The US Army Corps of Engineers is temporarily closing Chalk Ridge Falls Park at Stillhouse Hollow Lake after a dog developed respiratory problems over the weekend and had to be put down.

The owner took the dog to a veterinarian after the dog developed distress, with the suspected cause being the presence of blue-green algae, also known as cyanobacteria.

A Corp statement said these are aquatic organisms that have the potential to produce toxins that can be life threatening to people and pets when the population grows rapidly to produce sufficient toxin levels in the water.

This rapid population growth is known as a “bloom.”

Cyanobacteria blooms typically form in warm, slow moving waters that are rich in nutrients. Blooms are sometimes observed as colored bluish and/or greenish films on the water’s surface.  Blooms can also look like scum layers or algae mats on the water’s surface that most commonly occur near shorelines where wind and wave action accumulate them.

When blooms die the water can have a bad rotting odor. By better understanding environmental conditions that promote cyanobacteria and by being able to recognize harmful blooms, people can minimize or even eliminate the risk of exposure to these toxins. 

As a simple rule, the U.S. Army Corps of Engineers recommends that people and pets stay out of water that has visible colored surface films, scum layers and/or algae mats.  It is also best to avoid stagnant areas where there’s little to no water movement and where the water has a bad odor. Also, pets should be controlled on a six feet or shorter leash and should not be allowed to enter water with the above-described conditions and should not be allowed to ingest such waters. 

Until the cause of this incident is understood, the Corps of Engineers personnel at Stillhouse Hollow Lake will keep Chalk Ridge Falls Park temporarily closed. Lake staff are already working with other agencies to develop a plan to sample and test the water to confirm the presences of cyanobacteria and associated toxins.