'A predictably dangerous place'

A low-head dam on the Big River at Rockford Park in Jefferson County, shown here in 2014, was crumbling. In 2015, the EPA determined the dam must be saved to protect mussels downstream from lead-contaminated sediment.

In 2016, the Army Corps of Engineers stabilized the dam, shown here in 2024, by piling rocks and boulders across two-thirds of the river, leaving a gap between the structure and the bluffs. The Corps called it a temporary fix.

Potamologist Robb Jacobson says that now, during summer conditions, the river's flow is concentrated through the gap in the dam's structure. Eddies form on both sides of the highly turbulent flow.

Jacobson says under this dangerous flow there are deep scour holes in the streambed and a submerged sandbar with steep sides. Three recent drowning victims were trapped by an eddy over the deeper hole.