Coal Creek Parkway Culvert Replacement
We assisted the City of Bellevue with the replacement of a structurally deficient 96-inch-diameter culvert that conveyed Coal Creek beneath Coal Creek Parkway with a 38-foot-wide structure that greatly improves fish passage while also including an integrated pedestrian walkway adjacent to the widened creek crossing. The project entailed stream channel and bank improvements at either end of the new culvert structure to protect against bank erosion, removal of fish passage barriers, and enhancement of aquatic habitat. Herrera led hydraulic and geomorphic analysis and associated documentation of the new culvert structure and proposed channel modifications, and prepared final design plans and specifications for all in-channel and bank stabilization improvements on the project. Herrera designers and regulatory specialists also assisted the City and consultant team partners in preparing environmental permit application documents, including delineation and rating of wetlands within the project area. Herrera assisted with onsite inspections of stream channel and bank improvements, assuring that the constructed project met the intent of the design.