The state has issued a health alert for Harmful Algal Blooms (HAB), also known as toxic blue-green algae, at Maskenthine Reservoir in Stanton County, Willow Creek Reservoir in Pierce County, Calamus Reservoir in Loup County, Bluestem Lake in Lancaster County and Pawnee Lake (east and west beaches) in Lancaster County.

Iron Horse Trail Lake in Pawnee County and Swan Creek Lake (Willard Meyer Recreation Area) in Saline County are still on health alert.

Samples taken earlier this week at these lakes measure above the threshold of 8 parts per billion (ppb) of total microcystin, which is a toxin released by certain strains of blue-green algae. Based on recommendations issued in 2019 by the U.S. Environmental Protection Agency (EPA), the state of Nebraska adopted this limit after concluding that the new EPA threshold is based on the best scientific evidence available and is protective of public health.

When a health alert is issued, signs are posted to advise the public to use caution, and designated swimming beaches are closed during the alert. Recreational boating and fishing are permitted, but the public is advised to use caution and avoid exposure to the water, particularly avoiding any activity that could lead to swallowing the water. Do not let pets get in the water or drink from the lake. People can still use the public areas for camping, picnics and other outdoor activities.

Weekly sampling has been conducted at 53 public lakes since the first week of May. The lakes will continue to be monitored weekly through the end of September. Sampling results for HAB and bacteria will be updated every Friday and posted on NDEE’s website, https://dee.nebraska.gov/. The state’s monitoring is conducted at public lakes with swimming beaches and high public activity. HAB may also be present in other lakes in Nebraska that are not tested, so the public should use caution if they see signs of algal blooms.

For more information about what to look for, potential health effects from HAB and steps to avoid exposure, please refer to the following Fact Sheet. To view the weekly data for the lakes sampled, go to https://deq-iis.ne.gov/zs/bw/.

NDEE’s sampling partners include the Central District Health Department, Nebraska Public Power District, Upper Republican Natural Resources District, Lower Republican NRD, South Platte NRD, Middle Niobrara NRD, Lower Loup NRD, Nemaha NRD, Lower Elkhorn NRD and the United States Army Corps of Engineers.