Deepening may be key to rookery, lighthouse

The prized Crab Bank shorebird rookery is an eroding sliver of land in Charleston Harbor. The iconic Morris Island Lighthouse is battered by surf in the wash of the inlet between the island and Folly Beach.

Both of them need sand.

The sand loss for Crab Bank has been blamed at least partly on wake erosion from cargo ships in Charleston Harbor. Sand for the lighthouse has been shown to be cut off by the shipping channel jetties.

Now, a diverse group of environmental agencies and advocates wants the shipping channel to help save them.

The organizations are submitting comments to a Charleston Harbor deepening study now under way, requesting that the U.S. Army Corps of Engineers consider using "spoils" to restore the lost sand. The study is an early phase of a $300 million project to deepen the channel to accommodate larger cargo ships. Spoils are sands that would be dug up during the dredging to deepen the channel.

For Crab Bank, the groups include the U.S. Fish and Wildlife Service, Southern Environmental Law Center, Coastal Conservation League and Cape Romain Bird Observatory. For the lighthouse, they include Save the Light.

Crab Bank renourishment is "very much on the table and has been part of the initial discussion," said Jennifer Koches, of U.S. Fish and Wildlife.

"We're pursuing (Morris Island renourishment) aggressively," said Carl Hitchcock of Save the Light, a grassroots group that has spearheaded efforts to keep the century-old lighthouse standing.

Meanwhile, the S.C. Department of Natural Resources has expressed concerns about effects from the deepening on "water quality, air quality, fish and wildlife habitat … (and) species of recreational, commercial, or ecological importance," as DNR said in a letter to the Army Corps.

The Army Corps is looking at both renourishment possibilities as elements of a combined feasibility and environmental impact study, said Pat

O'Donnell, planning and environmental branch chief for the Charleston district. The study is expected to take four to five years to complete, but local, state and commercial officials are pushing to fast-track it.

Using the spoils would seem like a no-brainer. Crab Bank was created from dredge spoils. Morris Island loses much of its sand because the channel jetties disrupted the natural flow of sand north to south along the beaches.

But there are issues: contamination and cost.

As a precaution against contamination from polluted spoils in the commercial shipping lane, the preferred sand would be the sand dug farthest out. The farther that sand must be moved from where it's dug to where it's dumped, the more expensive a project becomes. O'Donnell said that when determining feasibility, the "environmental good" is balanced against the cost.

Crab Bank "is a shadow of its former self in terms of shorebird nesting. I don't think that you'll get an argument on that from anybody," said Nathan Dias of the bird observatory. "What good is (the spoil) material if you just dump it out at sea? I hope the (Army) Corps gets creative in what it wants to do with it."

Reach Bo Petersen at 937-5744 or follow him on Twitter at @bopete.