Taxpayers own the park. I'm already paying for flood insurance for people who build in flood zones, I don't need to pay for some liberal idiot's wildly overpriced house that is apparently expected to outlast a 12000 year old dune.
The way the great lakes levels have been steadily rising over the last 4 or 5 years. In another year or so they'll start whining that we have to protect those million dollar homes too. My sister posted pics to facebook that showed lake Michigan getting dangerously close to US 2 in the upper peninsula.
I took this pic 2 years ago. The beach should have been 100 yards wide and the water has continued top rise since then.

The fact is that the movement of the dune is nature taking its course or an act of God, take your pick but neither are a threat to life and limb nor are they something the rest of us should be fiscally responsible for. The owners should take the insurance payout and get out.
I guess y'all missed my point. If these lemons aren't spoiled, IOW, if the sand could be used for frac sand, there is a good chance it would be purchased from those whose property the sand has encroached on and removed or simply removed, gratis, from that private property by someone who would absorb that cost of doing so and sell the sand. As a geologist, windblown sand tends to be almost all quartz (relatively pure), well sorted (all about the same size because of the mechanism that moves it). It also tends to be fairly well rounded, another desirable aspect for sand used as a propant to hold fractures open that are induced in fraccing.
It wouldn't cost anyone a dime, but the sand would be hauled out as it encroached on private property, not dug out of the park. Jobs, a marketable product, tax revenue.
Let the millionaires build seawalls to protect their property, too, and rising water is less of a problem for erosion, again, at no cost to the State, only privately handled. More jobs, more tax revenue. If you can afford a million dollar beachfront home, you should be able to afford to protect it. I have built seawalls, it is feasible.
The principle: If there are animals in a National Park and they get out and eat my crops, I can eat those animals: fair game, and most states have crop degradation laws to allow the farmer to harvest them or to engage the services of someone else to do so. There are other rules, but those are the basics.
In this case, the encroaching and degrading object is inanimate, but the property owner should still have the right to harvest the resource and sell it, or sell the right to do so, in order to preserve the value of his property. This is something that can be removed from private property. It may well have commercial value.
Cost to the State? Zip, except to make sure no one is crossing the line to get more than they have a right to remove, and it could be a source of tax revenue by providing jobs and business income from the sale of the sand.
I'm offering a possible solution that does not involve millionaire property owners leaning on officials to have the State come in and save their dachas at taxpayer expense.