The existing Byrd Slough Bridge, built in 1940, was evaluated by the County for eligibility under the Federal Aid HBP program and found to be structurally deficient and functionally obsolete. Cornerstone was retained to provide the PS&E for the new, replacement structure. The profile of the new bridge had to be lowered to correct a passing sight distance problem. The lower profile, along with the requirement to provide for a 100-year flood flow plus freeboard, resulted in Cornerstone selecting a five-span 128-foot cast-in-place reinforced concrete slab bridge. Unique aspects of this project included securing a design exception with the Central Valley Flood Protection Board for vertical clearance, obtaining permission to allow construction during a normally non-permissible period, and permission to allow the placement of falsework in the waterway during construction.