Sea Level Rise Modeling using GIS: MDI Photo taken at Hadley point, October 9, 2014, during a king tide. By Anyuri M. Betegon A. Independent Study Gordon Longsworth TABLE OF CONTENTS INTRODUCTION 2 DISCLAIMER AND METHODOLOGY 3 INDEX MAP 4 SEA-LEVEL RISE AND TAX PARCEL OVERLEY 5 COMPARISON TO FEMA SEA-LEVEL RISE MODEL 11 CLAMFLAT AND SEA LEVEL RISE 12 KING TIDES AND SEA-LEVEL RISE IN MDI 13 WILDLIFE AND SEA-LEVEL RISE IN MDI 15 THE BIG PICTURE 16 ADAPTATION STRATEGIES 17 CONCLUSION 17 RESOURCES 18 1 INTRODUCTION This project is intended to project impacts of climate change specifically sea level rise on Mount Desert Island (MDI) in order to determining possible strategies for adaptation for MDI. Even small slight changes in sea level rise can produce rare floods increasing the impact of tides and storm surges. To account for storm surges requires to use SLOSH (Sea, Lake and Overland Surge from Hurricanes) modelling for this particular project we will not map SLOSH. This project an opportunity to look at losses and damages (the economic, physical, and human losses and damages caused by the effect of climate change). Climate change occurs when weather patterns are altered irreversibly. It is considered a global social, political, and environmental issue. The United Nations Framework Convention on Climate Change defines climate change as "a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods." The primary contributions to changes in the volume of water in the ocean are the expansion of the ocean water as it warms and the transfer to the ocean of water currently stored on land (ice sheets). The highest observed flood at the Hancock County in our records from 1958 to 2013, reached 4.95 ft. in 1997 (Climate Central, 2014). In many places climate change related impacts have reached a level beyond just using adaptation strategies to counteract them but rather they are at a level of having to deal with significant losses and damages that are deeply detrimental to livelihoods and life in these places. Loss and damage tackle changes and destructions arising from climate change. It includes economic and non-economic losses and damages. The impacts are classified into two: slow onset (sea-level rise, ocean acidification, etc.) and extreme events (hurricanes, droughts, floods, heat waves, etc.). The time factor does not make less slow onset processes. 2 GOALS To learn how to model sea level rise in GIS To have a better understanding of the economic and biophysical impacts that climate change can have on MDI To comprehend better what could be done to avoid irreparable loses and damages QUESTIONS What is an effective and accessible way for island communities to model climate change impacts and possible adaptation strategies? To what extent can possible examples of such modeling be built out of studying MDI? Is it worth it? To what extent will MDI will be affected through looking at the visible vulnerable areas? How does it stand beside other models? What can be proposed for MDI to adapt? Disclaimer about maps The maps in this report illustrate the scale of potential sea level rise from 1 to 5 ft rise, from mean high tide. The following places were selected because showed some degree of impact by the rise of sea level all the way to five feet. This study does not account subsidence, future constructions, storm surges or wind speed. Areas shown in the maps are susceptible to storm surge and wind speed, therefore possible impacts may be more dramatic as predicted by this model. Methodology GIS data used: MDI lidar (Digital Elevation model), MDI shore line, MDI parcels, MDI coastal marine geology and Aerial imagery. The digital elevation model was used to identify 1, 2, 3, 4, and 5 ft sea-level rise. Areas of study were overlaid with tax parcel to see economic impacts. On a different map mudflats were overlaid to understand the location of mudflats for the economic commentary. Secondary and Primary literature were used: Intergovernmental Panel for Climate Change (IPCC), United Nation Convention on Climate Change (UNFCCC), The Rocky Mountain Climate Organization, among others. 3 Index map Hulls Cove Town Hill N Bar Harbor Somesville Pretty Marsh Otter Creek Seal Harbor Northeast Harbor Seal Cove Southwest Harbor Bass Harbor Legend Study Areas Photo locations 0051 2 3 4 Miles This index map is meant to give you and overall view of the different places this report is going to look at for analysis. In the following pages each of the study areas will be look at more specifically: Head of the island, Bar Harbor, Somesville, Southwest Harbor, Bass Harbor, and Pretty Marsh. These places were chosen for various reasons, one of them is that these places are populated. 4 Sea level rise with tax parcel overlay Head of the island N Legend Parcels sea level rise (ft) Mean high tide 1 2 3 4 5 This map shows a model of possible sea level rise at the head of MDI. Notice how 1 - 5 ft. sea level rise partially or completely inundates some tax parcels. A rise like the one predicted will affect about 19 parcel in the map. Low lying areas are vulnerable to an increasing threat of storm surge flooding, which will affect road and sewer systems. 5 Bar Harbor Legend Parcels sea level rise (ft) Mean high tide 1 2 3 4 5 This map shows a model of the possible sea level rise Bar Harbor. Bar Harbor is an example of an area that because of its rocky coast is not adversely affected. 6 Somesvile N Legend Parcels sea level rise (ft) Mean high tide 1 2 3 4 5 This map shows a model of the possible sea level rise at Somesville. Coastal elevation changes rapidly, thus if the topographic landscape was gradual as we assume seal-level rise will be, there will have been greater impacts. In this map we can see that there are four parcels that will be partially affected. There is also a high chance that the road will be inundated at 5ft rise. 7 Southwest Harbor Legend Parcels sea level rise (ft) Mean high tide 1 2 3 4 5 This map shows a model of the possible sea level rise at Southwest Harbor. In this image you can observe about 12 tax parcels are partially affected. Some houses, and peers might be affected as well. 8 Bass Harbor Legend Parcels sea level rise (ft) Mean high tide 1 2 3 4 5 This map shows a model of the possible sea level rise at Bass Harbor. Observe how 1 - 5 ft. sea level rise partially or completely inundates some tax parcels. There are about 30 parcel that will be partially inundated. There is a possibility that roads and septic systems will be affected. This map shows a possible impact on wetland areas. Tidal wetlands will migrate inland and upslope in those areas where infrastructure and topography do not act as barrier. 9 Pretty Marsh Legend Parcels sea level rise (ft) Mean high tide 1 2 3 4 5 This map shows a model of the possible sea level rise at Pretty Marsh. In this map you can see that there are about 9 tax parcel that will be partially inundated. Wetland marshes are important contributors to the biological productivity of coastal systems. Marshes function as nurseries, and as refuges for commercially important shellfish and fish. 10 Comparison to GIS online maps on predicted sea level rise from NOAA Sea Level Rise and Coastal Flood NOAA's map we Sea Level Rise Confidence Marsh + Vulnerability Flood Frequency Mount Desert Narrows can see that the Sea Level Rise ? head of the island is 5ft SLR completely Legend Water Depth separated from the Low-lying Areas Thomas Island rest of the island. Area Not Mapped 1 Visualization Location View Levees Thomas Overview Bay Use the slider bar above to see how various levels of sea level rise will impact this area. Levels represent inundation at high tide. Areas that are hydrologically connected are shown in shades of blue (darker blue greater depth). Low-lying areas, displayed in green, are hydrologically "unconnected" areas that may flood. They are determined solely by how well the elevation data captures the area's hydraulics A more detailed analysis of these areas is required to determine the susceptibility to flooding. Understanding The Map Additional Information In the maps I made the sea rises but not to the point of complete separation from the rest of the island Legend Parcels sea level rise (ft) LE Mean high tide 1 2 3 4 5 11 Map showing mud flats in MDI Legend Sea ev XII Mean non tide 1 La 4 5 0 0,5 1 2 3 4 Mud tas E Mud flats are critical environment, not just for birds but also for humans. Clam men rely on a healthy marine environment. If the vanished then they will not provide nourishing whole food to citizens and contribute to the economy. Maine's shellfish industry is an essential part of Maine's culture and heritage. A sea level rise can change where the clam flat will be and the access people will have to them. In 1980 it was estimated that clam fishery value was $8 million. In 2006 the value has increase $16 million because of supply and demand and the effects of biotic and abiotic factors. This could be seen as the potential monetary lost if the clam industry retreats with the increase of sea level. 12 King tides and MDI The king tide is the highest predicted high tide of the year at a coastal location. It is above the highest water level reached at high tide on an average day. King tides are also known as perigean spring tides. King tides are important because they help us understand what would future water levels be like, and they are a way to communicate local sea level rise impacts over long time periods. Talking about king tides can help raise awareness of potential climate change impacts and identify high risk locations. Pictures taken at different parts of the island during a king tide on October 9th, 2014. 13 14 Wildlife and sea level rise in MDI "Birds that require the marsh for rearing young (e.g., Black and Clapper Rails, some terns and plovers) will be affected negatively by its loss, whereas birds that feed in shallow water or on intertidal sand and mud flats that replace the marsh (e.g., dabbling ducks, some shorebirds) will be affected positively." The Intergovernmental Panel on Climate Change predicted that sea level will rise two feet in the next century. Areas in Acadia that have low elevation, such as the Otter Cliffs causeway, are often flooded by a combination of astronomical high tide and severe storms. As the sea rises these coastal habitats will slowly flood and become uninhabitable to the plants and animals that depend on it. This causes a shift in biodiversity within the park as some coastal species are forced to adapt to the changing environment. Wetland plant systems might not be able to move inland as sea level rises on sedimentary shores because seaside development by humans limits that option. Many plant and animal species in Acadia can only exist in particular temperature ranges and climatic regions. Certain areas on the coast of MDI are habitat for rare, threatened, or endangered species of plants and animals, if this areas are negatively impacted, there will be serious losses. And the loss of "potentially significant genetic information." "Nesting birds in Acadia that could be adversely affected by a changed climate are loons, bald eagles, peregrine falcons, and seabirds that nest on low-lying islands." Sea level rise can affect Acadia's salt marshes and freshwater. These habitat support a great diversity of plant and animal life. Where there is no suitable space for salt marshes to migrate inland with the rising sea, entire ecosystems may be lost. 15 The big picture Relative SLR, 2008-2050 The process of sea (meters) level rise in MDI is the result of a larger picture. Since 1870 the global sea lever has risen about 8 inches. o 0.1-0.2 0.2-0.3 0.3-0.4 0.4-0.5 + Reset Figure 2. Sea level rise (mean estimate from 19 models temperature projections, under 6 scenarios and for 3 carbon cycle parameter settings) over the period 2008-50 at 55 tide gauges. Units of metres. C Tebaldi et al Every how many years will today's 100-year event recur in 2050? Many variables will influence and contribute to uncertainty around global mean sea level this century. This includes: the future trajectory of greenhouse gas emissions; the response of atmospheric and oceanic temperatures to these; and the melting and dynamic collapse of glaciers and ice sheets in response to changing 1 2 5 10 20 30 50 75 100 temperatures (Tebaldi et. al., 2012). Figure 4. For the ensemble average estimate of relative SLR at each gauge, projected return periods, by 2050, for floods currently qualifying as 100 yr events. Relative sea level rise also depends on local changes in currents, winds, salinity, and water temperatures, as well as proximity to thinning ice sheets. "Substantial changes in the frequency of what are now considered extreme water levels may occur even at locations with relatively slow local sea level rise, when the difference in height between presently common and rare water levels is small" (Tebaldi et. al., 2012). 16 Adaptation strategies This study suggest the following adaptation strategies: Areas at low elevation (the road network, utilities, and septic systems) will require periodic evaluation and upgrade to avoid losses. Measures to ensure the continued survival of wetland ecosystems as sea level rises need to be thoroughly assessed. Low impact development approaches that minimize new impervious surface area and maximize on-site infiltration of runoff will help to maintain the health of the coast of MDI. Increase protection of freshwater wetlands throughout watershed. Greater flexibility is needed in siting and in farming structures, and it is also important to take appropriate decisions to prevent land runoff and contamination of near shore environments. Conclusion As the earth's climate becomes warmer, sea level will slowly rise due to melting glaciers. This rise combined with an increase in storms and hurricane frequency and intensity would create more severe storm surges, surges that not only may damage ecosystems and coastal infrastructures but adversely impact plant and animal species. Sea-level rise will pose significant challenges to Mount Desert Island management strategies. Plans for maintenance and restoration of coastal areas will support wildlife and reduce flood's impacts. The identification of upslope migration of wetlands is key to restricting further development that could reduce the resilience of the ecosystems. As shown in the maps of this study the location of high risk areas vary because of the heterogeneity of the topography. A SLOSH model that includes sea-level rise used in this study will show a less conservative scenario. This scenario needs to be included in order to take better decision in relation to adaptation strategies. Acknowledgements Thanks to Gordon Longsworth, and Acadia National park for their insights on how to go about this project. 17 RESOURCES Climate Central. (2014). Sea Level Rise and Coastal Flood Exposure: Summary for Hancock County, ME. Ecosystem Indicator Partnership. Information on Change in the Gulf of Maine. 2010. Available at: http://www.gulfofmaine.org/esip/ESIPFactSheetAquacultureversion3pdf IPCC Report of the Science of Climate Change. 2013. Available at: http://www.climatechange2013.org/ Manomet Center. 2013. Manomet Center Report: A Summary of Vulnerability of Habitats and Priority Species. National Park Service. Geology Fieldnotes. Sand beach formation information. Available at: http://www.nature.nps.gov/geology/parks/acad/ New England Environmental Finance Center developed the Coastal Adaptation Climate Change Resilience Pilot Project. Available at: http://www.fhwa.dot.gov/environment/climate change/adaptation/ongoing and current research/vulnerability assessment_pilots/index.cfm Saunders, S., Easley, T., and Spencer, T. 2010. Acadia Perils: 1, 2, 3 and 4. Surging Seas Risk Finder. 2014. Available at: http://sealevel.climatecentral.org/ Tebaldi, C., Strauss, B., and Zervas, C. 2012. Modelling sea level rise impacts on storm surges along US coasts. The University of Maine. 2009. Maine Climate Future: An initial Assessment. Titus, J. Sea Level Rise and Wetland Loss: An Overview. Office of Policy Analysis U.S. Environmental Protection Agency Washington, D.C. 20460 18