When Army Corps of Engineers representatives recently set out to educate people across South Carolina about what the agency does, they heard a familiar refrain: Oh, yeah, I know you. Your permit is the reason it took me so long to get a dock.

Even its logo, a white castle set against a red background, bears some mystery. The document explaining the emblem burned in a pre-Civil War fire at the U.S. Military Academy at West Point, N.Y.

Best-known for its regulatory function, the agency also carries out a military mission and takes on a variety of projects around the state, including close interaction with real estate developers and harbor deepening.

More than 200 people work for the Corps of Engineers in South Carolina with operations spanning three construction offices, two regulatory outposts and a headquarters across the street from The Citadel's Johnson Hagood Stadium.

Recession aside, in the past two years, the agency grew by more than 40 percent, adding 60 new employees to accommodate an increasing workload.

Bottom-up business

The Army Corps' name winds up in the news most often because of its role in maintaining and deepening Charleston Harbor. It requests dredge money from the federal government, something that becomes more and more important as the Panama Canal's 2014 reopening approaches.

With an expanded canal will come larger ships that need a deeper draft to call without sucking mud into their engines as they float just feet above the channel bottom.

Port proponents often boast about Charleston's 45-foot "naturally deep harbor" at low tide, but as retired Army Corps project manager Joe Wilson once explained, "That's a misnomer. There is no natural depth. If we quit dredging, it would probably be the low 20s."

The Corps of Engineers spends $10 million to $15 million each year maintaining the depth with a full-time, 12-person team of engineers, technicians and survey personnel. It undertook a $90,000 federally funded study to consider future deepening and recently announced plans to proceed with the next step: a five- to seven-year feasibility study.

This next phase will determine the best depth, from an economic standpoint, for Charleston Harbor to serve the next generation of megaships calling the port.

As it stands now, the Army Corps removes 2 million to 3 million cubic yards of material every year. One million cubic yards would fill a football field and stack 39 stories high, according to Wilson.

Dredging runs in cycles, with windows set aside for natural events such as turtle nesting. Even without an active deepening project, the Corps keeps two survey boats in the harbor two or three days out of every week, running sonar to produce images of the channel bottom.

David Warren, Wilson's replacement, says those images ensure the channel remains clear for shipping traffic and that contracted dredge work finishes as planned.

In asking for federal dredge money, the Corps faces steep competition. Major operations across the country, including larger ports in Los Angeles and New York/New Jersey, all hold out their hands out for a piece of the same limited pie. That's what make dredge projects such as the Port of Georgetown, re-emerging as a noncontainerized cargo operation, tough to sell.

As deputy district engineer Bill Stein explains it, "The benefit of us spending $5 million to dredge to save $100 million in shipping (in Charleston) makes sense. But spending $5 million to dredge Georgetown if get five ships during the year -- it's not going to cut it."

Beyond docks

The fact that many members of the public identify the Corps with dock permits arises from the agency's long-standing role in wetlands protection and restoration.

It cleared channels in Pocotaligo Swamp between Sumter and Manning, draining water from 5,800 flooded acres and restoring the natural habitat. And it built a steel sheet pile ring wall to protect the foundation of the Morris Island Lighthouse off Folly Beach.

The agency's lesser-known projects include design and construction for other federal agencies. Corps employees perform no construction and only 20 percent of design themselves, so they hire private contractors within the community.

The local office oversaw construction of a new mental health building at the Veterans Affairs Hospital on Bee Street, for instance. It transformed the basic-training barracks and classrooms at Columbia's Fort Jackson, effectively taking them away from a World War II appearance. And it maintains and repairs warehouse sites across the country and abroad for the Defense Logistics Agency, which supplies nearly everything to troops overseas from food to fuel, uniforms and medical supplies.

These contracts explain the Corps' recent expansion.

"We needed people because, basically, we were a civil-works mission and regulatory" agency until recent years, Stein said. "We didn't have people with skill sets."

Lucky for the Corps, qualified people lived right here in town. In 2008, the Naval Facilities Engineering Command relocated from North Charleston to Jacksonville, Fla.

Stein said the Corps would ask, "Who's the best architect?" and hire that person. At last count, his agency had hired 29 people with at least 20 years of experience from the Navy operation.

Stein said Corps officials try to visit at least 10 county and city governments per year to educate them on federal programs and the services available, to let them know the breadth of their work beyond permitting docks.

Reach Allyson Bird at 937-5594 or abird@postandcourier.com.