Resilience of Ports Against Natural Hazards

Introduction

More than 90% of the world’s trade moves by sea, making the continuous operation of maritime ports a critical piece of the global economy. Ports also serve as a focal point for providing supplies and humanitarian support to communities after natural disasters. Unfortunately, the vast majority of the world’s ports are located in areas at high risk for natural hazards such as earthquakes, floods and windstorms. Moreover, climate change and the corresponding increase of sea-levels are leading to flooding at some of the major ports around the world. Economic losses resulting from port disruptions will be significant, and the functional recovery following a disaster will be a very time-consuming process. For example, the 1995 Kobe earthquake caused significant damage to the Port of Kobe and led to $5.5 billion in direct economic losses from damaged components (Burden et al. 2001) in addition to indirect economic losses due to the lack of functionality for an extended period of time. In this article, we will analyze the factors that contribute to more resilient ports following natural disasters.

Overview of Major Components of Ports and Their Operations

Ports are waterfront structures which can spread over a wide area. There are six main components of a port: (1) wharves and other waterfront structures such as breakwaters and bulkheads (2) cranes, (3) cargo handling equipment such as container handlers, (4) fuel facilities, (5) warehouses, and (6) office/management buildings. A schematic of a port with different components is shown in Fig. 1. Ports are generally divided into terminals where different types of cargo can be handled. Wharves are the key components of a port where ships dock and cranes unload containers. Areas of wharves where ships dock are called berths, and the number of berths per wharf varies by the size of the ships docked there. Once cargo is removed from ships, it is taken to container yards where it is stored temporarily and picked up by trucks, trains or barges. Unlike container yards, warehouses are typically used for long-term storage. Fuel facilities can be located within the port or outside the port and are needed for fueling of ships.

Review of Historical Damage and Recovery

We carried out an in-depth review of historical damage and recovery durations of ports around the world due to earthquakes, windstorms, and floods. A summary of the review highlighting some of the key events is discussed in this section.

Floods

The major impacts of floods on ports are: (1) shoaling of water channels, (2) flooding and debris accumulation on terminals, (3) floating of containers and damage to cargo handling vehicles, (4) damage to electrical equipment and (5) scouring and wash-out damage. Since most of the flooding instances at ports around the world have been caused by flooding due to tropical cyclones, the slow-down ahead of the storm and shutting down for the duration of the storm as discussed in the previous section applies here as well. The recovery durations discussed in this section refer to the durations after the flood waters have receded.

Key Controlling Factors

Based on the review of the historic damage and recovery, the following key factors controlling the resilience of ports to natural hazards were identified:

Repair of damaged components

Repair of damaged/affected components is one of the most important aspects governing the recovery of ports. Wharves, cranes, and electrical equipment were found to be the most vulnerable components of ports to natural hazards. There are other components of ports such as offices and warehouses which are also vulnerable to natural hazards, but they do not have much effect on the functionality of the ports because ports can function as long as ships can dock and cranes can unload the cargo.

Redundancy

Redundancy plays an important role in the resilience of ports against natural hazards. Ports typically have multiple wharves and cranes and thus damage/failure of some wharves and some cranes is not detrimental to the functionality of the entire port. An excellent example of the importance of redundancy is the Port of Oakland impacted by the 1989 Loma Prieta earthquake, where the port was fully functional following the event despite damage rendering one terminal inoperable because the demand from the damaged terminal was diverted to other non-damaged terminals.

Repair Vs functional recovery

Ports and businesses that depend on them are interested in the functional recovery durations rather than the actual repair durations. It is possible for ports to be functionally recovered while still being repaired, especially undergoing some cosmetic repairs following an event. It was revealed from the review of the historical damage and recovery data that while repairs and cleaning of debris can continue for a long period of time following the event, they should not impede the port functionality during that period of time. Cargo volume handled by a port could be a better indicator of the functional recovery of the port as opposed to the actual repair durations.

Scale of the disaster and interdependence on other infrastructure

It is also evident that not only the availability of parts, materials, and labours for repairs but also the availability of employees following disasters greatly depend on the size of the disaster and its impact on the larger community around the port. Since ports rely on other infrastructure components for their functionality, functioning of those infrastructure components is also important. For example, our review showed several instances where a port did not suffer any damage but was non-functional for several days after a disaster because of the flooded roads in the surrounding area or power outage (see for example ports impacted by 2017 Hurricane Harvey).

Pre-event slow-down and duration of hazard

Unlike earthquakes, which give little to no warning before they strike, windstorms and flooding can be predicted within a reasonable time before they strike. Typically ports slow down their operations ahead of a large windstorm and are shut down for the duration of the windstorm or flooding. This can result in several days of downtime before the actual physical recovery process can take place and thus must be considered in the resilience framework.

Conclusions

Evaluating the resilience of ports against natural hazards such as earthquakes, windstorms and floods is important. A systematic review of the damage and recovery durations from historical events as well as the identification of the key controlling factors discussed in this article serve as an important resource in developing predictive models. Our review highlights that the full recovery of ports can take from days to years depending on the type and the severity of the peril. Different components of ports are impacted by different perils in different manners. A number of external factors and dependency among infrastructure components were also found to be detrimental in the recovery process. Ports have redundancy built in them because they are typically composed of multiple wharves and cranes which must be considered in assessing their resilience. A holistic review considering all major hazards discussed in this article lays the foundation of developing tools and methods to assess port’s resilience against natural hazards.

--

--

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store
One Concern

One Concern

We’re advancing science and technology to build global resilience, and make disasters less disastrous