Emergency and Disaster Preparedness at Kansai International Airport

Kansai International Airport has implemented various measures against natural disasters. Below are some specific initiatives for natural disasters such as torrential rains, earthquakes, typhoons, and storm surges.

Efforts to Cope with Torrential Rain

Installation of Rainwater Drainage Pumps

Rainwater falling on Kansai International Airport flows through drainage pipes to the sea. Initially, rainwater was drained naturally to the sea by drainage pipes sloping outward from the interior of the island. However, the area near the seawall, being closer to the sea, experienced less subsidence than the inland areas. As a result, the slope of the drainage pipes gradually became gentler, and the drainage function, particularly near the seawall, started to deteriorate. To solve this problem, pumps were installed at the outlet of the drainage pipes to improve the efficiency of rainwater drainage. The installed pumps are capable of handling a heavy rainfall of 55 mm per hour, a level that could occur once in 10 years.

Inside of the drainage pump room.
Cross section of the airport's drainage system. With this system, rainwater that falls on the passenger terminals and runways, situated on reclaimed land, passes through storm water drains and is then discharged into the sea by drainage pumps.
A floor plan of the airport terminal building. There are 10 locations where drainage pumps are installed, which are indicated by red circles. There are a total of 37 pumps.

Installation Sites of the Drainage Pumps for rain water

Initiatives for earthquake-resistant

Seismic Reinforcement

There are many viaducts in the airport-island to ensure smooth traffic conditions. Even if a Great Hanshin-like earthquake occurred, we have secured passenger safety and will be able to keep the airport operating. Kansai Airports has improved its viaducts with anti-earthquake reinforcement.

An elevated road viewed from below.

A comparison diagram detailing the earthquake-resistant reinforcement work provided for the elevated road. Before reinforcement, there was a possibility that the bridge girders would fall in an earthquake, but after reinforcement, safety has been improved by (1) reinforcing the piers, (2) replacing the supports, (3) installing devices to prevent the bridge from falling, and (4) connecting the girders.

  1. Concrete filling reinforcement for steel bridge piers
 For areas where seismic performance cannot be ensured with concrete-filled reinforcement alone, steel plates (ribs) for reinforcement were installed on the outside of the steel piers.
  1. Installation of displacement limiting device
 In the case of bridge damage or destruction, we limited displacement through the installation of a displacement-limiting device.
  1. Installation of bridge fall prevention apparatus
 In the case of displacement-limiting device failure, and to prevent the collapse of the girder bridge, we have connected the bridge and the pier through a PC cable.
  1. Installation of faulting prevention device
 In the case of the bridge base being fragmented, we installed a fault-prevention device to secure the road as an emergency route right after an earthquake.

Typhoon Response

Typhoon wave mitigation

Typhoon Jebi (Typhoon No. 21) in 2018 flooded the airport island due to waves over the seawall and caused severe damage, including flooding of the runway, and it took more than two weeks to fully restore airport functions.
Based on this experience, Kansai International Airport reinforced its seawall by adding concrete to raise its height to withstand the highest tide recorded in Osaka Bay (assuming Second Muroto Typhoon). This elevation is designed to endure waves equivalent to those expected once in 50 years. In addition, the seawall is periodically raised in response to ground subsidence to ensure safety.

Cross section of a raised embankment.

Illustration of raised seawalls

Several workers are building a concrete wall on an embankment construction site.

Work on raising seawallss

Efforts to Address Storm Surges

Measures to Address the Rise in Groundwater Levels Due to Storm Surges

The rising groundwater is related to the structure of the island itself. Kansai International Airport is surrounded by an environmentally friendly rock seawall built with rock material quarried from a mountain. For this reason, the structure is extremely water permeable. Consequently, when the surrounding sea level rises, the seawater flows into the airport island ground and the groundwater level rises. Likewise, when the sea level drops, the groundwater escapes and the groundwater levels also drop.

Cross section of a sloping stone embankment. The embankment has been built by improving the alluvial clay layer on the seabed using the sand drain method and piling up sand, rubble, fill sand, cover stones, wave-dissipating blocks, etc. on top of that.

Airport island structure (Cross-section)

Water barriers (underground walls) were built as a radical solution to prevent seawater permeation into the airport island ground, and to curb rising groundwater. This involved excavating down to a depth of 30 m, where a non-permeable alluvial clay layer sits. Subsequently, a string of columns made from cement, soil and sand were constructed.

Cross section showing the role of the cut-off wall. Cut-off walls installed behind the embankment prevents water from seeping in from the sea and stabilizes the groundwater level of the airport.

Diagram of a water barrier

A diagram showing how to construct a cut-off wall. The flow of groundwater is blocked by rotating and driving steel pipe piles into the ground using a crane until they reach the alluvial clay layer about 30 meters below.

Groundwater levels prior to the construction of the water barriers

An overall view of the airport and location of cut-off walls. Approximately 11 km long cut-off walls, with their location indicated by red lines, surround the passenger terminal area, runway area, and other areas. Water-resistant steel cellular cofferdams are indicated by green lines.

Water barrier locations

In 2006, a watertight wall for the entire Phase 1 island was completed, preventing groundwater from rising during abnormal tides and typhoon-induced storm surges. This measure will prevent any impact on airport functions in the event of sea level rise or subsidence due to global warming. Watertight walls are being installed sequentially on Phase 2 island as well.