Physical Char
549
Part C | 25.1
25. Physical Characteristics of Coastal Hazards
Jennifer L. Irish, Robert Weiss, Donald T. Resio
Coastal hazards are among the world’s most
threatening hazards. With half of the world’s population living near the coast, an immense threat
is posed by these hazards to life and health,
livelihood, and the economy. In this chapter,
characteristics of coastal hazards are described,
first by presenting a historical context, then by
laying out our current understanding of the physical problems of interest for coastal design, and
finally by presenting simple methods for initial
interpretation of the hazard. A number of natural
processes and anthropogenic activities adversely
impact coastal communities, critical infrastructure,
and port facilities along the coast. Natural coastal
hazards may generally be classified into those that
are episodic and those that occur over long periods
of time. Episodic hazards include coastal storms
and tsunamis while long-term hazards include,
for example, sea-level rise. Many anthropogenic
activities also result in long-term impacts at the
coast. For example, inland dam construction pro25.1 Types of Coastal Hazards ...................... 549
25.1.1 Coastal Storms........................... 549
25.1.2 Tsunamis .................................. 551
25.1.3 Climate Variability,
Climate Change,
and Sea-Level Rise .................... 553
25.1.4 Anthropogenic Activities ............ 554
25.2 Coastal Impacts ................................... 555
25.2.1 Winds....................................... 555
25.2.2 Wind-Generated Waves ............. 556
25.2.3 Flood Levels and Runup ............. 557
25.2.4 Environmental Impacts .............. 560
25.3 Summary ............................................ 561
25.4 Nomenclature...................................... 561
References................................................... 562
duces long-term impacts on coastal sediment
supply. In the following, we describe the most
common coastal hazards and then discuss methods for evaluating their impacts at the coast.
25.1 Types of Coastal Hazards
25.1.1 Coastal Storms
Coastal storms are categorized either as tropical cyclones, for example, hurricanes, typhoons, or as extratropical cyclones, for example, Nor’easters in the United
States. While both storm types generate high winds,
surges, waves, and precipitation, there are several key
differences between the two.
Tropical Cyclones
Tropical cyclones, which by definition form in the
tropics, are generally well organized and compact.
Thus, tropical cyclones are characterized by moderately
strong to severe winds with the capacity to generate
very large waves and surges. Because they are compact
relative to other storms, the coastal region impacted by
high winds and large surges, and to a lesser extent by
large waves, is typically confined to a distance of the
order of hundreds of kilometers. These storms also tend
to pass fairly quickly across the continental shelf and
coastal region, meaning that the period of high winds
and large surges is generally of the order of hours, while
large waves may persist for several days.
Historically, tropical cyclones have taken hundreds
of thousands of lives and caused extensive destruction. The National Oceanic and Atmospheric Administration’s (NOAA) local forecast official Isaac Cline
(1900) commented on his firsthand experience during
the Galveston Hurricane of 1900 [25.1]:
Sunday, September 9, 1900, revealed one of the
most horrible sights that ever a civilized people
looked upon. About three thousand homes, nearly
half the residence portion of Galveston, had been
completely swept out of existence, and probably
more than six thousand persons had passed from
life to death during that dreadful night. The correct
number of those who perished will probably never
be known, for many entire families are missing.
Where 20 000 people lived on the 8th not a house
549
Part C | 25.1
25. Physical Characteristics of Coastal Hazards
Jennifer L. Irish, Robert Weiss, Donald T. Resio
Coastal hazards are among the world’s most
threatening hazards. With half of the world’s population living near the coast, an immense threat
is posed by these hazards to life and health,
livelihood, and the economy. In this chapter,
characteristics of coastal hazards are described,
first by presenting a historical context, then by
laying out our current understanding of the physical problems of interest for coastal design, and
finally by presenting simple methods for initial
interpretation of the hazard. A number of natural
processes and anthropogenic activities adversely
impact coastal communities, critical infrastructure,
and port facilities along the coast. Natural coastal
hazards may generally be classified into those that
are episodic and those that occur over long periods
of time. Episodic hazards include coastal storms
and tsunamis while long-term hazards include,
for example, sea-level rise. Many anthropogenic
activities also result in long-term impacts at the
coast. For example, inland dam construction pro25.1 Types of Coastal Hazards ...................... 549
25.1.1 Coastal Storms........................... 549
25.1.2 Tsunamis .................................. 551
25.1.3 Climate Variability,
Climate Change,
and Sea-Level Rise .................... 553
25.1.4 Anthropogenic Activities ............ 554
25.2 Coastal Impacts ................................... 555
25.2.1 Winds....................................... 555
25.2.2 Wind-Generated Waves ............. 556
25.2.3 Flood Levels and Runup ............. 557
25.2.4 Environmental Impacts .............. 560
25.3 Summary ............................................ 561
25.4 Nomenclature...................................... 561
References................................................... 562
duces long-term impacts on coastal sediment
supply. In the following, we describe the most
common coastal hazards and then discuss methods for evaluating their impacts at the coast.
25.1 Types of Coastal Hazards
25.1.1 Coastal Storms
Coastal storms are categorized either as tropical cyclones, for example, hurricanes, typhoons, or as extratropical cyclones, for example, Nor’easters in the United
States. While both storm types generate high winds,
surges, waves, and precipitation, there are several key
differences between the two.
Tropical Cyclones
Tropical cyclones, which by definition form in the
tropics, are generally well organized and compact.
Thus, tropical cyclones are characterized by moderately
strong to severe winds with the capacity to generate
very large waves and surges. Because they are compact
relative to other storms, the coastal region impacted by
high winds and large surges, and to a lesser extent by
large waves, is typically confined to a distance of the
order of hundreds of kilometers. These storms also tend
to pass fairly quickly across the continental shelf and
coastal region, meaning that the period of high winds
and large surges is generally of the order of hours, while
large waves may persist for several days.
Historically, tropical cyclones have taken hundreds
of thousands of lives and caused extensive destruction. The National Oceanic and Atmospheric Administration’s (NOAA) local forecast official Isaac Cline
(1900) commented on his firsthand experience during
the Galveston Hurricane of 1900 [25.1]:
Sunday, September 9, 1900, revealed one of the
most horrible sights that ever a civilized people
looked upon. About three thousand homes, nearly
half the residence portion of Galveston, had been
completely swept out of existence, and probably
more than six thousand persons had passed from
life to death during that dreadful night. The correct
number of those who perished will probably never
be known, for many entire families are missing.
Where 20 000 people lived on the 8th not a house