Schildberg (Atlantic) Quarry

A flooded limestone pit quarry owned by Schildberg Construction on the north edge of Atlantic, long used by Omaha- and Des Moines-area dive shops, clubs and public-safety teams for training. Average visibility runs 10-15 ft and drops sharply after storms; above roughly 60 ft the water is clear, while deeper water is about 41F, low-oxygen and sulfurous. Access has been intermittent - diving historically required written permission and liability waivers from Schildberg, and trespassing signage has been reported at the gate in some years, so confirm access before traveling.