Engineers Choose CULTEC Storm Water Systems for Bahamas Airport

When Lynden Pindling International Airport in the Bahamas began a three-phase, $400 million expansion and renovation, Stantec engineers came on board to design the airport’s new storm water management systems.

The airport presented significant challenges for storm water management. The large site has exceptionally flat terrain and a high level of groundwater, about 6 ft below the finished grade and about 3 ft below the existing ground. The site offered little opportunity for infiltration or for conveying storm water in piped systems.

For the airport’s landside areas, the engineers used two CULTEC underground storm water systems. The Recharger 180 HD unit is 36 in. wide by 20.5 in. high, with a chamber storage capacity of 3.45 cu ft per linear foot. It provided a large storage volume, and engineers determined it was the best fit in the given depth-restriction scenario.

“CULTEC allowed us to select from nine chamber sizes to accommodate the flat topography and high groundwater, solving our onsite issues,” said Stantec Project Engineer Patrick Clark, who designed the landside storm water systems.

Designed with HydroCAD modeling software, the CULTEC systems are able to handle at least 6 in. of runoff over the entire drainage area, or a rain event of 1-in. intensity for a duration of six hours, as required by the Bahamas’ storm water regulations.

The two specified CULTEC systems offered a combined 42,068 cu ft of storage. The storage volume was about 35.37 cu ft per installed chamber, including the storage capacity of the stone. While the systems function independently to distribute and balance storm water runoff, they are also interconnected in the event that any one system reaches capacity or overflows through the outlet control structure.

The systems also are connected to several open swales and retention ponds distributed throughout the site to allow for excess storage capacity. The open detention ponds are drained with deep drainage wells for rapid dewatering and provide for infiltration and evaporation.

The use of underground storm water systems helped solve yet another project challenge. The hard durable rock needed for the installation had to be imported to the Bahamas. According to CULTEC Vice President Fred Dotson, the company’s systems use less stone than other comparable systems on the market, lowering the overall installation costs.

Both CULTEC systems were installed using the company’s internal manifold, which allows manifolding to take place at any point within the storm water system, condensing the system while decreasing the required footprint. The custom manifold allowed for maximum design flexibility and eliminated the need for costly fabricated pipe manifolds. According to Clark, the advantages of the internal manifold capability contributed to the engineers’ decision to select CULTEC systems for the project.

Source: CULTEC