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Citation: Meehan, R., M. McCammon, D. Dugan, K. Murphy, J. Reynolds, and S.T. Gray. 2012. Coastal Hazards Workshop. http://www.aoos.org/workshops-and-reports/
Executive Summary
The Alaska Ocean Observing System, Western Alaska Landscape Conservation Cooperative (Western AK LCC), and the USGS Alaska Climate Science Center jointly conducted a Coastal Hazards Workshop May 30-31, 2012. Participants included a broad array of subject matter experts and stakeholders involved in coastal issues from a variety of perspectives, which included:
· coastal residents,
· those collecting coastal or marine information,
· local, state and federal agency managers,
· University researchers, and
· participants representing other information sharing and collaboration efforts.
Workshop participants reviewed the current state of the coast and the state of understanding of the coast from a systems perspective, discussed stakeholder information needs and developed the framework for a conceptual model focused on natural-human system impacts due to coastal erosion and inundation.
An overview of new sea ice modeling coupled with local observations, coastal landforms, and weather patterns provided a backdrop for evaluating coastal hazards. Adjacent marine studies in the Bering Sea through the BSIERP/BEST programs also provided insights for evaluating coastal issues. Ultimately, the ongoing project to digitally map Alaska will provide an important base layer for evaluating coastal issues.
Part of the workshop focused on the Coastal Hazards section of a proposed 10-year build out plan for AOOS (seehttp://www.aoos.org/aoos-drafts-10-year-build-out-plan/for link to draft plan). Workshop participants identified specific types of information needed to improve forecasts of extreme weather events. Recommendations called for identification of those gaps in both information types and geographic areas, which currently limit a more complete assessment of vulnerability.
Workshop participants developed framework elements for a conceptual model of the coastal ecosystem that ties together near-shore and marine processes that form and affect coastal landforms and human and biological use of this region and their resources. With further refinements, the conceptual model can be utilized to identify vulnerable locations and weather events that may affect coastal stability and near-shore function, and with further work, to assess relative vulnerability of coastal facilities and systems.
Developing the conceptual model allowed participants to identify specific information needs and gaps in current research and monitoring efforts. These were then prioritized based on perceived importance and feasibility. Of note, all recommendations carried high importance but varied in feasibility; the highest importance needs included:
· Evaluate existing coastal models linking nearshore and terrestrial components (relevant data and existing data) for applicability to Western Alaska Ocean
· Collect vertical datum with tidal benchmarks
o Terrestrial benchmarks tied to water level measurements particularly related to mean sea level
o This information provides a “Rosetta Stone” for linking bathymetry and topography and thus near-shore and on-shore processes
· Utilize community observations for storm surge, tide height, and general ice observations (such as ice-berm formation)
· Establish coastal “Sentinel Sites” for co-located collection of chemical, physical, and biologic parameters, providing a basis for elucidating the relationships among them.
o Example of Bristol Bay pilot program (Nushagak Bay Diversity Project, UAF Bristol Bay Campus, Environmental Science Laboratory) as a mechanism for site establishment that employs scientists, students and local residents to conduct baseline studies and long-term monitoring of physical parameters.
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Table of Contents
Introduction 1
Research and Collaboration Opportunities 2
State of the Coast 2
AOOS 10 Year Build-out Plan Review 6
Coastal Processes in Western Alaska 7
Stakeholder Needs 7
Information Inventory 8
Conceptual Model Development 8
Marine Open Water 9
Sea Ice 12
Nearshore Condition 13
Terrestrial 15
Ocean to Shore Data Needs 17
Key Recommendations and needs 19
Appendices 22
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Introduction
Alaska’s extensive coastline ranges from the temperate rainforests of southeastern Alaska to the permafrost dominated landscapes of the arctic. The majority of Alaska’s population lives along or near the coast. Most residents depend upon coastal access for a variety of reasons such as, transportation of goods and services, subsistence, recreation and resource development. Climate change is affecting coastal processes and potentially the pattern and scope of coastal hazards. Three organizations with specific interests in coastal issues collaborated in organizing this Coastal Hazards Workshop and while each organization has specific interests, all shared a general goal for the workshop to review the state of knowledge of the coast with an emphasis on Western Alaska and identify gaps in our knowledge of and ability to monitor processes that affect coastal resources and their use.
The Western Alaska Landscape Conservation Cooperative (Western AK LCC) and USGS Alaska Climate Science Center (AK-CSC) are both interested in developing coastal models that tie together those near-shore and related marine processes. In particular the WALCC and AK-CSC have identified a need to better understand ecosystem stressors in coastal areas, as well as understanding the processes that form and may affect coastal landforms. Moreover, the WALCC and AK-CSC have recognized a pressing need to link human and biological use of coastal resources to these physical processes. Their intent is to facilitate development of a model to help identify vulnerable locations, and to determine how different weather and climate events (with particular emphasis on coastal storms) may affect coastal stability and near-shore function. In turn, they hope to assess relative vulnerability of coastal biological and ecological resources, and delineate the gaps in current research and monitoring efforts. The model would be used to guide Western AK LCC and AK-CSC activities related to coastal systems.
The Alaska Ocean Observing System (AOOS) has a long-standing interest in coastal issues and this workshop builds on a similar workshop held in May 2010 that discussed data and modeling needs for dealing with coastal hazards in Alaska (http://www.aoos.org/workshops-and-reports/). The purpose of the 2010 workshop was to identify priority ocean observing activities (e.g. weather, waves, currents) needed to help stakeholders make decisions relative to coastal hazards. Participants included users of the data, decision makers, and information providers. A specific goal for AOOS was review of recommendations from the initial workshop in light of the draft AOOS 10-year build-out plan and to identify further implementation strategies.
Recognition of the significant overlap between participants in the AOOS efforts, the interests of the AK-CSC, and those that would be involved in evaluating needs and model development for the Western AK LCC geographic area resulted in the combined workshop. The AK-CSC also joined as a partner in the workshop as understanding coastal process dynamics under changing climate conditions is a key area of uncertainty related to climate change.
Expected workshop outcomes included:
· Review of the AOOS coastal hazard information gathering strategy.
· Refine stakeholder needs assessment to clarify Western Alaska concerns.
· Initial development of a coastal model linking near-shore and appropriate marine functions to impacts on coastal landforms and associated human and biological uses of that area.
Research and Collaboration Opportunities
Workshop organizers identified new research and collaboration opportunities that included initiation of the Western Alaska Landscape Conservation Cooperative (Western Alaska LCC) and the Alaska Climate Science Center (AK-CSC). The Western AK LCC, established in 2010, is a public and private partnership focused on identifying and addressing shared scientific information needs associated with landscape-scale processes affecting natural resource conservation under a changing climate. USGS established an Alaska Climate Science Center (AK-CSC) in 2010, in partnership with the University of Alaska, Fairbanks. The AK-CSC mission is to provide scientific information, tools, and techniques to anticipate, monitor, and adapt to climate change. AOOS and partners received funding from NOAA for a project to develop data integration and visualization tools for Alaska’s Arctic (Spatial Tools for Arctic Mapping and Planning – STAMP). Implementation strategies for the National Ocean Policy (signed in 2010) are under development to address environmental stewardship needs in the face of climate-induced and other environmental changes. The Local Environmental Observer (LEO) Network, facilitated by the Alaska Native Tribal Health Consortium, is a network of local experts who share their knowledge and experiences to describe environmental events in their communities through a map-based system to raise awareness about changes conditions in the north. (See Appendix 3 for additional details).
State of the Coast
The workshop began with presentations that gave an overview of some of the known information on coastal processes and the documented or suspected changes related to climate change. This section summarizes those presentations and provides some of the discussion topics that were influential in later discussions for developing conceptual models. When there were key recommendation or discussion topics that came from the workshop participants, they are described in paragraphs titled ‘Discussion’.
USGS developed region specific sea ice projections for the Bering and Chukchi Seas based on 18 general circulation models (http://pubs.usgs.gov/of/2010/1176/). Based on an analysis of the past three decades, historical changes in ice cover compared to current conditions differed throughout the year. June is projected to experience the least amount of sea ice loss among all months. For the Chukchi Sea, projections show extensive ice melt during July and ice-free conditions during August, September, and October by the end of the century, with high agreement among models. High agreement also accompanies projections that the Chukchi Sea will be completely ice covered during February, March, and April at the end of the century. Large uncertainties, however, are associated with the timing and amount of partial ice cover during the intervening periods of melt and freeze. For the Bering Sea, median March ice extent is projected to be about 25 percent less than the 1979–1988 average by mid-century and 60 percent less by the end of the century. The ice-free season in the Bering Sea is projected to increase from its contemporary average of five and a half months to a median of about eight and a half months by the end of the century. A 3-month longer ice- free season in the Bering Sea is attained by a one-month advance in melt and a two-month delay in freeze, meaning the ice edge typically will pass through the Bering Strait in May and January at the end of the century rather than June and November as presently observed. More details are available in Appendix 9.
Steve Ivanoff, a resident of Unalakleet on Norton Sound, provided local perspective on how sea ice conditions affect many subsistence activities. In the winter, locals harvest king crab through the ice when it is thick enough and stable enough to support this activity. In the early 1990s, ice condition was excellent as it was extensive, stable and not too thick. Locals could cut holes through the ice with a 3.5 to 4 foot auger. In contrast, ice in recent years is less predictable; in 2010, ice cover was extensive, but this past winter, ice was not as extensive but was too thick to cut through with the augers. Also, ice is melting more quickly now than twenty years ago. Previously, April was the only time for hunting marine mammals, traveling and hunting on the ice. Now, earlier breakup allows boating to begin in June and access to marine mammals on the broken ice.
Weather patterns appear to be changing, with implications for coastal vulnerability as the major on-shore drivers of change are affected by wind direction, fetch and tide cycle. As an example, the large November 2011 storm had 40-foot seas, wind gusts to 93 mph, blizzard conditions and an accompanying storm surge. The storm affected over a thousand miles of coastline and at least 35 communities sustained damage to facilities or other infrastructure. For example, in the community of Golovin, much of the infrastructure (notably the power plant) is in the inundation zone. The community faced difficult decisions about evacuating residents to buildings on higher ground due to an ongoing blizzard conditions and insufficient power at the evacuation site. Golovin, unlike most other coastal villages, did have tide predictions, which provided important information. Substantial damage occurred at a nearby fish camp (with cabins etc.) but considerable damage could have taken place within Golovin and other communities given the size of the storm. Fortunately several factors lessened the storm severity. The day that the storm hit the coast was one of the lowest tides of the month and the storm hit at low tide rather than high tide. Also, the strongest winds were offshore when the storm hit the coast; when the wind switched directions, the magnitude dropped significantly.
Discussion: Tidal information is needed to forecast time and height of high water. It is unrealistic to install gauging stations set to national standards (National Water Level Observation Network – see: http://www.co-ops.nos.noaa.gov/nwlon.html) in all villages; however, the information is still needed. Less expensive platforms with data standards designed to meet regional needs should be employed. The primary issue is that the cost of data recording stations that meet national standards is prohibitive, however, useful data for regional forecasting can be gathered within existing or reasonably obtainable resources. While methods exist to spatially interpolate tides for locations in between gauging stations, currently there are too few stations to provide adequate interpolation.
Storm intensity and number is predicted to increase in the Bering/Chukchi region due to increasing temperatures (climate change). Storm frequency and length of storm tracks has increased in the last 20 years. Sea ice can affect storm magnitude and impact; this is a complex relationship that needs further study. Note that a big storm can have a big effect but numerous smaller storms can also cause damage. US Army Corps of Engineers has gathered information identifying storms with greatest impact on each community. (See Appendix 10 and 11 for further details.)
Discussion: One of the data needs that limit forecasting storms in western Alaska is the lack of a good tidal circulation model. It is possible to build a model of tidal circulation for Bering and Chukchi (Tom Ravens) that is forced by tidal observations. Oregon State has created a worldwide model but Alaska is a special case (complex coastline and unused data sources), therefore development of an Alaska specific model would be beneficial.
A key factor in determining coastal landforms and coastal stability is surficial geology, basically rocky versus non-rocky substrate. The north and west coasts of Alaska are non-rocky and therefore subject to erosion, particularly in permafrost rich areas such as the North Slope where erosion rates can be as much as 15-20m/year. The Chukchi coast southwest of Barrow has a short beach that provides a buffer and the erosion rate averages less that 0.5m/year, although niche erosion occurs during storm events. Volcanic rock armors some parts of the coast in Western Alaska. “Living with the Coast of Alaska” (Mason et al. 1988) identifies coastal communities in which bluff erosion and coastal flooding were major hazards. All of these communities occurred in the Arctic, Bering, or Cook Inlet regions.