Specifications include, but are not limited to: 26-foot span by 9-foot rise, 80-foot long, precast concrete box culvert. The box culvert shall have 1-foot tall precast headwalls and 2-foot deep toe walls at the inlet and outlet. The upstream and downstream ends of the culvert will be slopetapered to match the 2H:1V (horizontal:vertical) sideslopes. Riprap aprons will be installed at the inlet and outlet. The box culvert invert will be embedded approximately 3 feet into the streambed, and 2 feet of special fill will be placed inside the bottom of the culvert and across the riprap aprons to create a natural streambed. Stream channel rock and streambed rock features will be installed on the special fill to facilitate fish passage. The box shall be placed on a 1-footthick leveling layer of Granular Borrow – Material for Underwater Backfill.
