Economic Costs of Long-Term Sea Level Rise on the
Oregon Coast: A Case Study of the Siletz Littoral Cell
by
William K. Fleck
Project Report
Submitted To
Marine Resource Management Program
College of Oceanic & Atmospheric Sciences
Oregon State University
Corvallis, Oregon 97331
September 25, 2004
in partial fulfillment
of the requirements for the degree of
Master of Science
June 2005
Acknowledgements
Thanks to Jim Good and Richard Adams for having a great amount of patience
throughout my time here at Oregon State University. I would also like to thank them
for there guidance and contributions to this project.
A special thanks to Randy Rosenberger for being my third committee member
on such short notice.
Thanks to Steve Williams with the Oregon Parks and Recreation Department
for his assistance with the shore protection structure aspect of this project. The data he
provided, although small, was crucial in enabling me to perform the economic aspects
of this project.
Thanks to JISAO for the funding they provided for the Year 1 of this project
and for providing me with such an interesting project.
Thanks to Joy Burk, Irma Delson, and Laurie Jodice for the continual and
much appreciated support throughout the years.
Thanks to my parents for their love and support in all my pursuits in life!
Finally, I am saving the biggest thanks of all to my girlfriend Erika who gave
me the inspiration and motivation to finish my project. E, we did it! B. And, I would
also like to thank my great group of friends for supporting me with their friendship:
Griz & Gayle, Lays & Les, Nathan, Michelle & Dave, Roger & Sarah, Granna & the
Professor, and most of all, my buddy for life, Woofer!
Table of Contents
Acknowledgements
ii
Table of Contents
List of Figures
List of Tables
List of Photos
vi
Abstract
vii
Introduction
1
Background
3
Climate Variability and Long-term Change 3
Global Warming
4
Pacific Decadal Oscillations (PDO)
6
El-Nino-Southern Oscillation (ENSO) 7
Climate, Sea Level Rise, and the Oregon Coast 10
Impacts of Sea Level Rise
10
Oregon's Chronic Hazard Vulnerabilities
11
Case Study Selection Criteria
13
Responses to Sea Level Rise
14
Oregon's Policy Response to Coastal Erosion
Oregon's Beaches and the Coastal Tourism Industry
ii
16
17
Methods
21
Objectives
21
Study Area Description: Siletz littoral cell 23
Physical Description
23
Development Trends
24
Coastal Hazards History
24
SPS Status Methods
26
SLR Impact Methods
27
Economic Costs Methods
28
Results and Discussion
29
Option #1: Protect Only
33
General discussion
33
Costs for SPSs
33
Lost Expenditure Costs
34
Aggregate Economic Costs of Protect Only Option
37
Option #2: Protect-Beach Nourishment
39
General Discussion
39
Costs of Beach Nourishment
39
Aggregate Economic Costs of Protect-Beach Nourishment Option 44
Option #3: Gradual Retreat
44
General discussion
44
Asset Inventory- Property Value Information 45
SPS Status and Retreat Costs
47
Aggregate Economic Costs of Gradual Retreat Option 48
Conclusions and Recommendations 50
List of References
54
Appendix A: Lincoln County Assessors' Office Property Information 57
Appendix B: Beach Inundation Scenarios for Siletz littoral cell 58
Appendix C: Siletz Cell Nourishment Costs
59
Appendix D: Beach Nourishment Project Costs 61
iv
List of Figures
Figure 1- Canadian global climate change model 5
Figure 2- PDO Index for the 20th century
6
Figure 3- ENSO Index
8
Figure 4- Normal vs. El-Nino conditions in the equatorial Pacific 9
Figure 5- Average sea level vs. major El-Nino sea level 12
Figure 6- Average wave height for Oregon
12
Figure 7- Elevation change along the Oregon coast
13
Figure 8- Wave direction in littoral cells
14
Figure 9- Total visitation rates for Siletz littoral cell 20
Figure 10- Siletz littoral cell looking south from Cascade Head 23
Figure 11- Cumulative SPS construction for Siletz 26
Figure 12- Case study from the north looking south 30
Figure 13- Case Study from the south looking north 31
Figure 14- Sample of erosion within the case study (-23 rd Street)
31
Figure 15- Commercial structure in case study (21 st Street)
32
Figure 16- Residential homes in case study (33rd Street)
32
Figure 17- Interior lots in the case study (33 rd Street)
46
List of Tables
Table 1- Typical responses to sea level rise 15
Table 2- Visitation rates for recreation sites in the Siletz littoral cell 19
Table 3- Annual revenue for Siletz recreation sites 35
Table 4- Beach recreation expenditure studies 35
Table 5- Protect option cost streams and PV scenarios 38
Table 6- Historic sand supply calculations 42
Table 7- Future sand supply blocked by SPSs and nourishment costs 43
Table 8- Retreat costs for Siletz littoral cell 49
Table 9- Comparison of present values: 20-year scenario 53
Table 10- Comparison of present values: 50-year scenario 53
vi
Abstract
Given the broad scientific consensus that global climate is changing, it is no longer a
question if sea level will rise, but rather by how much will it rise. The regional
estimates for the Eastern Pacific suggest that the Northwest coastlines will experience
a greater eustatic sea level rise than most areas, with 50-year estimates of sea level rise
on the order of 0.3 meters. This rise in sea level, while not extraordinary, will
exacerbate an already ongoing coastal erosion problem in the region. The majority of
Northwest ocean shoreline is experiencing tectonic uplift that more than negates the
effects of sea level rise. However, there are portions of the Oregon coast that have
essentially zero uplift and it is these locations that are already experiencing severe
episodic erosion problems. The typical response to coastal erosion along the Oregon
coast has been to install hard shore protection structures (SPSs). The Siletz littoral cell,
the case study, is one such case. It is one of the most developed portions of the Oregon
coast and is already more than half protected by SPSs. The trend for this area has
closely mimicked episodic climatic events in that after such events there are bursts of
SPS construction. The risk with such an approach is that there will, over the long-term,
be a narrowing and eventual loss of oceanfront beaches. Because the Oregon coast is
highly dependent on tourism and travel for its economic base, the loss or decrease in
the beach resource would have a substantial effect on the region's economy. More than
2 million visitors recreate annually just within our case study area—the Siletz cell
beaches. There have been attempts to place economic value on non-consumptive uses
such as beach recreation in other parts of the country, but not in the Pacific Northwest.
vii
Given the potential adverse impacts of fixing the shoreline in place with hard SPSs,
this option designed to protect uplands (not beaches) should not be the only
management choice utilized to address the issue of coastal erosion in the region.
This project starts the process of comparing other options to the typical option of
hardening, from an economic perspective. An analysis of the different options was
conducted for 20-year and 50-year scenarios. The results show that in the 20-year
scenario, the 'protect' option is clearly the least costly option due to the existing high
levels of development and it makes economic sense to protect the existing
infrastructure. However, the results for the 50-year scenario show an interesting cost
shift taking place between two of the options. The low range of the 'retreat' option is
now more favorable economically then the low end of the 'protect' only option. The
conclusion is that over a longer time frame, it simply becomes costlier in losing more
beach visitors than it is to continue protecting the existing infrastructure.
viii
Introduction
The coastal zone has always been a favored location for settlement. Centuries
ago the draw of this region was the great biological productivity and access to
transportation via ship. Although people have settled inland as well, today they are still
drawn to the coast for its bountiful recreational activities and more moderate climates.
A study of coastal populations shows that while coastal counties comprise only 17
percent of the land area in the contiguous United States, they are home to more than 53
percent of the total U.S. population (Culliton, 1998). Population growth rates of
coastal counties are generally not greater than other areas of the country, however, the
absolute number of people living in the coastal zone continues to increase
significantly.
Despite its attractiveness, there are inherent dangers associated with living in a
dynamic region like the coast. These dangers can express themselves in dramatic
fashion, as is the case with hurricanes and tsunamis, or they can occur gradually over
the long-term as is the case with global warming, sea level rise, erosion, and beach
narrowing, the focus of this paper. Both kinds of processes are problems for the
growing coastal populations and damages associated with each can reach into the
billions of dollars. The scientific community is making significant progress in
understanding how these processes work, but there still is a long way to go to achieve
good predictability, particularly at regional scales.
The goal of this paper is to further the understanding of climate change impacts
by attempting to assess and quantify the economic costs of sea level rise on the Oregon
coast for available adaptation options. Another goal is to provide an economic
perspective to policymakers, planners, and the public about the long-term risks,
impacts, and costs associated with sea level rise and help guide decision making.
The first section provides the reader with general information related to climate
change and variability, focusing on three primary time scales: long-term, decadal, and
inter-annual. Each of these will be introduced, with the focus being on the longer time
scale changes related to global warming and sea level rise. This is followed with a
discussion of the general impacts associated with sea level rise, and the factors that
make the Oregon coast especially vulnerable. Given these general impacts, the
available responses to sea level rise for threatened shorelines are explained from both
physical and political perspectives. Why this is of importance to Oregon's beaches and
the coastal tourism industry and how this could impact local economies is discussed.
Finally, this section concludes by introducing the valuation terminology, definitions,
and techniques used to determine the economic valuations of environmental amenities
such as beach recreation.
The second section outlines the methods utilized for the various portions of the
project. Part one starts with a description of the case study including its physical
characteristics and latest development trends. The second part describes the history of
shore protection structures (SPSs) along the Oregon coast, followed by the manner in
which the SPS status was updated and analyzed. The third part discusses how the
impacts associated with sea level rise will vary with each option. A comparison of the
different approaches taken by various states is presented. The last part describes the
specific economic valuation techniques that were used to determine the costs for each
option.
2
The third section discusses the results for the three options that were selected:
protect, protect with sand nourishment, and gradual retreat. Each option starts with a
general discussion in which the assumptions for each option are clearly defined. The
advantages and disadvantages of each option are discussed. Finally, the analysis is
presented along with the findings, which includes the present value of the economic
costs associated with each option.
Finally, the fourth section includes the conclusions and recommendations. This
compares the present value economic costs for all three options for both a 20-year and
50-year time period. The recommendations portion discusses a possible fourth option
and numerous recommendations directed toward local and state municipalities.
Background
Climate Variability and Long-term Directional Change
Climate variability and change generally occurs over three different time
scales: long-term, intermediate, and inter-annual. Global warming, Pacific Decadal
Oscillations (PDO), and El-Nino-Southern Oscillation (ENSO) serve as the primary
examples of each of these time scales and each will be introduced and their potential
impacts assessed. The discussion starts with global warming because it is the hardest
to predict, yet it provides a 'big picture' of the potential impacts of sea level rise. We
end our discussion with the short-term time scale because much more information is
known about El Nino and the temporarily elevated sea level that accompanies these
events. This provides us with a "snapshot" about what life at the beach might be like
in the future with higher sea level year-round.
3
Long-term time scale: Global Warming
For the last several decades, global warming and what to do about it has been
one of the most contentious of global environmental issues. Human activities have
substantially increased the atmospheric concentrations of the so-called greenhouse
gases: carbon dioxide, methane, chlorofluorocarbons, and nitrous oxide. Carbon
dioxide concentrations have increased 25% since pre-industrial times, methane
concentrations have doubled, and chlorofluorocarbons have been introduced into the
atmosphere for the first time. Warming occurs when these gases are trapped in the
atmosphere and block the escape of the earth's radiation to space. This process is better
known as the "greenhouse effect"(Edgerton, 1991). Some of the ramifications of
global warming include shifting temperatures across land masses, changes in
precipitation patterns, melting of the polar icecaps, and rising sea levels. The focus for
this project is the last outcome, rising sea levels.
Unfortunately, global warming is difficult to predict due to the long time frame
and inherent uncertainty. Numerous general circulation models (GCMs) have been
designed in an attempt to predict climate change patterns around the world. These
ocean predictors change various factors such as future temperature and precipitation
patterns. Using these GCMs as a starting point, other simulations have attempted to
predict the amount and rate of sea level rise caused by global warming temperature
scenarios. One model that looks at the potential changes that might occur in the
Eastern Pacific is the Canadian Regional Climate Model. This model suggests that the
greatest rise in sea level is going to occur in the Eastern Pacific (Figure 1). This
4
Canadian model predicts that by the Year 2091 the Eastern Pacific will rise by almost
0.7 meters or approximately 2.3 feet.
Figure 1: Canadian regional climate model (Canada, 2002)
Research has added some certainty to the subject because originally the
question was if sea level was rising. Now, it is no longer a question of whether sea
level will rise, rather at what rate it is rising. The global sea level is currently estimated
to be rising at an average rate of 5mm/year, within a range of uncertainty of 1.5-9
mm/year (IPCC, 2001). However, as seen from the Canadian GCM, there are
significant regional differences that need to be accounted for. This paper uses the
range from the Intergovernmental Panel on Climate Change (IPCC) study and the
figures from the Canadian GCM. These sea level rise forecasts can be found in the
Beach Inundation Scenario Table in Appendix B.
Intermediate-term time scale: The Pacific Decadal Oscillation
The Pacific Decadal Oscillation (PDO) is a recently discovered and named
phenomenon that has been occurring for the past couple of centuries. Causes for the
PDO are not currently known. Likewise, the potential predictability for this climate
oscillation is not known. What is understood is that it consists of two major phases: a
warm (positive) phase and a cold (negative) phase. Figure 2 shows the PDO Index
since 1900. According to this index, there have been two complete PDO cycles with
each phase of each cycle lasting between 20-30 years (Mantua, 2004).
Figure 2: PDO Index for the 20th century with anomalies shown in degrees Celsius
(Mantua, 2004).
In a warm phase (1925-1950 and –1975-2000), the Pacific Northwest
experiences below normal air temperature and sea level pressure, and above normal
coastal region sea surface temperatures (SSTs). As a result of these climatic changes,
the mountainous regions have reduced snow pack levels in winters, which in turn
result in lower than normal river discharge levels. For coastal areas, mean sea level
will be higher on average due to the higher than normal water temperatures, resulting
in more severe coastal erosion. However, because there are reduced discharge levels
from the rivers, bay-side erosion may be less severe.
In a cold phase (historically -4900-1925 and –1950-1975), the Pacific
Northwest experiences above normal air temperature and sea level pressure, and below
normal coastal region SSTs. The mountainous regions receive enhanced snow pack
levels, which result in higher than normal water discharge levels from rivers. For
coastal areas, mean sea level will be lower on average due to the below normal water
temperatures, resulting in less severe coastal erosion. However, with increased
discharge levels from the rivers, bay-side erosion may be exacerbated.
The interaction between the PDO and the ENSO climate patterns are clearly
related but not yet fully understood. How these different climatic events constrain or
impact each other remains to be seen.
Inter-annual Variability time scale: El-Nino-Southern Oscillation (ENSO)
ENSO is a disruption of the ocean-atmosphere system in the tropical Pacific
having important consequences for weather around the globe. Of all the climate
change activities discussed, ENSO is by far the most well understood phenomenon.
Several decades ago, ENSO was thought to be no more then a shift in currents and a
warming of the ocean waters west of South America, of interest only because it caused
extensive fish kills off the coast of Peru. No one imagined that an ENSO event had
such far-reaching consequences, especially such a major role in beach erosion along
7
the west coast of the United States (Komar, 1997). The ENSO index in Figure 3 shows
the patterns of this climatic event since 1950 (NOAA, 2004). The major El-Nino
events from 1982-83 and 1997-98 are obvious.
El Nino and La Nina are opposite phases of the El Nino-Southern Oscillation
(ENSO) cycle, with La Nina sometimes referred to as the cold phase of ENSO and El
Nino as the warm phase of ENSO. El Nifios are initiated by the breakdown of the
equatorial trade winds in the central and western Pacific. Shortly after the winds stop
blowing, the water surface that it was exerting a force against is released. This creates
an eastward flow of warm water known as a Kelvin Wave. This wave moves along the
equator toward the coast of Peru and once it reaches and collides with the South
American land mass the flow splits into two waves. One heads to the North and the
other to the South. These waves maintain their amplitude for many physical and
scientific reasons. The important point is that this heightened wall of water moves
unimpeded up along the West coast, elevating water levels and increasing storm
intensities. A comparison of normal versus El-Nino conditions in the equatorial Pacific
is shown in Figure 4. It will be explained later how this also increases the northward
transport of sand along Oregon beaches.
NOM/R.4E1 /TAO
Figure 4: Normal vs. El-Nino conditions in the equatorial Pacific (NOAA, 2004)
El Nino episodes occur roughly every four-to-five years and can last up to 12to-18 months. It has been nearly four years since the end of the 1997-1998 El Nino,
which was followed by three years of La Nina. La Nina conditions involve unusually
cold ocean temperatures in the Equatorial Pacific, cooler than normal temperatures,
and increased precipitation. It should be noted that La Nina's do not always necessarily
follow an El Nino and the intensities can vary from event to event (NOAA, 2004).
Climate, Sea Level Rise, and the Oregon Coast
What does global climate change and sea level rise mean to the Oregon coastal
environment? The remainder of this paper focuses on the impacts of sea level rise on
the coast and examines Oregon's vulnerabilities and coastal hazard history.
Impacts of Sea Level Rise
The principal environmental effects of sea level rise will be the erosion of
beaches, bluffs, and dunes, inundation of low-lying areas like small islands or
subsiding delta areas, saltwater intrusion into aquifers and surface waters, higher water
tables, and increased flooding and storm intensities and damage. Wholesale losses of
coastal wetlands can also be expected, particularly along low-lying coasts like
Louisiana (Leatherman, 2001). Wetlands are lost when a shoreline is protected with
hardened SPSs, as there is little to no room for wetlands to migrate upland. SPSs are
structures that restrict the natural migration of the shore landward, as is the situation
with coastal erosion. Consequently, wetlands get squeezed against these SPSs until
they are inundated by the rising seas. Finally, numerous natural habitats will be
10
impacted and altered due to intensified flooding and greater intrusion of saltwater into
estuaries and coastal aquifers. Estuaries serve multiple functions along coastal regions.
The functions relevant to the Oregon coast include serving as nursery grounds for
commercially valuable fish and shellfish species, and as effective systems for the
dispersal of pollutants. These latter impacts are important and demand further
research, but are beyond the scope of this project as the focus is on coastal erosion
along ocean beaches.
Oregon's Chronic Hazard Vulnerabilities
The Pacific Northwest coastline is known for its high wave energy and severity
of storms. Development along Oregon's coast has historically been threatened by
many types of chronic natural hazards. These include beach and dune erosion, sea cliff
recession, bluff slumping and landslides, and coastal flooding (Johnson, 1998). Longterm sea level rise is expected to exacerbate all of the above conditions and increase
the vulnerability of the Oregon coast with increased erosion, flooding, and higher
levels of property damage. Much of Oregon's coastal erosion has occurred in
conjunction with ENSO events. Comparing mean sea level for the Oregon coast during
an 'average' year and the ENSO events of 1982-83 and 1997-98 illustrates why
(Figure 5). Increases up to 20 inches occur during El-Niflos typically within 4-6
months (Komar, 1997). Research on El-Nirios over several hundred years shows that
strong to very strong events occur every 8-9 years (Quinn et al., 1987 as cited in Good,
1992).
11
Figure 5: Average sea level vs. major El-Nino sea level (Komar, 1997)
Another trend that increases the vulnerability of Oregon's coasts is an
increasing average wave height (Figure 6). Over the past 25 years, the average wave
height off the Oregon coast has increased almost three-quarters of a meter. Whether or
not this can be attributed to climatic changes is another question that needs further
research, but the potential of larger waves hitting the Oregon coast could greatly
exacerbate the coastal erosion problem.
Figure 6: Average wave height for Oregon (Allan & Komar, 2000)
Case Study Selection Criteria
The Siletz littoral cell was selected as a case study for several reasons. For one,
this region has been extensively developed and has a long history of shore protection
and coastal erosion. The Oregon coast is experiencing tectonic uplift along
approximately two-thirds of its shoreline (Figure 7). The southern half of the Oregon
coast is rising faster than the recent global rate of sea level rise, and most of the
northern half of the coast is being submerged by the rising sea (Komar, 1997). Not
surprisingly, it is this northern half of the coast that is experiencing the worst cases of
coastal erosion. Siletz littoral cell location is marked on Figure 7 with an asterisk.
Figure 7: Elevation change along the Oregon coast (Komar, 1997)
Secondly, the beaches in the Siletz area are some of the most popular in
Oregon and littoral cells offer a great opportunity for independent study. The majority
of sand remains trapped between the headlands and is either transported into the bay or
on or off shore. It is thought that the major headlands prevent most sand from being
transported north or south of an individual cell. This sand movement is highly
dependent on the seasons as sand generally is transported to the north during the
winter and to the south during the summer (Figure 8).
Figure 8: Wave direction and sand movement for a typical Oregon coast littoral cell
(Komar, 1997)
Finally, the Siletz littoral cell serves as a great example for assessing the
cumulative economic costs of having a hardened shoreline in relation to beach loss and
the availability of it for recreation.
Responses to Sea Level Rise
Most municipalities around the U.S. and virtually all along the Oregon coast,
did not take sea level rise into account when they developed comprehensive land-use
plans and established construction setbacks. In addition, some proposed and platted
development sites fall well within flood and coastal erosion zones. Until recently, the
Federal Emergency Management Agency (FEMA) was essentially promoting this type
of development by offering subsidized flood insurance. This changed on May 1, 1999
when FEMA published a final rule that increased the insurance rates for riskier type
properties such as oceanfront or flood zone properties (Federal Register, 1999).
However, the principal portion of the Siletz littoral cell that would be affected by this
rule is the sand spit enclosing Siletz Bay (Salishan), and that shoreline is fully
protected with SPSs (Good, 1992). In addition to this federal policy change, perhaps
the erosion associated with the latest El-Nino (97-98) will create the increased
awareness needed to facilitate consideration of climate variability and change factors
into the management and planning process (JISAO, 1999).
When a community does prepare for sea level rise through planning, there
generally three policy choices in response to sea level rise (Table 1).
Table 1: Typical responses to sea level rise (Fankhauser, 1995).
Retreat
abandon or move back structures in currently developed areas,
resettle the inhabitants, and require that any new development be
set back specific distances from the shore, as appropriate.
Accommodate
continue to occupy and use vulnerable areas, but accept the greater
degree of flooding and erosion.
Protect
defend vulnerable areas, especially population centers, economic
activities, and natural resources.
15
The optimal protection strategy will vary depending on the coastline and its
characteristics. Every coastline faces a different set of circumstances, such as the level
of development, the presence of natural resources, and the rate of tectonic movement
(uplift or subsidence). The optimal policy response to sea level rise is really a problem
of regional coastal zone management (Turner, Doktor, and Adger, 1995). The one
scenario that seems to be consistent on a region-wide basis assumes that if extensive
development already exists, then the protect strategy is generally economically
justifiable. That assumption is tested later in this report.
Oregon's Policy Response to Coastal Erosion
Public policies have often addressed natural hazard mitigation without
incorporating climate change and variability. For example, in response to beach
development, state legislators aimed to protect the public's access to Oregon beaches
by implementing and regulating the use of SPSs through the 1967 Beach Law and
associated permit program. This law created a permanent public recreational easement
to the ocean shore—the wet and dry sand beach from low water up to the vegetation
line. It also declared a public interest in the aesthetic qualities of the beach, thereby
enacting the permit program for shore protection structures (Good, 1992). The other
major Oregon policy affecting beaches, the Statewide Planning Goals, are standards
for comprehensive planning and set requirements on how land-use decisions are to be
made. Specifically, Goal 18 (Beaches and Dunes), Goal 17 (Shorelands), and Goal 7
(Natural Hazards) were enacted to address coastal natural hazards, ocean shore
protection, and to protect beach access and recreation. Relevant to this project is Goal
16
18's requirement that permits for beachfront protective structures be issued only where
"development" existed on January 1, 1977. It defined development as houses,
commercial and industrial buildings, and vacant subdivision lots which are physically
improved through construction of streets and provision of utilities to the lot, or areas
where special exceptions have been approved (Oregon LCDC, 1977).
Oregon's beaches are located primarily in littoral cells or pocket beaches. The
management/policy regime that created numerous policy objectives were supposed to
consider cumulative impacts and long-term considerations on events that will impact
beaches. It failed to do this because SPS permits are issued on an individual basis and
to date there still is no statewide setback requirement for developed properties. Each
jurisdiction handles it differently (e.g., Lincoln City and Lincoln County for the Siletz
Cell).
Oregon's Beaches and the Coastal Tourism Industry
Over the past several decades, tourism has become increasingly important to
Oregon's economy. Some regions within Oregon depend on tourism more than others
and the coast is one of them. One of the big attractions for visitors is the length and
access of the public beaches. Visitors traveling to the Oregon coast represent a
substantial component of the region's economic base. The Siletz littoral cell, being
centrally located along the coast, draws from Oregon residents (Corvallis, Salem, and
Portland Metro areas), as well as out-of-state and international visitors. The two
primary economic engines for Lincoln City and surrounding areas are tourism and
retirement (Chamber of Commerce, 1999). In 2002, 26.3% of employment in Lincoln
17
County was travel and tourism generated (Runyan, 2002). As might be expected,
tourism is highly seasonal, with the majority of the visitations occurring during the late
spring, summer, and early fall months. Visitation rates at day use parks and waysides
from 1993-2003 for the Siletz littoral cell show that visitor numbers have averaged
2,115,736 per year (Figure 8). Graphically, a noticeable downward trend in visitation
rates is observed, with a 17% decrease overall and a 1.5% per year decrease from 1993
to 2003 (Figure 9). More recent years (1998-2003) show a smaller annual decline of
only 0.4%/year. While there are likely many possible explanations for these visitation
trends, one contributing factor might be sea level rise and the consequent narrowing of
the beaches in the Siletz cell. Another factor might be a change in the type of visitors
and their activities, such as visitors to the Chinook Winds Casino, which was built
around 1995. However, the drop in visitation rates appears to have started before the
Casino was finished. Again, there are many potential reasons why beach visitation
rates are declining and this will require further study. It should be noted that a similar
trend was observed for the entire North Lincoln County area, including Newport to the
south.
18
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Methods
Objectives
The Third Assessment Report of the IPCC made specific note that little
progress had been made in costing and valuation methodologies between 1995
(Second Assessment Report) and 2001. This international perspective stated that much
work was needed to fill the large research gap of our inability to quantify the costs and
benefits of climate change on the economy. Some recommendations for future work
included:
•
increased consideration of community characteristics (e.g., socio-economic,
political, cultural) in costing studies, to provide policy-makers with a better
understanding of the regional impacts of climate change;
•
improved understanding and quantification of the connections between
sectors and regions;
•
enhanced estimates for losses involving non-market goods;
•
incorporation of vulnerability and the process of adaptation in the models;
•
evaluation of the importance of extreme events and climate variability; and
•
examination of the role of adaptive capacity in influencing the magnitude
and nature of climate change costs (of both impacts and adaptation)(IPCC,
2001).
21
The objectives of this project begin to address several of these needs. The three
primary objectives are as follows:
1. To evaluate the status of shore protection construction in the Siletz
Cell, determine whether or not the current trends are as expected,
greater than, or less than the historic trends.
2. To estimate the physical impact of long-term SLR on beaches of the
Siletz littoral cell.
3. To estimate the economic costs of possible beach narrowing and loss.
Case Study Area: The Siletz Littoral Cell
Physical Description
The 16-mile Siletz littoral cell is bounded on the north by Cascade Head and
on the south by Government Point, two erosion-resistant basalt headlands that
effectively isolate it from adjacent cells (Figure 10). The majority of the cell is fronted
by beaches with the primary stretch of beach extending 12.5 miles from Roads End at
the north to Fishing Rock at the south, with the only major interruption being the
mouth of the Siletz River at Siletz Bay. The cell contains two major coastal
drainages—the Siletz and Salmon Rivers—and several minor ones. Sea cliffs back the
beach along nearly 10 mi of the cell, averaging more then 50 ft in elevation (MSL).
Dune fields are found on the Salmon River spit at the very north end of the cell and the
Siletz spit in the central part of the cell (Good, 1992). It appears that much of the sand
on the present-day shore has been derived from erosion of sea cliffs with a smaller
22
portion of the sand budget being supplied by the Siletz and Salmon River outflows
(Komar, 1997).
Figure 10: Siletz littoral cell looking south from Cascade Head (J. Good photo)
Development Trends
The Siletz littoral cell is one of the most extensively developed and heavily
protected areas along the Oregon coast, with nearly continuous residential,
commercial, and recreational beachfront development. There are 874 buildable lots
located in this area which includes Lincoln City and the unincorporated communities
of Roads End, Salishan, Gleneden Beach, and Lincoln Beach. As of 1991, only 25% of
these lots were undeveloped (Good, 1992). To obtain a current estimate of
undeveloped lots and other information, a 1-mile sample population was analyzed.
From this, it is estimated that only 10% of the lots remain undeveloped. Other
information estimated from this sample includes the approximation that 75% of the
developed properties are single-family residential dwellings, and the other 25% consist
of motels and multi-family dwellings.
Coastal Hazards History
As revealed by a series of aerial photographs of the Siletz spit, a natural cycle
of erosion events existed well before its development occurred in the 1960s. This
natural cycle consisted of intermittent erosion events typically followed by a long
period of foredune rebuilding. Historically, the major erosion problems in the Siletz
cell have taken place along the Salishan spit and just to the south along Lincoln and
Gleneden beaches due to a combination of beach characteristics and ocean processes.
Developments first started appearing along the spit in the early 1960s. During each
erosion period, the maximum period of erosion corresponded to the largest storm wave
heights, demonstrating that this is the primary cause of erosion (Komar 1997). The
formation of numerous rip embayments, coupled with the fact that the beaches in this
part of the cell consist of coarser sand, caused them to respond more rapidly than finesand beaches to storm waves, and as a result underwent dramatic profile changes
(Komar, 1997). The other type of erosion affecting the spit is that of erosion on the
bay-side of the spit caused by the drainage of the Siletz River. This type of erosion has
been exacerbated due to the landfills in Siletz Bay for new developments in the late
1960s. These landfills prevent river floodwaters from spilling into the south part of the
bay. This causes the same volume of river outflow to be funneled out a narrower
portion of the mouth, with less time to dissipate, thereby forcing it into the back side
24
of the spit. As most of the spit is currently "hardened" on both sides, the erosion has
lessened substantially, however, in many areas the natural sand has been replaced by a
mound of rocks (Komar, 1997).
Even though the extent of erosion of the spit has been constrained by riprap
protective structures, coastal erosion is still affecting the beaches themselves and the
uplands along cliff-backed portions of the cell. All areas of the cell, except the
northernmost portion around the Salmon River mouth (foreground of Figure 10), are
experiencing cliff erosion. For example, the portion of the cell north of the Siletz Bay
mouth is experiencing cliff erosion at a rate of approximately 3-10 cm/year (Komar,
1997). As cliffs are more resistant to erosion than dune backed bluffs, it took longer
for erosion to become a hazardous event. The 1982-83 El-Nino was considered a
strong event and its high-powered storms and wave levels exacerbated the amounts of
erosion along these cliffs. As events like these are predicted to occur more frequently
under climate change, there clearly is a need to better understand the impact climate
change and variability will have on the coastal hazards.
SPS Status Methods
Along with development comes the risk of structures on the upland being
affected by natural processes such as coastal erosion. For the past several decades, the
typical response to coastal erosion has been to install shore protection structures
(SPSs). Figure 11 shows the cumulative mileage of SPSs that have been built between
1967 and 1991 (Good, 1992).
25
Figure 11: Cumulative length of and annual contribution to SPS construction along the
Siletz littoral cell.
To determine the current SPS status in the Siletz littoral cell, two primary
sources were utilized. Good (1992) provided detailed data on SPS construction rates
and linear footage from 1967 through 1991, as seen in Figurell. The second source
was the recently updated SPS database developed by the Oregon Parks and Recreation
Department (Steve Williams, pers. comm, 2004). However, the database was
structured such that comparable data to Good (1992) was available. Thus, while it
would have been ideal to get a year-by-year update for SPS construction, the only data
readily available was the total SPS linear footage to date. With this number, numerous
rates were determined, including the rates from 1991 thru the present, as well as the
historical rate of 1967 thru the present.
The trends revealed in the above data show that the rate of SPS construction
has varied greatly since 1967. Overall, from 1967 thru the present, SPS construction
was built at approximately 800 linear feet per year. Data from OPRD for the 19912003 period revealed a construction slowdown to just less than 400 linear feet per
year, when only one major El Nino event took place. During the period of 1967-1991,
when SPS construction occurred at the rate of just over 1000 linear feet per year, there
were three major El Nifios. Therefore, this project assumed that the future SPS
construction rate will follow the historical pattern of 800 linear feet per year.
Maintenance of SPSs will vary depending on which policy option is selected.
SLR Impact Methods
The impact of sea level rise on the shoreline depends primarily on how humans
choose to deal with it. The states of Maine, North Carolina, and South Carolina have
enacted legislation prohibiting the use of hardened SPSs in combating coastal erosion.
Numerous other states have enacted minimum setback requirements based on historic
erosion rates. However, some states, like Maryland, fully support hardened shore
protection structures when managing coastal erosion. The end result is that Maryland
will face drastically different impacts than states that have restricted SPS use as a
shoreline management response. Oregon has prohibited SPS construction for
properties developed after 1977. The impacts of SLR on the Siletz littoral cell will be
assessed for three different policy scenarios: (1) protect, (2) protect with beach
nourishment, and (3) gradual retreat of development from the shoreline.
27
Economic Costs Methods
To account for the economic costs of SLR in the Siletz Cell, several economic
data sources and techniques were utilized. For the Siletz situation, cost data from other
studies and projects are being used. There are several conditions that need to be met in
using other studies/projects. Some of these include pursuing similar measurements of
value for similar amenities, ensuring the markets for both the study site and policy
sites should be the same, and making sure the data being 'transferred' is drawn from
an adequate number of individual studies (Rosenberger & Loomis, 2000). Other
sources of economic estimates, (e.g., for construction of riprap revetments) come from
numerous local contractors and the Lincoln County assessor's office.
As noted above, there are several approaches used to determine the impacts of
sea level rise. The following case study methodology and steps for economic analysis
will be adhered to as closely as possible:
1. Development of regional scenarios of relative sea level change
2. Development of an analysis linking relative sea level change with zonespecific physical hazards- flooding, inundation, and erosion;
3. Subdivision of the hazard zone into separate physiographic units, based on
the risk of flooding and erosion
4. Collection of asset data for the hazard zone, in order to establish an
inventory of natural and artificially constructed capital assets;
5. Quantification and evaluation of the in-place sea defense and coastal
protection system in the hazard zone;
6. Definition of relative sea level change response options and an assessment
of their impact on coastal hazards and assets in the zone;
7. Economic valuation of the costs of the various response options, including
the 'do nothing' option (Turner, Doktor, and Adger, 1995).
28
This case study methodology enables coastal communities to walk through the
economic valuation process and determine the best course of action, or inaction, in
some cases. Research within this project focuses on Steps 6 and 7, with informed
assumptions and data drawn from other sources to meet the requirements of steps 1-5.
In calculating the present value of costs for each scenario, we use a 3%
discount rate and a 7% discount rate for valuing environmental resources. The high
end of the range (7%) is used to reflect expected inflation of benefits and costs. The
low end of the range is what is currently being used to value other natural resources
like wildlife refuges (OMB, 2004).
Results and Discussion
The three options analyzed for this project are protect, protect with beach
nourishment, and gradual retreat. In performing the economic analysis for each of
these options, it was necessary to select a smaller sample population (case study)
within the Siletz littoral cell to make the assessment manageable. Specifically, the
sample population is a one mile section located in the Lincoln City area (from 16th
Street up to 34th Street). This area was selected because it is an uninterrupted stretch of
development consisting of mostly residential and small commercial properties. The
following photos show various views of this stretch of beach as well as typical
properties that are in this case study section (Figures 12 to 16).
29
Figure 12: Case study from the north looking south
Figure 13: Case study from the south looking north
Figure 14: Sample of erosion within the case study (-23 `d Street)
Figure 15: Commercial structure in case study (--20 Street)
Figure 16: Residential homes in case study (33 rd Street)
Property information from this section was collected from the Lincoln County
assessor's office. The contractor estimates, percentage of vacant lots, and other
relevant information were based on this information. See Appendix A for details.
Option #1: Protect Only
General Discussion
The first scenario assessed in this project is the 'protect only' option. This
option assumes that shore protection structures will continue to be built whenever
oceanfront properties become impacted by coastal erosion and that the Statewide
Planning Goal 18 SPS prohibition on undeveloped as of 1977 property is either not
applicable or that the policy will be overturned. The construction of SPSs will thus
continue until the entire shoreline length is completely hardened. In the face of SLR,
the beach will gradually narrow and eventually be lost to sea inundation. It is assumed
that as the beach narrows, the number of visitors will decline due to decreased lateral
access, quality of experience, and safety concerns. However, it is also assumed that
these lost expenditure costs pertain only to the Siletz littoral cell as these visitors will
be able to find substitute beaches either to the north or south of the cell. Therefore, the
state of Oregon as a whole will experience a zero net change in expenditures related to
beach recreation. Therefore, the goal of this option is to determine the cost to construct
and maintain the SPS system, and the locally lost expenditures associated with a
narrowing beach.
Cost for SPSs
As of the spring of 2003, 54.5% or 40,304 feet of beachfront land was
protected with SPSs, with the remaining 33,669 feet unprotected. As discussed earlier,
it is assumed that the SPSs will be built at the historic SPS construction rate of 800
linear feet per year. To find the cost of SPSs, conversations were held with Steve
Williams, SPS Permit Coordinator for the Oregon Park and Recreation Department,
and with private contractors located in the Lincoln City area. From these
conversations, it was determined that the cost to install a new SPS is approximately
$200 per linear foot. Since it is assumed that 800 linear feet will be built every year,
the annual cost for new SPSs will be $160,000 annually ($200 X 800) or $800,000
every 5-year period.
The maintenance costs are much harder to determine, since there is a wide
range and timeframe in which SPSs might need maintenance (Williams, Personal
33
Communication). Based on the same conversations, it was determined that the cost to
maintain SPSs would be approximately $100 per linear foot and that 50% of the
existing SPSs would require maintenance every 10 year period. For example, in Table
3 at Year 0 there is 40,304 feet of SPSs. By year 10, 8000 linear feet (800ft/yr X 10
years) of SPSs will have been constructed, bringing the total existing SPSs at year 10
to 48,304 feet. Taking 50% of this number and multiplying it by $100 per foot results
in the SPS maintenance cost for that time period, $2,415,200. This same process is
continued out thru year 20 and year 50.
Lost Expenditure Costs
Given that the erosion of cliffs provides an important source of sediment for
natural beach replenishment, the placement of SPSs between the beaches and the cliffs
effectively eliminates this source. When the beach sand is removed via storms and
wave activities, it is not being replenished at its historical rates. As the beaches
narrow, it is assumed that fewer people will visit the beach due to narrowing
(overcrowding) and safety issues associated with the SPSs and increased run-up of
ocean waves, thereby reducing the expenditure costs linked to beach recreation. It was
mentioned earlier that visitation rates within the Siletz Cell have been decreasing
anywhere from 0.4% to 1.5% annually over the past 11 years. Since there could be
many reasons for this decline, it is assumed that this rate will continue to decline by
0.5% per year in order to calculate lost expenditure costs.
To determine the costs associated with a narrowing beach and subsequent
decline in beach recreation quality, the visitor data from the previous section is
34
coupled with expenditure studies to determine the annual expenditure costs on beach
recreation for the Siletz Cell (Table 3).
Table 3: Annual revenue for Siletz recreation sites
Annual Revenue for Siletz Recreation Sites
Location
Siletz littoral cell
11-year Average for
Annual Day-Use Visits
2.115.737
Annual
Expenditure Costs
@ $25/day
$52,893.425
Annual
Expenditure Costs
@ $48/day
$101,555,376
The average daily expenditures are based on a series of studies from Oregon
and California (Table 4). These studies determined what consumers actually spent to
recreate at the beach and involve both direct and indirect costs. For example, direct
costs would include such items as entrance/admission fees, parking fees, equipment
rentals, and guides/lesson fees. Indirect costs would include fuel expenditure, food and
drink purchases while traveling, and other transportation costs.
Table 4: Beach recreation expenditure studies (Rettig, 1999) (California, 2001)
Beach Recreation Expenditure Studies
Survey/Year
in 2004 dollars
Oregon/1989
$41.00-$48.00
Southern California/2000
$25.00
Southern California/2000
$37.00
Range in values
$25.00- $48.00
The primary study was conducted in 1988-1989 by the Department of
Agricultural and Resource Economics Department at Oregon State University. It
attempted to assess the value of recreation on Oregon beaches as it surveyed a sample
population of 870 Oregon residents via a telephone questionnaire. The data collected
from the survey focused on recreation activities, socioeconomic characteristics,
expenditures, and valuation. It is from this study that we hope to obtain a range of
costs that helps identify what consumers are willing to spend to recreate at the beach.
To support the Oregon numbers, two expenditure studies from southern
California for the summer of 2000 are utilized. These studies also involved
questionnaires and surveys about expenditure related costs towards beach recreation.
From the expenditure cost studies, the values ranged from $25.00 to $48.00.
These numbers will represent the low end and high end of our range. Taking the
assumed annual decline in visits of 0.5% for each time period gives you the
cumulative lost expenditure costs over time as seen in Table 5. For example, for every
5 year period the visitation rate will drop by 2.5% (0.5% X 5 years). At year 5, the
expenditure costs lost will be 2.5% times $52,893,425, or $1,322,336.
It should be noted that these expenditure studies represent only the costs
expended to travel to the site, recreate at the beach, and travel back home. These costs
do not include the value of the consumer's time, that is, their opportunity cost that
could have been spent doing some other activity.
Aggregate Economic Costs of Protect Only Option
The complete economic costs associated with this option is the summation of
the new SPS construction, the maintenance costs of the existing SPS, and the lost
recreation expenditures as a result of narrowing beaches. See Table 5 for detailed
breakdowns of the costs.
36
The formula for calculating the present value of the costs is:
PV(costs)= [(E)n + (C)n + (M)n)/(1+r)n
where n is for the time periods 5 through 50 (every 5-year period); E equals the lost
expenditure costs; C equals the amount of new SPS construction; and M equals the
amount of maintenance required on the existing SPS system.
Applying the above formula to Table 5 shows the present value range of total
economic costs associated with the 20-year scenario ranged from $14.2M to $22.1M
for a 3% discount rate and $8.5M to $13.2M for a 7% discount rate. The present value
range of total economic costs associated with the 50-year scenario ranged from
$37.9M to $54.8M for a 3% discount rate and $14.6M to $23.7M for a 7% discount
rate.
37
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Option #2: Protect-Beach Nourishment
General Discussion
Soft stabilization measures involve beach nourishment in which sand is
brought in from either offshore or other locations and used to replace the eroded and
displaced sand. Soft measures can also involve the rebuilding and revegetation of
previously eroded sand dunes. Beach nourishment projects are partially funded by the
Federal government. For the initial nourishment costs, the Federal share is 65% and
the State share is 35%. After that, the maintenance costs of nourishment are split 50/50
between the State and Federal governments (USACOE, 1995). The major issue will be
in determining what quantity of sand will be necessary for nourishment purposes. It is
assumed that there will be no change in beach width.
Under this option, it is assumed that the SPS construction rate will be the same
as in Option 1, and that the maintenance costs for SPSs will involve 25% of existing
structures every 10 year period. This is less then in Option 1, because it is assumed
that the nourishment added to the beach will improve the buffering capacity of the
shoreline, thereby inflicting less damage to the hardened shoreline. Therefore, the
costs associated with this option include new SPS construction, SPS maintenance, and
nourishment costs.
Costs of Beach Nourishment
Assessment of the economic feasibility of this option involves every step from
Option #1, and also includes the costs associated with beach nourishment. These
39
involve the initial beach nourishment effort, as well as a maintenance program to be
utilized on an as-needed basis. Data from historical beach nourishment projects were
collected from all over the country, including numerous beaches along the East and
Gulf coasts, and several beaches in California. See Appendix D for the collection of 40
different beach nourishment projects selected for use in this study. These projects
occurred between 1985 and 2003 and all dollar amounts were converted to 2004
dollars. Nourishment projects were not selected if they were classified as for
emergency situations, as these are typically more expensive.
A review was also conducted on the Army Corps of Engineer (Corps) data
related to beach nourishment projects. The Corps is the primary Federal agency
responsible in dealing with coastal erosion and flooding. The Corps have been
performing beach nourishment projects since the 1950's and a summary of these data
are included at the bottom of Appendix D. The historical average for the Corps
projects is just slightly higher then the 40 projects selected for this study, which
provides support to the high end range used here. The information collected for each
project includes the name of the beach and its location, total project cost, the length of
beach nourished, and the volume of sand used in the nourishment process. The average
cost of nourishment is $592/ft of linear beach utilizing 104 cubic yards/ft of beach.
In addition to these studies, several contractors were contacted to determine
costs to nourish the amounts of sand calculated in Tables 6 and 7. The cost for each
10-ton truckload of sand would be $22.50 so to nourish the beach at 100 cubic yards/ft
would cost $225 (Morris, 2004). Installation costs (50% extra) added on to the cost of
beach sand brings the total cost to approximately $350 per linear foot. It is unknown if
40
there is sufficient sand from these contractors to meet the requirements for
nourishment, but it helped establish the low end range. Therefore, it was decided that
the $/ft cost to nourish the beaches would be between $350/ft and $600/ft.
The next step is to determine how much sand to use for the nourishment
process and when to do it. The procedure behind this process involved calculating the
historic sand supply that has been blocked by SPSs since 1967. By using the average
rate of erosion, the average bluff or dune height, and the average length of SPSs in
place for a certain time period (Figure 11), it is possible to calculate the volume of
sand that has been blocked since 1967. The time periods were segmented to obtain
better accuracy. See Table 6 for details. The total sand blocked since 1967 was
977,387 cubic yards, and this will be the total initial nourishment.
As for the maintenance nourishment volumes, these were calculated in a
similar manner. Table 7 shows the initial nourishment volume and costs at year 0, as
well as for every 5-year period. The nourishment costs ranged from $350/ft to $600/ft.
With the average nourishment project using 100 cubic yards/linear foot, if the amount
of nourishment used in a certain time period is divided by 100 cubic yards, the length
of beach nourished can be calculated. For example, in year 10, 218, 658 cubic yards of
sand are needed for nourishment purposes. Dividing 218,658 by 100 cubic yards,
determines that 2,187 linear feet of shoreline can be nourished at a cost ranging from
$765,000 to $1.3M.
41
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Aggregate Economic Costs of Protect-Beach Nourishment Option
Appendix C lists the complete economic costs associated with this option.
The formula for calculating the present value of these costs is:
PV(costs)= [(BN)n + (C)n + (M)n1/(1+r)n
where n is for the time periods 5 through 50 (every 5-year period); BN equals the sand
nourishment costs; C equals the amount of new SPS construction; and M equals the
amount of maintenance required on the existing SPS system.
The present value range of total economic costs associated with the 20-year
scenario ranged from $9.5M to $13.6M for a 3% discount rate and $7.3M to $10.8M
for a 7% discount rate. The present value range of total economic costs associated with
the 50-year scenario ranged from $14.7M to $20.4M for a 3% discount rate and $8.7M
to $12.6M for a 7% discount rate.
Option #3: Gradual Retreat
General Discussion
The third option involves the decision to retreat. Retreat for this project will be
a gradual process that will occur on an "as needed" basis. This means that when a
coastal property is threatened by erosion, the structure will either be relocated towards
the back area of its lot or it will be demolished to allow for the natural landward
migration of the shoreline. If a property has a SPS in place, then maintenance will no
44
longer be allowed and the SPS will be removed once it is deemed a safety hazard.
When the SPS is removed, the previous decision tree will be adhered to the next time
the property is threatened by erosion. The "as-needed" basis of retreat is assumed to
equal the range of SPS construction, since it figures that these are the properties
threatened annually by erosion events. From the previous section, it was determined
that the SPS construction rates have ranged from 400 to 1000 linear feet per year.
Thus, the assumption is that 400 to 1000 linear feet per year of shoreline will be
required to retreat.
The case study methodology previously discussed, is now utilized to determine
the economic impact of this option. Costs will need to be determined for the following
items: SPS removal, structure demolition, structure relocation, average property value,
average tax revenue. To determine these, the 1-mile sample population previously
mentioned is utilized. It is assumed that all inland properties are residential structures.
Asset Inventory-Property Value Information
A common misconception is that the value being lost under this option is the
expensive oceanfront properties. In reality, the land being lost is the inland properties
because there will always be properties adjacent to the oceanfront. Essentially, these
oceanfront values are being transferred to the adjacent inland properties. What will be
lost is the tax revenues collected from these oceanfront properties, but only for the
short-term. Eventually, once the property values have been mostly transferred, the tax
revenues will adjust accordingly.
45
The first information need is the average property value of the inland
properties. Appendix A lists both the oceanfront and inland properties for the 1 mile
sample population that was selected. It is located in the Lincoln City area of the Siletz
littoral cell. This table also lists the average property values, square footage, and
annual tax revenues for each type of property (Lincoln County, 2004). For example,
the average inland property value is approximately $120,000 and the tax revenue is
about $1,400 per year. Figure 17 shows an example of some of the interior properties
in the case study.
Figure 17: Examples of interior lots in the case study
(33 rd
Street).
In this same stretch of shoreline, the oceanfront properties had an average property
value of $357,000 for residential properties and $1.4M for commercial properties. As
mentioned earlier,
75%
of the oceanfront properties are residential, with the other
25%
being commercial properties. The average annual tax revenue for oceanfront property
came out to $6,028 per property.
SPS Status and Retreat Costs
As mentioned in the general discussion, it is assumed that the range of retreat
would be the same as the range of SPS construction. To determine the costs associated
with this option, several calculations must be made. Earlier, it was shown that 54.5%
of the cell already has SPSs, so it is assumed that 54.5% of 400 and 1000 feet,
respectively, will incur costs to remove existing SPSs. Therefore, 218 and 545 feet,
respectively, multiplied by the cost of $75/ft to remove the SPSs, yields $16,350 and
$40,875 in annual costs for SPS removal.
The next decision pertains to the properties requiring retreat and whether a
property has to be demolished or relocated. It was determined that approximately 58%
of the existing buildup can be relocated further back at their current location (Good,
1992). Therefore, with a retreat of 400 feet, 232 feet (58%) can be relocated. Dividing
this number by the average frontage (50 feet) for oceanfront property, provides the
quantity of properties that need to be relocated. These 4.64 properties multiplied by the
average cost to relocate a property ($18,750) determine that the annual cost to relocate
properties will be $87,000. The remaining 168 feet is the length of shoreline requiring
demolition. Dividing 168 feet by 50 feet yields the number of properties that will have
to be abandoned annually. Taking these 3.36 properties and multiplying it by the
average cost to demolish a property, provides an annual cost of $52,500. For both the
relocation and demolition costs, the calculation was an average cost prorated at the
percentage of residential versus commercial property. See Table 8 for these
calculations and for the complete cost figures.
47
Aggregate Economic Costs of Gradual Retreat Option
The formula for calculating the present value of these costs is:
PV(costs)= (TARC)n/(1+r)n
where n is for the time periods 1 through 50; TARC equals the total annual retreat
costs which includes the SPS removal, relocation of structures, demolish of structures,
lost inland property values, and lost tax revenues.
The present value range of total economic costs with the 50-year scenario is
$30.1M to $75.3M for a 3% discount rate and $16.1M to $40.4M for a 7% discount
rate. The present value range of total economic costs with the 20-year scenario is
$17.4M to $43.5M for a 3% discount rate and $12.4M to $31.0M for a 7% discount
rate.
48
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Conclusions and Recommendations
Tables 9 and 10 summarize the present value findings for both the 20-year and
50-year cost scenarios for all three options. The tables compare the costs of each
option at a 3% and 7% discount rate. They are displayed from the least costly option to
the most costly option. The question then becomes: what do these tables tell us? What
it shows is that in the 20-year scenario, the 'protect' option is clearly the least costly
option due to the existing high levels of development. In the short term (20-years), it
makes economic sense to protect the existing infrastructure. However, it also shows
that protecting the shoreline with nourishment will be the least costly option. By using
beach nourishment as a management tool, the beach can be preserved and recreation
quality maintained, thereby minimizing the decline in beach visitation rates.
What happens when we look further out into the future? The 50-year scenarios
still show that the 'protect' and 'protect with beach nourishment' are still the two
lowest cost options due to the continued preservation of the beach and visitation rates
to the beach. However, an interesting cost shift occurs between two of the options. The
low range of the 'retreat' option is now more favorable economically then the low end
of the 'protect' only option. Over a longer time frame, it simply becomes costlier in
losing more beach visitors than it is to continue protecting the existing infrastructure.
The assumptions used in this analysis were meant to cover most scenarios
given a range of historical and current conditions. Many events could change that
would shift the preference of options. For example, increased storm and wave activity
could dramatically alter the rates of erosion. Difficulties in the nourishment process
and in locating adequate amounts of the right kind of sand could add to its cost
50
structure. If either or both of these events happen, than the preference might shift
toward a gradual retreat.
Another possible scenario is that the management of the beach could involve a
hybrid of the three policy options discussed. The rolling easement scenario is a good
example. A rolling easement policy allows construction near the shore, but requires the
property owner to recognize nature's "right of way" to advance inland as sea level
rises (Titus, 1998). SPSs would not be allowed in this option, but it is assumed that in
the interim, soft shore protection measures such as nourishment, sand berms, and
vegetation might be allowed and utilized until it becomes economically unfeasible to
do so. This would combine the gradual retreat option with beach nourishment to delay
the rate at which retreat would take place. Once a property becomes threatened, then if
relocation is not an option, abandonment would occur and it would allow for the
natural progression of the shoreline.
Whatever policy option is selected, it should be noted that this paper only
assessed the cost side of this problem. There are many types of values that will need to
eventually be accounted for to determine the total economic impact of sea level rise.
These values are known as non-use values and share three important featuresirreversibility, uncertainty, and uniqueness. One example is bequest value which
captures the desire to endow a resource to future generations (Pearce and Turner,
1990). Further research is needed to determine these types of values for Oregon's
beaches to give a more complete accounting.
The coast is a popular area to recreate for millions of people. However, in the
face of climate change and rising sea levels, many unforeseen consequences are on the
51
horizon. Hopefully, this paper will alert and inform local communities and government
agencies who manage the beach and oceanfront development, and provide additional
rationale to take a precautionary approach in the face of chronic coastal hazards. To
efficiently and successfully deal with sea level rise and chronic coastal hazards, it is
going to take the unified effort of local, state, and federal officials, and a wellinformed public to preserve the priceless amenity of Oregon beach recreation.
52
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References
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54
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55
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56
Appendix A: Lincoln County Assessors' Office Property Information
Property Information
Total ValueCommercial
Oceanfront
$2,195,160
$782,460
$725,940
$2,082,460
$588,290
$1,335,290
$1,367,110
$1,286,120
$1,429,220
$3.077,050
$1,198,500
$1,028,200
$1,463,690
$1,960,000
$1,176,540
$1,189,330
$22,885,360
$1,430,335
Taxes
$28,738
$10,115
$8,347
$26,056
$8,156
$16,359
$16,644
$15,190
$16,241
$36,801
$14,145
$15,903
$21,961
$25,360
$15,036
$16.189
$182,647
$11,415
Total ValueResidential
Oceanfront
$347,350
$311,870
$360,280
$551,590
$422,350
$499,430
$360,130
$398,820
$391,500
$309,290
$319,510
$495,860
$295,180
$319,220
$401,880
$319,470
$325,850
$328,670
$301,310
$339,960
$365,200
$328,150
$583.700
$292,350
$279,300
$350,100
$392,410
$308,130
$282,640
$370,150
$259,790
$468,030
$327,170
$458,250
$307,700
$289,040
$261,310
$376,160
$315,380
$260,770
$383,650
$14,658,900
$357,534
Taxes
$3,600
$3,392
$4,085
$6,707
$4,902
$6,122
$4,107
$4,591
$5,079
$3,441
$3,258
$5,449
$3,015
$3,801
$4,390
$3,338
$3,328
$3,437
$3,184
$3,924
$4,215
$3.871
$7,669
$3,401
$3,485
$4,612
$5,348
$3,726
$3,564
$4,842
$4,018
$5,235
$4,430
$5,806
$3,784
$3,486
$3,043
$4,691
$3,646
$3,052
$4,437
$173,511
$4,232
Total Value
for Inland
Property
$243,480
$56,740
$176,220
$94,930
$88,630
$106.410
$156,570
$122,120
$137,220
$129,340
$136,570
$106,560
$76,380
$75,240
$87,350
$165,340
$117,890
$110,570
$85,910
$117,690
$94,860
$120,950
$84,620
$257,440
$135,930
$96,590
$124,150
$113,540
$95,080
$98,210
$79.700
$98,260
$171,020
$76,740
$127,280
$169,910
$158,120
$95.570
$4,589,130
$120,767
Taxes
$3,634
$792
$2,446
$1,342
$1,181
$1,235
$2,058
$1,612
$1,885
$1,743
$1,842
$1,440
$973
$943
$1,040
$1,998
$1,709
$1,471
$1,233
$1,738
$1,360
$1,661
$1,205
$3,949
$2,001
$1,407
$1,860
$1,693
$1,282
$1.343
$1,051
$1,335
$2,437
$1,029
$1,836
$1,894
$2,199
$1,317
$63.174
$1,404
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