Manley Road Repairs: Clark County, Washington
In all four locations where Daybreak Creek crosses Manley Road were fish barriers in the form of culverts. As part of roadway improvements, these culverts would be replaced while assessing the stream habitat and addressing Endangered Species Act (ESA) permitting.
Endangered Species Act Compliant Culvert Replacements
Safety improvements would adjust the horizontal and vertical alignment of a nearly one mile stretch of Manley Road. Daybreak Creek – which intersects the road – exists within the Lower Columbia Recovery Domain for West Coast Salmon and other ESA-listed fish species, necessitating the preparation of environmental baseline documentation and permit strategy. An extremely steep channel slope downstream of the 20-ft wide culvert replacements would influence a design that features a fish-passable cascade-pool channel form. The channel design mimics existing geomorphic conditions and reduces the slope by creating cascades that are short in length and adjacent to resting pools, limiting the extended effort needed for fish to maneuver upstream. A private driveway also posed a fish barrier that would need to be replaced with contained culverts underneath. Otak team led this project through design and permitting including biological assessment and wetland delineation for State and Federal regulatory compliance.