Howland Hill Culvert Replacement

This project proposes to replace culverts located along Howland Hill Road in Jedediah Smith Redwoods State Park to allow for adequate drainage in the event of heavy rainfall which will reduce the chance of roadway flooding and damage. Work will use large and small mechanical and handheld equipment to replace two (2) existing undersized culverts as follows: If necessary, divert stream water away from the proposed excavation areas and relocate any amphibians; Excavate trenches to remove the existing culverts and dispose of the materials offsite; Excavate the trenches further to accommodate new 36-in diameter culverts; Use excavated materials to backfill over the new culverts, compacting in 6-inch lifts; Install appropriately sized rock slope protection (RSP) at inlet headwalls to protect the ground from saturation and scouring and to direct water flow into the culverts; Install RSP on the outlet fill slopes to stabilize and protect the embankments from scour; Install compacted aggregate along the road surface at the culvert approaches and exits to minimize road sediment entering the nearby stream; and Fully mulch all disturbed soil areas within the project areas.