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Indiana Reservoir and Lake Sampling Update

August 30, 2024

Sampling of the DNR’s swimming beaches began on May 13th for the 2024 recreation season to prepare for DNR’s opening of these areas on Memorial Day weekend and will end the week of August 26th in advance of Labor Day weekend. IDEM samples for blue-green algae and analyzes those samples for the type and quantity of blue-green algae present and for the following toxins which may be produced by certain types of blue-green algae: microcystins, cylindrospermopsin (beginning in July because species that can produce it show up in warmer months), anatoxin-a, and saxitoxin.

For protection of human health from exposure to blue-green algae and any of the toxins, cyanobacteria will be compared to the World Health Organization (WHO), United States Environmental Protection Agency (EPA) and Ohio Department of Health (ODH) guidelines. IDEM uses an action level of 100,000 cells/ml of cyanobacteria to post beach advisory signs. For cyanotoxin exposure for dogs, the California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment has developed action levels for microcystin, anatoxin-a and cylindrospermopsin. The Oregon Health Authority Public Health Division has set an action level for saxitoxin.  A warning or closure will be issued to dog owners using the Fort Harrison State Dog Park when cyanotoxins are detected above the levels in the table below.

Exact cell counts, species composition, and toxin levels can be found in the Test Results section of the web site. Swimming areas will stay on the Beach Advisory Alert until the cell counts fall below 100,000.

Toxin Exposure Thresholds
Exposure Reference Values ug/lMicrocystinCylindrospermopsinAnatoxin-aSaxitoxin
Human Recreation Advisory 8 6 8 0.8
Human Recreation Prohibited 20 15 30 3
Dog Recreation Advisory 0.4 0.5 - -
Dog Recreation Prohibited 0.8 1.0 0.4 0.05

Sampling Results - Beach Closed Alert Level

This alert level is based on “Human Recreation Prohibited” toxin thresholds referenced in the table above.

Algae and toxin levels make beach currently unsafe for swimming.

  • None

Sampling Results - Beach Caution Alert Level

This alert level is based on “Human Recreation Advisory” toxin thresholds referenced in the table above.

Swimming and boating permitted. Children and those with compromised immune systems should not swim. Avoid contact with algae. Avoid swallowing water while swimming. Take a bath or shower with warm soapy water after coming in contact with lake water. Do not use lake water for cooking or bathing. Although our test results are specifically for the beach where pets are not permitted to swim, please keep pets out of the water along shallow banks and the shoreline.

  • None

Sampling Results - Beach Advisory Alert Level

This alert level is based on a cyanobacteria cell count greater than 100,000 cells per milliliter of water.

Swimming and boating permitted. Avoid contact with algae. Avoid swallowing water while swimming. Take a bath or shower with warm soapy water after coming in contact with lake water. Do not use lake water for cooking or bathing. Do not allow your pets to swim or drink water where algae are present.

  • Brookville Lake - Mounds SRA Beach
  • Brookville Lake - Quakertown SRA Beach
  • Cagles Mill Lake - Lieber SRA Beach
  • Cecil M. Harden Lake - Raccoon Lake SRA Beach
  • Ferdinand State Forest - Ferdinand Lake Beach
  • Hardy Lake - Hardy Lake SRA Beach
  • Lincoln SP - Lake Lincoln Beach
  • Mississinewa Lake - Miami SRA Beach
  • Monroe Lake - Fairfax SRA Beach
  • Monroe Lake - Paynetown SRA Beach
  • Patoka Lake - Newton Stewart SRA Beach
  • Potato Creek SP - Worster Lake Beach
  • Salamonie Lake - Lost Bridge West SRA Beach
  • Starve Hollow SRA - Starve Hollow Lake Beach
  • Whitewater Memorial SP - Whitewater Lake Beach

Sampling Results - Beach Low Risk Alert Level

This alert level is based on a cyanobacteria cell count less than 100,000 cells per milliliter of water.

Don't drink the water, shower after you swim.

  • Chain O’Lakes SP - Sand Lake Beach
  • Deam Lake - Deam Lake SRA Beach
  • Ouabache SP - Kunkel Lake Beach
  • Pokagon SP - Main Beach
  • Pokagon SP - Potawatomi Inn Beach
  • Summit Lake SP - Summit Lake Beach

Sampling Schedule

Sampling will resume in May 2025!

ISDH cautions Hoosiers of possible high levels of blue-green algae at many of Indiana's reservoirs and lakes. Swimmers and boaters should be careful in all recreational waters during this time of the year. Precautionary measures include avoiding contact with visible algae and swallowing water while swimming. Take a bath or shower with warm, soapy water after coming in contact with water in ponds and lakes, especially before preparing or consuming food. Pets and livestock should also not be allowed to swim in or drink untreated water from these sources. Exposure to blue-green algae during recreational activities such as swimming, wading, and water-skiing may lead to rashes, skin, eye irritation, and other uncomfortable effects such as nausea, stomach aches, and tingling in fingers and toes. If you should experience any symptoms after water recreational activities, please contact your doctor.

Livestock, pets and wild animals can be poisoned by the toxins produced by some algal blooms. Small animals can ingest a toxic dose quickly. Dogs are particularly susceptible to blue-green algae poisoning because the scum can attach to their coats and be swallowed during self-cleaning. Clinical signs of blue green algae poisoning in animals include vomiting, diarrhea, decreased appetite, weakness, seizures and sudden death, especially in livestock. If you see a blue-green algae bloom in the water or where you visit, do not allow pets or livestock swim in or drink from areas where blooms are seen. If pets swim in scummy water, rinse them off with soap and water immediately to remove the toxin. Do not let them lick the algae off their fur. Direct livestock to water sources away from algal infected waters. If your animal shows any of the clinical signs listed above, contact your veterinarian immediately.

More information is available from the Indiana Board of Animal Health and the Indiana State Department of Health.

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