After Cherry Island, Where Will We Bury Our Trash?

In response to my latest post on recycling yard waste, Fritz Schranck at Sneaking Suspicions asks a troubling question:

Where should we put the next New Castle County landfill, when the Cherry Island facility finally fills up?

I have written that the Delaware Solid Waste Authority (DSWA) estimated the cost of a new landfill to be $106 million, a figure I think is likely to go much higher given the rising price of land. But Schrank writes that the needed land may not be available at any price:

First, here’s a link to a Google satellite photograph of the Cherry Island landfill site.
Second, here’s a link to a Google satellite photograph of the DSWA’s landfill that serves Sussex County, near Millsboro.
Both of these photos are on the same scale, at roughly 1 inch = 2000 feet.
Now click back to the Google map of New Castle County above, and while keeping to the same scale, try and find another location equivalent to either of these two current landfills anywhere above the Chesapeake and Delaware Canal.
Not easy, is it?

Isn't there any open land still available?

Much of the apparently vacant land above the Canal is already a State Park, such as White Clay Creek SP, Brandywine Creek SP, or Lums Pond SP. Beyond those out-of-consideration parcels, look at all of the other development crowding around what little remaining open space remains above the Canal.
It’s not appreciably easier below the Canal, either, and down there is the additional obstacle of all the wetlands dotted throughout southern New Castle County.

As New Castle County gets paved over, the cost of land to build a landfill, including an adequate buffer zone, will go through the roof. A landfill will have to compete with other land uses, which means the price of land for a landfill could be comparable to the price of land for residential use. And if existing land use has to be displaced to build a landfill, the cost will go even higher. To compare, the cost of displacing 167 homes on 52 acres was $34 million. A new landfill would require at least ten times as much land. Keep in mind that trash disposal is something that our modern civilization needs; it's not something we can do without if the price of land goes too high.
Even if the land and the money could be found, siting and building a landfill takes time, 17 years as Schranck points out in one case.
In this context, the eagerness with which some legislators want to pile more and more trash at Cherry Island seems shortsighted, even foolhardy. Landfill space is not a renewable resource.