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UPDATE - A cyanobacteria WARNING (ADVISORY) has been issued for Showell Pond

Last Updated: September 20, 2023 - 11:41am

UPDATE 9/20/23 - Showell Pond was resampled on 9/20/23. The cyanobacteria density continues to exceed the state limit of 70,000 cell/mL, so the advisory will remain active. The sample reviewed today had a density too numerous to count (Aphanizomenon, Chrysosporum, and Woronichinia).

UPDATE 9/14/23 - Showell Pond was resampled on 9/13/23. The cyanobacteria density continues to exceed the state limit of 70,000 cell/mL, so the advisory will remain active. The sample reviewed today had a density of 455,370 cells/mL.

UPDATE 9/7/23 - Showell Pond was resampled today. The cyanobacteria density continues to exceed the state limit of 70,000 cell/mL, so the advisory will remain active. Density is holding around 135,600 cells/mL.

UPDATE 8/30/23 - Showell Pond was resampled today. The cyanobacteria density continues to exceed the state limit of 70,000 cell/mL, so the advisory will remain active. The cell count was 105,500 cells/mL (Aphanizomenon and Chrysosporum).

UPDATE 8/22/23 - Unfortunately the cyanobacteria density has continued to climb. The sample collected today had 1,906,333 cells/mL of the cyanobacteria Aphanizomenon, Chrysosporum, and Woronichinia. As this exceeds the state limit of 70,000 cell/mL, the advisory will remain active.

UPDATE 8/15/23 - Showell Pond was resampled today and cyanobacteria concentrations have increased at the beach access area to 59,533 cells/mL. The advisory will remain in place for another week. If you want updates on the current cyanobacteria advisory status, please go to the Healthy Swimming Mapper. If you click on the advisory symbol, you can see the most recent sampling date. When advisories are lifted, the red symbol for the waterbody will no longer be on the map.  

UPDATE 8/9/23  - based on NHDES sampling on August 8, 2023, the levels of cyanobacteria remain higher than the state limit, therefore the advisory remain in place. NHDES continues to advise lake user not to wade or swim in the water during an advisory.  Please keep pets and livestock out of the water. NHDES will resample in one week.

The bloom was first reported on July 31, 2023, appearing as dark water and dark clumps of material. Samples collected and reviewed on August 1, 2023 had cyanobacteria (Aphanizomenon, Phormidium, and a mix of additional cyanobacteria at low densities) in concentrations up to 137,420 cells/mL in areas of highest observed accumulations. Advisories are issued when cell counts exceed 70,000 cells/mL. NHDES advises lake users to not wade or swim in the water during an advisory. Please also keep pets and livestock out. The advisory is not based on a toxin evaluation and is intended as a precautionary measure for short term exposure. NHDES will resample in a week.