RIVERDALE — The U.S. Army Corps of Engineers announced it will conduct a planned flow test of the Garrison Dam spillway on or around June 24 as part of ongoing investigations related to the spillway modification project.

The test is expected to involve opening about 23 of the dam’s 28 spillway gates for a total duration of about two hours. The purpose of the test is to verify the operability of the spillway structure and evaluate the performance of the spillway subdrain system.

This controlled release is strictly for testing and evaluation purposes and is not related to flood control operations. Releases at the powerhouse will temporarily be reduced to offset the increased flow from the spillway, maintaining a constant total release volume from the dam during the test. Although this temporary spillway release is not expected to have impacts to upstream or downstream water levels, the public should avoid boating and fishing near the spillway area during the test.

“This testing is an important part of our ongoing efforts to assess and maintain the long-term reliability and safety of the spillway system,” said Matt Stobbe, U.S. Army Corps of Engineers, Omaha District civil engineer.

The exact timing of the test may vary depending on weather and operational conditions. Additional updates will be provided if schedules change.