By Nebraska Department of Health and Human Services
LINCOLN, Neb. – Nebraska has issued a health alert for Harmful Algal Blooms (HABs), also known as toxic blue-green algae, at Rockford Lake in Gage County.
Samples taken earlier this week at Rockford Lake measure above the threshold of eight parts per billion (ppb) of total microcystin, which is a toxin released by certain strains of blue-green algae.
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 by 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 57 public lake sites since May 18, 2026. The lakes will continue to be monitored weekly through Sept. 14, 2026. To view the weekly data for the lakes sampled and to access the Nebraska Department of Water, Energy and Environment’s (DWEE) new interactive Beach Watch map, visit https://deq-iis.ne.gov/zs/bw/.
The state’s monitoring is conducted early in the week at public lakes with swimming beaches and high public activity. Sampling results for microcystin and bacteria are updated every Friday and posted on https://dwee.nebraska.gov/.
HABs may potentially develop in the time between sample collection and sample reporting, so the public should use caution if they see signs of algal blooms. HABs may also be present in other lakes in Nebraska that are not sampled. For more information about what to look for, potential health effects from HABs and steps to avoid exposure, please refer to the HAB Fact Sheet.
DWEE’s sampling partners include the Central District Health Department, Nebraska Public Power District, Upper Republican Natural Resources District (NRD), 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.