Approve first amendment to Agreement No. 18-164 with Mark Thomas & Company, Inc. to provide for additional environmental and right of way work, increasing the total contract amount by $313,644.21 for two bridge replacement projects on County Road (CR) 96 and one bridge replacement on CR 49. (No general fund impact) (Lindbo/Christison)

Approval of the first amendment to Agreement No. 18-164 will provide additional environmental and right of way services in the transition from preliminary design and environmental clearance to construction of the three bridge replacement projects.  This agreement amendment will provide continuity over the life of the projects allowing the County to benefit from the efficiencies of the same team preparing the design and all required right of way appraisals and purchases.

Background

On July 10, 2018, the Board of Supervisors approved an agreement with Mark Thomas & Company, Inc. for bridge design and environmental services for three County bridge replacement projects: CR 49 Bridge over Hamilton Creek, CR 96 Bridge over Union School Slough, and CR 96 Bridge over Dry Slough.

The CR 49 Bridge over Hamilton Creek (No. 22C-0095) Replacement Project is located approximately 0.11 miles north of the intersection with CR 50. The existing two-lane bridge was built around 1911 and is approximately 26 feet long and 22 feet wide. The bridge has been determined to be functionally obsolete and needing replacement.  The safe load capacity has been estimated as only legal loads.

The CR 96 Bridge over Union School Slough (No. 22C-0126) Replacement Project is located approximately 1.38 miles south of the intersection with CR 27 in Yolo County. The existing two-lane bridge was built around 1930 and is approximately 40 feet long and 23 feet wide. The 2013 Caltrans inspection found the bridge was determined to be structurally deficient and needing replacement.  The safe load capacity has been estimated as only legal loads.

The CR 96 Bridge over Dry Slough (No. 22C-0127) Replacement Project is located approximately 0.45 mile north of the intersection with CR 31. The existing two-lane bridge was built around 1929 and is approximately 44 feet long and 24 feet wide. The 2013 Caltrans inspection determined the bridge to be functionally obsolete and needing replacement. The safe load capacity has been designated as only legal loads.

These three bridge replacement projects have received federal Highway Bridge Program funding preliminary engineering.  The CR 96 Bridge over Dry Slough was recently approved to proceed into the right of way phase.  The original scope in the request for proposals for these projects did not include right of way services, and this amendment will add those needed services to the contract for each bridge, as county staff is not able to complete these specialized responsibilities in as timely a fashion that is needed at this time.  An additional amount of environmental coordination will be required due to changes made to the California Environmental Quality Act guidelines since work began on these projects in 2018, and due to transitioning to using the recently adopted Yolo County Habitat Conservation Plan/Natural Community Conservation Plan (HCP/NCCP) for environmental mitigation.  Increases for each bridge from the original scope and budget are needed for these right of way and environmental efforts.

The consultant's proposed cost for the additional work totals $313,644 for all three bridges. The amendment would increase the contract cap by $313,644, to $1,591,908.

County Counsel has approved the agreement amendment as to form.

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