Harrenburg Wash Enhancement

Coconino County Parks and Recreation received a grant in 2020 from Arizona Water Protection Fund to improve the stability, productivity, and habitat quality of Harrenburg Wash just upstream from its confluence with Pumphouse Wash in Kachina Village, South of Flagstaff. Harrenburg Wash and the associated wetland habitat had been negatively impacted by several factors including:

  • The building, filling, and partial breeching of an earthen dam
  • previous channel excavations that initiated channel headcuts and created areas of excess floodplain fill,
  • The invasion and infestation of non-native weeds in part due to soil disturbing activities in the project area.

To enhance and restore Harrenburg Wash, the project implemented the following activities:

  • Construction of channel improvements included repairing headcuts and adding grade control (rock sill at dam breach and one rock dams)
  • Revegetation of the project area including planting cottonwoods and willows, seeding disturbed areas, and overseeding select weedy areas.
  • Invasive weed (diffuse knapweed) treatments of the project area were successfully conducted via multiple methods over the course of 2-3 years.

Since the implementation of work, NCDE has maintained a photo monitoring system and soil moisture monitoring network to gage the success of enhancement work. Results suggest that wetland plant species are returning after reseeding and revegetation work. In areas that were restored (previously impaired) vs un-restored (unimpaired) areas, recently restored areas have slowly increased soil moisture but have a lower average soil moisture than the unimpaired areas, indicating that vegetation and soil conditions are slowly recovering after restoration work.

Lower headcut prior to construction

Lower headcut during construction

Lower headcut after construction

Lower headcut 1 year after construction

 

 

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