Vulnerable Coasts

Shorelines are subject to destructive forces that erode the banks. Houses originally constructed at a comfortable distance from the edge may eventually end up perched precariously above the beach, often supported by poles extending downslope. Such structures frequently collapse following an extreme weather event or normal coastline erosion. Usually during winter, heavy storm waves 

FIGURE 11.1 Coastal regions are subject to damage from storm surges, normal erosive processes, and human influences. Much of the damage and loss stems from unwise construction practices along the coastline. 

The most valued part of a coastline is often the sandy beach. Sand is washed into the ocean as the result of weathering of silicon-rich quartz and feldspar rocks upstream and distributed along the shoreline by the action of ocean currents and waves. Human intervention has reduced the amount of sand available. Dams built on streams trap sand as sediment, depriving the ocean of its source of sand. Improper beach management can result in loss of beach sand. The term littoral cell applies to a region of shoreline that includes inflow of sand from a stream or from seacliff erosion, transport of sand generally parallel to the coast by ocean currents and wave action, and eventual loss of sand from the coastal region. 

About 40% of Japan s 32,000-km coastline is protected by seawalls designed primarily to hold back tsunamis caused by earthquakes. Much of the damage from the March 11 earthquake off the coast of Sendai, Japan, occurred when seawalls were breached by the tsunami that followed. Large areas of farmland were contaminated by seawater as a result. 

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Titus J. G. and Richman C. (2000) Maps of lands vulnerable to sea level rise Modeled elevation along US Atlantic and Gulf coasts. Climate Res. 18, 205—228. 

Berger AR, Schaumburg HH, Schroeder C, et al. (1992) Dose response, coasting, and differential fiber vulnerability in human toxic neuropathy A prospective study of pyridoxine neurotoxicity. Neurology 42(7) 1367-1370. 

Seals, sea lions, and walruses are particularly vulnerable to oiling because they live on the shorelines of small islands, rocks, or remote coasts with few options for new territory. Despite this, only the young are killed by severe oiling. 

Du, W. Mathur, A.P. 1998. Vulnerability Testing of Software System Using Fault Injection. COAST technical report. West Lafayette Purdue University. 

Some coastal environments may be regarded as rather stable (rock and reef coasts) while others are more vulnerable (sand and mud coasts, soft cliffs). In this last case, coastal users and managers aU over the world are frequently faced with serious erosion of their sandy coasts. Possible causes of erosion include natural processes (i.e., action of waves, tides, currents, sea level rise, etc.) and sediment deficit due to human impact (i.e., river regulations, sand mining, and coastal engineering works). Countermeasmes for beach erosion control function depend on local conditions of shore and beach, coastal chmate, and sediment transport. Continuous maintenance and improvement of the coasthnes, together with monitoring and studies of coastal processes have yielded considerable experience on various coastal protection measures all over the world. 

Crescent City harbor, located in northern Cahfornia, is one of the oldest harbors in Cahfornia. The surrounding area is well known for its tsimami vulnerability. Due to its location and topography along the Pacific coast (Fig. 25.2), many have described it as a sitting duck for tsunami waves originated from the Pacific Ocean. It was severely damaged by tsunamis in the past such as the one generated by Alaskan earthquake in 1964, in which 11 people were killed and the property loss was estimated to be tens of million US dollars.Most recently, another heavy loss... 

Eisenbcrg, N. A., C. J. Lynch, and R. J. Breeding (1975). CG-D-136-75 and NTIS AD-015-245 Vulnerability Model A Simulation Systemfir Assessing Danube Resulting from Marine Spills. U.S. Coast Guard. 

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