And Swimming/Wading Advisory
Public Affairs Officer: Debbie Maneely
PRESCOTT, AZ – September 25, 2021 – Warning for Granite Basin
Lake and Horsethief Basin Lake located on the Bradshaw Ranger District
and Mingus Lake located on the Verde Ranger District: An increase in
vegetation growth has occurred on Granite Basin Lake this summer. As the
vegetation dies and decomposes there is greater biochemical oxygen
demand (BOD). The consequence of high BOD causes low dissolved
oxygen that stresses aquatic organisms. This has ultimately resulted in fish
kill at Granite Basin Lake. This is a natural phenomenon that is normal for
small bodies of water susceptible to higher water temperatures and high
levels of vegetation growth.
Wading and full-body contact is highly discouraged at Granite
Basin Lake, Horsethief Basin Lake, and Mingus Lake as well any
other Forest Lakes exhibiting similar fish die-off. The situation is
being further investigated. Thank you for your patience and
For more information, please call the Bradshaw Ranger District at 928-
443-8000 or Verde Ranger District at 928-567-4121.
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