Transportation Vulnerability Due to Climate Change

NEWS

The Transportation Asset Climate Change Risk Assessment Report was delivered to Federal Highway Administration on December 2, 2011. A copy of the report may be downloaded from this link (19.6MB).
Posted December 16, 2011

The presentation from the Public Meeting held on Wednesday, May 18, 2011 is available for download here.
Posted May 24, 2011

Background

FHWA awarded five grants nationwide to validate a conceptual model for determining the affects of climate change on transportation infrastructure.  In addition to the OahuMPO, grants were received by the North Jersey Transportation Association, San Francisco Metropolitan Transportation Commission, State of Virginia Department of Transportation, and the State of Washington Department of Transportation. The model consists of three parts:

Determining what are the likely climate stressors that will be faced by the local region and the probability of their occurrence in the future,
Determining what the critical transportation infrastructure assets are for the local region and their relative priority, and
Assessing the vulnerability of those priority assets to impacts from the climate stressors.

The study does not actually look at the measures needed to adapt the infrastructure, as may be required, to ensure its integrity in the face of climate change.

A diagram of the model may be found at this link.

Planning for Climate Variability

OahuMPO held a workshop on March 8-9, 2011 at the East-West Center to which it invited a number of climate scientists with specific expertise in how weather will be changing in Hawaii along with both planners and engineers from the Federal, State, and City as well as the University of Hawaii. While climate change is often seen as something that will happen in the future, as an island state – along with a number of Pacific island nations – Hawaii is already experiencing some of the impacts that can be expected to intensify in coming years. For example, flooding in Mapunapuna and parts of Waikiki and at Campbell Industrial Park during high tide, the 44 days of rain in 2006 that caused severe damage to the slopes of Tantalus/Roundtop, and the unanticipated topical storm that knocked down power and telephone lines along Farrington and Kamehameha highways illustrate the problems that can occur.

The workshop focused on three climate stressors:

Sea-level rise
Consensus among climate scientists appears to be coalescing around a future sea level that is about 3 feet higher than it is today. Low-lying costal infrastructure will be particularly at risk from higher tides and tidal surges.

Flooding
Hawaii will likely receive less total rainfall, and drought may be more common. However, rainfall events, when they do occur, are likely to be significantly heavier than they are today. The drought-heavy rainfall cycles may result in loss of critical vegetation that supports hillsides and embankments. It is likely there will be greater potential for wildfires, thereby exacerbating flooding and degrading slope stability.

Increased storm frequency and intensity
Tropical storms and even hurricanes may occur over Hawaii more frequently than they have in the recent past. It is expected that storm events will become more intense. Sea-level rise will likely increase the impacts, especially from storm surge.

Oahu is uniquely vulnerable given its location mid-Pacific and, based on the more current climate science, needs to begin planning for these weather-related events now. Many other states along both the East and West Coasts as well as in the Gulf are planning for these changes, too. However, the dynamics of climate change they will experience may be much different from Hawaii’s because they have far more land and options for addressing potential impacts.

The engineers and planners who attended the workshop, in concert with the climate scientists, identified the following as Oahu’s five most critical areas of transportation vulnerability:

  1. Honolulu Harbor (and the adjacent roadways of Ala Moana Boulevard and Nimitz Highway)
  2. The Hickam/Honolulu International Airport Complex (including access roadways, drainage, and the tidal effects seen in Mapunapuna)
  3. Access to both Kalaeloa Barbers Point Harbor and Campbell Industrial Park. Campbell Industrial Park, in particular, is at low elevation.
  4. The three bridges providing access to and egress from Waikiki (including the McCully Street Bridge, Kalakaua Avenue Bridge, and Ala Moana Boulevard Bridge.
  5. Lack of system redundancy for multiple access routes to communities, such as Waianae (via Farrington Highway) and Campbell Industrial Park, as well as coastal roadways such as Kamehameha Highway and Kalanianaole Highway.

This is not intended to represent the full listing of all possible transportation infrastructure that may be vulnerable to climate stressors but, based on the experience of the senior engineers and planners as well as climate scientists, these are a valid, representative sample of critical infrastructure components appropriate for this study.

Copies of the presentations given at the March 8-9 workshop may be found at this link.