Water infiltration and flooding has been a persistent issue in the below-ground levels of Hawaii’s largest airport, the Daniel K. Inouye International Airport (HNL), for more than 10 years. HNL’s 360,000-square-foot basement was constructed in 1973 to accommodate an expanded baggage handling area, among other operations, and sits below sea level. At the time the basement was built, a liner was installed to keep groundwater and sea water out of this below-ground level.
In the years since 1973, leaking/flooding began to be observed through drainage outlets, cracks in the concrete, and elsewhere. The leaking basement had not significantly interfered with airport operations until recently (2017), when increases in flooded water levels significantly restricted the use of the north and south basement areas of the Overseas Terminal and International Arrivals Building (IAB). To address this issue, Oceanit was contracted by the Hawaii Department of Transportation Airports Division (DOTA) to conduct a thorough investigation into the water infiltration source(s) and to provide engineering solutions and design services to prevent flooding recurrence.
With rising sea levels and increasingly common storm surges, urban areas near the coast face the risk of groundwater inundation, where groundwater rises above the ground surface, causing flooding. Basements and cesspools are often the first areas affected, and HNL is no exception. Situated on the coast, HNL’s basement level is below the groundwater table and flooding into its basement, particularly when ocean tides pushed water inland, began interrupting operations by ramp workers and airport staff.
Groundwater infiltrated the basement through damaged areas in the basement waterproofing liner, and through the cracks in several floor slabs. The ground water was also coming in via a damaged and blocked floor drain system, which was originally installed to collect and dispose condensate water from the massive AC units that cooled the passenger terminal building above.
Oceanit meticulously surveyed and mapped all potential infiltration areas, including every crack in the basement. Subsequently, the team presented several conceptual engineering solutions. Our proposals included filling in the existing floor drain system and redesigning it to be accessible for maintenance and repair, repairing and sealing damaged areas in the floor slab, and re-landscaping the area adjacent to the IAB walls to divert rainwater away from the building.
Oceanit’s comprehensive investigation into the water infiltration issue at the Daniel K. Inouye Airport has provided valuable insights and actionable solutions to mitigate the impact of groundwater inundation on the Overseas Terminal and International Arrivals Building basement. By addressing damaged waterproofing liners, cracks in floor slabs, and blocked drain systems, our proposed engineering solutions aim to restore functionality to these critical areas while also enhancing resilience against future water infiltration events.
Other projects Oceanit has worked on for DOTA and HNL include asbestos abatement work in older terminal facilities, invasive mangrove removal from Ke’ehi Lagoon, boarding gate facial biometrics implementation, and providing new corrosion protected fences for HNL.
