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== Coastal Hazards ==
== Coastal Development Hazards ==


=== Definition of a Hazard in a Coastal context ===
=== Definition of a Hazard in a Coastal context ===


In theoretical terminology the risk of a hazard is the likelihood of an event or incident occurring multiplied by the seriousness of the event or incident if it occurred. The seriousness is controlled by how vulnerable the adversely affected party was to the hazard. Hazard likelihood and vulnerability interact to create this risk <ref name="mac07"/>.<br />
In theoretical terminology the risk of a [[hazard]] is the likelihood of an event or incident occurring multiplied by the seriousness of the event or incident if it occurred. The seriousness is controlled by how vulnerable the adversely affected party was to the hazard. Hazard likelihood and vulnerability interact to create this risk <ref name="mac07"/>.<br />


As coasts become more developed, the vulnerability component of the equation increases as there is more value at risk to the hazard. The likelihood component of the equation also increases in terms of there being more value on the coast so a higher chance of hazardous situation occurring <ref name="SmallandNicholls2003" />. Fundamentally humans create hazards with their presence. In a coastal example, erosion is a process that happens naturally on the Canterbury Bight as a part of the coastal geomorphology of the area and strong long shore currents <ref name="kirk69"/><ref name="hart08" />. This process becomes a hazard when humans interact with that coastal environment by developing it and creating value in that area.<br />
As coasts become more developed, the vulnerability component of the equation increases as there is more value at risk to the hazard. The likelihood component of the equation also increases in terms of there being more value on the coast so a higher chance of hazardous situation occurring <ref name="SmallandNicholls2003" />. Fundamentally humans create hazards with their presence. In a coastal example, [[erosion]] is a process that happens naturally on the [[Canterbury Bight]] as a part of the coastal [[geomorphology]] of the area and strong long shore currents <ref name="kirk69"/><ref name="hart08" />. This process becomes a hazard when humans interact with that coastal environment by developing it and creating value in that area.<br />


In Burton 1978 ''‘The Environment as Hazard’'' a natural hazard is defined as the release of energy or materials that threaten humans or what they value <ref name="burton78" />. In a coastal context these hazards vary temporally and spatially from a rare, sudden, massive release of energy and materials such as a major storm event or tsunami, to the continual chronic release of energy and materials such long-term coastal erosion or sea-level rise <ref name="burton93" /><ref name="fink94" />. It is this type coastal hazard, specifically around erosion and attributes surrounding erosion that this article will focus on.<br />
In Burton 1978 ''‘The Environment as Hazard’'' a natural hazard is defined as the release of [[energy]] or [[materials]] that threaten humans or what they value <ref name="burton78" />. In a coastal context these hazards vary temporally and spatially from a rare, sudden, massive release of energy and materials such as a major [[storm]] event or [[tsunami]], to the continual chronic release of energy and materials such long-term [[coastal erosion]] or [[sea-level rise]] <ref name="burton93" /><ref name="fink94" />. It is this type coastal hazard, specifically around erosion and attributes surrounding erosion that this article will focus on.<br />




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Globally the number of people living on the coast is increasing. It has been stated that there has been over a 35% increase in the population of people living on the coasts since 1995 <ref name="goudarzi06" />. The average density of people in coastal regions is 3 times higher than the global average density <ref name="SmallandNicholls2003" />. Historically city development especially large cities were based on coasts due to the economic benefits of the ports. In 1950 there were only 2 megacities (cities with greater than 8 million people) in the coastal zone, London and New York. By the mid ninety’s there were 13 <ref>NICHOLLS, R. J. 1995. Coastal megacities and climate change. GeoJournal, 37, 369-379.</ref>. Although coastal areas globally have shown population growth and increases in density, very few in-depth quantitative global studies of population have been carried out, especially in terms of distribution across specific environs, like coasts <ref name="SmallandNicholls2003" /><ref>NICHOLLS, R. J. 2002. Improved estimates of coastal population and exposure to hazards released. EOS, Transactions, American Geophysical Union, 83, 301.</ref>. The spatial distribution and accuracy of global data must be significantly improved before realistic quantitative assessments of the global impacts of coastal hazards can be made. As currently much of the data is collected and analysed in the aftermath of disasters <ref>SMALL, C., GORNITZ, V. & COHEN, J. E. 2000. Coastal hazards and the global distribution of human population. Environmental Geosciences, 7, 3.</ref>. <br />
Globally the number of people living on the [[coast]] is increasing. It has been stated that there has been over a 35% increase in the [[population]] of [[people]] living on the coasts since 1995 <ref name="goudarzi06" />. The average [[density]] of people in coastal regions is 3 times higher than the global average density <ref name="SmallandNicholls2003" />. Historically [[city]] development especially large cities were based on coasts due to the [[economic]] benefits of the [[ports]]. In 1950 there were only 2 [[megacities]] (cities with greater than 8 million people) in the [[coastal zone]], [[London]] and [[New York]]. By the mid-nineties there were 13 <ref name="nicholls95" />. Although coastal areas globally have shown population growth and increases in density, very few in-depth quantitative global studies of population have been carried out, especially in terms of distribution across specific environs, like coasts <ref name="SmallandNicholls2003" /><ref name="nicholls02" />. The spatial distribution and accuracy of global data must be significantly improved before realistic quantitative assessments of the global impacts of coastal hazards can be made. As currently much of the data is collected and analysed in the aftermath of [[disasters]] <ref name="smalletal00" />. <br />


Historic studies have put estimates of the number of deaths due to cyclones over the last 200 years around the Bay of Bengal exceeding 1.3 million <ref>NICHOLLS, R. J. 1995. Coastal megacities and climate change. GeoJournal, 37, 369-379.</ref>. However in developed countries, as can be expected, the death toll is significantly lower but the economic losses due to coastal hazards are increasing. The United States for example had major losses in Hurricane Andrew, which hit Florida and Louisiana in 1992 <ref>NICHOLLS, R. J. 2002. Improved estimates of coastal population and exposure to hazards released. EOS, Transactions, American Geophysical Union, 83, 301.</ref>.<br />
Historic studies have put estimates of the number of deaths due to [[cyclones]] over the last 200 years around the [[Bay of Bengal]] exceeding 1.3 million <ref name="nicholls95" />. However in [[developed countries]], as can be expected, the death toll is significantly lower but the economic losses due to coastal hazards are increasing. The United States of America ([[USA]]) for example had major losses in [[Hurricane]] Andrew, which hit [[Florida]] and [[Louisiana]] in 1992 <ref name="nicholls02" />.<br />


This rushing to the coast is exhibited in property value. A study by Bourassa et al. (2004) found in Auckland New Zealand, wide sea views contributed on average an additional 59% to the value of a waterfront property. This effect diminished rapidly the further from the property was from the coast. In another study it was found that moving 150m away from the Gulf of Mexico lowered property values by 36% <ref>BOURASSA, S. C., HOESLI, M. & SUN, J. 2004. What's in a view? Environment and Planning A, 36, 1427-1450.</ref><ref>MILON, J. W., GRESSEL, J. & MULKEY, D. 1984. Hedonic amenity valuation and functional form specification. Land Economics, 60, 378-387.</ref>.<br />
This rushing to the coast is exhibited in [[property value]]. A study by Bourassa et al. (2004) found in [[Auckland]] [[New Zealand]], wide sea views contributed on average an additional 59% to the value of a waterfront property. This effect diminished rapidly the further from the property was from the coast. In another study it was found that moving 150m away from the [[Gulf of Mexico]] lowered property values by 36% <ref name="bourassa04" /><ref name="milon84" />.<br />


Insurance premiums in coastal hazard areas are an inconsequential determinant of property values, given the significant amenity values provided by the coast in terms of views and local recreation. Sea-level rise, coastal erosion, and the exacerbating interaction between these two are likely to pose a significant threat for the loss of capital assets in coastal areas in the future <ref>BIN, O. & KRUSE, J. B. 2006. Real estate market response to coastal flood hazards. Natural Hazards Review, 7, 137.</ref>. It is hard to say if the vulnerability to coastal hazards by those residing there is perceived yet dominated by the amenity value of coasts or simply ignored.<br />
[[Insurance]] premiums in coastal hazard areas are an inconsequential determinant of property values, given the significant amenity values provided by the coast in terms of views and local [[recreation]]. Sea-level rise, coastal erosion, and the exacerbating interaction between these two [[natural]] [[phenomena]] are likely to pose a significant threat for the loss of [[capital assets]] in coastal areas in the future <ref name="binandkruse06" />. It is hard to say if the vulnerability to coastal hazards by those residing there is perceived yet dominated by the amenity value of coasts or simply ignored.<br />




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Coastal erosion is one of the most significant hazards associated with the coast. Not in terms of a rare massive release of energy or material resulting in loss of life, as is associated with tsunami and cyclones, but in terms of a continual chronic release that forms a threat to infrastructure, capital assets and property <ref>CASALE, R. & MARGOTTINI, C. 2003. Natural disasters and sustainable development, New York, Springer-Verlag.</ref><ref name="burton93" />. <br />
Coastal erosion is one of the most significant hazards associated with the coast. Not in terms of a rare massive release of energy or material resulting in loss of life, as is associated with tsunami and cyclones, but in terms of a continual chronic release that forms a threat to infrastructure, capital assets and property <ref name="casaleandmarg03" /><ref name="burton93" />. <br />




=== Beach Erosion Process ===
=== Beach Erosion Process ===


Storm induced large erosion events are a part of the natural evolutionary process of fine sediment, gently sloping beaches. Increased wave energy in storms leads to the removal of foreshore, berm and dune sediments. These displaced sediments are then deposited as near shore bars and act to dampen the wave energy lessoning the amount of sediment that is being eroded from the coast. When wave energies decrease post storm events, the sediments from these newly deposited near shore bars are returned to the upper beach, rebuilding the berm. This self-correcting cycle is an active balance between wave energies and fine sediment deposition <ref name="hart08" />. This store of sediment being available for erosion in storms and re-depositing when the event has subsided is an important natural buffer mechanism against protecting the mainland from erosion and minimising coastal retreat <ref>(Carboni et al., 2009)</ref><ref>( Bell and Gorman, 2003)</ref>. <br />
Storm induced large erosion events are a part of the natural [[evolutionary]] process of fine [[sediment]], gently sloping [[beaches]]. Increased [[wave energy]] in storms leads to the removal of [[foreshore]], [[berm]] and [[dune]] sediments. These displaced sediments are then deposited as near [[shore]] [[bars]] and act to dampen the wave energy lessoning the amount of sediment that is being eroded from the coast. When wave energies decrease post storm events, the sediments from these newly deposited near shore bars are returned to the upper beach, rebuilding the berm. This self-correcting [[cycle]] is an active balance between wave energies and fine sediment [[deposition]] <ref name="hart08" />. This store of sediment being available for erosion in storms and re-depositing when the event has subsided is an important natural [[buffer]] [[mechanism]] against protecting the [[mainland]] from erosion and minimising coastal retreat <ref name="carbonietal09" /><ref name="bellgorman03" />. <br />




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Sand dunes are very dynamic fragile structures that act as stores of sediment used to carry out the coastal processes mentioned above. This removal of the upper beach sediments is important from a hazard perspective as this is the area of the coast that is often utilised for property development due to the high prices sea front properties with a view can achieve <ref>(Bourassa et al., 2004)</ref>. In Pegasus Bay, New Zealand, storm events in 1978 and 2001 caused significant erosion of the New Brighton and Waimairi sand beaches. In the 1978 storm event houses on the seaward side of the New Brighton Spit suffered from undercutting as the dune sediment in which they were built on was eroded by high wave energy <ref name="hart08" />. This same storm event caused similar erosion damage to houses built on the upper dunes in Raumati, on the west coast of the North Island, New Zealand <ref name="kirk2001" /><ref>( Wright, 1988)</ref>. Bulldozing and bulk removal of sand from protective coastal dunes is therefore an extremely hazardous activity, and one that has been widely carried out in New Zealand in order to form a surface on which to build on to obtain sea views <ref name="kirk2001" />. <br />
[[Sand dunes]] are very [[dynamic]] [[fragile]] structures that act as stores of sediment used to carry out the coastal processes mentioned above. This removal of the upper beach sediments is important from a hazard perspective as this is the area of the coast that is often utilised for property development due to the high prices sea front properties with a view can achieve <ref name="bourassa04" />. In [[Pegasus Bay]], New Zealand, storm events in 1978 and 2001 caused significant erosion of the [[New Brighton]] and Waimairi sand beaches. In the 1978 storm event houses on the seaward side of the New Brighton Spit suffered from undercutting as the dune sediment in which they were built on was eroded by high wave energy <ref name="hart08" />. This same storm event caused similar erosion damage to houses built on the upper dunes in [[Raumati Beach]], on the [[west coast]] of the [[North Island]], New Zealand <ref name="kirk2001" /><ref name="wright88" />. Bulldozing and bulk removal of sand from protective coastal dunes is therefore an extremely hazardous activity, and one that has been widely carried out in New Zealand in order to form a surface on which to build on to obtain sea views <ref name="kirk2001" />. <br />



=== Canterbury Bight ===
=== Canterbury Bight ===




In Kirk (2001) coastal erosion on the Canterbury bight, South Canterbury was said to have reached up to 8 m per year. This coastal process could be measured in more ways than one, the afore mentioned distance of coastal retreat or the decreased dollar value of developed assets, land and infrastructure that are at risk <ref name="kirk2001" />. To date, erosion on the Canterbury Bight has led to the loss of agricultural land, threatened valuable infrastructure including holiday settlements, and reduced coastal lagoons and wetlands <ref>(Environment Canterbury (ECan), 2005)</ref>.<br />
In Kirk (2001) coastal erosion on the Canterbury bight, South Canterbury was said to have reached up to 8 m per year. This coastal process could be measured in more ways than one, the afore mentioned distance of coastal retreat or the decreased [[dollar]] value of developed assets, land and [[infrastructure]] that are at risk <ref name="kirk2001" />. To date, erosion on the Canterbury Bight has led to the loss of [[agricultural land]], threatened valuable infrastructure including [[holiday]] [[settlements]], and reduced coastal lagoons and wetlands <ref name="ecan05" />.<br />


Historically, erosion on the Canterbury Bight was a natural process, but has now been exacerbated by human intervention. The Waitaki River was the dominant source of sediments for the beaches between Oamaru and Timaru. Since the damming of the Waitaki River in 1935 erosion of the coastal cliffs has become the primary source of sediment in the north flowing current moving up the coast of south Canterbury <ref name="kirk2001" />.<br />
Historically, erosion on the Canterbury Bight was a natural process, but has now been exacerbated by human intervention. The [[Waitaki River]] was the dominant source of sediments for the beaches between [[Oamaru]] and [[Timaru]]. Since the damming of the Waitaki River in 1935 erosion of the coastal cliffs has become the primary source of sediment in the north flowing current moving up the coast of [[South]] [[Canterbury]] <ref name="kirk2001" />.<br />




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This destruction of sand dunes is often then mitigated with construction of seawalls, revetments and groynes in often futile attempts to prevent storm erosion hazards to unsuitably located assets and infrastructure on coasts. These engineered methods are commonly ineffective and frequently actually magnify the hazard or just move the hazard down coast. In Porthcawl, South Wales, a seawall constructed to stop erosion in 1887 was replaced in 1906, 1934 and finally in 1984 when the beach was paved as each prior structure was undermined by further erosion. The loss of aesthetics due to the lack of a sand beach resulted in tourists utilising alternative beaches. Therefore incurring an even greater economic loss on top of the cost of the engineering <ref>(Phillips and Jones, 2006)</ref>.<br />
This [[destruction]] of [[sand dunes]] is often then [[mitigated]] with [[construction]] of [[seawalls]], [[revetments]] and [[groynes]] in often futile attempts to prevent storm erosion hazards to unsuitably located assets and infrastructure on coasts. These [[engineered]] methods are commonly ineffective and frequently actually [[magnify]] the hazard or just move the hazard down coast. In [[Porthcawl]], [[South Wales]], a seawall constructed to stop erosion in 1887 was replaced in 1906, 1934 and finally in 1984 when the beach was paved as each prior structure was undermined by further erosion. The loss of [[aesthetics]] due to the lack of a sand beach resulted in [[tourists]] utilising alternative beaches. Therefore incurring an even greater economic loss on top of the cost of the engineering <ref name="phillip&jones06" />.<br />




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The alternative to hard engineering measures is sand dune conservation. This involves protecting the sand dunes and allowing the natural buffering processes to occur. Dune protection and conservation can be facilitated in a number of ways, actively with dune planting and sand fencing, or with better planning by developing away from or well behind the dune structures not on them <ref>(Bergin and Kimberley, 1999)</ref><ref>( Grafals-Soto and Nordstrom, 2009)</ref>. On the New Brighton Spit the spread of marram grass ''(Ammophila arenaria)'' has resulted in effective dune stabilisation in areas. However this invasive exotic species has mostly replaced indigenous species like pingao ''(Desmoschoenus spiralis)'' meaning that although the stability of the coastal area has gained the historic, native cultural values of the area have suffered <ref>(Bergin and Kimberley, 1999)</ref><ref name="kirk2001" />.<br />
The alternative to hard engineering measures is sand dune [[conservation]]. This involves [[protecting]] the sand dunes and allowing the natural buffering processes to occur. Dune protection and conservation can be facilitated in a number of ways, actively with [[dune]] [[planting]] and [[sand]] [[fencing]], or with better [[planning]] by developing away from or well behind the dune structures not on them <ref name="bergin&kim99" /><ref name="grafals-sotoandnordstrom09" />. On the New Brighton [[Spit]] the spread of [[marram grass]] ''(Ammophila arenaria)'' has resulted in effective dune [[stabilisation]] in areas. However this [[invasive]] [[exotic]] [[species]] has mostly replaced [[indigenous]] species like [[pingao]] ''(Desmoschoenus spiralis)'' meaning that although the [[stability]] of the coastal area has gained, the [[historic]], [[native]] [[cultural]] [[values]] of the area have suffered <ref name="bergin&kim99" /><ref name="kirk2001" />.<br />




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A further soft-engineering method for protecting the shoreline is beach nourishment, due to cost this is a solution that has been used primarily for the benefit of the tourism industry <ref>(Phillips and Jones, 2006)</ref>. As a result of erosion Miami Beach had almost no stored sediment left by the mid 1970’s, consequently, visitor numbers declined and development of the area decreased. A beach nourishment program was setup resulting in an influx of development and infrastructure in the late 1970s. Miami Beach was rejuvenated to such an extent that annual revenue from foreign tourists alone is $2.4 billion, compared to the $52 million cost of the 20-year nourishment project. Tax revenue from tourists who visit Miami Beach alone more than covers the cost of beach nourishment projects across the nation. Using the capitalised annual cost of the project, for every $1 that has been invested annually on the nourishment, Miami Beach has received almost $500 annually in foreign exchange <ref>(Phillips and Jones, 2006)</ref><ref>( Houston, 2002)</ref>.<br />
A further soft-engineering method for protecting the [[shoreline]] is [[beach nourishment]], due to cost this is a solution that has been used primarily for the [[benefit]] of the tourism [[industry]] <ref name="phillip&jones06" />. As a result of erosion [[Miami Beach]] had almost no stored sediment left by the mid 1970’s, consequently, visitor numbers declined and development of the area decreased. A beach nourishment program was setup resulting in an [[influx]] of development and infrastructure in the late 1970s. Miami Beach was rejuvenated to such an extent that annual [[revenue]] from [[foreign]] tourists alone is $2.4 billion, compared to the $52 million cost of the 20-year nourishment project. [[Tax]] revenue from tourists who visit Miami Beach alone more than covers the cost of beach nourishment projects across the [[nation]]. Using the capitalised annual cost of the project, for every $1 that has been invested annually on the nourishment, Miami Beach has received almost $500 annually in foreign exchange <ref name="phillip&jones06" /><ref name="Houston02" />.<br />


== Notes ==
== See also ==
* [[Coast#Human impacts|Human Impacts on Coasts]]
* [[Current sea level rise]]
* [[Erosion]]
* [[World population|Global population]]
* [[Natural hazard]]
* [[Dune#Coastal dunes|Sand Dunes]]
* [[Sand dune stabilization|Dune Restoration]]
* [[Hard Engineering]]
* [[Coastal Management]]
* [[Integrated coastal zone management|ICZM]]
* [[Beach nourishment]]

== References ==
{{Reflist|refs=
{{Reflist|refs=
<ref name="SmallandNicholls2003">Small and Nicholls (2003)</ref>
<ref name="SmallandNicholls2003">SMALL, C. & NICHOLLS, R. J. 2003. A global analysis of human settlement in coastal zones. Journal of Coastal Research, 19, 584-599.</ref>
<ref name="kirk2001">Kirk (2001)</ref>
<ref name="kirk2001">KIRK, R. 2001. Marine processes and coastal landforms. The physical environment: a New Zealand perspective.</ref>
<ref name="burton93">Burton et al. (1993)</ref>
<ref name="burton93">BURTON, I., KATES, R. W. & WHITE, G. F. 1993. The Environment as Hazard, The Guilford Press.</ref>
⚫
<ref name="hart08">HART, D., MARSDEN, I., FRANCIS, M., WINTERBOURNE, M., KNOX, G. A. & BURROWS, C. 2008. Coastal Systems: Natural History of Canterbury. 653-684.</ref>
<ref name="hart08">Hart et al. (2008)</ref>
<ref name="kirk69">Kirk (1969)</ref>
<ref name="kirk69">KIRK, R. 1969. Beach erosion and coastal development in the Canterbury Bight. New Zealand Geographer, 25, 23-35.</ref>
⚫
<ref name="mac07">MACCOLLUM, D. V. 2007. Construction safety engineering principles: designing and managing safer job sites, McGraw-Hill Professional.</ref>
<ref name="mac07">MacCollum (2007)</ref>
<ref name="burton78">Burton et al. (1978)</ref>
<ref name="burton78">BURTON, I., KATES, R. W. & WHITE, G. F. 1978. The Environment as Hazard, New York, Oxford University Press.</ref>
<ref name="fink94">Finkl (1994)</ref>
<ref name="fink94">FINKL, C. W. 1994. Coastal hazards: perception, susceptibility and mitigation, Coastal Education & Research Foundation.</ref>
<ref name="goudarzi06">Goudarzi (2006)</ref>
<ref name="goudarzi06">GOUDARZI, S. 2006. Flocking to the coast: world’s population migrating into danger. Live Science.</ref>
⚫
<ref name="nicholls95">NICHOLLS, R. J. 1995. Coastal megacities and climate change. GeoJournal, 37, 369-379.</ref>
⚫
<ref name="nicholls02">NICHOLLS, R. J. 2002. Improved estimates of coastal population and exposure to hazards released. EOS, Transactions, American Geophysical Union, 83, 301.</ref>
⚫
<ref name="smalletal00">SMALL, C., GORNITZ, V. & COHEN, J. E. 2000. Coastal hazards and the global distribution of human population. Environmental Geosciences, 7, 3.</ref>
⚫
<ref name="bourassa04">BOURASSA, S. C., HOESLI, M. & SUN, J. 2004. What's in a view? Environment and Planning A, 36, 1427-1450.</ref>
⚫
<ref name="milon84">MILON, J. W., GRESSEL, J. & MULKEY, D. 1984. Hedonic amenity valuation and functional form specification. Land Economics, 60, 378-387.</ref>
⚫
<ref name="binandkruse06">BIN, O. & KRUSE, J. B. 2006. Real estate market response to coastal flood hazards. Natural Hazards Review, 7, 137.</ref>
⚫
<ref name="casaleandmarg03">CASALE, R. & MARGOTTINI, C. 2003. Natural disasters and sustainable development, New York, Springer-Verlag.</ref>
⚫
<ref name="phillip&jones06">PHILLIPS, M. R. & JONES, A. L. 2006. Erosion and tourism infrastructure in the coastal zone: Problems, consequences and management. Tourism Management, 27, 517-524.</ref>
⚫
<ref name="bergin&kim99">BERGIN, D. O. & KIMBERLEY, M. O. 1999. Rehabilitation of coastal foredunes in New Zealand using indigenous sand-binding species. Science for Conservation.</ref>
⚫
<ref name="carbonietal09">CARBONI, M., CARRANZA, M. L. & ACOSTA, A. 2009. Assessing conservation status on coastal dunes: A multiscale approach. Landscape and Urban Planning, 91, 17-25.</ref>
⚫
<ref name="bellgorman03">BELL, R. G. & GORMAN, R. 2003. Coastal hazards. Tephra 20 (June), 21–26.</ref>
⚫
<ref name="wright88">WRIGHT, L. W. 1988. The Sand Country of the ‘Golden Coast’, Wellington, New Zealand. New Zealand Geographer, 44, 28-31.</ref>
⚫
<ref name="ecan05">Environment Canterbury (ECan) 2005. Regional Coastal Environment Plan for the Canterbury Region. 238.</ref>
⚫
<ref name="grafals-sotoandnordstrom09">GRAFALS-SOTO, R. & NORDSTROM, K. 2009. Sand fences in the coastal zone: Intended and unintended effects. Environmental Management, 44, 420-429.</ref>
⚫
<ref name="Houston02">HOUSTON, J. R. 2002. The economic value of beaches-a 2002 update. Shore and Beach, 70, 9-12.</ref>
}}
}}


== References ==
== External Links ==

⚫
*BELL, R. G. & GORMAN, R. 2003. Coastal hazards. Tephra 20 (June), 21–26.<br />

⚫
*BERGIN, D. O. & KIMBERLEY, M. O. 1999. Rehabilitation of coastal foredunes in New Zealand using indigenous sand-binding species. Science for Conservation.<br />

⚫
*BIN, O. & KRUSE, J. B. 2006. Real estate market response to coastal flood hazards. Natural Hazards Review, 7, 137.<br />

⚫
*BOURASSA, S. C., HOESLI, M. & SUN, J. 2004. What's in a view? Environment and Planning A, 36, 1427-1450.<br />

*BURTON, I., KATES, R. W. & WHITE, G. F. 1978. The Environment as Hazard, New York, Oxford University Press.<br />

*BURTON, I., KATES, R. W. & WHITE, G. F. 1993. The Environment as Hazard, The Guilford Press.<br />

⚫
*CARBONI, M., CARRANZA, M. L. & ACOSTA, A. 2009. Assessing conservation status on coastal dunes: A multiscale approach. Landscape and Urban Planning, 91, 17-25.<br />

⚫
*CASALE, R. & MARGOTTINI, C. 2003. Natural disasters and sustainable development, New York, Springer-Verlag.<br />

⚫
*ENVIRONMENT CANTERBURY (ECAN) 2005. Regional Coastal Environment Plan for the Canterbury Region. 238.<br />

*FINKL, C. W. 1994. Coastal hazards: perception, susceptibility and mitigation, Coastal Education & Research Foundation.<br />

*GOUDARZI, S. 2006. Flocking to the coast: world’s population migrating into danger. LiveScience.<br />

⚫
*GRAFALS-SOTO, R. & NORDSTROM, K. 2009. Sand fences in the coastal zone: Intended and unintended effects. Environmental Management, 44, 420-429.<br />

⚫
*HART, D., MARSDEN, I., FRANCIS, M., WINTERBOURNE, M., KNOX, G. A. & BURROWS, C. 2008. Coastal Systems: Natural History of Canterbury. 653-684.<br />

⚫
*HOUSTON, J. R. 2002. The economic value of beaches-a 2002 update. Shore and Beach, 70, 9-12.<br />

*KIRK, R. 1969. Beach erosion and coastal development in the Canterbury Bight. New Zealand Geographer, 25, 23-35.<br />

*KIRK, R. 2001. Marine processes and coastal landforms. The physical environment: a New Zealand perspective <br />

⚫
*MACCOLLUM, D. V. 2007. Construction safety engineering principles: designing and managing safer job sites, McGraw-Hill Professional.<br />

⚫
*MILON, J. W., GRESSEL, J. & MULKEY, D. 1984. Hedonic amenity valuation and functional form specification. Land Economics, 60, 378-387.<br />

⚫
*NICHOLLS, R. J. 1995. Coastal megacities and climate change. GeoJournal, 37, 369-379.<br />

⚫
*NICHOLLS, R. J. 2002. Improved estimates of coastal population and exposure to hazards released. EOS, Transactions, American Geophysical Union, 83, 301.<br />

⚫
*PHILLIPS, M. R. & JONES, A. L. 2006. Erosion and tourism infrastructure in the coastal zone: Problems, consequences and management. Tourism Management, 27, 517-524.<br />


{{coastal management}}
⚫
*SMALL, C., GORNITZ, V. & COHEN, J. E. 2000. Coastal hazards and the global distribution of human population. Environmental Geosciences, 7, 3.<br />


[[:Category:Coastal engineering]]
*SMALL, C. & NICHOLLS, R. J. 2003. A global analysis of human settlement in coastal zones. Journal of Coastal Research, 19, 584-599.<br />


[[ru:Закрепление песков]]
⚫
*WRIGHT, L. W. 1988. The Sand Country of the ‘Golden Coast’, Wellington, New Zealand. New Zealand Geographer, 44, 28-31.

Latest revision as of 23:19, 9 June 2020

Coastal Development Hazards

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Definition of a Hazard in a Coastal context

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In theoretical terminology the risk of a hazard is the likelihood of an event or incident occurring multiplied by the seriousness of the event or incident if it occurred. The seriousness is controlled by how vulnerable the adversely affected party was to the hazard. Hazard likelihood and vulnerability interact to create this risk [1].

As coasts become more developed, the vulnerability component of the equation increases as there is more value at risk to the hazard. The likelihood component of the equation also increases in terms of there being more value on the coast so a higher chance of hazardous situation occurring [2]. Fundamentally humans create hazards with their presence. In a coastal example, erosion is a process that happens naturally on the Canterbury Bight as a part of the coastal geomorphology of the area and strong long shore currents [3][4]. This process becomes a hazard when humans interact with that coastal environment by developing it and creating value in that area.

In Burton 1978 ‘The Environment as Hazard’ a natural hazard is defined as the release of energy or materials that threaten humans or what they value [5]. In a coastal context these hazards vary temporally and spatially from a rare, sudden, massive release of energy and materials such as a major storm event or tsunami, to the continual chronic release of energy and materials such long-term coastal erosion or sea-level rise [6][7]. It is this type coastal hazard, specifically around erosion and attributes surrounding erosion that this article will focus on.


Coastal population growth and development on coasts

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Globally the number of people living on the coast is increasing. It has been stated that there has been over a 35% increase in the population of people living on the coasts since 1995 [8]. The average density of people in coastal regions is 3 times higher than the global average density [2]. Historically city development especially large cities were based on coasts due to the economic benefits of the ports. In 1950 there were only 2 megacities (cities with greater than 8 million people) in the coastal zone, London and New York. By the mid-nineties there were 13 [9]. Although coastal areas globally have shown population growth and increases in density, very few in-depth quantitative global studies of population have been carried out, especially in terms of distribution across specific environs, like coasts [2][10]. The spatial distribution and accuracy of global data must be significantly improved before realistic quantitative assessments of the global impacts of coastal hazards can be made. As currently much of the data is collected and analysed in the aftermath of disasters [11].

Historic studies have put estimates of the number of deaths due to cyclones over the last 200 years around the Bay of Bengal exceeding 1.3 million [9]. However in developed countries, as can be expected, the death toll is significantly lower but the economic losses due to coastal hazards are increasing. The United States of America (USA) for example had major losses in Hurricane Andrew, which hit Florida and Louisiana in 1992 [10].

This rushing to the coast is exhibited in property value. A study by Bourassa et al. (2004) found in Auckland New Zealand, wide sea views contributed on average an additional 59% to the value of a waterfront property. This effect diminished rapidly the further from the property was from the coast. In another study it was found that moving 150m away from the Gulf of Mexico lowered property values by 36% [12][13].

Insurance premiums in coastal hazard areas are an inconsequential determinant of property values, given the significant amenity values provided by the coast in terms of views and local recreation. Sea-level rise, coastal erosion, and the exacerbating interaction between these two natural phenomena are likely to pose a significant threat for the loss of capital assets in coastal areas in the future [14]. It is hard to say if the vulnerability to coastal hazards by those residing there is perceived yet dominated by the amenity value of coasts or simply ignored.


Coastal erosion hazards

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Coastal erosion is one of the most significant hazards associated with the coast. Not in terms of a rare massive release of energy or material resulting in loss of life, as is associated with tsunami and cyclones, but in terms of a continual chronic release that forms a threat to infrastructure, capital assets and property [15][6].


Beach Erosion Process

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Storm induced large erosion events are a part of the natural evolutionary process of fine sediment, gently sloping beaches. Increased wave energy in storms leads to the removal of foreshore, berm and dune sediments. These displaced sediments are then deposited as near shore bars and act to dampen the wave energy lessoning the amount of sediment that is being eroded from the coast. When wave energies decrease post storm events, the sediments from these newly deposited near shore bars are returned to the upper beach, rebuilding the berm. This self-correcting cycle is an active balance between wave energies and fine sediment deposition [4]. This store of sediment being available for erosion in storms and re-depositing when the event has subsided is an important natural buffer mechanism against protecting the mainland from erosion and minimising coastal retreat [16][17].


Dune Destruction

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Sand dunes are very dynamic fragile structures that act as stores of sediment used to carry out the coastal processes mentioned above. This removal of the upper beach sediments is important from a hazard perspective as this is the area of the coast that is often utilised for property development due to the high prices sea front properties with a view can achieve [12]. In Pegasus Bay, New Zealand, storm events in 1978 and 2001 caused significant erosion of the New Brighton and Waimairi sand beaches. In the 1978 storm event houses on the seaward side of the New Brighton Spit suffered from undercutting as the dune sediment in which they were built on was eroded by high wave energy [4]. This same storm event caused similar erosion damage to houses built on the upper dunes in Raumati Beach, on the west coast of the North Island, New Zealand [18][19]. Bulldozing and bulk removal of sand from protective coastal dunes is therefore an extremely hazardous activity, and one that has been widely carried out in New Zealand in order to form a surface on which to build on to obtain sea views [18].

Canterbury Bight

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In Kirk (2001) coastal erosion on the Canterbury bight, South Canterbury was said to have reached up to 8 m per year. This coastal process could be measured in more ways than one, the afore mentioned distance of coastal retreat or the decreased dollar value of developed assets, land and infrastructure that are at risk [18]. To date, erosion on the Canterbury Bight has led to the loss of agricultural land, threatened valuable infrastructure including holiday settlements, and reduced coastal lagoons and wetlands [20].

Historically, erosion on the Canterbury Bight was a natural process, but has now been exacerbated by human intervention. The Waitaki River was the dominant source of sediments for the beaches between Oamaru and Timaru. Since the damming of the Waitaki River in 1935 erosion of the coastal cliffs has become the primary source of sediment in the north flowing current moving up the coast of South Canterbury [18].


Erosion Mitigation

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Engineered Structures

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This destruction of sand dunes is often then mitigated with construction of seawalls, revetments and groynes in often futile attempts to prevent storm erosion hazards to unsuitably located assets and infrastructure on coasts. These engineered methods are commonly ineffective and frequently actually magnify the hazard or just move the hazard down coast. In Porthcawl, South Wales, a seawall constructed to stop erosion in 1887 was replaced in 1906, 1934 and finally in 1984 when the beach was paved as each prior structure was undermined by further erosion. The loss of aesthetics due to the lack of a sand beach resulted in tourists utilising alternative beaches. Therefore incurring an even greater economic loss on top of the cost of the engineering [21].


Restorative Dune Planting

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The alternative to hard engineering measures is sand dune conservation. This involves protecting the sand dunes and allowing the natural buffering processes to occur. Dune protection and conservation can be facilitated in a number of ways, actively with dune planting and sand fencing, or with better planning by developing away from or well behind the dune structures not on them [22][23]. On the New Brighton Spit the spread of marram grass (Ammophila arenaria) has resulted in effective dune stabilisation in areas. However this invasive exotic species has mostly replaced indigenous species like pingao (Desmoschoenus spiralis) meaning that although the stability of the coastal area has gained, the historic, native cultural values of the area have suffered [22][18].


Beach Nourishment

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A further soft-engineering method for protecting the shoreline is beach nourishment, due to cost this is a solution that has been used primarily for the benefit of the tourism industry [21]. As a result of erosion Miami Beach had almost no stored sediment left by the mid 1970’s, consequently, visitor numbers declined and development of the area decreased. A beach nourishment program was setup resulting in an influx of development and infrastructure in the late 1970s. Miami Beach was rejuvenated to such an extent that annual revenue from foreign tourists alone is $2.4 billion, compared to the $52 million cost of the 20-year nourishment project. Tax revenue from tourists who visit Miami Beach alone more than covers the cost of beach nourishment projects across the nation. Using the capitalised annual cost of the project, for every $1 that has been invested annually on the nourishment, Miami Beach has received almost $500 annually in foreign exchange [21][24].

See also

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References

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  1. ^ MACCOLLUM, D. V. 2007. Construction safety engineering principles: designing and managing safer job sites, McGraw-Hill Professional.
  2. ^ a b c SMALL, C. & NICHOLLS, R. J. 2003. A global analysis of human settlement in coastal zones. Journal of Coastal Research, 19, 584-599.
  3. ^ KIRK, R. 1969. Beach erosion and coastal development in the Canterbury Bight. New Zealand Geographer, 25, 23-35.
  4. ^ a b c HART, D., MARSDEN, I., FRANCIS, M., WINTERBOURNE, M., KNOX, G. A. & BURROWS, C. 2008. Coastal Systems: Natural History of Canterbury. 653-684.
  5. ^ BURTON, I., KATES, R. W. & WHITE, G. F. 1978. The Environment as Hazard, New York, Oxford University Press.
  6. ^ a b BURTON, I., KATES, R. W. & WHITE, G. F. 1993. The Environment as Hazard, The Guilford Press.
  7. ^ FINKL, C. W. 1994. Coastal hazards: perception, susceptibility and mitigation, Coastal Education & Research Foundation.
  8. ^ GOUDARZI, S. 2006. Flocking to the coast: world’s population migrating into danger. Live Science.
  9. ^ a b NICHOLLS, R. J. 1995. Coastal megacities and climate change. GeoJournal, 37, 369-379.
  10. ^ a b NICHOLLS, R. J. 2002. Improved estimates of coastal population and exposure to hazards released. EOS, Transactions, American Geophysical Union, 83, 301.
  11. ^ SMALL, C., GORNITZ, V. & COHEN, J. E. 2000. Coastal hazards and the global distribution of human population. Environmental Geosciences, 7, 3.
  12. ^ a b BOURASSA, S. C., HOESLI, M. & SUN, J. 2004. What's in a view? Environment and Planning A, 36, 1427-1450.
  13. ^ MILON, J. W., GRESSEL, J. & MULKEY, D. 1984. Hedonic amenity valuation and functional form specification. Land Economics, 60, 378-387.
  14. ^ BIN, O. & KRUSE, J. B. 2006. Real estate market response to coastal flood hazards. Natural Hazards Review, 7, 137.
  15. ^ CASALE, R. & MARGOTTINI, C. 2003. Natural disasters and sustainable development, New York, Springer-Verlag.
  16. ^ CARBONI, M., CARRANZA, M. L. & ACOSTA, A. 2009. Assessing conservation status on coastal dunes: A multiscale approach. Landscape and Urban Planning, 91, 17-25.
  17. ^ BELL, R. G. & GORMAN, R. 2003. Coastal hazards. Tephra 20 (June), 21–26.
  18. ^ a b c d e KIRK, R. 2001. Marine processes and coastal landforms. The physical environment: a New Zealand perspective.
  19. ^ WRIGHT, L. W. 1988. The Sand Country of the ‘Golden Coast’, Wellington, New Zealand. New Zealand Geographer, 44, 28-31.
  20. ^ Environment Canterbury (ECan) 2005. Regional Coastal Environment Plan for the Canterbury Region. 238.
  21. ^ a b c PHILLIPS, M. R. & JONES, A. L. 2006. Erosion and tourism infrastructure in the coastal zone: Problems, consequences and management. Tourism Management, 27, 517-524.
  22. ^ a b BERGIN, D. O. & KIMBERLEY, M. O. 1999. Rehabilitation of coastal foredunes in New Zealand using indigenous sand-binding species. Science for Conservation.
  23. ^ GRAFALS-SOTO, R. & NORDSTROM, K. 2009. Sand fences in the coastal zone: Intended and unintended effects. Environmental Management, 44, 420-429.
  24. ^ HOUSTON, J. R. 2002. The economic value of beaches-a 2002 update. Shore and Beach, 70, 9-12.
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Category:Coastal engineering

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