4ae) Adoption of Resolution Approving Amendment Number 4 to Board of Supervisors Agreement Number 12-079/Department of Transportation Agreement Number 110123, with Willdan Engineering in the Amount of $56,917, for the Term Starting Upon Execution of this Amendment Through December 31, 2021, for Additional Professional Engineering Design Services for the Mattole River Bridge Replacement on Briceland Road, County Road 435, Milepost 0.63 (Whale Gulch Area)