Reise Reise
Development Strategies for Bremenports
in Response to Sea Level Rise and Climate Change
Henning Roedel
CEE 224A
Professors Martin Fischer and Ben Schwegler
9 December 2008
STANFORD UNIVERSITY ENGINEERING AND PUBLIC POLICY FRAMEWORK PROJECT:
Climate Change and its Impacts on the Built Environment in the Coastal Zone
0.0 Project Introduction
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). Although the MSL changes differ depending on
the location in question (Church et al. 2001) it is clear that new risk management strategies are needed. These include
managing subsidence, landuse planning, selective relocation, and flood warning and evacuation (OECD). 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. 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 177 most significant ports in terms of economic value will cost
approximately $70 billion (USD) and will take about 50 years, assuming unconstrained resources and simultaneous
construction at all ports. 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 177 ports rises to 170 years.
This paper is a case study on developing a protection strategy for the Ports of Bremen and Bremerhaven. 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 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. Ports are also tied to the coast and very difficult—if not impossible—to
relocate, due to the vast 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 updated data availability for them.
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 Bremerhaven and Bremen, 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 Bremerhaven would require 3 marine dredges during construction, which would then not be
available to be used simultaneously in other concurrent projects. If the schematic design 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 local, regional, and worldwide levels.
This is intended to be a collaborative effort. As part of this teamwork, we have begun a shared listing of resources that
are useful in preparing a case study, which can be accessed by clicking here. Please update this listing with material that
you have found useful.
0.4 Summary of Desired Result
The successful case study will include a schematic design of a port protection system and an estimate of the resources
required to fully design and construct it. This shall take into account regional resource availability, costs, and feasibility.
Each of these requirements are described in detail below.
0.5 Audience
The intended audience for this methodology is student research teams at universities worldwide that are taking part in
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).
0.6 Units
Every attempt is made to use metric units throughout this project. All prices are in US dollars ($) unless otherwise
indicated.
0.7 Roadmap of the Method
A quick summary of the steps involved in developing a case study is shown below, and much more detail is given to each
in subsequent sections:
•
Site identification
•
Conceptual design alternatives evaluation
•
Schematic design development
•
Incorporation of results in overall project
1.0 Site Identification: bremenports
Situated along the Weser River, two of Germany’s three largest ports, the Port of Bremerhaven and the Port of Bremen
handle more than 55 metric tons of cargo every year and serve as major hubs of the German economy. For this case
study, the two ports are being studied in conjunction because of the single management group in charge of both ports,
their close proximity to each other and their shared use of the Weser River.
These sites were selected because of their high economic value and relatively low elevation with respect to sea level. As
with most major ports, these two ports are essential for economic vitality, have a concentration of valuable
infrastructure, and would be very difficult to relocate.
1.1 Port Operations, Infrastructure, and Contiguous Community
Bremenports has been managing the Bremen / Bremerhaven port group on behalf of the Free Hanseatic City
of Bremen (municipality) since January 2002. The establishment of bremenports represents a milestone in Bremen’s port
policy. For the port location to the private sector concept signifies an adaptation of the previous port administration to the
structure of the companies operating here and thus an enhancement of the efficiency and flexibility of the ports in
general1.
Through bremenports a German universal port is managed on a private enterprise basis for the first time. In this way the
Ports of Bremen and Bremerhaven have achieved a unique position among the northern German seaports during a period
of fierce competition, but have also opened up great market opportunities1.
The legal form of the company is that of a GmbH & Co. KG (limited commercial-partnership with a limited liability
company as general partner)1.
According to Bremenports’ strategic plans, the operators have focused on individual port growth based on increasing
demands in automotive transport (for Bremerhaven), and general goods (for Bremen). The ports handled a combined
total of more than 55.6 metric tons of cargo, more than 4.5 million TEUs.
Recently, Bremenports has announced that it is looking into the issues regarding sea level rise and climate change
events2.
Logistical support for the ports is largely provided by the Bremen rail company, a public railway infrastructure company
that provides its users with an efficient track network for transporting goods of all kinds1. The tracks are intimately linked
to major container facilities in both ports and connect with greater rail lines throughout the German mainland.
1.2 Topography and Bathymetry
1.2.A Bremen
Figure 1 - An image from Google Earth showing the topography around the Port of Bremen (shown in red)
1.2.B Bremerhaven
Figure 2 - An image from Google Earth showing the topography and bathymetry around the Port of Bremerhaven
(shown in red)
It should be noted that the area surrounding Bremerhaven is low and flat, which is subject to flooding during major storm
events from the North Sea and is also subject to flooding from the Weser River. The area subject to flooding extends
down to Bremen, and can be seen in Figure 3.
Figure 3 - Bathymetry of German Coastline, dark areas are prone to flooding from Sea Level Rise
1.3 Design Conditions, Acceptable Risk, and Vulnerability Assessment
Based on calculations from a 1 meter sea level rise scenario, the recurrence of storm floods that presently have a
probability of 1:100 will increase to a 1:10 or even 1:1 probability. It is well understood by the German people and
Government that there are great risks associated with even 1 meter of sea level rise, and actions are going to be taken to
mitigate and adapt to sea level rise and climate change. However due to flood frequency changes associated with sea
level rise and climate change, assets at risk are hard at this point to quantify accurately4. However, German Engineers
typically use a 100-year design scenario.
For the Bremenports area, assets affected have been valued at DM151 billion (1995), with an area of 323 km2 affected.
The affected population for the Bremen State is estimated to be 631,000, or 92% of the population in that area4.
Looking at the German Coastline affected by 1 meter sea level rise and climate change, a total of 3.9% of the country’s
population, 3.8% of Germany’s country side, and 3% of the country’s assets are affected4.
1.4 Hydrology and Hydraulics
The longest river located entirely within Germany, the Weser River is the primary link between the two ports and the link
to the international shipping lanes. The river has an average discharge of 327m3/s and a length of 427km along its
discharge basin3.
Figure 4 - Weser River Watershed
The Weser River has recently been heavily engineered to curb flooding in historical flood basins. The local area receives
an annual rainfall of 800-1000mm/yr.
From the city of Bremen down to the Weser’s mouth, the river is subject to a 4 meter tidal cycle from the North Sea, as
seen in Figure 5 below. A major lock separates the typical river flow from tidal fluctuations, and can be seen in Figure 6,
also below.
Figure 5 - Weser Stage Height downstream of Bremen
Figure 6 - Lock Separating Weser River Flows from Tidal Fluctuations
Flooding from the North Sea is also an issue for Bremenports, as Bremerhaven is located along a flat low-lying area.
Figure 7 - Bathymetry Flooding for 2M Sea Level Rise
Figure 8 - Flooding of the North Sea near Bremerhaven
2.0 Conceptual Design Alternatives
The goal of this section is to consider the most commonly used designs in coastal protection— both structural and nonstructural—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.
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 (Mass. CZM).
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.
Sort
Category
Protection
Strategy
Primary Application
Cost
Implementation
Time
Design
Tradeoffs
Scale
Complexity
Strengths
Weaknesses
Example
Applications
1
Hard construction
Artificial Reef
Retard erosion, promote
natural sedimentation,
establish wetlands, enhance
ecology
$$$
1-5 years
materials
10 to
10,000 m
High
Both wave
mitigation
and
ecological
benefits
Does not
control
flooding
USACE
structures
1
Hard construction
Breakwater
Retard erosion, promote
natural sedimentation,
establish wetlands, shelter
harbor basins/entrances
$$$
1-5 years
materials,
subaerial vs.
subaquatic
100 to
10,000 m
Medium
Wave
mitigation,
wellestablished
Does not
control
flooding
USACE
structures
1
Hard construction
Dike (wet-wet)
prevent or alleviate flooding
by the sea of low-lying areas
$$$
1-10 years
materials,
geometry,
revetment
250 to
20,000 m
High
Both flood
control and
wave
mitigation
Large scale,
aesthetic and
navigational
impacts
Netherlands
1
Hard construction
Enhanced
gravity
drainage
Combine drainage sewers with
locks and flapgates to prevent
excess flooding during high
tide / flood conditions
$
1-2 years
modifying
existing
systems vs.
building new
systems
1 to
1,000+
km2
Low
Simple,
retrofit
options
Limited
applicability
in low-lying
areas
1
Hard construction
Forced
drainage
(pumping)
Prevent flooding by moving
water
$
3-6 months
pumping
capacity,
power source
0.1 to
100+
km2
Medium
Flood
control in
low-lying
areas
Energy
intensive
1
Hard construction
Groin
Prevent local beach erosion
$$
1-2 years
materials,
design life
100 to
500 m
Low
Simple,
wellestablished
Can cause
increased
erosion
USACE
structures
1
Hard construction
Jetty
Stabilize navigation channels
at river mouths and tidal
inlets
$$
1-2 years
materials,
design life
100 to
5,000 m
Low
Simple,
wellestablished
Can cause
increased
erosion
USACE
structures
1
Hard construction
Levees /
Training Walls
Keeps river from flooding its
banks
$$$
1-10 years
materials
1 to
100+ km
Medium
Does not
interfere
with
navigation
Landintensive due
to large scale
USACE
structures
1
Hard construction
Lock
Allow ships to access a
channel that is maintained at
a different elevation than the
sea
$$$
1-10 years
gate type,
ship size,
operational
complexity,
energy input
100 to
1,000+
m2
High
Allows for
flood
control
Cost,
complexity
Panama
Canal
1
Hard construction
Pile structure
Provide deck space for traffic,
pipelines, etc., and provide
mooring facilities
$$
1-2 years
flexibility
as
needed
Low
Simple
Difficult to
retrofit
1
Hard construction
Pipeline outfall
Supports the pipeline
$
6-12 months
flexibility
as
needed
Low
Simple
Vulnerable to
storms,
aesthetics
1
Hard construction
Scour
protection
Prevents the undermining of
shorefront structures
$
3-12 months
design life
as
needed
Low
Simple,
retrofit
option
Limited
protection
1
Hard construction
Seawall (wetdry)
Protect land and structures
from flooding and overtopping
$$
1-5 years
materials,
design life
100 to
5,000 m
Low
Simple,
wellestablished
Can cause
increased
erosion
1
Hard construction
Storm surge
barrier
Protect estuaries against
storm surges
$$
1-5 years
materials
100 to
10,000 m
High
Wave
mitigation,
some flood
control
Complexity
1
Hard construction
Tidal barrage
Protect embayments against
storm surges
$$
1-5 years
materials
100 to
10,000 m
High
Wave
mitigation,
some flood
control
Complexity
2
Medium construction
Dune
construction
Prevent beach erosion,
protect against flooding
$$
1-2 years
vegetation
type, material
sourcing and
transportation
100 to
10,000 m
Medium
"Natural"
solution
Hard to
control
2
Medium construction
Floating
breakwater
Shelter harbor basins and
mooring areas against shortperiod waves
$$
6-12 months
materials,
design life
100 to
5,000 m
Medium
Wave
mitigation
Does not
control
flooding
2
Medium construction
Flood diversion
channel
Divert floodwaters away from
sensitive structures
$$
1-2 years
materials
as
needed
Medium
Simple
Need
receiving
body
Oosterschelde
- Netherlands
Japan
3
Soft construction
Beach
Nourishment
Prevent beach erosion,
protect against flooding
$$
3-6 months
material
sourcing and
transportation
100 to
20,000+
m
Low
"Natural"
solution
Hard to
control
4
Non-construction
Holistic
management
To be applied to ports or other
coastal infrastructure
$
3-6 months
education
as
needed
Low
No
construction
Institutional
and
legislative
inertia
4
Non-construction
No action
Areas with no risk from sea
level rise or severe storms
$
immediate
level of detail
in analysis
as
applicable
Low
Cheap,
simple must
be
considered
Difficult to
delineate
when this is
appropriate
4
Non-construction
Planned
retreat
Low-value coastal
development can be
purchased by local
government or traded for
inland property
?
?
timescale,
compensation,
removal vs.
eventual
abandonment
as
applicable
Low
No
construction
Institutional
and
legislative
inertia
4
Non-construction
True-cost
insurance
Price property insurance
according to a real evaluation
of flooding, erosion, and sea
level rise related risks
$
3-6 months
level of detail
in analysis
as
applicable
Low
No
construction
Institutional
and
legislative
inertia
4
Non-construction
Zoning
restrictions
Limit development in areas
prone to flooding, erosion,
and/or wave impacts
$
3-6 months
level of detail
in analysis
as
needed
Low
No
construction
Institutional
and
legislative
inertia
Notes
1. Category: the "hardness" of a coastal structure refers to its permanence
2. Protection Strategy: these strategies have been compiled from various sources (please see Works Cited)
3. Primary Application
4. Secondary Application
5. Cost: refers to the full lifecycle cost of implementing the protection strategy relative to the other stragies in the matrix
6. Implementation Time: refers to the time needed from the beginning of the design phase to the beginning of full functionality
7. Design Tradeoffs: the main choices to be made in designing an application of the protection strategy (not including obvious decisions like site selection, layout, etc.)
8. Shoreline length protected: typical and/or feasible linear shoreline length directly protected by implementing the strategy
9. Complexity: an overall metric of the complexity of the strategy's design, implementation, and maintenance
10. Example Applications: projects where this strategy has been implemented that can be studied as sources for additional information
Design Criteria focused the following priorities, which were chosen based on a 2 meter sea level rise event
Primary Goals
1) Protect port facilities
2) Protect rail infrastructure
Secondary Goals
1) Minimize length
2) Minimize cost
3) Minimize blockage of Weser River
Based on these criteria, and available data, design options for each port incorporating wet-wet and wet-dry dikes and
locks were created. Figures 9 and 10 show the proposed locations for each design. As an alternate to this design
scenario a similar option is suggested that would replace the wet-wet dikes with wet-dry sea walls along the port existing
port facility perimeter.
It should be noted that protecting the coastline of Lower Saxony, which is intrinsically linked to the North Sea and Weser
River, was not taken into consideration because the guidelines of this project were to protect the ports. As such a third
option is considered, which is derived from an official General Plan recently put in place for Bremen and Lower Saxony,
which will also be discussed in this paper.
Southern
California
beaches
Figure 9 - Bremerhaven Port Protection Design Outline (shown in yellow)
Figure 10 - Bremen Port Protection Defense Outline (shown in yellow)
Based on the original options, there are 43.39km of levee for Bremerhaven and 17.22km of levee for Bremen.
2.0.1 Material Cost Data
Material
Cost
Unit
Rip-rap and rock lining, machine
placed for
slope protection
Gabions, galvanized steel mesh mats
or
boxes, stone filled, 36 inches deep
Aggregate, select structural fill,
spread with
200 H.P. dozer, no compaction, 2 mi
RT
haul
Concrete, plant-mixed bituminous, all
weather patching mix, hot
$52
Linear m3
$145
m2
$17
m3
$87
m3
2.1 Option 3 – Official Response5
As it has been mentioned previously throughout this report, Germany has realized the risks associated with their
situation, and has begun to take action. Instead of constructing any new major facilities, the current proposal is
increasing current protection structure heights by 25 cm across the area shown in Figure 11 below. The current plan is
scheduled to be complete by 2017, and further adjustments to be made in 20 year increments, or earlier if necessary.
The proposal set forth from Germany incorporates mitigation and adaptation strategies, including but not limited to
reduction of greenhouse gases from operations and daily life, development of retention areas, and the aforementioned
existing structure improvement.
Figure 11 - Location of Improvements to be Completed by 2017
Figures 12 and 13 show current dike heights along Bremerhaven, an explanation for their variance has not be provided.
Figure 12 - Current Heights of Dikeline in Bremerhaven From Southern State Boundaries to Sport boat Flood Gate
Figure 13 – Current Heights of Dikeline in Bremerhaven From Sportboat Flood Gate to Northern State Boundaries
Additionally, improvements in the Luneplate region, just west of Bremerhaven have been discussed at length. The
Luneplate region is being developed with an increased dikeline, with flood and tide gates to allow use of retention fields
and power generation. Figure 14 shows the conceptual schematic for this line.
Figure 14 - Luneplate Retention Development Schematic
2.1.1 Option 3 – Estimated Costs
Based on estimates from Germany, costs for the Bremen and Lower Saxony General Plan are expected to run 85 Million
€/year until 2017. Coastal development costs for the whole of Germany are expected to run 160 Million €/year until
2017.
3.0 Schematic Design Development
For the basis of comparison only, costs associated with option 1 were developed, and are compared to option 3, the
actual General Plan. This section will display costs and construction requirements of the improvements, show a typical
cross section for the proposed dikes, and discuss the implications of choosing such a design.
3.1 Costs, Materials, and Labor
The total costs for the development of option 1 is $2.99 billion, split 80% for Bremerhaven and 20% for Bremen. This
can be attributed to higher design requirements for Bremerhaven, which has a significant portion of its dike in the Weser
channel, whereas Bremen’s defenses are located on land, and are much lower.
Total Materials requirements for Bremerhaven are listed in the table below.
Material
Quantity
Unit Price (including
Labor)
Structural Fill
71,000,000 m3
$17/m3
Concrete
4,030,000 m3
$87/m3
Riprap
14,400,000 m3
$52/m3
Geosynthetic Membrane
7,590,000 m2
$5/m2
Pumps
5 ea
$8,250,000/ea
PVC
2,650,000 m
$1/m
Total Materials requirements for Bremen are listed in the table below.
Material
Quantity
Unit Price (including
Labor)
Structural Fill
11,900,000 m3
$17/m3
Concrete
1,600,000 m3
$87/m3
Riprap
3,910,000 m3
$52/m3
Geosynthetic Membrane
2,030,000 m2
$5/m2
Pumps
5 ea
$8,250,000/ea
PVC
710,000 m
$1/m
Expanded Price
$1.21 billion
$351 million
$750 million
$38 million
$41 million
$2.65 million
Expanded Price
$202 million
$139 million
$203 million
$10.2 million
$41 million
$0.71 million
Based on an average production rate of 0.015 man-hour/m3 for dike construction, 0.5 man-hour/m for pipe installation,
and 80 man-hour/ea for pump installation, total man-years were calculated for each project. Bremerhaven had a total of
701 man-years, and Bremen had a total of 140 man-years. From this crew sizes for Bremerhaven and Bremen were
chosen to be 200 and 150 respectively, which gave a total duration of 3.5 years and 0.9 years respectively.
Costs, and labor for locks are estimated to be $330 million each, and require 288,000 man-hours each. Option 1 did not
attempt to quantify how many locks were necessary to support current ship traffic for each port, due to the complexity of
waterfront change associated with the design.
3.1.1 Equipment
It should be noted that the types of equipment required for this design have not been chosen, however a general
assumption of heavy earthwork and dredging equipment would be necessary to build such an option.
3.2 Typical Dike Cross Sections
Show in Figures 15 and 16 on next page are the typical dike cross sections for Bremerhaven and Bremen.
Figure 15 - Typical Dike Cross Section for Bremerhaven
Figure 16 - Typical Dike Cross Section for Bremen
3.3 Impacts of Design
Unfortunately option 1 is truly unfeasible due to the impacts it would have on the German landscape. If chosen, the
Weser River would dump into the North Sea at Bremen, instead of Bremerhaven. Many thousands of square kilometers
would be lost due to sea level rise flooding, greatly affecting Lower Saxony.
Additionally sedimentation backup issues in the Weser River would arise in the Port of Bremen due to the blockage of the
river into the North Sea by the proposed lock system.
Issues regarding the infrastructure to the ports, while considered, were not strictly taken into account, as the primary
focus was just to protect the ports. Regrettably, the infrastructure of Bremerhaven would most likely be underwater due
to flooding from sea level rise.
4.0 Incorporation of Results into Overall Project
Use of the data from option 1 in the overall project is not recommended. Instead, research effort should be placed on the
General Plan that has been adopted by Bremen and Lower Saxony, of which, pertinent data (such as materials, labor, and
equipment) should be incorporated into the overall project.
Furthermore, it is recommended that similar research be conducted on the Netherlands project which will be consuming
an estimated 2 billion euro/yr from now until 2050. With two major projects competing for resources in the same area, it
is this author’s belief that many insights that would benefit the overall project can be discovered by looking into the
projects.
5.0 Annotation
1. http://www.bremenports.de/
2. Email conversation with Mr. Uwe Von Bargen
3. Wikipedia article on Weser River
4. Assessment of Vulnerability and Adaptation to Sea-Level Rise for the Coastal
Zone of Germany.pdf, Horst Sterr, March 2008
5. Meeresspiegelanstieg.pdf, Uwe von Bargen, November 2008