Inspectors from the Nebraska Public Power District found what appears to be blue-green algae Monday along the shoreline of Hershey Beach at the Sutherland Reservoir.
As a precaution, visitors to that area of the reservoir, which is south of Sutherland, are asked to refrain from entering the water until further notice.
Blue-green algae can be toxic. It exists naturally in marine waters, rivers, lakes, and ponds, but it can be harmful to humans and animals in high enough quantities.
The algae samples will be tested by the Nebraska Department of Environmental Quality to determine exactly what the material is. Results are expected back later this week, NPPD said in a prepared statement.
Pets should also stay out of that water.
Once the analysis is completed, NPPD will work with the DEQ and the Nebraska Game and Parks Commission to determine if any further action is necessary.
When environmental conditions are just right, blue-green algae can grow very quickly in number. Most species are buoyant and will float to the surface, where they form scum layers or floating mats, also known as a "blue-green algae bloom.”
Blue-green algae sometimes releases toxins that cause stomach cramps, diarrhea, vomiting, headache, fever, muscle weakness and/or difficulty breathing, in both humans and animals.
These toxins are not produced all of the time and there is no easy way to tell when blue-green algae are producing them and when they are not. The only way to be sure if the toxins are present is to have water samples analyzed in a laboratory using sophisticated equipment, according to health officials.