Engineers Devise Water Management Plan at Hilton Head Airport

Arnold Palmer landed the first aircraft at Hilton Head Airport in South Carolina in 1967, bringing with him a champion’s heart, an entertainer’s charisma and a burgeoning rivalry with Jack Nicklaus, a young blond bomber who challenged Palmer’s status as the game’s best player.

That year, Nicklaus won five PGA Tour events and the Player of the Year award as the rivalry between the golf legends took root. Palmer won four events and finished second in the Player of the Year voting. His career was winding down, however, and two years later, he returned to Hilton Head and ended a winless slump with a victory at the Heritage Golf Classic. A well-timed victory for the golfer known as “The King” brought instant credibility and attention to the region, kickstarting its status as a resort and vacation destination.

When Palmer won in 1969 at Hilton Head, the 42-square-mile island included 2,500 full-time residents and hardly any tourism. The community now has more than 39,000 residents and attracts nearly 2.7 million visitors, including nearly 79,000 airline passengers in 2015. “I wouldn’t be here today if it wasn’t for Arnold Palmer putting Hilton Head on the map,” Steve Wilmot, president of the RBC Heritage, said in an interview with the Island Packet of Hilton Head after Palmer died in 2016. RBC Heritage is a tournament that is still played at Hilton Head on the PGA Tour.

Palmer, an avid pilot, did more than open people’s eyes to Hilton Head as a resort destination. He also helped bring in air traffic to the coastal community, which is located between Savannah, Ga., and Charleston, S.C. As the region has become popular with tourists, Hilton Head Airport has tried to keep pace with the surge in popularity.

While tourism has been an important part of Hilton Head’s growth since Palmer’s victory cast attention on the island, so too has been the commitment toward protecting the environment by officials in Beaufort County, where Hilton Head is located, and residents of the island. Hilton Head incorporated in 1983 and immediately adopted an emergency ordinance to control island development. The town also approved master plans for several of the region’s most popular tourist destinations. Since that time, politicians and town leaders have been cautious about approving expansion and continue to plan carefully to protect the town’s water resources.

Beaufort County and Hilton Head developed a master plan in 2011 to provide direction and guidance regarding airport sustainability. Officials devised a plan to increase the length of the airport runway at Hilton Head Airport by more than 16 percent to 5,000 feet. The proposed expansion would enhance safety, accommodate more tourists, and give nearby residents more travel options. The expansion would also make the airport more competitive with airports in nearby Savannah and Charleston, both of which have runways exceeding 9,000 feet.

The airport is in a watershed area that includes the Calibogue Sound and May River, Cooper River, Broad Creek and other tributaries and lakes. The watershed area comprises nearly 81,000 acres. The diversity of water flow produces a good habitat for marine and wild life, including osprey, bald eagles, sandpipers and even dolphins in Calibogue Sound. The area teems with unique plants and animals.

Key points in the plan addressed the airport project’s impact on long-term water quality. The plan expressed concern about pollution wash off, specifically biochemical oxygen demand, chemical oxygen demand, volatile suspended solids, oil, grease, pesticides, total and suspended solids, algal nutrients, heavy metals, salts, asbestos and coliform bacterial indicators. The plan also had to comply with the Clean Water Act, and required coordination between federal and state agencies. Clearly, Hilton Head had come a long way since Palmer’s victory in 1967. The 18-month, $9.25 million extension project finally started in February 2015.

Stormwater management experts faced several challenges in determining the best plan to manage runoff. “There were some dry detention basins and a very large canal that held water,” said Paul Moore, project manager for Ward Edwards Engineering, a Bluffton, S.C., civil engineering firm. “The function of the airport made it necessary to fill in the canal and eliminate standing water onsite. The option of underground detention was very valuable to the design of the site.”

Moore discovered, however, that the project also required a system to function both as a conveyance and as a detention system. “The system was designed as a long liner system that would store water during low-flow conditions to help with water quality treatment, but then convey water downstream during high-flow periods,” Moore said. “The permeable nature of the system also allowed for continued interaction with the groundwater, and temporary surface storage in the swale above the system.”

Moore and his team devised two systems with CULTEC chambers to manage the runoff. The northern system featured the 30.5-inch-high CULTEC Recharger® 330XLHD™ chambers. One thousand pieces of the low-profile chambers were configured into a narrow five-row-wide system that extended to 1,403 feet. They occupied an area of just over 36,000 square feet. The chambers lie above and beneath six-inch layers of stone and the outside perimeter of the system is surrounded by a 12-inch-wide stone border. With an effective storage bed depth of 3.54 feet (without additional cover), the system has a total storage capacity of 84,420 cubic feet, with 63 percent of the storage accomplished by the chambers and manifold and the balance stored within the voids of the stone.

The southern system used 646 of the 48-inch-high Recharger® 902HD™ high-capacity chambers arranged in a bed area of 18,681 square feet with an effective storage depth of 5.75 feet. The chambers were placed on a 9-inch base of stone and covered by an additional 12 inches of stone. Total storage capacity exceeded 68,000 cubic feet.

In all, engineers used 1,641 chambers to manage more than 144,000 cubic feet of stormwater. “We wanted our systems to feature the largest storage volume chamber we could fit with sufficient cover for each system,” Moore said. “While the runway is flat, the elevations drop as you move south to north. This meant we could use the taller chambers on the south end where the surface grades were higher, and the shorter chambers on the north end.”

Once engineers designed the system, construction teams worked irregular hours to install it. Because of its location next to the runway, work could only be done at night. Contractors worked from 10 p.m. to 5 a.m. and the project had to be covered each morning to make it appear to pilots and passengers as if nothing had occurred. “Typically, our systems are installed in a few days and are only closed when the job is completed,” CULTEC’s Jon Shell said. “It was the most unorthodox installation we’ve ever seen.”

The first phase of the runway extension project is complete, and the full runway extension should be completed by the middle of 2018.

Palmer returned to Hilton Head in 2011 to christen a golf course that his company redesigned. Then-Mayor Drew Laughlin proclaimed the day to be Arnold Palmer Day. “I don’t know that I deserve that,” Palmer said to the Island Packet.

Nearly everyone living at Hilton Head now — and those who visit — will disagree. Thanks to its airport expansion and smartly designed system for managing water runoff, the delicate ecosystem is safe, and even more visitors will be able to enjoy the majestic seaside environs Palmer helped open to the masses more than a half century ago. WW

About the Author: Gina Carolan is the chief operating officer and director of marketing for CULTEC.