Mount Baldy is going on a diet and getting a vegetation toupee to become more presentable.

Indiana Dunes National Park Superintendent Jason Taylor outlined plans Monday night at the Indiana Dunes Visitor Center in Porter to haul sand away from the south face of the dune, a process expected to take 100 days.

The plan is subject to approval by his higher-ups in the National Park Service and the cooperation of the U.S. Army Corps of Engineers.

Unlike other dunes at the national park, Mount Baldy is on the march.

Over the past two centuries, wave action interrupted by the pier at Washington Park in Michigan City has deposited sand on the east side of the pier, building up Michigan City, while starving the flow of sand to the west.

The erosion has sent sand flying across the top of Mount Baldy, depositing it on the south face of the dune.

So far, the sand has encroached on the parking lot and a picnic shelter. Unchecked, Mount Baldy would gobble up the restroom facility within a few years. Within the next year, a lift station for the septic system could be covered without action in 2025, Taylor said.

“It’s a slow freight train, and we saw it coming, but we didn’t do a whole lot about it,” Outdoor Recreation Planner Rafe Wilkinson said.

Taylor said it’s a maintenance issue, albeit maintenance that has been deferred for decades.

“It still is expensive to move sand but it’s the least expensive option, we think, because it’s investing in a long-term fix,” he said.

The park staff looked at a series of alternatives, none of which was perfect.

One would have been to create another access point for visitors. But that would potentially have disturbed forests that have been there for decades.Another would have been to just remove the restrooms and septic system and put in portable toilets. “We’re not going to let that infrastructure be buried under the sand,” Taylor said.

But replacing the cleanest restrooms in the park system, as Taylor put it, with portable toilets would have been not only temporary but also a significant downgrade for the visitor experience.

Trucking the recently deposited sand from the south face of Mount Baldy to Crescent Dune, between Mount Baldy and the Michigan City Generating Station, would require about 100 days next year, Taylor said. After that, the number of trucks would be reduced as marram grass planted atop Mount Baldy takes hold and initially slows, then stops, the flow of sand across the top of the dune.

Geologist Erin Argyilan, education coordinator at the Great Lakes Research and Education Center at Indiana Dunes National Park, gave a tutorial on Mount Baldy’s history, including how a young boy, now an adult, was swallowed by a sinkhole there and miraculously rescued.

“I became fascinated with Mount Baldy when somebody said, ‘When I was a kid, I stood on the shoreline and I couldn’t see the Michigan City water tower behind it, and now I can see it,’ ” she said. “We haven’t been talking about how this dune is changing in three dimensions. We always talk about how it’s moving and advancing in two dimensions, but the whole darn thing is changing in size and shape and geomorphology.”

Mount Baldy is known for swallowing trees. But that hides the fact that a dune underneath was stable long enough to have vegetation atop it create soil and hold an oak savanna.

“When you erode at the beach base, the sand has a choice of two places it can go,” Argyilan explained. “It can either stay in the water and move down the coast to the west, where it’s going to start accumulating right in front of Dune Acres, where it’s actually been building up over in that area thanks to another harbor structure, or it can go up on the landscape and over. That’s the story of what we’ve been seeing at Mount Baldy.”

Argyilan showed a series of images that showed the progression of erosion on the north and accumulation on the south.

A black line that seems to snake across the dune reveals the paleosol, the ancient soil from a dune stabilized about 3,500 years ago.

“So what we call Mount Baldy is actually a dune on top of a dune,” she said.

The fresh sand blowing across the top of the forested landscape in the past two centuries comes from that pier in Michigan City, erected in 1838, changing the natural flow of sand along the shoreline. Manmade structures reshape the shoreline itself over time.

After that boy was buried alive in 2013, Argyilan and other scientists have devoted more attention to studying Mount Baldy.

The best way to understand the inside of this dune, called the stratigraphy of the dune, is with ground penetrating radar, she said. Information was confirmed by taking core samples.

“Essentially, we go through the upper fluffy stuff, which is the stuff that’s blown up in the last 200 years. Eventually, the core would hit the paleosol, or those ancient dunes. It would rod right through that into the stabilized older dune below,” verifying what the ground penetrating radar indicated, Argyilan said.

“If you’ve been to Mount Baldy, you know that either in the water or at the base of the dune, there’s usually clay, so back when Mount Baldy or that whole shoreline had advanced, there was a barrier beach that trapped a little room behind it and created clay. After that clay was formed, that’s when the sand dunes moved in around 3,500 years ago,” she said.

To determine which sand is recent, scientists use optically stimulated luminescence. “You can actually go in and sample right above the soil, right below the soil, and tell the last time that those sand grains saw light,” Argyilan said.

Radiocarbon dating helped, too.

Now it’s a matter of planning to shovel all that sand, somewhere around 40,000 cubic yards the first year, Taylor said.

After the Corps of Engineers, hopefully, has a few trucks hauling the sand for about 100 days next year, park staff would be able to move some sand each year until the dune stabilizes, Taylor said.

As anyone who has dug a hole at the beach knows, removing sand causes more sand to fall.

For years, the park’s natural resource team has been planting vegetation atop Mount Baldy. “If we can get up there and plant marram grass and allow that sand, or above that vegetation, to catch more grass, maybe we don’t have to move any sand,” Taylor said. He isn’t sure when the dune will stabilize enough for that to happen.

But sitting still and allowing Mount Baldy to continue its march southward isn’t going to happen.

“The park intends to maintain its parking lot and facilities by moving recently deposited sand back on the beach where it belongs,” he said.

Doug Ross is a freelance reporter for the Post-Tribune.