Coastal Solutions

On our last day, we toured the eastern and southern Upolu coasts, where the tsunami had its biggest impact. We were struck by the widespread devastation, not dissimilar from that of hurricanes (cyclones). In a few low-lying locations there was evidence that the tsunami reached inland approximately 1 kilometer.

Unlike in American Samoa (Tutuila), there were long, straight stretches of sandy beaches. In many of these beach communities, the tsunami caused total damage to both beach fales and the residential homes located on the landward side of the coastal road.

Rubble-mound revetments lined much of the coastal area. Due to the relatively small stone size, these revetments were heavily damaged by the tsunami in most areas. For example, in Satitoa, on the eastern coast, stones were strewn across the coast, with many stones transported tens of meters inland.

Toward the end of the day, we stopped in Poutasi, a small coastal village situated just to the east of a National Park. Unlike some of the totally devastated coastal communities to the east, damage to residences and public buildings in Poutasi varied from total destruction to partial destruction. This was likely due to a relatively lower flood depth in this region. Of note was a newly constructed home on the beach which appeared to be structurally sound, although damage to windows and interior walls was evident. The village church also sustained some damage; indicated by destruction of lower window-panes only, the water level reached about midway up the wall.

At the end of the day we returned to Apia via the cross-island road, stopping at our host’s plantation to pick fresh bananas for the following day’s breakfast.

– ASCE/COPRI tsunami assessment team

Lesley Ewing, P.E., Team Leader, Coastal Engineer, California Coastal Commission

Jennifer L. Irish, Ph.D., P.E.; Assistant Professor, Texas A&M University

On arrival in Western Samoa we were struck by both the marked landscape and cultural differences between Western and American Samoa. An independent country with a population of 170,000, Western Samoa has a more urban and touristic feel than its American counterpart. The mountains of Upolu, the most populated of the Western Samoan islands, are less constraining than those in American Samoa (Tutuila). This afforded the opportunity for communities to relocate and spread into higher ground in response to the devastating cyclones of 1990 and 1991. Thus, residential villages along the Upolu coast were, in general, more dispersed, and many had residences spread through upland as well as coastal areas.

During this first day in Western Samoa, we met with another ASCE member, Bill Gordon, and his business partner Tom Tinai of Tinai, Gordon, and Associates LTD, based in the urban center Apia. Bill and Tom shared their local knowledge on coastal, transportation and residential construction and then we talked about structural performance during the tsunami.

Of particular note, they told us about Bailey bridge, built originally for a stream crossing on the north coast and recently relocated to Salani. While sustaining some abutment toe-protection damage, the bridge maintained its structural and functional integrity during the tsunami, even though the tsunami waves reached the bridge deck— which we later confirmed during our site visit.

– ASCE/COPRI tsunami assessment team

Lesley Ewing, P.E., Team Leader, Coastal Engineer, California Coastal Commission

Jennifer L. Irish, Ph.D., P.E.; Assistant Professor, Texas A&M University