Boltz Lake Harmful Algal Bloom Lowered to Watch Level

FRANKFORT, Ky. (April 18, 2017) – The Kentucky Division of Water (DOW) and the Kentucky Department for Public Health (KDPH) have reduced the harmful algal bloom (HAB) recreational public health warning for Boltz Lake to the “watch” level. The lake is located in Grant County, Ky. near Dry Ridge.

A Recreational Public Health Watch means algal toxins present are at elevated levels. Swimming, wading, and water activities that create spray are not recommended because water ingested during recreational activities in this lake may increase the risk of gastrointestinal symptoms such as stomach pain, nausea, vomiting and diarrhea. Skin, eye and throat irritation and/or breathing difficulties may also occur after contact.

The decision to reduce the advisory  to watch level occurred on April 12 when DOW  received its second consecutive water sample on Boltz Lake indicating a drop in the level of HABs present in the water. The Division of Water received two samples indicating the level had fallen below 20 parts per billion for cylindrospermopsin, which is below the warning level but still above the watch level.

Blue-green algae occur naturally in the environment and are a vital part of the ecosystem.  Harmful algal blooms arise when there are excess nutrients (phosphorus and nitrogen), sunny conditions, warm temperatures and low-flow or low-water conditions. The more typical green algae, which do not produce toxins, come in many forms and may appear as underwater moss or stringy mats. HABs, on the other hand, appear as slicks of opaque, bright-green paint. A closer inspection often reveals a grainy, sawdust-like appearance of individual colonies or bacteria. The color of the algae may also appear red or brown.

The following guidelines are recommended to avoid exposure to HABs:

  • Individuals should avoid direct contact with affected water that has unusual color or where blue-green bacteria have been identified, including swimming, wading, paddling, diving and water skiing.
  • People who are prone to respiratory allergies or asthma should avoid areas with HABs. Children may be particularly sensitive.
  • If contact has been made with water containing blue-green algae, wash off with fresh water. In some cases, skin irritation will appear after prolonged exposure. If symptoms persist, consult your health care provider.
  • If fishing in affected waters, fish fillets (not organs) may be consumed after the fillets have been rinsed in clean, non-lake water.
  • Prevent pets and livestock from coming into contact with water where HABs are apparent.


If you are concerned that you have symptoms that are a result of exposure to HABs please see your doctor and call your local health department. For additional information about this advisory, contact Andrea Keatley at the Kentucky Division of Water at 502-564-3410. – HAB Viewer