CHARLESTOWN — In 1940 the population of Charlestown was about 900 people. In just two years those numbers would skyrocket to about 27,000 due to the Indiana Army Ammunition Plant.

Vestiges of that plant still stand sentry on the land now occupied by the River Ridge Commerce Center, which stretches for 6,000 acres between Charlestown and Jeffersonville. Many of the above-ground structures have been lopped off, but their foundations still sit rooted in the soil — about 1,200 of them.

Like the days of old, when the ammunition plant bustled with workers and production, River Ridge leaders seek to usher in a new era of development as one of the Midwest’s biggest commerce centers. In an update to the Charlestown Chamber of Commerce on Thursday, Dustin Coffman, finance and marketing director at River Ridge, said the facility is on pace to do just that.

Businesses that occupy the 20 percent of the property that is developed at River Ridge account for about 10,000 jobs, Coffman said, and that number swells to about 14,000 when construction workers are taken into account. All told River Ridge is on pace to have a more than $2 billion economic impact on the region this year.

“People ask me: ‘What’s your goal?” Coffman said. “Well, I quickly say, ‘to replace 27,000 people.’ That’s an easy one.”

What’s more difficult is how to clear what the Army left scattered over 2,200 acres in the Charlestown sector of the center, which is where the bulk of the ammunition plant had its production facilities. What’s left is what Tom Vittitow, River Ridge’s development director, refers to as “zombies” — those 1,200 structures that require removal.

“Each and every one of those structures that the Army built is full of concrete, asbestos and other little jewels that we get to remove,” Vittitow said. “It’s a new set of challenges every time we go up there and knock a building down, or put a shovel in the ground, that we’re faced with.”

And those are just the structures that River Ridge officials can see. More “zombies” could be lurking in heavy vegetation still untouched by development.

“That’s been a huge undertaking for us,” Vittitow said, noting that equipment has been purchased and contractors hired just to remove the scrub. “There’s just a lot of dollars you get into when you pull that stuff out.”

River Ridge is about $9 million into a large-scale demolition project that is anticipated to cost another $20 million — and that’s just the stuff visible to the eye.

“Again, we run into surprises,” Vittitow deadpanned.

One such surprise, which River Ridge officials suspected was an Army construction debris landfill that turned out to be asbestos, rang up a $250,000 removal tab. And don’t forget the steam line that ran the entire length of the site, with 7-foot-tall foundations and a pipe larger in circumference than a beach ball.

“It just keeps on going,” Vittitow said. “We’re at the tip of the spear because there are a whole more structures that we need to tackle. There’s not a lot of people that get excited about coming into a piece of property with a bunch of Army structures on it. There’s a negative connotation associated with that. When we get in here and clean this area up you’ll start to see more development.”

The most recent development is what’s being called the “gateway project” on the Jeffersonville end, where work is underway to transform the first exit off the Lewis and Clark Bridge into a regional showcase.

“What’s interesting is I have heard others say that it’s not just the gateway into River Ridge, but the gateway into Indiana,” Coffman said.

Amenities of the park-like portion of the project include a lake with three waterfalls and a fountain, an amphitheater and nearly seven miles of walking trails. A bridge will allow cars to directly access the office park, while heavy trucks will travel underneath the bridge into the center’s industrial area.

River Ridge signed a deal that will allow Louisville-based Hollenbach-Oakley the exclusive right to develop up to 600 acres at the park, with marketing and selling of the property to begin in January. The development would be completed in two phases — the first 300 acres as the River Ridge Gateway Office Campus, and the remaining 300 acres as the River Ridge Research Campus.

While development is rapidly gobbling up the Jeffersonville side of River Ridge, the Charlestown end is slowly gaining ground. Businesses like D.A. Inc., J. Knipper and Co. and Magnolia Automotive Services are leading the way, and Vittitow expects more to follow.

“When we get done with all this there’s going to be a tremendous number of jobs out here, and the transformation you can already see going on in this area right now is evident,” he said. “And it’s not going to slow down. We’re going to see more success in the future.”

Jason Thomas is an assistant editor at the News and Tribune. Contact him via email at jason.thomas@newsandtribune.com or by phone at 812-206-2127. Follow him on Twitter: @ScoopThomas.