In a partnership with Coconino County, Arizona and the City of Flagstaff, Arizona, Civiltec Engineering completed a drainage capacity expansion project at Linda Vista Drive to address flood risk stemming from the Museum Fire of 2019.
The Museum Fire (July 2019) burned through 1,961 acres in the Dry Lake Hills area above Flagstaff. The watershed that was burned drains through residential and commercial areas within the City of Flagstaff. The City assembled an emergency response team was assembled to survey and model potential flooding impacts from rainfall over the burned watershed. They also coordinated work with Coconino County, Flagstaff, construction crews and volunteers in the field to implement mitigation strategies that would minimize the impacts of potential flooding.
Linda Vista Drive is the first road crossing where potential flood water and debris will enter Flagstaff. Debris posts were installed previously upstream of the culvert inlet to minimize the potential for debris clogging at the culvert inlet. Existing utilities in the project area limit the size and number of additional culverts that could be added to this road crossing without utility relocations.
To increase the capacity of the existing drainage crossing, Civiltec designed
- One 53-inch by 41-inch corrugated metal pipe-arch (CMPA),
- An inlet headwall with beveled edges and trash rack, and
- A gabion mattress for culvert outlet protection.
These improvements minimized the potential for debris clogging at the culvert inlet and increased the capacity of the crossing from 184 cfs to 325 cfs with no roadway overtopping.