The Arizona Department of Transportation rolled out plans for four safety and road improvement projects on State Route 89A between Flagstaff and Sedona, the earliest of which could start in fall 2019.
The four projects, which will be done in conjunction with the Federal Highway Administration, include: Pumphouse Wash bridge rehabilitation; pavement rehabilitation from the Sedona city limits to Bear Howard Drive; rockfall mitigation along two sections of the road; and sediment control and drainage along the Oak Creek switchbacks.
According to an ADOT release, options to rehabilitate or replace the 87-year-old Pumphouse Wash Bridge have been studied since October 2006, and the department determined rehabilitation was the best course of action.
Because the bridge is listed on the National Register of Historic Places, a full replacement would negatively impact the historic nature of the bridge, while also negatively affecting stream water quality and area species.
Work on the bridge is planned for late summer or early fall of 2019 and will result in single-lane closures for about three months. When one travel lane is closed to allow work on the bridge deck, the other lane will remain open to accommodate traffic. Additional bridge rehabilitation work will take place in summer 2020, but is not expected to close any traffic lanes.
The 12.1 miles of highway between the Sedona city limits to Bear Howard Drive — from milepost 374.5 to 386.6 — has experienced rapid degradation because of harsh winter weather conditions in recent years, according to the release.
The project includes pavement preservation work to the existing pavement, replacing guardrail along the roadway to meet current safety standards and turnout modifications to improve safety.
Work on this stretch of Route 89A from north of Sedona to south of Pumphouse Wash Bridge is tentatively scheduled to begin in late summer 2019 and extend until winter of the same year. Single-lane closures and restrictions will occur along the stretch of road for about five months during work hours.
The rockfall mitigation project will reduce the potential of rocks falling onto the travel lanes at the two locations: near the Sedona city limits at milepost 375.1 and in the switchback section at milepost 389.2. Work on this project is tentatively set for fall 2020 and will last about three months. To maintain safety during rock-removal operations, complete but intermittent closures are necessary.
The erosion control project will preserve deteriorating slopes and reduce sediment transport between mileposts 387.9 to 389. It’s anticipated to start in the fall of 2019 and will include installing retaining walls, stabilizing slopes, increasing roadside ditch capacity, and adding inlets and roadway cross-culverts.
ADOT spokesman Steve Elliott said coordinating these four projects will minimize the impacts for those who live, work and travel to the area for recreation, and he added that the most immediate needs are addressing the pavement and potential for rock fall.
“The many freeze-thaw cycles in that area accelerate pavement deterioration. Removing and replacing the top three inches of pavement can extend the service life by 10-15 years,” Elliott said. "And there have been several incidents in which falling rocks have resulted in closures of SR 89A with significant traffic disruptions.”
Elliott said ADOT’s Five-Year Construction Program has assigned $2.75 million to the Pumphouse Wash bridge rehabilitation and $3.362 million to the rock-fall mitigation.
The amounts for the Oak Creek Drainage and Sediment Control project and the Sedona City Limits to Bear Howard Drive Pavement Rehabilitation project were not immediately available.
ADOT held a public meeting about the projects in Sedona on July 12. Project team members explained the improvements and shared information about proposed construction schedules and traffic plans. Elliott said about 20 people attended the meeting and asked questions to the project team after the presentation.
Those who were unable to attend the meeting can ask questions and submit comments by calling the toll-free, bilingual ADOT project information line at (855) 712-8530, or they can email questions or comments to SR89A@hdrinc.com.