ST. LOUIS (AP) – Barge operators along a key stretch of the Mississippi River braced Monday for months of restricted shipping as crews prepared to begin blasting large rock formations that are impeding navigation on the drought-plagued waterway.

Contractors from Iowa and Ohio could begin drilling holes into the troublesome Mississippi River bedrock south of St. Louis and detonating explosives inserted inside as early as Tuesday, the Army Corps of Engineers said. They expect to remove enough rock to fill about 50 dump trucks, possibly more.

The demolition of the massive formations near Thebes coincides with an unusual move by the agency to release water from a southern Illinois lake, adding a few inches of depth to a river that is getting lower by the day – largely because of the lingering effects of the nation’s worst drought in decades.