Sea Level Rise and Delaware Infrastructure

The costs of sea level rise from global warming will not be limited to beachfront property and wetlands. A look at DNREC's sea level rise maps reveals significant impacts for the infrastructure serving Wilmington and northern New Castle County. DNREC's interactive maps show the effects of 0.5 meters, 1.0 meter and 1.5 meters:

The maps show that even a modest rise in sea level would undermine or flood much of the major infrastructure in and around Wilmington.

I-95 would be flooded at several points between Rt. 141 and Wilmington. I-495 would be undermined near Edgemoor, under the bridge over the Christina River, at the interchange with Rt. 13, and at the interchange with I-95 and I-295. The S. Market Street, S. Walnut Street and 4th Street Bridges across the Christina River would be inundated. The Port of Wilmington would be partially underwater. Erosion along the banks of the Cherry Island Landfill and the Wilmington Wastewater Treatment Plant would threaten the structural integrity of these facilities that serve most of New Castle County. Amtrak lines would be flooded at several points, including the maintenance facility along I-495.

DNREC's Sea Level Rise Advisory Committee is looking at the potential costs associated with inundated or flooded infrastructure. One current project provides a useful benchmark:

Market Street Safety Project - Wilmington: This project would elevate the roadway out of the floodplain; reducing the impact flooding has on residents and businesses. The contract will also add the following streetscaping: sidewalks, pedestrian lighting and trees. Improvements also include undergrounding utilities. The limits are Market Street from "A" Street to just north of the Market/Walnut Street intersection. Bid opening date was Tuesday, June 8. The contract was awarded to Mumford & Miller Concrete, Inc., on July 9, 2010 with a bid amount of $4,430,809.05. The construction began on September 6, 2010. 684 Calendar Day Project.

That’s $4.4 million for less than a mile of roadway and associated infrastructure. I expect that the total infrastructure costs associated with sea level rise will be very large indeed. And what would the cost be if we decide that shoring up or replacing these transportation lines is just too expensive? Wilmington would be cut off from the highways and rail lines that connect New York and Washington.

When I discussed this at a meeting of environmental advocates with then Senator Ted Kaufman, he responded with the words, "Buffalo, New York." I sat there puzzled for a moment, and he explained that Buffalo's economic relevance began to decline when the Erie Canal was replaced by rail lines and highways as the country's main commercial arteries.