&EPA
United States
Environmental Protection
Agency
Climate Resilience Evaluation and Awareness Tool Exercise with Manteo and
Columbia, North Carolina and the Albemarle-Pamlico National Estuary
Partnership
Potential Inundation
0.4 meters (1.3 feet)
1.0 meters (3.3 feet)
^| 1.4 meters (4.6 feet)
Figure 1. Map of Sea Level Rise Vulnerability
Credit: Tom Allen, Eastern Carolina University
CLIMATE READY
J/VATER UTILITIES
CLIMATE READY
ESTUARIES
Office of Water (4608-T) | EPA 817-B-13-002 | June 2013
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Foreword 1
1. Introduction 2
1.1 Project Background 2
1.2. Manteo - Background Information 3
1.3 Columbia- Background Information 3
1.4 Albemarle-Pamlico National Estuary Partnership (APNEP) 4
2. GREAT Exercise Results 4
2.1 GREAT 2.0 and Sea Level Rise Data and Resources 4
2.1.1 Sea Level Rise Projections 6
2.1.2 GREAT SLR Data 6
2.1.3 Data from the NC Science Panel 8
2.1.4 Sea Level Rise Mapping-NC Coastal Atlas Tool 9
2.2 Scenario Planning, Time Periods, and Consequence Weighting 9
2.2.1 Scenario Planning 10
2.2.2. Time Periods 10
2.2.3 Consequence Weighting 10
2.3 Prioritizing Assets 11
2.4 Prioritizing Threats 11
2.5 Existing Adaptive Measures 12
2.6 Potential Adaptive Measures 14
2.7 Baseline and Resilience Analysis Discussion 14
2.7.1 Re-assessing Consequences 15
2.7.2 Adaptive Measure Contribution 16
2.7.3 Examining Risk Reduction- Resilience Analysis 16
2.8 Implementation Planning - Adaptation Packages for Manteo and Columbia 17
2.9 Results and Reports 19
3. Conclusion 20
3.1 Future Use of GREAT in Manteo, Columbia, and other North Carolina Communities 20
3.2 Additional Feedback from Participants and Next Steps 20
References 22
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Appendices
Appendix A. Exercise Participants List
Appendix B. Baseline and Resilience Consequence Weighting Inputs
Appendix C. Adaptive Measure Contribution Inputs
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Climate Ready Water Utilities - Climate Ready Estuaries GREAT Exercise Report
Foreword
Current watershed management practices may not be sufficient to cope with the potential effects
of climate change on aquatic ecosystems, water supply, water quality and coastal flooding. As a
result, there is a need to identify regional consequences from climate change and to develop
adaptation strategies that can be integrated at a watershed scale. The U.S. Environmental
Protection Agency's (EPA) Climate Ready Water Utilities (CRWU) and Climate Ready
Estuaries (CRE) initiatives are working to coordinate their efforts and support climate change
risk assessment and adaptation planning. Both EPA initiatives focus on addressing climate
change and water resource issues with stakeholders that share common interests regarding
watershed management. This report details a recent climate change adaptation exercise that
provided an opportunity for these parties to collaborate on assessment and planning with respect
to potential climate change impacts on natural resources and utility infrastructure.
EPA's CRWU and CRE initiatives collaborated with a workgroup comprised of town officials
and water managers from Manteo and Columbia, North Carolina, as well as representatives from
the Albemarle-Pamlico National Estuary Partnership (APNEP). This exercise provided an
opportunity for the towns to increase their awareness of climate change and begin the process of
developing both a climate change risk assessment and adaptation plan. Additionally, this
exercise educated workgroup members, including APNEP staff, on EPA's Climate Resilience
Evaluation and Awareness Tool (GREAT) in order to support their use of the tool in other
APNEP communities.
For this exercise, GREAT was used as a framework to identify climate change threats and
vulnerable assets and to evaluate adaptation options in both Manteo and Columbia.
Stakeholders collaborated on risk assessment and adaptation planning related to projected
climate change impacts. The exercise also provided an opportunity to compare climate change
projections for sea level rise (SLR) from GREAT to SLR projections developed by the North
Carolina Coastal Resources Commission's Science Panel on Coastal Hazards (NC Science
Panel). GREAT also provides climate change projections for temperature, precipitation and
intense precipitation. These projections helped to support the identification of potentially
vulnerable assets and assist each town with beginning the process of adaptation planning to
address potential vulnerabilities. GREAT's risk assessment framework and input from
workgroup members provided valuable information and perspectives on water resources
management throughout this exercise. To address projected climate change impacts in each town,
participants discussed potential adaptive measures that may be implemented in the future.
Participants noted the value of the collaborative process throughout the GREAT exercise,
especially as the workgroup identified vulnerable assets and climate change threats in Manteo
and Columbia, refined consequence levels and examined potential implications related to future
regional SLR. The risk assessment and planning framework supported by GREAT enabled
stakeholders to gain new perspectives to inform future planning efforts.
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Climate Ready Water Utilities - Climate Ready Estuaries GREAT Exercise Report
1. Introduction
To assess projected climate change impacts and build upon ongoing water resources
management efforts in the Albemaiie-Pamlico watershed, EPA's CRWU and CRE initiatives
collaborated with a workgroup comprised of representatives from APNEP and the Towns of
Manteo and Columbia1, NC. This workgroup identified consequences from climate change,
began to develop adaptation strategies at the watershed level and helped to inform ongoing planning
efforts in the region. This exercise consisted of a series of webinars and two-in person meetings
held from June through September 2012, as well as follow-on discussions.
Exercise Objectives:
• Utilize EPA's Climate Resilience Evaluation and Awareness Tool (GREAT) to develop
and document climate change risks/consequences as they relate to Manteo and Columbia,
including consideration of the reasonable range of potential climate impacts.
• Begin to assemble adaptation strategies for effectively addressing climate change risks
through implementation of adaptive measures in Manteo and Columbia.
• Educate workgroup members, including APNEP staff, on EPA's GREAT in order to
support the use of the tool in other APNEP communities.
Note: Throughout this exercise, inputs for each town's GREAT analysis files were suggested by
various members of the workgroup. These inputs are not necessarily exhaustive of all possible
inputs andean be revised in the future.
1.1 Project Background
The Towns of Manteo and Columbia are located in North Carolina's Albemarle-Pamlico
watershed. Manteo is situated along the coast on Roanoke Island in Dare County. Columbia is
located approximately 40 miles west of Manteo, along the banks of the Scuppernong River in
Tyrell County.
Both locations have suffered some damage to natural resources and water-sector infrastructure
from heavy precipitation events, as well as coastal and inland storm surge. This damage is
expected to be further exacerbated by projected climate change impacts unless adaptation steps
are taken. Scientific projections indicate that coastal North Carolina may experience significant
SLR of approximately 1 meter by 2100 (NC Science Panel, 2010). Climate change projections
also indicate that the southeastern United States will experience an increase in the intensity of
Atlantic hurricanes. Projected increases in evaporation and plant water-use rates are also likely
to lead to saltwater intrusion into shallow aquifers (EPA, 2012).
Manteo and Columbia are very familiar with impacts from extreme weather events such as
hurricanes. In August 2011, Hurricane Irene made landfall in North Carolina, bringing
approximately 7-8 inches of rainfall to many coastal and inland communities. Climate change
1 For a list of exercise participants, see Appendix A.
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Climate Ready Water Utilities - Climate Ready Estuaries GREAT Exercise Report
projections, in addition to recent impacts from extreme weather events, illustrate the current and
potential natural resource and infrastructure vulnerabilities along the North Carolina coast.
1.2. Manteo - Background Information
Manteo is a small coastal community, with a resident population of approximately 1,434 (U.S.
Census Bureau, 2010). Manteo is approximately 1.8 square miles in size, and situated within the
100-year floodplain of the Albemarle and Pamlico sounds. Because of its geographic location,
Manteo experiences extreme weather events and is susceptible to climate change impacts.
Recently, Manteo experienced severe impacts from Hurricane Irene and has taken action to adapt
to impacts from extreme weather events and climate change. To better adapt to flooding from
coastal storm surge and heavy precipitation events and associated disruptions in wastewater
treatment processes, Manteo raised its wastewater treatment plant's (WWTP) master lift station
at Bowsertown Road. Manteo also installed a new SCAD A system, allowing the plant to operate
in a more energy efficient manner at various treatment stages, which has reduced the utility's
energy bills. While the increased resilience of the WWTP master lift station and energy bill
savings are encouraging steps, stakeholders noted that the town's capital budget for future
upgrades is currently limited due to these recent expenditures.
During the GREAT exercise, Manteo focused on assessing impacts associated with wastewater
infrastructure. Manteo receives its drinking water from a wholesale provider, Dare County
Water Department. While stakeholders from Manteo acknowledged that drinking water
infrastructure may be impacted by climate change, the town's drinking water infrastructure was
not considered during the GREAT analysis.
1.3 Columbia - Background Information
Columbia's resident population is approximately 891. The town is situated almost entirely in
the 100-year floodplain of the Scuppernong River, and the water table is just inches below the
ground's surface (Nicholas Institute, 2011).
Heavy precipitation events and inland effects from coastal storm surge, as well as saltwater
intrusion, already impact Columbia's natural and built infrastructure. During Hurricane Irene,
Columbia's drinking water treatment plant was not flooded, but the water was uncomfortably
close to inundating its facility. Given projections of increased rainfall amounts and the risk
associated with flooding from extreme weather events, the treatment plant is projected to be
more vulnerable in the future. Saltwater intrusion into the town's Castle-Hayne Aquifer is
starting to occur, and the town relies on three groundwater wells in this aquifer for its drinking
water supply. Columbia's WWTP infrastructure includes a treatment plant, three lift stations,
three secondary pump stations, and one primary pump station. Columbia treats its wastewater
and discharges it using a dispersed discharge system into the Scuppernong River. In addition to
residences and small businesses, two major industries in Columbia contribute to the amount of
treated wastewater, a professional laundry facility and a seasonal blue crab processing plant.
Currently, heavy precipitation events and inland flooding from storm surge already impact pump
stations and parts of the collection system. In order to reduce inflow and infiltration into its
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Climate Ready Water Utilities - Climate Ready Estuaries GREAT Exercise Report
wastewater collection system during intense heavy precipitation and flood events, Columbia
recently replaced many of its sewer lines. Local stakeholders noted that additional projects to
adapt to climate change impacts may be limited by lack of available staff to manage projects,
given the small size of the town's workforce.
1.4 Albemarle-Pamlico National Estuary Partnership (APNEP)
Prior to the GREAT exercise, APNEP supported a number of scientific and planning initiatives
designed to initiate the process of climate change adaptation planning. In 2008, APNEP hosted
listening sessions throughout the APNEP region, and in 2010 the program partnered with Duke
University's Nicholas Institute for Environmental Policy Solutions to develop strategies for
addressing climate change. The result of this partnership was the report "Climate Ready
Estuaries Blueprint". APNEP also works with communities to address climate change in the
region. APNEP's 2012 "Comprehensive Conservation and Management Plan" is designed to
address the challenges posed by a changing climate on the Albemarle-Pamlico region. This plan
calls for the development of improved scientific products that support decision-making, with a
specific charge for APNEP to engage with local communities to help them integrate climate
projections into their planning processes.
Staff from APNEP played an integral role throughout the GREAT exercise. The workgroup
leveraged APNEP's experience with water resource management in and around Manteo and
Columbia. Additionally, APNEP provided the workgroup with relevant background information
on environmental management in North Carolina, as well as the state's policy and calculations
for future SLR. APNEP is active throughout the Albemarle-Pamlico watershed, with
management efforts in both North Carolina and Virginia. Efforts by APNEP staff to engage and
collaborate with partners across community and state boundaries made them valuable members
of the workgroup.
2. CREAT Exercise Results
The workgroup used CREAT to examine climate change impacts to water resources and
infrastructure to inform adaptation planning efforts in Manteo and Columbia. More specifically,
the workgroup discussed potential adaptive measures that may reduce impacts associated with
SLR and coastal/inland storm surge, heavy precipitation events, and saltwater intrusion. The
workgroup also used GREAT's risk assessment framework to discuss the implementation of
these potential adaptive measures to reduce risk from climate change impacts.
2.1 CREAT 2.0 and Sea Level Rise (SLR) Data and Resources
While each town's CREAT analysis utilized CREAT version 1.0, this exercise provided an
opportunity for EPA to evaluate data included in CREAT version 2.0. This version of CREAT
provides access to more comprehensive climate datasets for historical and projected conditions to
support awareness building, definition of future climate scenarios and risk assessment. For this
reason, climate data from CREAT 2.0 was presented to the workgroup during this exercise.
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Historical climate data within GREAT 2.0 provides a benchmark of historical climate conditions
for comparison to projected changes. Historical temperature and precipitation data represent
spatial averages of observed data for a 30-year time period (1971-2000) accessed from the
Parameter-elevation Regressions on Independent Slopes Model (PRISM). PRISM is recognized
globally as the highest quality spatial climate dataset. Data for historical intense precipitation are
sourced from the National Oceanic and Atmospheric Administration's National Climatic Data
Center, which collects information for over 10,000 climate stations in the U.S. Historical data
were selected based on climate station proximity to Manteo and Columbia. For Manteo, data
were selected from the Manteo AP Climate Station. Data for Columbia were selected from the
Plymouth 5 E Climate Station.
For each defined location, GREAT provides three pre-loaded scenarios - hot and dry, central,
and warm and wet model projections - which capture a range of possible future climate
conditions. Future scenarios include projections for temperature, precipitation, intense
precipitation, and SLR at 2035 and 2060. The years 2035 and 2060 represent a 30-year average
for data from 15 years on either side of 2035 and 2060, respectively. Therefore, it is important to
note that these projections do not explicitly reflect the climate projections for the years 2035 and
2060. Temperature and precipitation data provided context during the exercise discussions,
while SLR was discussed in greater detail. Based on the data presented to workgroup
participants, Manteo and Columbia representatives felt that their utility infrastructure and
operations could be impacted by projected climate change. While GREAT's range of future
climate scenarios provides valuable information about potential conditions; future utility
thresholds related to temperature and precipitation are not yet known. Local historical and
projected climate conditions for temperature, precipitation and intense precipitation are included
in Tables 1 & 2.
Table 1. Temperature and Precipitation Data from GREAT 2.02
Temperature
Historical Temperature
2035 Temperature Projection
2060 Temperature Projection
Precipitation (Inches)
Historical Precipitation
2035 Precipitation Projection
2060 Precipitation Projection
Manteo
61.8
63.4
64.8
52.1
53.7
55.1
Columbia
61.7
63.3
64.7
51.3
53.0
54.5
2 Table 1 illustrates CREAT's 'warm and wet' scenario, providing CCSM model projections for temperature and
precipitation data. GREAT users can also select 'hot and dry' and 'central' model projections to examine a range of
future scenarios.
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Table 2. Intense Precipitation Event Data from GREAT 2.0
Intense
Precipitation
(Inches per
24-hour event)
Manteo
Historical
2035 Projection
2060 Projection
Columbia
Historical
2035 Projection
2060 Projection
5-year
4.25
4.36
4.45
4.29
4.40
4.50
10-year
4.72
4.85
4.95
4.80
4.94
5.05
15-year
4.97
5.10
5.22
5.08
5.23
5.36
30-year
5.35
5.52
5.66
5.47
5.66
5.82
50-year
5.59
5.78
5.94
5.71
5.93
6.11
100-year
5.91
6.13
6.32
6.02
6.29
6.50
2.1.1 SLR Projections
Many scientific reports indicate that the North Carolina coast is vulnerable to impacts from SLR,
with approximately 2,300 square miles of land below one meter in elevation, over 300 miles of
beaches, and more than 4,600 miles of shoreline along sounds, coastal rivers and wetlands
(RENCI, 2012). In addition to the current and projected climate impacts in Manteo and
Columbia, North Carolina's population growth is estimated to increase by 14.8% between 2010
and 2020. Much of that growth will occur along coasts, leading to more densely populated
shorelines (McGlade, et al., 2009). The combination of these factors illustrates the importance of
looking at SLR projections during the GREAT analysis.
2.1.2 CREAT SLR Data
Using climate model data and simulation outputs from MAGICC / SCENGEN4, CREAT
provides information on a range of SLR projections in addition to other climate change data.
More specifically, CREAT provides projections of sea level that is rising as a result of two
processes: thermal expansion of the ocean and ice melt. The SLR curves in CREAT are based
on model averages for global SLR with local scalar calculations. Locations, such as Manteo and
Columbia, are found in 0.5-degree grid cells that also contain coastlines of tidally influenced
water bodies including oceans, bays, estuaries and large river systems. Due to the influence of
regional and local factors, such as subsidence, the local rate of SLR can be much greater or much
less than the global average. To accommodate this, CREAT allows users to incorporate local
subsidence rates obtained from outside sources, like observed tidal gauge data. For the purposes
of this exercise, the workgroup input a subsidence value of 0.168 inches per year to represent the
current rate of SLR at the Duck, NC tidal gage. This value is then applied to GREAT's regional
projection to calculate future SLR that may be observed. While the local SLR data for Columbia
is a few percentage points lower than that for Manteo, the difference in SLR projections is small
3 Table 2 illustrates CREAT's 'warm and wet' scenario, providing CCSM model projections for intense
precipitation data. CREAT users can also select 'hot and dry' and 'central' model projections to examine a range of
future scenarios.
4Reference: http://www.cgd.ucar.edu/cas/wigley/magicc.
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Figure 2 shows GREAT SLR curves using Manteo AP climate station data, with a one meter
sea level rise scenario at 2100. Figure 3 shows the GREAT SLR curves using Manteo AP climate
station data with an applied local subsidence value of 0.168 inches.
Local SLR projected for 21st century at this Location
Figure 2. GREAT SLR Curves, Manteo
Local SLR projected for 21st century at this Locatio
Figure 3. GREAT SLR Curves with Subsidence, Manteo
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2.1.3 Data from the NC Science Panel
The NC Science Panel produced a report in 2010 assessing relevant peer-reviewed literature and
reviewing available North Carolina SLR data. The report concluded that the most likely SLR
scenario for 2100 is a rise of 15 to 55 inches (0.4m to 1.4m), with 39 inches (1m) recommended
as the amount of anticipated rise for policy development and planning purposes. While the NC
Science Panel has not formally endorsed SLR projections or planning recommendations before
the year 2100, a relatively simple constant acceleration model was used to estimate SLR
scenarios in 2035 and 2060. The constant acceleration model assumes that: tidal gage data from
Duck, NC is used for initial velocity of rise; the rate of acceleration is assumed to be constant,
and the SLR curve should not be extrapolated past 2100. As illustrated in Table 3, GREAT SLR
rates and the SLR rates from the constant acceleration method are relatively similar, and these
slight differences did not have an impact on the ultimate adaptation strategies recommended in
this report. Table 3 illustrates GREAT SLR data with and without subsidence rates; along with
SLR values calculated using the constant acceleration method.
Table 3. SLR Projections5
Data
GREAT
GREAT with subsidence
Constant acceleration method
Projected SLR
at 2035 (inches)
4.4
6.6
6
Projected SLR
at 2060 (inches)
13.4
17.8
16
Derived independently, the constant acceleration method provides an easily calculable check for
the sophisticated SLR projections provided by GREAT. This method is not a mechanistic model
of SLR. Rather, it is a kinematic equation that describes linear motion6. In a region where some
citizens and officials are distrustful of complex modeling approaches, examination of this
complementary approach may be warranted as a way to confirm the veracity of GREAT
modeling outputs for skeptical participants. It may also provide a useful preliminary estimate for
officials building support for a climate planning exercise such as that facilitated by GREAT.
Table 4 provides a range of SLR estimates that were calculated using the constant acceleration
method. The high, medium, and low scenarios in Table 4 describe varying degrees of SLR
projected for 2100, with the one meter scenario recommended for planning purposes in North
Carolina. Figure 4 provides a visual illustration of the SLR rates that were calculated using the
constant acceleration method.
Table 4. SLR Rate in Manteo and Columbia
Constant Acceleration Method
Scenario
High- 1.4m by 2 100
Medium- 1m by 2 100
Low -0.4m by 2100
2035
7 inches
6 inches
4 inches
2060
21 inches
16 inches
9 inches
5 Based on 1 meter SLR scenarios at 2100, which is the median scenario provided by GREAT and the one chosen
for planning by town participants.
6 The following equation was presented to the exercise workgroup to describe the SLR calculation used by the NC
Science Panel: D= V (T-2010) + 0.5A (T-2010)2, where D = distance (amount of SLR); V = velocity (rate of SLR);
A= acceleration of SLR; and T = time (year of projection).
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Projected SLR in NE North Carolina
Constant acceleration methodology
60
^g
-J
0)
-M 2O
10
3.28 feet by 2100
4.59 feet by 2100
1.31 feet by 2100
2O1O 2O15 2O2O 2O25 2030 2035 2040 2045 2050 2O6O 2070 2O8O 21OO
Figure 4. SLR Projections - NC Science Panel
2.1.4 SLR Mapping-NC Coastal Atlas Tool
During Meeting 3 of this exercise, the North Carolina Coastal Atlas Tool was demonstrated for
participants. This tool is an interactive map that uses a compilation of SLR geospatial tools to
provide users with an illustrative map of SLR and floodplain layers. While the tool may not be
appropriate for site-specific analysis, it provides local insights on the geographical
patterns and extent of SLR projections over time. The maps are primarily based on elevation
data, with some refinements to better approximate rising water levels. Potential uses of this tool
include: identifying changing land use patterns, siting infrastructure projects, and developing
SLR adaptation strategies. The North Carolina Atlas Tool is currently in development, but the
preliminary version can be found here: http://nccohaz.ecu.edu/flex/.
2.2 Scenario Planning, Time Periods, and Consequence Weighting
During GREAT's Setup step, users can select basic settings which include: scenario planning,
time period selection, and consequence weighting. Each of these setup features is described
below in more detail.
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Climate Ready Water Utilities - Climate Ready Estuaries GREAT Exercise Report
2.2.1 Scenario Planning
GREAT provides two options for assessing the likelihood of specific climate change threats.
The scenario-based approach assumes that all specified threats will occur in the time periods
considered. The assessing likelihood approach allows users to qualitatively assess the likelihood
of threat occurrence as low, moderate, high, and very high. The workgroup selected the
scenario-based approach as they did not have enough information to determine the specific
timing or probable likelihood of threat occurrence. Because the specified threats are currently
occurring to some degree in each town, this approach seemed appropriate.
2.2.2 Time Periods
A total of five time periods can be selected in a GREAT analysis. Users may choose time
periods for a variety of reasons such as to coincide with existing time periods for asset
management cycles, capital/infrastructure planning cycles, or projected timing of climate change
impacts. For this exercise, the workgroup selected the time periods 2035 and 2060 to match the
time periods of climate data provided. As previously mentioned, during the exercise, EPA was
in the process of finalizing its update the GREAT software, and this exercise provided an
opportunity to evaluate the data included in GREAT version 2.0. See Section 2.1 for further
discussion on the data presented during this exercise.
2.2.3 Consequence Weighting
GREAT also allows users to evaluate consequences across five impact categories. The
categories are provided to ensure that the analysis considers a range of impacts throughout the
watershed due to climate change:
• Business Impacts
• Equipment/facility Impacts
• Source/receiving water Impacts
• Environmental Impacts
• Community Impacts
Users can choose one of two methods for combining the consequence assessments across
categories. The highest level method assigns the highest level of consequence for any category
as the overall consequence value. The weighted sum aggregates the categories based on relative
weights. This method allows users to weigh some categories more heavily than others in order
to reflect overall priorities. For example, Community Impacts may be weighted more highly
than all other categories, while discounting Business Impacts.
Stakeholders chose to use the weighted sum method to aggregate the categories based on equal
weights. During this exercise, weighting values of twenty percent were distributed evenly across
the categories. Later in the GREAT process, workgroup members further examined these
consequence evaluation categories as they relate to each asset-threat pair. For more complete
definitions of the above categories, see Table 5.
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Table 5. Consequence Evaluation Categories
Consequence Evaluation Categories
Business Impacts
Equipment/facility Impacts
Source/receiving water Impacts
Environmental Impacts
Community/Public Health Impacts
Definition
Revenue or operating income loss evaluated in
terms of the magnitude and recurrence of service
interruptions.
Costs of replacing the service equivalent provided
by a facility or piece of equipment evaluated in
terms of the magnitude of damage and financial
impacts.
Degradation or loss of source water or receiving
water quality and/or quantity evaluated in terms of
the recurrence.
Evaluated in terms of environmental/ecosystem
damage or loss and compliance with environmental
regulations
Public health impacts evaluated in terms of the
duration and extent.
2.3 Prioritizing Assets
GREAT users have an opportunity to analyze each vulnerable asset and climate-related threat at
specific time periods. Within GREAT, users can select vulnerable assets from two categories:
natural resources and infrastructure. For example, the Albemarle-Pamlico Estuary would be a
"natural resource" asset, while WWTP infrastructure would be considered an "infrastructure"
asset. Specific natural resource assets were not assessed during the Manteo and Columbia
GREAT exercise. Rather, it was understood that impacts to the natural environment would be
considered when evaluating consequences/risk to Environmental Impacts for each asset-threat
pair.
During this exercise, a few participants mentioned that "receiving waters" were not listed as
priority assets. While GREAT intends to examine concerns at the watershed level, participants
decided to leave receiving waters off the prioritized assets lists for each town and consider
receiving waters when evaluating consequences during the Baseline and Resilience Analyses.
While there are a number of natural resource and infrastructure assets in Manteo and Columbia,
the workgroup realized that they could not analyze all vulnerable assets throughout the
watershed, and therefore would need to prioritize these assets.
2.4 Prioritizing Threats
Discussions about climate-related threats in each town revealed a variety of important
considerations. Manteo and Columbia are impacted by similar climate-related threats. High
flow situations from heavy precipitation events impact both towns currently and projections
indicate that heavy precipitation events are estimated to increase in frequency and magnitude in
the future (EPA, 2012). Manteo is directly impacted by coastal storm surge, while Columbia
sees impacts to inland waters from coastal storm surge. Columbia is also experiencing saltwater
intrusion in its aquifer. Furthermore, two of Columbia's three groundwater wells have flooded in
the past, and the wastewater treatment plant has also experienced flooding. Columbia's drinking
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water treatment plant has not been impacted by past flooding, but recent flood waters came very
close to the facility.
Manteo has three lift stations at sea level, which flood regularly during storm surge and high
precipitation/high flow events. Manteo retrofitted those pump stations so that they are
submersible, but they still may face impacts from future severe flooding and floating storm
debris.
Threats related to climate change are considered in respect to the potentially impacted asset.
Together, GREAT refers to this combination as a user's "asset-threat pair". For a complete list
of prioritized asset-threat pairs in each town, see Table 6.
Table 6. Prioritized Assets and Threats at 2035 and 2060
Town
Manteo
Columbia
Asset
Bowsertown Rd. Facilities
(Structures- Buildings and
SCADA)
Bowsertown Rd. Facilities
(Structures- Buildings and
SCADA)
WWTP Collection System
(pumps, gravity sewers, and
mains)
WWTP Collection System
(pumps, gravity sewers, and
mains)
Wastewater Treatment
(MLSS/MLVSS and
treatment equipment)
Wastewater Treatment
(MLSS/MLVSS and
treatment equipment)
Drinking Water Treatment
Plant, Wells, and Equipment
Drinking Water Treatment
Plant, Wells, and Equipment
Wastewater Collection
System (pump stations,
sewers and manholes)
Wastewater Treatment Plant
Wastewater Treatment Plant
Threat
Coastal Storm Surge
High Flow/Heavy Precipitation Events
Coastal Storm Surge
High Flow/Heavy Precipitation Events
Coastal Storm Surge
High Flow/Heavy Precipitation Events
High Flow/Heavy Precipitation Events
Saltwater intrusion into aquifers
High Flow/Heavy Precipitation Events
Effects from coastal storm surge on
inland surface waters
High Flow/Heavy Precipitation Events
2.5 Existing Adaptive Measures
Each town provided input on existing adaptive measures. The measures listed in Table 7 are the
existing adaptive measures for all asset-threat pairs at the 2035 and 2060 time periods identified
by Manteo and Columbia. Adaptive measures do not necessarily need to involve infrastructure
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improvements. Adaptive measures can also include planning and/or operational actions. For
example, Columbia recently created a town ordinance requiring that all new residential and
commercial buildings be constructed two feet above base flood elevation.
Table 7. Existing Adaptive Measures in Manteo and Columbia
Columbia
Monitor sludge
Insurance adjusted to climate change
Emergency response plan - water supply
Backflow prevention
Infiltration reduction
Manteo
Optimized pumping
Supply-demand models
Water quality models
Sewer/collection models
Infrastructure inspection
Monitor treatment or system
Monitor pressure, structures, weather, temperature, runoff, water quality, sludge, treatment
Facility safety plan
Insurance adjusted to climate change
Emergency response plan - community, flooding, water supply
Partner with research community
Treatment alternatives
Community outreach
Rationing
Adaptive rates
Temporary flood barrier
Alternate water supply
Alternate wastewater/storm water capabilities
Back-up power
Interconnections
Backflow prevention
Sedimentation points
Altered treatment
Infiltration reduction
Wet repair
Leakage reduction
Silt removal
Sewage separation
Ecosystem for water quality
Ecosystem in greenhouse gas inventory
Wetlands for flood protection
Targets for land use change
Land acquisition
Building code changes
Green infrastructure at facility and Rainwater collection/use
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GREAT Exercise Report
2.6 Potential Adaptive Measures
With a better understanding of anticipated climate-related threats at 2035 and 2060, stakeholders
discussed optimal climate change adaptation strategies to help adapt to projected climate change
impacts. As part of the Resilience Analysis in GREAT, users select "potential" adaptive
measures aimed at reducing asset vulnerabilities associated with the specified threats. During the
GREAT exercise, workgroup participants identified potential adaptive measures that could be
implemented at both time periods. A list of potential adaptive measures for each town is
included in Table 8. Further discussion of potential adaptive measures is warranted, as
stakeholders recognized that each measure has varying costs and benefits associated with
implementation. Potential adaptive measures are discussed in more detail later in this report.
Table 8. Potential Adaptive Measures Selected during the GREAT Exercise
Manteo
Increased capacity- wastewater & stormwater
Effluent re-use studies
Decision making to incorporate uncertainty
Performance models
Biosolids management
Flood risk management
Sludge management
Climate training for personnel
Sanitary sewer overflow strategies
Effluent re-use
Collaborate with stakeholders
Sea walls and/or levees
Submersible pumps (new assets)
Elevate vulnerable assets
Columbia
Increased raw storage
Alternate water sources
Optimized pumping
Green infrastructure at facility
Green infrastructure in community
Facility safety plan
Partner with research community
Infiltration reduction (potential)
Collaborate with stakeholders
Sea walls and/or levees
Submersible pumps (new assets)
Elevate vulnerable assets
2.7 Baseline and Resilience Analysis Discussion
CREAT's Baseline Analysis establishes a benchmark for the level of risk that threats associated
with climate change may pose to utility assets. The results of the Baseline Analysis include the
examination of climate change threats with existing adaptive measures and describe the current
risks to assets due to the occurrence of future climate-related threats. After performing a
Baseline Analysis, GREAT users define and select potential adaptive measures to lower risk
posed to assets. Similar to the Baseline Analysis, the Resilience Analysis involves a specific
series of steps including: 1) selecting potential adaptive measures; 2) re-assessing consequences;
3) assigning contribution to each adaptive measure; and 4) reviewing analysis results. For
Manteo and Columbia, the Resilience Analysis builds on the Baseline Analysis by examining the
same asset-threat pairs while considering new, potential adaptive measures that can be
implemented at 2035 and 2060.
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Climate Ready Water Utilities - Climate Ready Estuaries
GREAT Exercise Report
Setup
Regional and Local
Historical & Projected
Climate Information
,
Threats
Assets
Baseline
Analysis
Resilience
Analysis
Adaptive
Measures
Adaptation
Planning
Results and Reports
GREAT Process: Application of climate information and utility knowledge to assess risks and challenges presented by
climate change.
Figure 5. CREAT Process
2.7.1 Re-assessing Consequences
As with the Baseline Analysis, consequence levels must be selected in each of the five
consequence categories for each asset-threat pair during the Resilience Analysis. As an example,
Figure 6 illustrates a description of the consequence levels for the Environmental Impact
category. CREAT users select consequence levels of Very High, High, Medium, or Low. The
change in consequence level between the Baseline and Resilience Analyses, following the
implementation of potential adaptive measures, contributes to the relative change in risk
reduction provided for each asset-threat pair.
Impacts
A Very High: Significant environmental damage - may incur regulatory
action
Ljj»k Persistent environmental damage - may incur regulatory
action
Medium: Short-term environmental damage, compliance can be
quickly restored
Low: Nc mpact or environmental damage
Figure 6. Consequence Levels for Environmental Impacts
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Climate Ready Water Utilities - Climate Ready Estuaries GREAT Exercise Report
2.7.2 Adaptive Measure Contribution
As part of the Resilience Analysis in GREAT, users select potential adaptive measures aimed at
further reducing vulnerabilities from specified threats. The next step is to identify the risk
reduction contribution for each potential adaptive measure and asset-threat pair. For example,
Manteo identified increased treatment capacity for stormwater and wastewater and biosolids
management as potential adaptive measures. These measures could significantly contribute to
risk reduction associated with coastal storm surge and high precipitation events/high flow
impacting Manteo's WWTP. An adaptive measure contribution value of 20 percent was
assigned to increased stormwater and wastewater capacity and 10 percent was assigned to the
implementation of biosolids management for this asset-threat pair. The adaptive measure
contribution inputs were discussed among workgroup members, and these inputs can be revised
in each town's analysis file in the future. For more information about the specific adaptive
measure contribution values assigned by workgroup members, see Appendix C.
2.7.3 Examining Risk Reduction - Resilience Analysis
GREAT provides a way to compare current and future risk as it relates to threats posed by a
changing climate. Building resilience to climate-related threats by considering and deciding to
implement adaptive measures facilitates the decision making process. In GREAT, the reduction
of risk can be visualized in a risk matrix (Figure 7), where each asset-threat pair analysis falls
into a specific combination of likelihood of threat occurrence and level of consequence. This
matrix considers both the user-defined reduction in consequence levels from the Baseline to
Resilience Analysis and the attribution percentage value given to each selected potential adaptive
measure. Risk matrices in Figure 7 also show the number of asset-threat pairs for each
likelihood-consequence combination for all Baseline (top row) and Resilience (bottom row)
analyses. For example, in Manteo's GREAT analysis six asset-threat pairs have a very high
likelihood of occurrence, but their consequence level is reduced to medium during the Resilience
Analysis after considering implementation of potential adaptive measures.
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Climate Ready Water Utilities - Climate Ready Estuaries
GREAT Exercise Report
Manteo
Columbia
2035
(25 years)
2060
(50 years)
Baseline
*«Ą
U. 0
Resilience
0 0 0
0 0 0 0
0 0 0 0
i°- 0000
0 00
0000
0000
oooo
10- "ifllT Urfl *
206O
(50 years)
Resilience
Figure 7. Risk Reduction Matrices for Manteo and Columbia
2.8 Implementation Planning - Adaptation Packages for Manteo and Columbia
Selecting potential adaptive measures in GREAT does not imply that these measures will resolve
all impacts related to climate change in Manteo and Columbia. Rather, GREAT offers a
comparative framework to analyze the risk reduction of consequences associated with existing
and potential adaptive measures. During GREAT's Implementation Planning step, users can
build adaptation packages, which include adaptive measures and user-defined estimated costs for
each package. Example adaptation packages were developed for each town to illustrate which
adaptive measures, if implemented, could potentially offer the highest level of risk reduction
from specified climate change threats. These packages allow users to create reports and compare
risk reduction units (RRUs) and estimated costs associated with the implementation of selected
adaptive measures. RRUs within GREAT provide a metric for users to compare packages. The
change in consequence level from the Baseline Analysis to the Resilience Analysis is used to
calculate RRUs for each asset-threat-time period combination. For example, if the consequences
for an asset paired with a high likelihood threat changes from Very High (Baseline) to Medium
(Resilience), then the RRUs are calculated as 100 - 60 = 40 RRUs (circled locations in Figure 8).
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Climate Ready Water Utilities - Climate Ready Estuaries
GREAT Exercise Report
Very
High
High
Low
4B
(40)
4C
(3?)
4D
<35)
^-^
3B
(45)
3C
(40)
3D
(37)
2B
(55)
2C
(45)
2D
(40)
Low Medium High Very
High
Consequences
Figure 8. Matrix Used to Calculate Risk Reduction Units (RRUs)
Adaptation packages were assembled for both Manteo and Columbia. In both towns, the first
package was assembled based on the potential for the greatest amount of risk reduction utilizing
all selected potential adaptive measures. In Manteo's GREAT file, two additional packages were
assembled and include: 1) an increase in WWTP capacity, and 2) infrastructure improvements
related to flooding. For Columbia, three additional adaptation packages were assembled to adapt
to various threats. These three packages include: 1) green infrastructure and sludge and biosolids
management, 2) infrastructure improvements related to flooding, and 3) saltwater intrusion
adaptive measures.
Table 9 provides an example adaptation package for Manteo, illustrating the RRUs associated
with each adaptive measure at 2035 and 2060. The RRUs are the same at each time period
(104), assuming that each potential adaptive measure will be implemented at both 2035 and
2060. GREAT calculates RRUs for asset-threat pairs by taking the value of reduction in
consequences (Figure 8) combined with the individual adaptive measure contribution percentage.
GREAT users can compare total RRUs for each adaptation package to support the
implementation of specific adaptation packages during decision making processes.
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Climate Ready Water Utilities - Climate Ready Estuaries
GREAT Exercise Report
Table 9. Example Adaptation Package for Manteo - "Increased WWTP Ca
Potential Adaptive Measures Included
Collaborate with stakeholders
Biosolids management
Submersible Pumps (new assets)
Increased capacity - wastewater/stormwater
Decision-making frameworks that incorporate
uncertainty
Total Package RRUs
RRUs at 2035
16
20
8
48
12
104
RRUs at
2060
16
20
8
48
12
104
pacity"
Total
Package
RRUs
32
40
16
96
24
208
In addition to evaluating potential risk reduction associated with each adaptive measure, users
can compare costs. Estimated cost inputs are completely user-driven. Example cost estimate
inputs were included for select adaptive measures in both towns' GREAT files. These cost
estimates are meant to be illustrative and do not represent the actual costs for the selected
adaptive measures. If more robust cost estimates are developed, town stakeholders can
assemble a more complete adaptation package that illustrates costs related to implementing
adaptive measures in comparison with the risk reduction associated with those measures.
2.9 Results and Reports
The Results & Reports feature in GREAT includes a variety of ways to visually illustrate relative
risk reduction after considering the implementation of potential adaptive measures. This risk
reduction can be seen in the bar graphs on the Results Summary tab, as illustrated in Figure 9.
Results Summary
The Results Summary is G high level overview of thconolysi 5 performed by CHEAT. The total s for Li lieli hiced of Threat and Consequences for both the
Bdieline dml Feiil itriLe Aridlyiii dreiliuwn. Jte Uit Time PeriuJ Di iIl-Duwn lu ejiuluie Ihe ddLd.
Baseline Consequence Risk Profile
Resilience Consequence Risk Profile
n All Adaptive Measures r* Selected Adaptation Package |jl potential adaptive measures ^r]
Number of I hreats bvaluated by I imc Period
(with Consequence Risk Profile)
nber ot Adaptive Measures Evaluated by Time Period
Figure 9. Example Results Summary Tab
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Climate Ready Water Utilities - Climate Ready Estuaries GREAT Exercise Report
Risk matrices are also displayed in GREAT's Results and Reports step. GREAT assesses risk
based on the likelihood of occurrence and overall reduction in consequences. Figure 7 depicts
these matrices and shows each town's total asset-threat pairs, six and five, for Manteo and
Columbia respectively. This figure also illustrates the likelihood-consequence combination for
all Baseline (top boxes) and Resilience (bottom boxes) Analyses at the 2035 and 2060 time
periods. As previously mentioned, the "scenario-based" approach was selected during the setup
step. This approach assumes a very high likelihood of occurrence for all asset-threat pairs. This
concept is illustrated in Figure 7, as all asset-threat pairs remain in the top row. The
implementation of potential adaptive measures during the Resilience Analysis can lower the
consequences for each asset-threat pair. This concept is illustrated in Figure 7, as the asset-threat
pairs move left from the Very High column into the Medium column for Manteo, and into the
High column for Columbia to indicate lower consequences.
3. Conclusion
This exercise in North Carolina was an important step to determine how GREAT can best
provide a useful risk assessment framework and planning tool for stakeholders in small
communities. It also served as an important demonstration of how GREAT can be used in areas
that are vulnerable to extreme weather and SLR.
3.1 Future Use of GREAT in Manteo, Columbia, and other North Carolina Communities
Manteo and Columbia will each receive a final GREAT analysis file to modify as new
information and data become available. These files will be compatible with GREAT version 2.0
and can be edited in the future. Risk assessment involves a continuous cycle of review which
may include examining vulnerable assets, projected climate change threats and adaptive measures
to ensure adequate protection of the towns' natural resources and built infrastructure from future
climate change impacts.
Town stakeholders noted that the GREAT exercise process was valuable, especially for gaining a
better understanding of climate change threats, vulnerable assets and potential adaptive
measures. In addition to the GREAT exercise in Manteo and Columbia, APNEP may continue
working with GREAT in communities throughout North Carolina. Participants suggested that
EPA could consider focusing outreach efforts for GREAT 2.0 on regional planning
organizations, noting that towns like Manteo and Columbia already work with regional planning
organizations for trainings and workshops. This approach may be helpful to promote the use of
GREAT within these existing planning networks.
3.2 Additional Feedback from Participants and Next Steps
In addition to the formal discussions, this planning exercise spawned numerous discussions
among participants that also helped to shape possible future asset management, capital
improvement, and master plans for the implementation of potential adaptive measures in Manteo
and Columbia. Participants mentioned that including the GREAT Analysis results as part of
their capital improvement plans would be a useful way to incorporate the results from the
exercise. Columbia is currently in the process of revising their capital improvement plan and
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Climate Ready Water Utilities - Climate Ready Estuaries GREAT Exercise Report
will consider the discussions and results from the GREAT exercise as they plan for impacts from
climate change. Participants also stated that documenting the GREAT risk assessment process in
Manteo and Columbia was helpful as this documentation could be included on various grant
applications, such as the North Carolina Clean Water Management Fund to potentially finance
new adaptive measures. Demonstrating that the towns have already begun to assess their
climate change vulnerabilities through a formal planning process such as the GREAT exercise
may also increase their chances of receiving future grants.
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Climate Ready Water Utilities - Climate Ready Estuaries GREAT Exercise Report
References
McGlade, Katherine, Sagarin, Raphael and Kirshenbaum, Sheril. 2009. Nicholas Institute for
Policy Solutions. Duke University. "Drawing the Line in Sand or in Cement: Preparing North
Carolina's Estuaries for Climate Change and Population Growth".
NC Coastal Resources Commission's Science Panel on Coastal Hazards (NC Science Panel).
2010. North Carolina Sea-Level Rise Assessment Report.
RENCI at Eastern Carolina University, http://www.ecu.edu/renci/Focus/SeaLevelRise.html.
Website Accessed on November 2, 2012.
U.S. Census Bureau. 2010. Table 3. "Annual Estimates of the Resident Population for
Incorporated Places in North Carolina: April 1, 2010 to July 1, 2011 (SUB-EST2011-03-37)".
Accessed on October 24, 2012.
U.S. Environmental Protection Agency (EPA). 2012. Adaptation Strategies Guide for Water
Utilities.
The Nicholas Institute for Environmental Policy Solutions, Duke University. 2011. Climate
Ready Estuaries A Blueprint for Change. [Prepared for Albemarle-Pamlico National Estuary
Partnership]
22
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Appendix A
EPA CREAT Exercise for Manteo and Columbia, North Carolina
Participants List
EPA
Curt Baranowski, Office of Water, Climate Ready Water Utilities (CRWU)
John Whitler, CRWU
EPA Oak Ridge Institute for Science and Education (PRISE) Fellows
Laura Dubin
Amy Posner
Albemarle-Pamlico National Estuary Program (APNEP)
Jim Hawhee
Town of Manteo
Josh O'Brien
Kermit Skinner
Town of Columbia
Rhett White
EPA Contractors
Kathleen McAllister, Horsley Witten Group, Inc. (HW)
Tom Noble, HW
This list above includes individuals that participated in the project at various times from May-
September 2012.
-------
Appendix B
Baseline Analysis
Manteo's Consequence Weighting Inputs for Each Asset-Threat Pair at 2035 and 2060
Manteo's Asset -Threat Pairs
Coastal Storm Surge - Bowsertown Rd. Facilities at 2035
Coastal Storm Surge - Bowsertown Rd. Facilities at 2060
High Flow/Heavy Precipitation Events - Bowsertown Rd.
Facilities at 2035
High Flow/Heavy Precipitation Events - Bowsertown Rd.
Facilities at 2060
Coastal Storm Surge - WWTP Collection System at 2035
Coastal Storm Surge - WWTP Collection System at 2060
High Flow/Heavy Precipitation Events - WWTP Collection
System at 2035
High Flow/Heavy Precipitation Events - WWTP Collection
System at 2060
Coastal Storm Surge - Wastewater Treatment ("Bugs", lagoons,
etc.) at 2035
Coastal Storm Surge - Wastewater Treatment ("Bugs", lagoons,
etc.) at 2060
High Flow/Heavy Precipitation Events - Wastewater Treatment
("Bugs", lagoons, etc.) at 2035
High Flow/Heavy Precipitation Events - Wastewater Treatment
("Bugs", lagoons, etc.) at 2060
Utility-
Business
Impact Impact
Very High Very High
Very High Very High
Very High Very High
Very High Very High
Very High Very High
Very High Very High
Very High Very High
Very High Very High
Very High Very High
Very High Very High
Very High Very High
Very High Very High
Source/
Receiving Environmental Community
Water Impact Impact
Impact
High
High
High
High
Medium
High
Medium
High
High
Very High Very High
High
Very High Very High
High
Very High Very High
High
Very High Very High
Medium
High
Medium
High
High
Very High
High
Very High
High
Very High
High
Very High
Medium
High
Medium
High
-------
Appendix B
Reslience Analysis
Manteo's Consequence Weighting Inputs for Each Asset-Threat Pair at 2035 and 2060
Manteo's Asset -Threat Pairs
Coastal Storm Surge - Bowsertown Rd.
Facilities at 2035
Coastal Storm Surge - Bowsertown Rd.
Facilities at 2060
High Flow/Heavy Precipitation Events -
Bowsertown Rd. Facilities at 2035
High Flow/Heavy Precipitation Events -
Bowsertown Rd. Facilities at 2060
Coastal Storm Surge - WWTP Collection
System at 2035
Coastal Storm Surge - WWTP Collection
System at 2060
High Flow/Heavy Precipitation Events -
WWTP Collection System at 2035
High Flow/Heavy Precipitation Events -
WWTP Collection System at 2060
Coastal Storm Surge - Wastewater Treatment
("Bugs", lagoons, etc.) at 2035
Coastal Storm Surge - Wastewater Treatment
("Bugs", lagoons, etc.) at 2060
High Flow/Heavy Precipitation Events -
Wastewater Treatment ("Bugs", lagoons, etc.)
at 2035
High Flow/Heavy Precipitation Events -
Wastewater Treatment ("Bugs", lagoons, etc.)
at 2060
Utility-
Business
Impact
Equipment/Facility
Impact
Medium Medium
Medium Medium
Medium Medium
Medium Medium
Medium Medium
Medium Medium
Medium Medium
Medium Medium
Medium Medium
Medium Medium
Medium Medium
Medium Medium
Source/
Receiving
Water Impact
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Environmental
Impact
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Commu
Impact
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
Medium
-------
Appendix B
Baseline Analysis
Columbia's Consequence Weighting Inputs for Each Asset-Threat Pair at 2035 and 2060
Columbia's Asset -Threat Pairs
Saltwater Intrusion - DWTP Facility and
Equipment at 2035
Saltwater Intrusion - DWTP Facility and
Equipment at 2060
Coastal Storm Surge (on inland waters) -
WWTP at 2035
Coastal Storm Surge (on inland waters) -
WWTP at 2060
High Flow/Heavy Precipitation Events -
WWTP at 2035
High Flow/Heavy Precipitation Events -
WWTP at 2060
High Flow/Heavy Precipitation Events-
WW Collection System at 2035
High Flow/Heavy Precipitation Events-
WW Collection System at 2060
High Flow/Heavy Precipitation Events -
DWTP Facility and Equipment at 2035
High Flow/Heavy Precipitation Events -
DWTP Facility and Equipment at 2060
Utility-
Business
Impact
Very High
Very High
Very High
Very High
Very High
Very High
Very High
Very High
Very High
Very High
Equipment/
Facility Impact
Very High
Very High
Very High
Very High
Very High
Very High
Very High
Very High
Very High
Very High
Source/
Receiving
Water Impact
Medium
High
High
Very High
High
Very High
High
Very High
Medium
High
Environmental
Impact
Medium
High
High
Very High
High
Very High
High
Very High
Medium
High
Community
Impact
Medium
High
High
Very High
High
Very High
High
Very High
Medium
High
-------
Appendix B
Columbia's Consequence
Columbia's Asset -Threat Pairs
Saltwater Intrusion - DWTP Facility and
Equipment at 2035
Saltwater Intrusion - DWTP Facility and
Equipment at 2060
Coastal Storm Surge (on inland waters) -
WWTP at 2035
Coastal Storm Surge (on inland waters) -
WWTP at 2060
High Flow/Heavy Precipitation Events -
WWTP at 2035
High Flow/Heavy Precipitation Events -
WWTP at 2060
High Flow/Heavy Precipitation Events -
WW Collection System at 2035
High Flow/Heavy Precipitation Events -
WW Collection System at 2060
High Flow/Heavy Precipitation Events -
DWTP Facility and Equipment at 2035
High Flow/Heavy Precipitation Events -
DWTP Facility and Equipment at 2060
Resilience Analysis
Weighting Inputs for Each Asset-Threat Pair at 2035 and 2060
umiiy-
Business
Impact
High
High
High
High
High
High
High
High
High
High
Equipment/
Facility Impact
High
High
High
High
High
High
High
High
High
High
ouurut:/
Receiving
Water Impact
Low
Low
Medium
High
Medium
High
Low
Low
Low
Medium
Environmental
Impact
Low
Low
Medium
High
Medium
High
Low
Low
Low
Medium
Community
Impact
Low
Low
Medium
High
Medium
High
Low
Low
Low
Medium
-------
Appendix C
Asset-Threat Pairs
Bowsertown Rd. Facilities
(Structures- Buildings and SCADA)
Coastal Storm Surge at 2035
Coastal Storm Surge at 2060
High Flow/
Heavy Precipitation Events at 2035
High Flow/
Heavy Precipitation Events at 2060
WWTP Collection System
(pumps, gravity sewers, and mains)
Coastal Storm Surge at 2035
Coastal Storm Surge at 2060
High Flow/
Heavy Precipitation Events at 2035
High Flow/
Heavy Precipitation Events at 2060
Increased Decision-
Capacity - Making to Climate Collaborate Sea Walls Submersible Elevate Total
WW and Effluent Re-use Incorporate Performance Biosolids Flood risk Sludge training for SSO with and/or Pumps (new vulnerable Contribution
Stormwater studies Uncertainty Models mgmt mgmt mgmt personnel Strategies Effluent re-use Stakeholders Levees assets) assets (%)
100
100
100
100
20
20
20
20
10
10
10
10
5 5 10 5 5 5
5 5 10 5 5 5
5 5 10 5 5 5
5 5 10 5 5 5
10
10
10
10
10
10
10
10
10
10
10
10
5
5
5
5
20
20
20
20
10
10
10
10
5 5 5 5 5 5 10
5 5 5 5 5 5 10
5 5 5 5 5 5 10
5 5 5 5 5 5 10
10
10
10
10
5
5
5
5
10
10
10
10
100
100
100
100
Wastewater Treatment
(MLSS/MLVSS and treatment equipment)
Coastal Storm Surge at 2035
Coastal Storm Surge at 2060
High Flow/
Heavy Precipitation Events at 2035
High Flow/
Heavy Precipitation Events at 2060
20
20
20
20
10
10
10
10
5 5 10 5 5 0
5 5 10 5 5 0
5 5 10 5 5 0
5 5 10 5 5 0
10
10
10
10
10
10
10
10
5 10
5 10
5 10
5 10
100
100
100
100
-------
Appendix C
Increased raw Alternate Optimized
storage water sources pumping
Green Green Partner with Infiltration Collaborate Submersible Elevate Total
infrastructure infrastructure Facility research reduction with Sea Walls Pumps (new vulnerable contribution
at facility in community safety plan community (potential) Stakeholders and/or Levees assets) assets (%)
Asset —Threat Pairs
Drinking Water Treatment Plant,
Wells, and Equipment
High flow events at 2035
High flow events at 2060
Saltwater intrusion into aquifers at 2035
Saltwater intrusion into aquifers at 2060
Wastewater Collection System
(pump stations, sewers and manholes)
High flow events at 2035
High flow events at 2060
Wastewater Treatment Plant
Effects from coastal storm surge
on inland surface waters at 2035
Effects from coastal storm surge
on inland surface waters at 2060
High flow events at 2035
High flow events at 2060
10
10
Increased raw
storage
20
20
Biosolids mgmt
5
5
Green
infrastructure at
facility
5
5
Optimized
Pumping
5
5
10
10
Alternate
water sources
30
30
Facility safety
plan
5
5
Green
infrastructure
in community
5
5
Green
infrastructure
at facility
5
5
10
10
Optimized
pumping
0
0
Sludge mgmt
5
5
Biosolids
mgmt
10
10
Green
infrastructure
in community
5
5
5
5
Green
infrastructure
in community
10
10
Partner with
research
community
5
5
Facility safety
plan
10
10
Biosolids
mgmt
5
5
0
0
Rainwater
collection/use
20
20
Backflow
prevention
(potential)
20
20
Sludge mgmt
10
10
Facility safety
plan
5
5
10
10
Partner
with
research
community
10
10
Infiltration
reduction
(potential)
20
20
Partner
with
research
community
10
10
Sludge
mgmt
10
10
5
5
Collaborate
with
Stakeholders
10
10
Collaborate
with
Stakeholders
10
10
Backflow
prevention
(potential)
10
10
Partner with
research
community
5
5
10
10
Sea Walls
and/or
Levees
10
10
Infiltration
reduction
(potential)
10
10
Submersible
Pumps (new
assets)
10
10
Collaborate
with
Stakeholders
10 10
10 10
Backflow
prevention
(potential)
10
10
Infiltration
reduction
(potential)
10
10
10
10
Elevate
vulnerable
assets
10
10
Sea Walls
and/or Levees
20
20
Collaborate
with
Stakeholders
10
10
Sea Walls
and/or
Levees
30
30
20
20
100
100
100
100
100
100
100
100
100
100
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