Employees at Ameristar Casino spent 16 days on edge last spring — from the moment the Mississippi River was projected to hit a new record height in Vicksburg until it crested May 19 a few hairs below that mark.

“We had a lot of sleepless nights in here,” said George Stadler, the Washington Street casino’s senior vice president and general manger.

If a new barrier under construction holds any water, Stadler is confident the facility’s workers and supervisors should sleep more comfortably.

“I think we’re in pretty good shape,” he said.

A mountain of gravel and dirt visible on the main casino’s river side will become part of a 4-foot steel-and-concrete addition to Ameristar’s flood wall — left intact but severely tested by the river’s 57.1-foot crest in Vicksburg.

An earthen levee topped with sandbags and a concrete block wall was built in the weeks before the river crested. The previous wall protected the casino only to the 1927 flood mark, which was surpassed by nine-tenths of a foot.

“When Ameristar was built in 1993, it was built to the 100-year flood plain level. Obviously, as we’ve seen, it went well beyond that,” Stadler said.

The main casino was placed on a concrete foundation in 2007.

Crews with Hayward Baker Inc. should complete the higher wall in six months, which will not affect parking for the general public, Stadler said, adding some of the leftover material from the temporary wall will be used to build the new one.

Ameristar and Riverwalk casino, which was built slightly higher than this year’s new benchmark flood, remained open during the river’s rise. DiamondJacks Casino closed for 36 days before it reopened June 15. Rainbow Casino reopened May 27 after a two-week closure. The former Horizon Casino was closed for renovations between mid-March and June 2, when it reopened as Grand Station Casino.