casestudy_auckland_hinojosa

Document Sample
casestudy_auckland_hinojosa Powered By Docstoc
					            Monetizing Exposure
            & Planning Defenses:
        Assessing Risk Due to Sea Level Rise
       in the Port of Auckland, New Zealand




                        Jessica Hinojosa
                           CEE224A
               Martin Fischer and Ben Schwegler
                      11 December 2008




STANFORD UNIVERSITY ENGINEERING AND PUBLIC POLICY FRAMEWORK PROJECT:
 Climate Change and its Impact on the Built Environment in the Coastal Zone
December 11, 2008                    Monetizing Exposure & Planning Defenses 1


Table of Contents

0.0 Project Introduction…………………………………………………………………………………
0.1   Coastal Ports Justification……………………………………………………………………..
0.2   Case Study Goals………………………………………………………………………………………….
0.3   Design Approach…………………………………………………………………………………………
0.4   Audience………………………………………………………………………………………………….
0.5   Units……………………………………………………………………………………………………….

1.0 Site Identification…………………………………………………………………………………
1.1    Port Operations, Infrastructure, and Contiguous Community………………
1.2    Topography and Bathymetry……………………………………………………………………..
1.3    Design Conditions and Acceptable Risk…………………………………………………
1.4    Hydrology and Hydraulics……………………………………………………………………..
1.5    Coastal and Wind Data……………………………………………………………………..
1.6    Geology and Sediment Regime……………………………………………………………………..
1.7    Land Use Patters and Historical Reserves…………………………………………………
1.8    Natural Resources and Ecosystem Services………………………………………………
1.9    Estimating the Local Rate of Sea Level Rise…………………………………………………
1.10 Vulnerability Assessment……………………………………………………………………..
1.11 Historic Extreme Events……………………………………………………………………..
1.12 Preliminary Site Delineation……………………………………………………………………..

2.0 Conceptual Design Alternatives Evaluation…………………………………………
2.1   Cost Data……………………………………………………………………………………………….
      2.1.1 Construction Materials……………………………………………………………………..
      2.1.2 Construction Equipment……………………………………………………………………
      2.1.3 Labor – Design, Skilled, and Unskilled………………………………………………
2.2    Selecting the Conceptual Design………………………………………………………………
      2.2.1 Conceptual Design A: Control Port Water Level with Locks…………………
      2.2.2 Conceptual Design B: Storm Surge Barrier…………………………………..
      2.2.3 Conceptual Design C: Non-Structural Approach………………………………
2.3    Alternative Selection……………………………………………………………………..

3.0 Schematic Design Development…………………………………………………………
3.1    Design Layout………………………………………………………………………………………
       3.1.1 Dike………………………………………………………………………………………………
       3.1.2 Gates & Lock…………………………………………………………………………………
       3.1.3 Pumping and Drainage System………………………………………………………
3.2    Materials……………………………………………………………………………………………….
3.3    Equipment……………………………………………………………………………………………
3.4    Labor……………………………………………………………………………………………………..
3.5    Construction Time and Sequencing…………………………………………………………
3.6    Cost…………………………………………………………………………………………………………
3.7    Impact on Ecosystem Functions and Landforms…………………………………………
December 11, 2008                  Monetizing Exposure & Planning Defenses 2


3.8   Societal Impacts……………………………………………………………………………………..
3.9   Design Limitations and Next Steps…………………………………………………………
      3.9.1 Data Availability……………………………………………………………………..
      3.9.2 Environmental Impacts……………………………………………………………………..
      3.9.3 Damage from storm event greater than design storm…………………………
      3.9.4 Permitting Requirements……………………………………………………………

4.0 Incorporation of Results in Overall Project………………………………………………




0.0 Project Introduction
December 11, 2008                          Monetizing Exposure & Planning Defenses 3



Climate change is undoubtedly the most vigorously debated environmental issue of
the 21st century. Among the many predicted scenarios likely to result from climate
change is an increase in the mean sea level (MSL) on a planetary scale---greater than
that attributable to the eustatic rate of sea level rise (IPCC 2007)1. Although the MSL
changes differ depending on the location in question (Church 2001) it is clear that
new risk management strategies are needed. These include managing subsidence,
landuse planning, selective relocation, and flood warning and evacuation (Nicholls
2008). However, aside from these “soft” protection strategies, at some point
additional “hard” construction in the form of dikes, levees, sea walls, etc. will be
required to protect ports, harbors and other coastal developments where the cost
and practicality of relocation is not believed to outweigh the constructed alternative.
Several studies have attempted to estimate the cost of constructing protective
structures, yet none have been based on an analysis of actual design alternatives,
nor have they attempted to quantify the ability of the design and construction
industry (DCI) to deliver the improvements envisioned.

The Stanford Engineering and Public Policy Framework Project on Climate Change
and its impacts on the Built Environment in the Coastal Zone (the Stanford Project)
will address these gaps by preparing a global simulation of the construction
response required to protect the world's major ports from a significant rise in MSL,
which will include estimates on the requirements for construction materials,
equipment, labor, and cost (Fischer 2008). Additionally, the project will compare
these requirements to the current capacity of the DCI in order to estimate the
duration of the global simulation. Our preliminary results show that protecting the
178 most significant ports in terms of economic value will cost approximately $90
billion (USD) and will take about 50 years, assuming unconstrained resources and
simultaneous construction at all ports. The mean project will take 8 years to
construct, and the median project will take 4 years. If we add the material constraint
of sand and gravel production by region—which we have determined to be the most
limiting resource—then the time required to protect all 178 ports rises to 220 years.

This paper is a case study on developing a protection strategy for Long Beach
Harbor, which includes the Port of Long Beach and the Port of Los Angeles. With the
results of this case study and the development of further case studies in various
ports around the world, we expect to the project-level estimates to change and
improve in accuracy as they are refined by the knowledge gained in each case study.


0.1 Coastal Ports Justification

In determining the scope of this project, much thought was given to what kinds of
coastal areas should be studied. First, a distinction was made between the built
coastal environment and the undeveloped coastal environment. Although
undeveloped areas have a significant ecological value and may provide many
economic benefits, it is difficult to justify implementing an engineering project that
December 11, 2008                           Monetizing Exposure & Planning Defenses 4


will attempt to preserve some baseline state when it is not clear that such a baseline
exists in a naturally dynamic environment. It is also complicated to determine
whose responsibility this protection would fall to and how it would be prioritized
given the more pressing work that would be required to protect the built
environment. Within the built environment, we have decided to look at land uses
that are entirely dependent on coastal access and are largely immobile. Although
there are growing levels of residential and commercial development along the coast
worldwide, these structures could potentially be relocated inland or abandoned and
reconstructed inland. Home values are also highly sensitive to flood risk, so it is
difficult to assess exactly what their value is.

In light of these factors, coastal ports emerge as a good simplifying target, since they
are central to the economic productivity and trade of most coastal nations. For the
United States, 95% of all goods entering the country arrive via waterborne
transportation (POLA 2007a). Ports are also tied to the coast and exceedingly
difficult—if not impossible—to relocate, due to the intricate infrastructure that
connects them to the land and the sea. Finally, another practical reason to choose
ports as the target of this study is the relatively complete and regularly maintained
data availability on their operation, their surrounding geophysical environment, etc.


0.2 Case Study Goals

The overall goal of this case study is to provide guidance on the development of a
coastal port protection strategy that is applicable for Long Beach Harbor and other
similar ports throughout the world, which will be used to validate the approach
used in the Stanford Project at large. In conjunction with a range of very different
case studies that are being developed, the limitations of this approach will be tested
and it will be expanded to better match reality.


0.3 Design Approach

By preparing an engineering design at a schematic level, we will be able to assess
the minimum design specificity required in order to create a global simulation that
does not double-count resources. For example, we foresee that the port protection
system for Long Beach Harbor would likely require 3 marine dredges during
construction, which would then not be available to be used simultaneously in other
concurrent projects (Johnson 2008). If the schematic designs produced according to
this case study can identify the most critical resources needed, then we can better
estimate the limiting factors for the scheduling of the simulated port protection
activities on regional and global levels.

Taking the design from a case-study level to a larger statistical analysis of the
world’s top ports involves using the following variables:
December 11, 2008                          Monetizing Exposure & Planning Defenses 5


    Dependent Variable
         o    Cost to implement port protection systems
                Materials
                Equipment
                Time
                Labor
    Independent Variables
         o    Rate of sea level rise
         o    Design type
         o    Extreme water level
         o    Exposed population & assets


0.4 Audience

The intended audience for this case study is student research teams at universities
worldwide that are taking part in the Stanford Project. Once the methodology and
results have been further tested and verified, this paper will then be a source for the
development of project-level documents to be disseminated throughout the
scientific and engineering community, as well as to the general public.


0.5 Units

Every attempt is made to use SI units throughout this project. All prices are in US
dollars ($) unless otherwise indicated.


1.0 Site Identification

The port of Auckland, New Zealand is the country’s largest port and a hub for cruise
ships, making it extremely important to the country’s economic well-being. Damage
to the port could severely impact New Zealand through disturbance of trade and
tourism, two of the countries biggest industries. Furthermore, Auckland is located
along the southwestern edge of the Pacific Ring of Fire, an area experiencing
frequent earthquakes; this seismic activity leads to tsunamis in the region and
provides an interesting extra dimension in planning the design and construction of
any port defenses.

Many of the data necessary for performing an engineering design to protect the port
of Auckland are publicly available, so here is a compilation of a host of sources
presented in a logical order. For certain aspects, data may not be available, in which
case either new data could be collected or values could be interpolated from other
known values.
December 11, 2008                         Monetizing Exposure & Planning Defenses 6


1.1 Port Operations, Infrastructure, and Contiguous Community

The Port of Auckland has been in operation since 1871 when the settlement of
Auckland started its development as an urban area. Because New Zealand is a
relatively isolated island, a well-functioning harbor was necessary for imports of
goods. From 1871 to 1988, the port was run by the Auckland Harbour Board. In
1988, the board was corporatized, creating the Ports of Auckland Limited. This
company now operates the port of Auckland along with several other smaller ports
in the region, bought the port. Now, the port sees over $10.8 billion in exports and
imports annually and provides 155,000 jobs (POAL 2006).

The port is also working to improve efficiency and support environmental
measures. The recent Floodlight Upgrade Project implemented in 2005 has cut
energy use by 15% in the port, and 11 new “eco” straddle carriers further reduce
fuel and energy usage. The 2006 “Environment and Sustainability Report” also
discusses increasing recycling, decreasing noise pollution, supporting
environmental projects, and emergency environmental response, yet there is no
mention of response to or danger of sea level rise (POAL 2006).

The port of Auckland accounts for 37% of New Zealand’s shipping volume, and over
half of the volume for the North Island alone. A table containing summary statistics
is shown below (POAL 2006):

Data Category                    Value
Total annual trade value         $10.8 billion
Annual shipping volume           685,000 TEU
Persons employed                 155,000
Cruise traffic                   100,000 people/year
Population density               1305 people/sq. km
Existing defense(s)              Breakwater, barrier islands
Associated river                 Tamaki River
Tidal datums                     MHHW: 3.30m; MTL: 1.86m; MLLW: 0.42m

Existing infrastructure and key features are shown in the map below:
December 11, 2008                          Monetizing Exposure & Planning Defenses 7




Figure 1. Existing infrastructure of the port of Auckland (POAL 2006).


1.2 Topography and Bathymetry

For a quick initial visualization of low terrain that is prone to flooding, we used a
web-based tool that is easy to manipulate to show elevation data for most of the
world. Using NASA’s Shuttle Radar Topography Mission (SRTM) topographic data,
this tool shows flooding based simply on the elevation of land points at the time of
data collection, without accounting for erosion, subsidence, etc.
December 11, 2008                         Monetizing Exposure & Planning Defenses 8




Figure 2. Map showing a simple elevation-based flooding due to a 2m sea level rise
(Tingle 2008) http://flood.firetree.net/?ll=-36.8252,174.7593&z=4&m=2.




Figure 3. Map showing a simple elevation-based flooding due to a 7m sea level rise
(Tingle 2008) http://flood.firetree.net/?ll=-36.8241,174.7367&z=4.
December 11, 2008                        Monetizing Exposure & Planning Defenses 9




Figure 4. Map showing a simple elevation-based flooding due to a 14m sea level rise
(Tingle 2008) http://flood.firetree.net/?ll=-36.8241,174.7367&z=4&m=14.




Figure 5. Nautical chart showing bathymetry and dredging in the entry to the port
(Land Information of New Zealand 2008).
December 11, 2008                                 Monetizing Exposure & Planning Defenses 10


1.3 Design Conditions and Acceptable Risk

To calculate the design return period events (e.g., the 10,000-year event), it is best
to have a large dataset to work with. Sometimes these return period events have
already been calculated. If, for instance, the 10-year and 100-year return period
storm magnitudes are available, then the 1,000-year and 10,000-year storms can be
calculated from that information as follows (Mays 2005):

Assume log-normal distribution:
10000-year storm magnitude=q10000; P(Q<=q10000)=0.9999; z10000=3.49
1000-year storm magnitude=q1000; P(Q<=q1000)=0.999; z1000=3.08
100-year storm magnitude=q100; P(Q<=q100)=0.99; z100=2.33
10-year storm magnitude=q10; P(Q<=q10)=0.90; z10=1.28
5-year storm magnitude=q5; P(Q<=q5)=0.80; z10=0.84
2-year storm magnitude=q2; P(Q<=q2)=0.50; z2=0.00

Given:
q100
q10

Calculate standard deviation (!) and mean (µ):
!=[ln(q10)-ln(q100)]/1.05
µ=ln(q100)-2.33*!

Calculate new design storms:
1,000-year storm magnitude=q1000=e(3.08*!+µ)
10,000-year storm magnitude=q10000=e(3.49*!+µ)



It should be noted that calculating return period events in this manner is a limited
approach, as it uses data from the past to forecast future conditions. Thus, this
obviously neglects the impacts of climate change on storm severity and frequency. If
desired, a safety factor can be applied to the calculated results in order to account
for the uncertainty that arises from this and other factors.

For many types of construction projects in the U.S., the acceptable risk is assumed to
be the “100-year” event; that is, the event that has a 1% chance of happening every
year. Also, the typical expected life of an infrastructure project is 100 years.
However, the design standard in the Netherlands calls for protection against the
10,000-year event (0.01% chance every year) for coastal protection structures.
Thus, we will evaluate both the 100-year and the 10,000 year events for our designs,
and make a site specific determination of the acceptable risk.


1.4 Hydrology and Hydraulics

There are no major rivers that discharge into the harbor of Auckland. The Tamaki
River, located southeast of the port, is actually a misnomer; the body of water is in
fact an estuarial arm and separate harbor of the Hauraki Gulf, which is the larger
gulf outside of the port of Auckland as well. Because the Tamaki River is more of an
December 11, 2008                         Monetizing Exposure & Planning Defenses 11


estuary, there is not an outward flow or sedimentation from the body of water.

1.5 Coastal and Wind Data

The return period wave height in Auckland was calculated by averaging monthly
wave height data, as the example shows below.




Figure 6. Measurement of wave heights during October 1996 off the coast of
Auckland using wave buoys (Tindle and Murphy 1999).

Over the several months in which waves were measured, an average wave height of
2m was found, but a peak of 7m was found during the study period. Because this
information was taken over a limited period of time, a safety factor of 20% could be
added to the largest wave height to obtain the design wave. Thus, with a safety
factor of 20%, the design wave is: 1.20 * (7m) = 8.4m.

Below is a wind rose for Auckland that shows the predominant directions of winds.
Stronger winds generally come from the SW quarter, however NE winds also can be
strong, especially when tail ends of tropical cyclones sporadically stray south to
New Zealand. The data was collected at a height of 200m.
December 11, 2008                         Monetizing Exposure & Planning Defenses 12




Figure 7. Wind rose for Auckland at a height of 200m. The graph peaks at 240
degrees, though the entire range from 210 to 250 is fairly high (Auckland
UniServices Ltd. 1992).

Wind data collected from the same buoys that measured wave height data show
similar wave directions:




Figure 7. Off-coast measurement of wind direction; again, the most common range is
around 250m (Tindle and Murphy 1999).

Storm surges are generally highest during tsunami events, which typically originate
from the western coast of South America and propagate across the Pacific Ocean.
The runup levels from past tsunamis reach over 3.5m within the Hauraki Gulf. The
most recent major tsunami event was in 1964; other major historic events will be
discussed later on in Section 1.11.
December 11, 2008                          Monetizing Exposure & Planning Defenses 13




Figure 9. Runup heights for past major tsunamis in the Auckland region (De Lange
and Healy 2001).


1.6 Geology and Sediment Regime

The island of New Zealand exists because of the ongoing subduction of the Pacific
plate underneath the Australian plate, therefore the country’s entire east boundary
is mostly delineated by a fault line along the Hikurangi trench. However, the North
Island veers west from the subduction zone, thus the seismic activity and geological
deformation is not as pronounced in Auckland.
Figure 10. The tectonic environment of New Zealand. Faults are represented by
white lines. The triangles represent active volcanoes, and the shading represents
topography of the region (Liu and Bird 2002).

1.7 Land Use Patterns and Historical Resources

The port has some major road-based transportation resources that are threatened
by possible sea level rise, particularly the bridge in the western part of the harbor
and Tamaki Drive, a major road along the southern coast of the harbor.
December 11, 2008                          Monetizing Exposure & Planning Defenses 14




Figure 11. Google Earth snapshot showing the road transportation system around
Auckland (Google Earth 2008).


1.8 Natural Resources and Ecosystem Services

While it is hard to monetize the value of natural resources and ecosystem services,
they add an important factor in deciding what to protect and what is most cost-
effective. Ecosystem services, a public good, are commonly defines as benefits
people derive from natural ecosystems. The Millenium Ecosystem Assessment, a
project of the United Nations to assess the world’s ecosystems, broke up ecosystem
services into four categories: provisioning services, regulating services, supporting
services, and cultural services (USDA 2008). Because New Zealand is one of the
world’s top biodiversity hotspots with over 80% endemic species (Conservation
International 2007), the preservation of natural resources is a high priority.


1.9 Estimating the Local Rate of Sea Level Rise

Based on existing research, we have chosen to select two SLR design scenarios: one
resulting in a SLR of 1m by 2100, and another resulting in a SLR of 2m by 2100.
However, there will be regional variations in the rate of SLR, so this should be
considered in developing the criteria for the case study. Data from the
December 11, 2008                           Monetizing Exposure & Planning Defenses 15


20th century shows this variability. One simple way to estimate localized impact of
SLR is the Bruun Rule, given below (French 2001):

s'=[(zR)/x]*[1+(r/100)]*[1+(c/100)]

where:
s' is sea level rise
x is width of profile
z is depth of profile
R is landward movement of the shoreline (erosion)
[1+(r/100)] is a constant expressing sediment composition
[1+(c/100)] is a constant expressing losses from the system (i.e. offshore or longshore
transport)

Roll-Over Model
R1/t=(s'/t)tan

where:
R1/t is the rate of landward migration due to roll-over
s' is the sea level rise
t is time
 is the shore face angle


1.10 Vulnerability Assessment

A simple vulnerability assessment should be performed to understand the resources
and infrastructure that would be affected in the event of the design storm. Flood
maps or a hydraulic/hydrologic model—which could be as simple as the one
available through http://flood.firetree.net (Tingle 2008)—can be used to show what
areas would be flooded. A simplistic way to attribute a very conservative risk of the
design storm event can be quantified as the value of the structures that would be
rendered inoperable or would be destroyed. A more detailed analysis, typically
performed at a more detailed design level, would include the value of economic uses
disrupted and eliminated, rehabilitation and relocation costs, ecosystem functions
lost, morbidity and mortality, etc.

A valuable source of information on the economic value of ports can be found in the
OECD working paper titled "Ranking Port Cities with High Exposure and
Vulnerability to Climate Extremes." Under scenario FAC, the following summary
statistics apply to the San Pedro Bay ports. The exposed population and assets
figures are based on a “1 in 100-year surge induced flood event (assuming no
defenses).” The scenario FAC, using projected population and economic growth into
the year 2075, also accounts for global sea level rise of 0.5 m, storm enhancement,
and natural and anthropogenic subsidence (these last two factors could add on up to
1m to the extreme water level). The wind damage index is a scaling factor with
December 11, 2008                         Monetizing Exposure & Planning Defenses 16


values from 0 to 100 that also accounts for increased severity of storms (Nicholls
2008).

Auckland                                   Value
Wind Damage Index                          3
2005 Population                            1,148,000
Exposed Population (2005)                  7,000
Exposed Assets (2005)                      $900,000,000
Exposed Population (2075)                  18,000
Exposed Assets (2075)                      $7,860,000,000


1.11 Historic Extreme Events

There have been 11 major storm events since 1840 in the Auckland area. The causes
of the events were mostly earthquakes from the coast of South America, though
others came from events in Indonesia and the Kermadec Islands, located off the
coast of northern New Zealand.




Figure 12. Major past storm events, their respective sources, and the maximum
runup (De Lange and Healy 2001).
The largest runup recorded from a tsunami was 1.8m in 1883, while the largest
storm surge recorded was 0.88m in 1968; however, historical storm surge data is
much more sparse than tsunami data.

Auckland is also particularly sensitive to the fluctuations from the El Niño Southern
Oscillation (ENSO) and its counterpart, La Niña. During La Niña events, the mean sea
level rises an average of 0.1-0.2m. A similar depression occurs during El Niño
events.
December 11, 2008                           Monetizing Exposure & Planning Defenses 17




Figure 13. The measured anomalies of mean sea level during El Niño/La Niña events
(Bell et al. 2000).

Another possible source of storm surge could be a small magnitude earthquake
originating from the Kerepehi fault, located to the east of New Zealand. The danger
of this type of event would be the high dissipation rates of the tsunami wave in the
shallow waters of the Hauraki Gulf. Furthermore, the tsunami becomes trapped in
the gulf and creates a rotating Kelvin wave, which causes the tsunami to last longer
(de Lange and Healy 2001).


1.12 Preliminary Site Delineation

Once a site location has been set (i.e., a port or harbor), the site boundaries can be
determined based on an elevation cutoff, a population density cutoff, an economic
value cutoff, or some other objective or subjective criteria. Some consideration
should be given to the political climate in the study area (applicable regulations,
funding sources, etc.).

Using a spatial analysis tool the following attributes were laid out over the Auckland
region in order to delineate the study area boundaries and begin to consider design
locations (Google 2008):

• Land use patterns
• Major infrastructure
• Population density
December 11, 2008                           Monetizing Exposure & Planning Defenses 18


• Presence of unique resources (natural, historical, etc.)
• Bathymetry
• Hydrology
• Windrose
• Tides
• Flood maps

The site delineation for Auckland is shown below, where the blue area indicates the
water body enclosed by a proposed dike structure, and the red area indicates the
port infrastructure to be protected:




Figure 14. Auckland site delineation.



2.0 Conceptual Design Alternatives Evaluation

The goal of this section is to consider the most commonly used designs in coastal
protection— both structural and non-structural—and to assist in determining
which are the best alternatives for the study site. Note that this is an iterative
process, in which a few design alternatives were rapidly selected and then evaluated
to decide whether to proceed or to go back and consider a different approach.
December 11, 2008                           Monetizing Exposure & Planning Defenses 19


A diversity of coastal protection approaches have been successfully implemented,
and choosing the right one is a very site-specific process. The following tables list
the benefits and impacts that are possible outcomes of addressing various design
function goals. Then, the most prevalent approaches to structural and non-
structural designs are listed, along with their associated benefits and impacts. This
should make it possible to narrow the list of suitable alternatives for the project site
to three or four. If appropriate, two or more alternatives can be combined to create
a multifaceted design that may be better suited to the project requirements than the
alternatives by themselves (Massachusetts Office of Coastal Zone Management
2007).




Figure 15. Benefits and impacts possible with different design alternatives.
December 11, 2008                           Monetizing Exposure & Planning Defenses 20




Figure 16. Various design alternatives and their respective benefits and impacts.

A different categorization of protection strategies is laid out in the table below. This
table is meant to assist in the cost estimating and feasibility evaluation for choosing
one of the options listed as a design alternative (Massachusetts Office of Coastal
December 11, 2008                          Monetizing Exposure & Planning Defenses 21


Zone Management 2007) USACE EM 1110-2-1100 (Part VI).




Figure 17. Cost estimation and feasibility evaluation for different design
alternatives.

For Auckland, there are a number of primary and secondary objectives that a
successful design should meet, while avoiding negative impacts as much as possible:

    Primary objectives:
         o     Navigation: preserve safe navigation and shipping activities (N-a)
         o     Societal Goals: promote public safety and public welfare (S-a, S-c)
         o     Biological Resources: maintain ecological values and ecosystem
             functions (B-a)
         o     Design lifespan: 100 years (minimum)
         o     Sustainability: economical, ecological, and social
    Secondary objectives:
         o     Minimize cost
         o     Minimize disruption to port activities during construction (e.g.,
             minimize construction time)
December 11, 2008                           Monetizing Exposure & Planning Defenses 22


           o     Enhance ecological values (B-b)

Given these guidelines, a design should be able to work in two scenarios: extreme
events and everyday functions. The extreme event that is used as a metric in this
study is the 100-year storm event. An event of this magnitude should be able to hit
the port of Auckland and normal port functions should resume quickly after the
storm. However during the storm, the design structure may require port functions
to stop.

The design should also maintain normal day-to-day shipping and port operations
even with the estimated sea level rise without hindering current or planned
expanded operations.

Very few of the listed options preserve navigability—only the bulkhead, jetty, and
inlet relocation allow for this. However, none of these options were optimal, thus
two other options were considered: a dike combined with a lock system, allowing
for ships to have navigational access. The second design would be a storm surge
barrier similar to the Oosterschelde barrier in the Netherlands.

A final consideration of elevating all infrastructure is necessary, especially since
Auckland’s port facilities are concentrated and not too complex or large. While this
would be an extremely complex operation, it would maintain navigability and meet
almost all of the other primary and secondary objectives as well.


2.1 Cost Data

In order to evaluate design alternatives against each other, it is important to know
the site-specific cost of constructing each one.

2.1.1. Construction Materials

Unit costs of typical construction materials in New Zealand (RS Means 2006).

Material                                    Cost (material,     Units
                                            labor, equipment)
Rip-rap and rock lining, machine            $52                 Linear m3
placed for slope protection
Gabions, galvanized steel mesh mats or      $145                m2
boxes, stone-filled, 36” deep
Aggregate, select structural fill, spread   $17                 m3
with 200 H.P. dozer, no compaction, 2
mi RT haul
Concrete, plant-mixed bituminous, all       $87                 m3
weather patching mix, hot
December 11, 2008                           Monetizing Exposure & Planning Defenses 23


2.1.2 Construction Equipment

Unit costs of typical construction equipment in New Zealand.

Equipment                 Approx. units      Rental Cost      Hard Asset Cost
                          available in
                          local market
Bulldozer
Crane
Cement mixing station
Backhoe
Vibration compactor
Crane barge
Hopper dredge


2.1.3 Labor – Design, Skilled, and Unskilled

Since the unit costs for materials include the cost of labor, a detailed analysis was
not performed for this section. For a more refined estimate, unit costs of typical
contracted labor in New Zealand should be located and applied.


2.2 Selecting the Conceptual Design

After narrowing the conceptual design strategy to a few alternatives, a preliminary
design should be performed for each one. Each design should include a broad-level
overview of the requirements for the following elements (more detail will be sought
in a subsequent step):

• Design layout and typical cross-section(s)
• Materials required by category
• Construction equipment
• Time to construct (e.g., in years)
• Cost drivers
• Fulfillment of primary and secondary criteria

This will allow for a more detailed comparison of the alternatives and the selection
of the preferred approach. It should be noted that the preferred approach might be a
combination of several of the design alternatives.

For Auckland, it should be noted that the extreme design conditions are as specified
in Section 1:
     Assumed SLR: 2m
     Mean high high water: 3.3m
December 11, 2008                          Monetizing Exposure & Planning Defenses 24


      Storm surge/tsunami runup: 1.8m
      Design wave: 8.4m
      Freeboard: 0.5m
      Estimated subsidence: negligible

Thus, for a structure to withstand overtopping, its elevation needs to be a sum of the
above qualifications: 2 + 3.3 + 1.8 + 8.4 + 0.5 = 16.0m.


2.2.1 Conceptual Design A: Control Port Water Level with Locks

Here is a conceptual diagram of what the wet-wet dike system would look like:




Figure 18. Schematic cross-section of the proposed dike. NOTE: not to scale.

Several locations were considered for the location of the dike, especially given the
complexity of the opening of the harbor and the nearby barrier islands that could
serve as anchors for the dikes.

A first layout sets up a two-dike system using the barrier islands; the first dike
extends from the north part of the harbor to west coast of Rangitito Island, while the
second starts at the east coast of Motutapu Island and extends to Oneroa. The
advangtage of this design would be total protection of the developed area around
Auckland, with the water directed to Rangitito, an uninhabited island. The combined
length of the two dikes would be 7.8 km at an average depth of -1m.
December 11, 2008                         Monetizing Exposure & Planning Defenses 25




Figure 19. A two-dike system closing off the entire mouth of the port of Auckland;
locks would be necessary on the west dike to allow shipping channels to remain.
Dikes shown in red; major road infrastructure shown in orange and yellow (Google
Earth 2008).

A second proposed design would consist of a single dike across the narrowest entry
of the port. The length of this dike would be 1.8 km at an average depth of -1m.




Figure 20. A singe dike system shutting off the mouth of the harbor but leaving some
of the eastern developed shore of the North Shore exposed. Dike in red, roads in
orange and yellow (Google Earth 2008).
December 11, 2008                          Monetizing Exposure & Planning Defenses 26


Between these two options, the second is more appealing due to cost-effectiveness
and less need for materials. Both interfere with shipping channels, so a lock system
will be necessary regardless.

With a dike structure, the key failure mechanism is overtopping. Given the design
conditions, to avoid failure the crest elevation of the dike must be at least 16.0m
above MLLW (0.42m). The average bathymetric depth along the proposed dike was
-1m. Thus, an average structure height of 17.5m is necessary.

To maintain shipping operations, a lock system will need to be built into the dike.

The major cost drivers for the design are materials needed, labor to construct, and
equipment. While the dike design is fairly simple, the wet construction, along with
the complexity of a lock system, is also an added factor.


2.2.2 Conceptual Design B: Storm Surge Barrier

Another considered option was the storm surge barrier, similar to the one currently
in place in the Netherlands, the Oosterscheldeking. The barrier consists of 65 piers,
each with an adjoining steel door that usually remains opened but can be closed in
storm events. The major advantages of this design are continuously open shipping
channels, maintenance of ecological value, and no need for dredging beyond the
customary dredging of the shipping channels. The design is also based on a 4,000
year event, increasing the longevity of the structure and decreasing risk of
overtopping. However, the major drawback to this design would be cost: the
construction of the Oosterscheldeking cost over $3.2 billion dollars in the 1980s
(Deltawerken 2004). While this value still is less than the future exposed assets
quantified by the OECD, cheaper options that are also effective exist.

2.2.3 Conceptual Design C: Non-Structural Approach

There are other possible solutions for Auckland that do not necessarily involve
defense structures. The port could undergo a planned retreat in which the most
vulnerable assets were relocated, replacing them with uses that are less sensitive to
sea level rise.

Because there is available land further east along the harbor, this option could be
considered. The port is already planning expansion in the next several years;
perhaps the resources going to this expansion could consider relocating SLR-
sensitive sites to the expansion locations and restructuring the existing locations for
other uses.


2.3 Alternative Selection
December 11, 2008                            Monetizing Exposure & Planning Defenses 27



Objective              Design A (Dike w/ Design B (Storm              Design C (Planned
                       Locks)            Surge Barrier)               Retreat)
Navigation                     -                 +                             +
Societal goals                 +                 +                             -
Biological                     -                 +                             -
resources
Design lifespan                  -                      +                       +
Sustainability                   -                      +                       +
Minimize cost                    +                      -                       -
Minimize time                    +                      -                       -
Enhance ecological               -                      -                       -
values

In determining the best option, a strong consideration of energy and material input
was necessary. While the storm surge barrier successfully met many of the
objectives set out, the cost and complexity makes it a less desirable option. Planned
retreat may be a possibility, but it is hard to quantify the costs of this and the port
authorities would have the ultimate say whether or not they would want to change
the layout of the port.


3.0 Schematic Design Development

Once the preferred approach has been selected, a more detailed schematic design
should be performed to evaluate the technical feasibility of the design and the
resources required to implement it. This design procedure will be iterative in
nature. For the purposes of this case study, this level of detail will be sufficient and it
is not necessary to go to the level of complexity of construction drawings and bid
documents.


3.1 Design Layout

Drawings should be produced of the project site showing the design layout and the
critical data layers described in the site characterization. If applicable, typical cross-
sections should be developed.


3.1.1 Dike

Figure 18 shows the cross-section of a wet-wet dike that could be used in the
selected design. The structure would not have a dike toe due to low wave intensity.
Based on bathymetric data, an average depth of -1m was used in order to calculate
the height of the structure. While bathymetry may fluctuate, most of the
December 11, 2008                         Monetizing Exposure & Planning Defenses 28


surrounding area exists at -1m, indicating that the underwater topography is
relatively flat.

Here is an outline of the design parameters:
Location                            Auckland
                                    Symbol             Value           Units
Design Objectives                   Symbol             Value           Units
Projected Sea Level Rise                                           2   m
Design Event Return Period                                     10000   year
Protect harbor?                     Yes
Inlet Stabilization?                Yes
Design Criteria
Protection Length                                              1834    m
Freeboard                                                       0.5    m
Design Wave                                                     8.4    m
Storm Surge Level                                               1.9    m
                                                                       m
                                                                       (NGVD2
Mean High High Water Level                                       3.3   9)
                                                                       m
                                                                       (NGVD2
Mean Low Low Water Level                                        0.42   9)
                                                                       m
                                                                       (NGVD2
Sea Floor Elev. (avg.)                                            -1   9)
Management and Maintenance
methodology                         Roadtop access
Water Temperature (avg.)                                         10    deg. C
Dike Type                           Wet-Wet
Avg. shore-dike distance                                         20    m
Existing Conditions
Cold climate (ice issues)?          No
Latitude                                                        -36    degrees
Longitude                                                      174     degrees
Geologic stratification             Sand (x m), then bedrock (y m)
Foundation required?                No
Monitoring required
Subaerial beach profile             Yes
Subaquatic sediment profile         Yes

Design Elements
Dike Foundation Material            Concrete
Equipment Required
Base Width                                                  158.8      m
Height                                                        0.5      m
Volume                                                   145619.6      m3
                                                                       man-
Unit Labor                                                     0.015   hours
                                                                       man-
Total Labor                                               2184.294     hours
Unit Cost                                                       87     $/m3
COST                                                    12,668,905     $
Dike Toe Material                   Structural Fill
Equipment Required
Base                                                             33    m
December 11, 2008                        Monetizing Exposure & Planning Defenses 29

Inner side slope                                              1   m/m
Outer side slope                                             10   m/m
Height                                                        3   m
Volume                                                    90783   m3
                                                                  man-
Unit Labor                                                0.015   hours
                                                                  man-
Total Labor                                            1361.745   hours
Unit Cost                                                    17   $/m3
COST                                                  1,543,311   $
Dike Material                      Structural Fill
Equipment Required
Base                                                     125.8    ft
Inner side slope                                             3    m/m
Outer side slope                                             5    m/m
Height                                                    15.1    m
"Flat" top length                                            5    m
                                                     1549803.8
Volume                                                       6    m3
                                                                  man-
Unit Labor                                                0.015   hours
                                                                  man-
Total Labor                                               23247   hours
Unit Cost                                                    17   $/m3
COST                                                 26,346,666   $
Dike Armouring Material
(would allow for an access road)   Riprap
Equipment Required
Notional Permeability Factor       P                 NA           [-]
Inner side slope                                             3    m/m
Outer side slope                                             5    m/m
Exterior area                                           231983    m2
Depth                                                        2    m
                                                     463966.94
Volume                                                      97    m3
                                                                  man-
Unit Labor                                              0.015     hours
                                                    6959.5042     man-
Total Labor                                                46     hours
Unit Cost                                                  52     $/m3
COST                                               24,126,281     $
Underdrainage material             Geosynthetic membrane
Equipment Required
"Extra" material %                                        0.01
Width                                                  127.058    m
                                                     233024.37
Area                                                         2    m2
                                                                  man-
Unit Labor                                               0.015    hours
                                                     3495.3655    man-
Total Labor                                                  8    hours
Unit Cost                                                    5    $/m2
COST                                                 1,165,122    $
Underdrainage piping               PVC
Equipment Required
Diameter                                                   0.03   m
December 11, 2008                        Monetizing Exposure & Planning Defenses 30

Interval                                                      5    m
"Extra" material %                                          0.1
Indiv. Pipe length                                       138.38    m
Total pipe length                                     50757.784    m
                                                                   man-
Unit Labor                                                   0.5   hours
                                                                   man-
Total Labor                                           25378.892    hours
Unit Cost                                                     1    $/m
COST                                                     50,758    $
Pump Station Design                1000 HP Pump
Equipment Required
Total pumping capacity req'd                            450,000
Pump capacity                                           100,000    cfs
# of pumps                                                    5
Actual total pumping capacity                           500,000
                                                                   man-
Unit Labor                                                    80   hours
                                                                   man-
Total Labor                                                  400   hours
Unit Cost                                              8,250,000   $/unit
COST                                                  41,250,000   $
Dike Doors/Gates Required?         Yes
Space between doors                                          15    m
Door Width                                                   40    m
% Span covered by doors                                      25    %
Number of doors                                               8
                                                                 man-
Unit Labor                                                   200 hours
                                                                 man-
Total Labor                                                 1600 hours
Unit Cost                                                  1,000 $/door
COST                                                      15,000 $
Construction Crew Size                                        70 men
                                                                 man-
TOTAL CONSTRUCTION LABOR                                      20 years
TOTAL CONSTRUCTION TIME                                      0.3 years
TOTAL CONSTRUCTION COST                                      122 $M


3.1.2 Lock

To keep shipping channels open, a lock system would be necessary to pass traffic
through the dike.


3.1.3 Pumping and Drainage System

In order to properly dewater the area behind the dike, both gravity and enhanced
drainage are required. The average distance between the shoreline and the dike
structure is 20m.
December 11, 2008                          Monetizing Exposure & Planning Defenses 31


3.2 Material

Based on the design layout, the materials needed to construct the design should be
categorized and quantified.

For Auckland, materials were chosen based on sustainability for the design and a
spreadsheet tool was used to calculate the volume of each material needed. For
example, this is how to calculate the main dike section:

Main dike volume = (structure length)*[(outer trapezoid area)-(inner trapezoid area)]
Area of trapezoid = h*(B+b)/2


3.3 Equipment

The construction equipment required to carry out the design is an important factor
to consider when assessing the demands and limitations in constructing multiple
port protection projects simultaneously. For instance, there is a limited number of
large dredges available to gather sediment from the sea floor for use in construction.

While the Jones Act limits the use of foreign naval equipment in the United States,
New Zealand’s small size and limited resource base merits the need for foreign
vessels; thus, no such restrictions seem to apply.


3.4 Labor

An estimate of the required design labor, skilled labor, and unskilled labor should be
performed.


3.5 Construction Time and Sequencing

With the design scope and labor requirements laid out above, an estimate of the
construction duration should be calculated. Some level of construction sequencing
should be considered in order to show when the various resources will be needed
and for how long.

There are several timescales to be considered:
• Design – we estimate approximately 2 years of design work
• Construction – we estimate approximately <1 years of construction work
• Port growth and expansion – at the rate that the Port of Auckland is projected to
grow, this protection strategy will only grow more valuable over time
• Coastal management policies
• Sea level rise and global climate change
• Coastal landforms
December 11, 2008                          Monetizing Exposure & Planning Defenses 32



3.6 Cost

The objective of the case study is to develop a reasonable estimate of the cost to
implement the schematic design, and compare this to the value of the societal
benefits, physical capital, ecosystem services, and economic uses protected by it.

For the Auckland design, cost data from RS Means was used to estimate the cost of
materials, equipment, and labor required. However, this data does not incorporate
regional fluctuations in pricing. Monitoring and operations and maintenance were
excluded from this report for simplicity.

Here is a breakdown of the cost of the chosen design:

Design Element                              Cost($M)
Dike                                        122
Gates system                                330
Pump system                                 41
Annualized dredging cost                    0.3

TOTAL                                       493.3

Considering the value of exposed assets—both current and future—and the port
revenue, the total cost would be a net gain for the Port of Auckland.

The cost of the proposed project amounts to $493.3 million USD.


3.7 Impact on Ecosystem Functions and Landforms

Any project on the scale to protect a port will require some type of Environmental
Impact Assessment/Report (EIA/EIR), although the specifics of this analysis will
vary from country to country. At a minimum, in order to develop a sustainable and
satisfactory design, the following areas must be addressed in the impact analysis
(POLB 2006):
      • Sediment budget
      • Biota and Habitat creation/loss
      • Air quality and health risks (including projected emissions based on traffic
      increase forecasts)
      • Best management practices (BMPs) to be used
      • Environmental justice considerations
      • Geologic resources, coastal processes
      • Noise
      • Aesthetic and visual resources
      • Water quality
December 11, 2008                           Monetizing Exposure & Planning Defenses 33



3.8 Societal Impacts

A project of this scale will have significant societal impacts, which should be
anticipated and addressed as part of the design.
      • Socio-economics
      • Recreation
      • Utilities and service systems
      • Cultural Resources
      • Transportation - vessels, ground


3.9 Design Limitations and Next Steps

Along with the strengths we have highlighted in the proposed design, we wish to
truthfully and fully acknowledge its weaknesses and limitations.


3.9.1 Data Availability

One of the hardest aspects of this report was access to pertinent data. Much of the
cost data, bathymetric data, and port-specific data were hard to find, not available
without payment, or difficult to decipher.

This presents an interesting challenge for all coastal engineers; if the most basic of
data necessary to embark on such a project is not readily available, how quickly can
plans be drawn up and realized? While true engineers surely have better access to
data, there should be no reason to limit the concerned public from investigating
themselves.


3.9.2 Environmental Impacts

This project is a response to one of the biggest effects of climate change: sea level
rise. Thus it would seem responsible to keep climate issues and environmental
accountability in mind throughout this project. Construction and use of materials
can have a large carbon footprint; this is part of the reason the dike model was
chosen instead of the storm surge barrier.

The structure itself will inevitably have an environmental impact. By placing a large
barrier on the sea floor, marine habitats are disrupted, sedimentation occurs and
leads to build-up, and deflected wave energy may cause erosion in areas previously
not experiencing such an effect. While these impacts are a) hard to predict, and b)
hard to monetize, they should be considered as consequences in any potential
design.
December 11, 2008                         Monetizing Exposure & Planning Defenses 34


3.9.3 Impacts from storm events greater than design storm

Much of the current coastal protection paradigm is based on the notion of maximum
acceptable risk. Thus, our design is centered on the extreme water level expected to
have a 1 in 100 chance of occurring every year. However, little has been said about
what the damages and repercussions would be if the storm event were to exceed
this level. Would it completely destroy infrastructure to a degree that a massive,
lengthy reconstruction effort would be required, or would it simply cause a several-
day disruption of port operations?


3.9.4 Permitting Requirements

A project on the scale proposed in this case study would require a complex
permitting effort in order to be approved and constructed. Although every effort has
been made to create a detailed and rigorous proposal, it is understood that a much
more detailed design would be required in order to submit this project for a bid and
for permitting.


4.0 Incorporation of Results in Overall Project

The results from this case study and the various other case studies being developed
will contribute to the overall goals of the Stanford Project. In particular, the 178
ports that we are studying will be divided into groups according to the case study
they are most similar to. In this way, we will have a suite of 5-10 different design
alternatives to choose from and adjust to each port (rather than applying the first-
pass design to all ports).

In order to generate widespread dialogue and interest, it is important to make the
results of the case study widely available. There are many avenues through which
this can be pursued, for example:

     • Academic journal article
     • Google Earth - upload data to the online Gallery
     • Talks/presentations
     • Academic course

In conclusion, through this project we have determined an upper bound on the
engineering effort and the cost associated with protecting the major ports of the
world. Put another way, the world should not spend more than $XYZ billion on
coastal defenses for the top 178 ports; however, if they did spend $XYZ, it can be
reasonably guaranteed that they will be protected from the 1 in 1,000 year event. As
acknowledged by the authors of the 2008 OECD report, any concerted effort to
address the issue of sea level rise via a proactive response will require decades of
December 11, 2008                          Monetizing Exposure & Planning Defenses 35


planning and construction before becoming operational. As we look at the
challenges of the 21st century, protecting the populations, assets, and international
trade systems made vulnerable by global climate change looms large. Our desire is
that this project will generate widespread dialogue and interest on this issue so that
this problem can be addressed in a sustainable manner not just for those countries
with high GDP, but also for all those who will be affected.
December 11, 2008                           Monetizing Exposure & Planning Defenses 36


References Cited

Auckland UniServices Limited. (1992). “Wind Opinion on the Proposed Apartment
      Building ‘The Beaches’, Corner of Wharf Road and Hattaway Avenue,
      Bucklands Beach.”

Bell, R.G., Goring, D.G., and de Lange, W.P. (2000). “Sea-level change and storm
        surges in the context of climate change.” IPENZ Transactions 27(1) 1-10.

Conservation International. (2007). “New Zealand.”
      <http://www.biodiversityhotspots.org/xp/hotspots/new_zealand/Pages/de
      fault.aspx>. (Dec. 7, 2008).

De Lange, W.P., and Healy, T.R. (2001). “Tsunami Hazard for the Auckland Region
      and Hauraki Gulf, New Zealand.” Natural Hazards 24 267-284.

Deltawerken. (2004). “The Oosterschelde storm surge barrier.” <
      http://www.deltawerken.com/The-Oosterschelde-storm-surge-
      barrier/324.html>. (Dec. 2, 2008).

Fischer, M., et al. (2008). “STANFORD UNIVERSITY ENGINEERING AND PUBLIC
       POLICY FRAMEWORK PROJECT: Climate Change and its Impacts on the Built
       Environment in the Coastal Zone.”

Google. (2008). “Google Earth.”

Land Information New Zealand. (2008). “Auckland Harbour East.”

Liu, Z., and Bird, P. (2002) “Finite element modeling of neotectonics in New
         Zealand.” J. Geophys. Res., 107(B12).

Murphy, Martin J., and Tindle, Chris T. (1999). “Microseisms and Ocean Wave
     Measurements.” IEEE Journal of Oceanic Eng., 24(1) 112-115.

Nicholls, R. J. e. a. (2008). “Ranking Port Cities with High Exposure and Vulnerability
       to Climate Extremes.” OECD Environment Working Papers, OECD Publishing.

POLB, P. o. L. B. P. D. (2006). "Environmental Protocol."

Ports of Auckland. (2006). “PortFolio 2006.”

RS Means. (2006). Building Construction Cost Data, 64th Annual Edition, Construction
      Publishers and Consultants, Kingston, Massachusetts.

Tingle, A. (2008). “Firetree Flood Maps.”

United States Department of Agriculture: Forest Services. (2008). “More About
       Ecosystem Services.”
       <http://www.fs.fed.us/ecosystemservices/About_ES/index.shtml>. (Dec. 7,
       2008).

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:4
posted:12/25/2010
language:English
pages:37