A natural channel by design

Picture Canyon lies just below the City of Flagstaff’s Wildcat Hills Wastewater Treatment Plant. Tertiary treated sewage effluent flows through the area in a northerly and northeasterly direction.

Thirty years ago the natural meanders below the treatment plant were straightened and channelized. The Rio de Flag no longer had access to its adjacent floodplain, so wetland function and the riparian plant community declined.

In 2010, with funding from the Arizona Water Protection Fund, contributions from Coconino County and the Arizona Game and Fish Department (AGFD), and cooperation and support from the Arizona State Land Department, City of Flagstaff Stormwater Management contracted with Natural Channel Design, Inc. to restore the stream meanders. Critical to the project was an agreement between the City and AGFD that provides for minimum flows from the Wildcat Plant to ensure adequate water for the Picture Canyon ecosystem.

The approximate length of the channel through the project site is one mile.  About 0.75 mile of the channel was suitable for restoration work and enhancement. The stream corridor ranges from 50 to 100 feet in width and is largely bounded by rocky canyon escarpments.

The restoration includes extensive weed work and revegetation, thereby serving as mitigation for the loss of other ephemeral wetlands, which are rare in this region. The reconnection of the historic meanders has nearly doubled the size of the riparian and wetland area to five acres. Stream flows have slowed and important stable channel wetland features and functions such as cleansing have been restored. Part of the agreement between the City and AGFD provides for a three-acre Watchable Wildlife area to be located in the upper reach.