09/14/2026
During September, the U.S. Army Corps of Engineers will conduct vegetation management activities on sandbars in the Missouri River between Yankton and Vermillion, SD, the upper portion of Lewis and Clark Lake near Springfield, SD and Niobrara, NE, as far upstream as Pickstown, SD.
Certified applicators using helicopters will begin spraying after Labor Day only on vegetated portions of the sandbars. Approximately 1,000 acres have been identified for treatment. Spraying will be done with glyphosate and imazapyr herbicides, both are approved for aquatic use by the US Environmental Protection Agency.
Spraying will take place only when environmental conditions allow, such as little to no wind and no rainfall in the immediate forcast. While efforts will be made to conduct spraying during the week, when public use is lower, spraying may occur on weekends since good spraying days can be limited due to wind or rain.
The U.S. Army Corps of Engineers began current vegetation control and removal activities on selected sandbars in 2012 and will continue each fall, as needed, into the future.
