National Park Service and USGS Partner for Air Sampling Study at Winnewissa Falls

PIPESTONE, Minn. - From approximately August 9-14, 2026, the U.S. Geological Survey (USGS) will conduct air sampling around Winnewissa Falls at Pipestone National Monument. The sampling is part of a partnership between USGS and the National Park Service to understand contaminants in Pipestone Creek and assess public health risks.

The current phase of the study seeks to understand whether any contaminants in the creek's water can also be detected in the mist near the falls. To collect this information, USGS scientists will use a small, football-sized air sampler on a stand that emits a gentle hum while it operates. The equipment will be attended by USGS staff for about three hours in the morning and three hours in the afternoon during the sampling period. The Circle Trail, including the Winnewissa Falls bridge, will remain open throughout the sampling window.

This study is part of a three-year partnership with USGS to study water quality, determine animal sources of contamination and assess public health risks. Information from this research will help ensure safe and enjoyable experiences for visitors, while also assisting park managers with decision-making and coordination with local stakeholders on water quality initiatives.

"Clean water at Pipestone National Monument is important to so many-local residents, Tribal members, and the public," said Superintendent Lauren Blacik.

This effort expands on a previous USGS water quality study conducted in 2018-19, which detected a range of contaminants in Pipestone Creek including pesticides, pharmaceuticals, algal toxins and bacteria. The study also found that E. coli and fecal coliform levels exceeded recommended levels in all creek samples. For more details, see the U.S. Geological Survey's 2023 report.

Preliminary testing at the falls did not show harmful pathogens in the air, and no illnesses related to the air near the falls have been reported to NPS. The current air sampling will allow NPS and USGS to test under different conditions and further evaluate whether microbes in the water can become airborne in the mist near the falls. Following previous testing of the water, NPS posted cautionary signs to avoid entering the water, and this study will provide further information about possible risks. For more information, please visit www.nps.gov/pipe.

Photo Information: Air sampling equipment that will be used at Winnewissa Falls, photo courtesy of USGS.