334/36105011. (Cont. 8/15/2023, Item 20)
FUNDING: N/A
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DISCUSSION / BACKGROUND
Phase 1B of the Diamond Springs Parkway Project (Project) will construct a 4-lane arterial roadway that will connect Missouri Flat Road and State Route 49 near the community of Diamond Springs. A portion of the Project will be constructed on the site of a former lime plant with recognized environmental conditions. Residual lime materials exist at various depths within the site and are currently contributing to storm water runoff with elevated pH levels.
In 2018, the Department of Transportation (Transportation) retained Aptim Environmental & Infrastructure, Inc., to provide environmental remediation support services. These services included additional site characterization work, including subsurface investigation and testing, coordination with the California Regional Water Quality Control Board, Central Valley Region (Regional Water Board), and preparation of a Remedial Action Plan (RAP) for approval and implementation.
The remediation work identified in the RAP will be carried out as part of the future construction contract for the Project. The remediation work will involve excavating approximately 20,000 cubic yards of residual lime material from the site, of which a portion will be re-used as blended engineered fill, with the remaining disposed at an approved offsite facility.
Since the County’s remediation scope will not remove all the residual lime material from within the County right-of-way, the Regional Water Board requires the County to enter into a Covenant and Agreement (Agreement) in an effort to prevent any remaining lime waste from impacting the health and safety of the public in the future.
The County's proposed remediation scope is consistent with that of adjacent properties and has been approved by the Regional Water Board. The remediation work will remove residual lime deposits existing within saturated areas eliminating its contact with groundwater, thereby reducing pH levels of groundwater and runoff downgradient of the site. However, the County's remediation scope will not remove all the residual lime material from within the County right-of-way.
ALTERNATIVES
The Board could choose not to sign the Agreement; however, this would require the County to demonstrate to the Regional Water Board, through testing, that any residual lime waste existing within the County’s right-of-way does not meet the definition of a designated waste per Water Code §13173(b).
PRIOR BOARD ACTION
1) September 14, 2004 (Item 81) - Project adopted as part of the Fiscal Year 2003-04 Interim CIP as project 72334, under former CIP Project name “Missouri Flat Road / Pleasant Valley Road Connector.”
2) February 11, 2008 (Item 14, Legistar 08-0038) - Project adopted as part of the 2008 CIP, under the current CIP Project name.
3) May 24, 2011 (Item 39, Legistar 11-0448) - Certified Final Environmental Impact Report adopted for the Project.
4) December 18, 2012 (Item 57, Legistar 12-1540) - Board approved to support economic development and create special revenue fund and direct Transportation to immediately proceed with completion of design and right-of-way.
5) June 10, 2014 (Item 23, Legistar 14-0725) - Board approved commencement of acquisition process for the Project.
6) May 3, 2016 (Item 23, Legistar 16-0370) - Certified Supplement to the 2011 Environmental Impact Report adopted for the Project.
7) August 28, 2018 (Item 24, Legistar 18-0977) - The Board approved Agreement for Services 3171 with Aptim Environmental & Infrastructure, Inc., to provide environmental remediation services.
8) February 9, 2021 (Item 32, Legistar 21-0178) - Diamond Springs Parkway Phase 1B Presentation, CIP 72334.
OTHER DEPARTMENT / AGENCY INVOLVEMENT
County Counsel has reviewed and approved the Agreement.
On May 22, 2023, the Regional Water Board issued a Conditional Concurrence Letter for the remediation work outlined in the RAP.
On July 21, 2023, at the request of Transportation, the Regional Water Board issued a follow up letter providing clarification to the conditions presented in the Conditional Concurrence Letter.
CAO RECOMMENDATION / COMMENTS
Approve staff recommendation.
FINANCIAL IMPACT
There is no fiscal impact or change to net County cost associated with this item.
CLERK OF THE BOARD FOLLOW UP ACTIONS
1) The Clerk of the Board will obtain the Chair’s notarized signature on two (2) originals of the Agreement.
2) The Clerk of the Board will return two (2) partially executed originals of the Agreement to Transportation, Fairlane Engineering, Attn: Shanann Findley.
TRANSPORTATION FOLLOW UP ACTIONS
Transportation will forward the two (2) partially executed originals to the Regional Water Board for final signature and return one (1) fully executed original to the Clerk of the Board for their records.
STRATEGIC PLAN COMPONENT
Infrastructure
CONTACT
Rafael Martinez, Director
Department of Transportation