Topographic Levee Survey for FEMA Certification

Client—Cornforth Consulting

City of Castle Rock: Work involved surveying the existing Cowlitz River levee a distance of 4,150 feet to a distance 15 feet on each side of the levee slope and identifying locations for existing walking path, retaining wall, and dredge spoil fill features, all existing levee penetrations and 750 feet of a recently constructed levee cutoff wall. The data was tied horizontally and vertically to existing control points utilized in the US Army Corps of Engineers plans for the cutoff wall project.

Port of Camas/Washougal: Work involved surveying the existing Columbia River levee for a distance of 5.3 miles feet to a distance 100 feet on each side of the levee centerline and identifying locations of pavement limits, power poles, fences, structures, trees, bore locations and all existing levee penetrations.

For both surveys, field information was collected from multiple datums using both GPS/RTK and Total Station methods. An AutoCAD electronic data file and hardcopy drawings were provided to the client that included surface model, contours and levee ownership and easement limits.