Sonoma County Public Infrastructure proposes to replace two existing culverts on Spring Hill Road at PM 11.78 and 15.07 and five existing culverts on Guglielmetti Road.
At each site a trench will be cut through the pavement and road base to excavate the existing culvert, with equipment working from the roadway. The new culvert will then be placed in the trench and backfilled with a slurry composed of sand, cement and water delivered in a ready-mix concrete truck. There are 10 cubic yards of existing inlet RSP at the Guglielmetti Road PM 10 .22 site that will be either reused or replaced in-kind. 3 .5 cubic yards of new RSP will be added at the outlet of PM 10.22. All debris will be loaded onto dump trucks for disposal within a permitted and fully legal disposal site, and all excavation will occur within the existing culvert/road footprint. No work is proposed to occur while flowing water is present. No exposed soils that could lead to future sources of sediment will remain following the completion for construction. Erosion control BMPs will be used and stored on site. The expected temporary impact area will be less than 0.01 acres at each site. Temporary impacts will be limited to culvert excavation and installation, staging and site preparation.