Important Mingus Lake and Granite Basin Lake Fish Die-Off

    And Swimming/Wading Advisory

    Public Affairs Officer: Debbie Maneely 

    (928) 499-4736 

    [email protected]

    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. 

    Stay up to date on Prescott National Forest news by checking the Prescott  

    NF website and following us on Facebook and Twitter.

    Latest articles

    Local Spotlight

    Related articles

    Join our newsletter: