Inner Basin Waterline Project Update
FLAGSTAFF, Ariz - On June 12, 2022, the Pipeline Fire began in the Schultz Pass area north of
Flagstaff, Arizona. Due to high winds, the fire moved rapidly to the east and north affecting
26,532 acres including portions of the 2010 Schultz Fire. High rainfall totals were measured in and
near the Pipeline Fire scar during the 2022 monsoon, resulting in numerous large flood events.
These flooding events resulted in severe erosion, extensive damage to Waterline Road (Forest
Service Road 146), and multiple broken or compromised sections of pipeline which gravity-feed water
from the Inner Basin to the City of Flagstaff.
On the afternoon of 1 August, spring water from the Inner Basin began to flow into the City of
Flagstaff water distribution system for the first time since the Pipeline Fire and following
monsoon season flooding events compromised the infrastructure. This was made possible by the
monumental repair efforts of Hunter Contracting, Jacobs Engineering in partnership with the US
Forest Service, Department of Forestry and Fire Management, and the City of Flagstaff.
The repair and restoration of the waterline was the first repair priority for this project and was
accomplished ahead of schedule. The repairs and construction work will continue through late fall
2024. Waterline Road remains impassable and is closed to motorized travel, recreationalists, and
the public due to active construction and heavy equipment traffic.
The images below are of one of the most-heavily impacted sites, Site I. The first picture shows the
incision of erosion via flooding, post Pipeline Fire in 2022. The second picture shows some of
recent repairs, including a storm drain culvert under the new concrete-encased waterline, barely
visible as it is under the fill material.
The Inner Basin Pipeline is a 13-mile pipe that delivers to the City of Flagstaff snowmelt/spring
water complimented with several wells from the Inner Basin of the San Francisco Peaks. The pipeline
was originally constructed in 1898 and has been serving the city for over 120 years. The pipeline
provides up to 20-percent of the city’s potable water supply during summer months.
Thank you for your patience while we restore these critical community assets.
For questions regarding these projects contact David Pedersen, Project Manager, at DPedersen@flagstaffaz.gov.