Upper and Lower Box Creek Reservoirs Algal Bloom Monitoring 2018

The Upper and Lower Box Creek Reservoirs are located closely together on Monroe Mountain in the Fishlake National Forest.

Update July 30, 2018

July 16, 2018 Lower Box Creek.

July 16, 2018 Lower Box Creek.

Lab results from samples collected from Lower Box Creek Reservoir on July 16, 2018, showed 0.18 micrograms per liter (µg/L) of anatoxin-a. While this level exceeds the recreational health-based threshold for anatoxin-a, it is very low.

Cyanobacteria cell-count concentrations, primarily Aphanizomenon, were approximately 6,000 cells per milliliter (cells/ml), well below the 20,000 cell/ml health-based threshold.


Update July 25, 2018

The Forest Service collected samples of both Upper and Lower Box Creek Reservoirs on July 16, 2018. Both lakes have experienced blooms in the past, but usually not until late September/October. Microscope examination of the samples showed the presence of Aphanizomenon, a genus of cyanobacteria capable of producing toxins.

The Central Utah Health Department tested the samples with rapid toxin test strips. Results are as follows:

  • Upper Box Creek: non-detect for both anatoxin-a and microcystin
  • Lower Box Creek: 2.5 micrograms per liter (µg/L) for anatoxin-a; non-detect for microcystin

The anatoxin-a level on Lower Box Creek exceeded the recreation health-based threshold for primary contact such as swimming.

Samples were submitted to the Utah Public Health Lab and Utah Department of Agriculture and Food (UDAF) lab for toxin confirmation.