Coastal Adaptation Impacts on Water Quality and Flooding

Principal Investigators Philip Orton, Nickitas Georgas, Alan Blumberg, Stevens Institute of Technology; James Fitzpatrick, HDR, Inc.

Funding Agency:  Department of Interior, National Parks Service

Project Period:  November 2014 – October 2016

  1. Summary

Hundreds of thousands of NYC residents in Jamaica Bay’s watershed live on land vulnerable to flooding from a hurricane storm tide. Many types of coastal protective features, ranging from surge barriers to natural features like wetlands and oyster beds, have been suggested as solutions for coastal flooding around the bay. Water quality and storm damage avoidance are integrally linked research topics, as storm protection efforts can harm water quality and alter ecosystems. A project is outlined here to improve upon existing mathematical computer modeling capabilities for Jamaica Bay and to run experiments to study climate change, sea level rise and coastal adaptation impacts on water quality and storm damages. An important part of the project plan is to build Jamaica Bay Science and Resilience Institute consortium technical capacity by making these models available for consortium member use.

View of New York City's skyline, over Jamaica Bay wetlands (credit: Jeanne Hillary)

View of New York City’s skyline, over Jamaica Bay wetlands 

  1. Introduction

Hurricane Sandy was a painful reminder that coastal storms are among the world’s most costly and deadly disasters, capable of causing tens-to-hundreds of billions of dollars in damages and destroying entire neighborhoods. For New York City, hundreds of thousands of NYC residents live at low elevations (below 5 m) surrounding Jamaica Bay, a bay situated on the south-east edge of the city.

Jamaica Bay has an area of 107 km2, is ecologically rich, and has some of the largest remaining tidal wetlands in New York State. However, aerial photographs from 1974 to 1999 show that 2.5 km2 of marshes in the bay’s interior and nearly 80 percent of the interior islands vegetative cover disappeared over this period [Hartig et al., 2002]. The total loss of interior wetlands for the bay since the mid-1800s is estimated to be 12000 of the original 16000 acres [DEP, 2007], and the bay once supported a large oyster fishery producing 700,000 bushels of oysters per year in the early 1900s [Franz, 1982].

Many types of coastal protective features, ranging from surge barriers to natural features like wetlands and oyster beds, are being studied as solutions for coastal flooding. Decisions on which coastal protections to use require detailed studies using computer models that are not available or fully developed for most locations. These models must include many features in addition to physical storm surges, such as chemistry and water quality, to be able to evaluate whether water quality and ecosystems will be harmed by the protections.

Mathematical modeling is useful for understanding water circulation, waves, flooding, water quality, and ecosystem dynamics, among other topics.  Model experiments can reveal dynamics of each of these systems, within the constraints of a given model construct.  Modeling connects with observations, which are used for model development and validation, yet are also interpolated in time and space by the model, to provide a more complete picture a water body, such as Jamaica Bay.  As a result, modeling has major benefits for any comprehensive analysis of the bay, such as for quantification of flood damage reductions.  Modeling also connects with decision analysis, as it opens the door to experimentation to understand future changes due to climate change, sea level rise, and human alterations around and within the bay.

A project is outlined here to improve upon existing modeling capabilities for water quality, flooding and waves for Jamaica Bay, and to run experiments to study climate change, sea level rise and coastal adaptation impacts on water quality and storm damages. An important part of the plan is to build Jamaica Bay Science and Resilience Institute consortium technical capacity by making these models available for consortium member use at CUNY’s High Performance Computing Center (HPCC).

 The primary goals in the project will be to:

  • Improve the existing water quality modeling in Jamaica Bay (J-Bay) with enhanced model representations of wetlands, macro-algae, and wetland and benthic chemical/nutrient fluxes.
  • Improve hydrodynamic model representations of J-Bay wetlands and air-sea interaction
  • Utilize higher-resolution modeling in the bay and improve modeling of exchanges with the coastal ocean by coupling the J-Bay models with inputs from regional scale models
  • Calibrate the improved models using data collected by the consortium and USGS in J-Bay
  • Run experiments to study climate change, sea level rise and coastal adaptation impacts on flooding, waves, water quality and residence time

The two-year project brings together some of the best ocean and water quality modelers from the region, leveraging extensive experience with Jamaica Bay.  It will also include an educational research component and be carried out, in part, by a PhD student and a post-doctoral researcher.

References

DEP (2007), Jamaica Bay Watershed Protection Plan, Volume 1, New York, 128pp pp.

Franz, D. R. (1982), An historical perspective on mollusks in Lower New York Harbor, with emphasis on oysters, Ecological Stress and the New York Bight: Science and Management. Columbia SC: Estuarine Research Federation, 181-197.

Hartig, E. K., V. Gornitz, A. Kolker, F. Mushacke, and D. Fallon (2002), Anthropogenic and climate-change impacts on salt marshes of Jamaica Bay, New York City, Wetlands, 22(1), 71-89.

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Collaborative Climate Adaptation Planning for Urban Coastal Flooding

PIs:  Philip Orton, Alan Blumberg, Peter Rowe (New Jersey Sea Grant Consortium), Tanya Marione-Stanton (Jersey City Department of City Planning)

Funding agency:  NOAA Sea Grant

Project period:  July 2013 – January 2015

 

Photograph from one of the meetings where Jersey City planning personnel (project team members; Jeff Wenger and Co-PI Tanya Marione-Stanton are pictured at right) and Stevens PI Philip Orton (left) interacted on GIS delineations of coastal protection features.

Photograph from one of the meetings where Jersey City planning personnel (project team members; Jeff Wenger and Co-PI Tanya Marione-Stanton are pictured at right) and Stevens PI Philip Orton (left) interacted on GIS delineations of coastal protection features.

Coastal cities across the country are weighing their options for adapting to rising floods, yet there is limited quantitative information available to help make these decisions. Here, we propose a collaboration between coastal flooding scientists and Jersey City planners to develop and test several options for adapting the region’s urban coasts to flooding and sea level rise. Jersey City (JC) is the second-most populous city in NJ, yet has 43% of its land within the new FEMA 100-year flood zones. We lay out a plan to leverage existing storm surge modeling to quantify the performance of a set of protective measures for Jersey City, including a variety of grey and green options such as storm surge barriers, deployable barriers, and wetlands.

Outcomes and outputs from the proposed research include: (1) flood zone maps that account for future sea level rise and storm climatology changes, (2) model-based map animations of how floodwaters enter JC to help understand how the pathways can be blocked, (3) a report on the flood protective benefits of a collaboratively determined set of coastal adaptation options, and their performance with future climate change, (4) an outreach workshop where we present the project’s results to additional regional stakeholders, and (5) a transferable, peer reviewed and published adaptation planning and evaluation framework. Lastly, a primary performance measure for success will be that at least Jersey City, and possibly additional area cities, will implement climate change planning policies to adapt to coastal flooding.

The framework can also be utilized for many other U.S. coastal regions – anywhere that hydrodynamic models are already being used to simulate storm surges or map flood zones. FEMA has embarked on an ambitious effort to re-evaluate the nation’s coastal flood zone maps, and many of these regional efforts are utilizing these models. Many areas also have storm surge forecast models in place that can be similarly used for adaptation studies.

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Quantifying the Value and Communicating the Protective Services of Living Shorelines

PIs:  Alan Blumberg, Philip Orton, Eric Sanderson (Wildlife Conservation Society), Mark Becker (Columbia CIESIN; 1961-2014), Kytt MacManus (Columbia CIESIN)

Funding agency:  NOAA Coastal and Ocean Climate Applications (COCA)

Project period:  January 2014 – December 2015

Coastal storms are among the world’s most costly and deadly disasters, with strong winds, floodwater inundation, and coastal erosion capable of damaging and disabling infrastructure. Increased damage from storm surge flooding is one of the most certain impacts of climate change, with the potential for intensified storms, increased rainfall, and with storm surges coming on top of rising sea levels. Sea level rise is expected to accelerate over the 21st Century, primarily due to increasing expansion of warming seawater and accelerated melting of land-based ice sheets. A conservative estimate of 30-60cm for New York City (NYC) by 2080 will change a 100-year flood event to a 30-year flood event, and “rapid ice-melt” scenarios call for over a meter of sea level rise over this period [Horton et al. 2010].

Hundreds of thousands of NYC residents in Jamaica Bay’s watershed live on land within range of a 5 m hurricane storm tide (Figure 1), and Hurricane Sandy (3.5 m above mean sea level) flooded some of these neighborhoods. Hurricanes made direct hits on NYC four times over the last 400 years including 1693, 1788, 1821, and 1893 and will likely do so again [Scileppi and Donnelly, 2007]. Moreover, sea level rise of 1 m will mean that a severe extra-tropical storm (a “nor’easter”) will lead to flooding levels nearly as bad as Sandy or the historic hurricanes – the worst nor’easters (e.g. 1992) have an annual probability of occurrence of one in twenty and cause maximum water levels of about 2.0-2.5 m [Orton et al. 2012].

Figure 1:  NYC map showing population and density in low-elevation coastal zones (LECZ) below 5 m above mean sea level (Columbia CIESIN; http://sedac.ciesin.columbia.edu/gpw/ lecz.jsp). Hurricane Sandy’s flooding was extensive in neighborhoods surrounding Jamaica Bay.

Figure 1: NYC map showing population and density in low-elevation coastal zones (LECZ) below 5 m above mean sea level (Columbia CIESIN; http://sedac.ciesin.columbia.edu/gpw/lecz.jsp). Hurricane Sandy’s flooding was extensive in neighborhoods surrounding Jamaica Bay.

In past centuries, a large expanse of tidal wetlands, oyster beds, riparian systems, barrier beaches, and shallow water depths in and around Jamaica Bay likely helped shield Southeast Brooklyn and South Queens from storm surge flooding. Today those wetlands are depleted, the oysters gone, the riparian systems and barrier beaches partially paved over, and the depths of Jamaica Bay altered by dredging and land fill. A successful experimental Corps of Engineers program that has rebuilt a small portion of the tidal wetland islands in Jamaica Bay from 2009-2012 raises the possibility that these losses can be reversed, but the cost of rebuilding the losses from 1974-1999 alone has been estimated to be $310 million at ~$500/acre [S. Zahn, NY State Department of Environmental Conservation, pers. comm, 2012].

Nationwide, living shorelines of many types are still disappearing, in spite of society’s qualitative knowledge of their benefits. In recent decades, the decline of tidal wetlands has continued [Dahl, 2006]. Much like wetlands, shellfish reefs also can provide protective benefits from storm-driven waves and flooding, due to their rough surfaces and added frictional effect on rapidly moving waters. Unfortunately, wild oyster biomass in U.S. estuaries has declined by 88 percent over the past century [Zu Ermgassen et al. 2012]. These changes are likely only partially a result of sea level rise – both wetlands and shellfish reefs are to a varying extent ecosystem engineers and can grow upward with sea level rise, though the maximum rates at which they can rise are uncertain. Other issues that continue to wipe out wetlands include eutrophication due to excessive nutrient inputs [Deegan et al. 2012], a particularly difficult problem to solve in urban estuaries, typically requiring billions of dollars in grey infrastructure [e.g., NYC-DEP, 2010; Taylor, 2010].

Quantifying the economic values of these protective services for socioeconomic analyses is a crucial step for conserving these beneficial coastal ecosystems [NRC, 2005]. NYC and many other municipalities across the nation are weighing restoration or protection of living shoreline ecosystems, yet there is limited quantitative information available to help make these decisions. An old rule of thumb holds that 14.5 km of wetlands reduces a storm surge by 1 meter, though this is based on an observational study of historical Louisiana hurricanes that actually showed variations of over a factor of three in the surge reductions [USACE, 1963]. More recent research has shown that the attenuation of storm surge by marshes actually varies even more than a factor of three, and wetlands sometimes do not attenuate storm surges at all. The attenuation by wetlands depends on many details including direction and duration of the storm’s winds and waves, and the coastal topography and bathymetry around the wetlands [Resio and Westerink, 2008]. It is becoming accepted that the protective benefits are larger for storms with winds that blow onshore only for a short duration [Gedan et al., 2010; Resio and Westerink, 2008]. This is an important factor for the NYC region, because historical hurricanes making landfall in this region have moved rapidly at speeds of 45-110 km h-1 [Orton et al. 2012], often passing in only a matter of hours, so coastal wetlands may have more protective potential than in other places where hurricanes often move more slowly.

A key opportunity exists to leverage existing model-based flood zone mapping and risk assessment work, and use them to help quantify the value of living shorelines and map their flood protection services. The Federal Emergency Management Agency (FEMA) has embarked on an ambitious effort to re-evaluate the nation’s coastal flood hazard for the purpose of updating all the coastal flood zone maps. Many of these regional efforts are utilizing hydrodynamic modeling of storm surges, and FEMA is amassing and producing detailed and publically-available datasets for areas such as New York, New Jersey, Delaware Bay and Philadelphia, Mississippi, South Carolina, West Florida, and Florida’s Big Bend. Using hydrodynamic models and accounting for simple frictional influences of land-cover data, it is possible to use these data with storm surge models to quantify the influence of coastal wetlands and shellfish on the particularly sensitive and expensive issue of flooding.

Here, research is proposed with an overriding goal of developing methods to quantify the economic value and communicate the protective services of living shorelines across the United States. The primary scientific objectives include:

  • Map the extent of Jamaica Bay wetlands, beaches, mud flats, and other ecosystem features and the bathymetric depth profile for the late 1800s and modern-day periods
  • Quantify the flood resilience of historical versus present-day coastal zone using model runs of the Stevens Estuarine and Coastal Ocean Model (sECOM) that is used within the Stevens Storm Surge Warning System (http://stevens.edu/SSWS).
  • Work with decision-makers and natural resource managers to develop three realistic future living shoreline scenario options that can reduce storm surge flood elevations
  • Perform a cost-benefit analysis of future living shoreline landscape scenarios based on construction cost analyses and a full risk assessment for storm-driven flooding
  • Give both decision-makers and the general public an online tool that helps them obtain an improved, quantitative understanding of the role that living shorelines like wetlands and shellfish reefs can have on coastal flooding. The tool will enable users to explore future flood zones, and to select future living shoreline adaptation scenarios to view their influence on these flood zones.

 

References

Dahl, T. E. (2006), Status and trends of wetlands in the conterminous United States 1998 to 2004, 112 pp., Washington, D.C.

Deegan, L. A., D. S. Johnson, R. S. Warren, B. J. Peterson, J. W. Fleeger, S. Fagherazzi, and W. M. Wollheim (2012), Coastal eutrophication as a driver of salt marsh loss, Nature, 490(7420), 388-392.

DEP (2007), Jamaica Bay Watershed Protection Plan, Volume 1, edited, p. 128pp, New York City Department of Environmental Protection (DEP), New York.

Gedan, K. B., M. L. Kirwan, E. Wolanski, E. B. Barbier, and B. R. Silliman (2010), The present and future role of coastal wetland vegetation in protecting shorelines: answering recent challenges to the paradigm, Climatic Change, 1-23.

Horton, R., V. Gornitz, M. Bowman, and R. Blake (2010), Chapter 3: Climate observations and projections, Annals of the New York Academy of Sciences, 1196(1), 41-62, DOI: 10.1111/j.1749-6632.2009.05314.x.

NRC (2005), Valuing ecosystem services: Toward better environmental decision-making., National Academy Press, National Research Council, Washington, D.C.

NYC-DEP (2010), NYC Green Infrastructure Plan: A sustainable plan for clean waterways, 143 pp, New York City.

Orton, P., N. Georgas, A. Blumberg, and J. Pullen (2012), Detailed Modeling of Recent Severe Storm Tides in Estuaries of the New York City Region, J. Geophys. Res., 117, C09030, DOI: 10.1029/2012JC008220.

Resio, D. T., and J. J. Westerink (2008), Modeling the physics of storm surges, Physics Today, 61, 33.

Scileppi, E., and J. P. Donnelly (2007), Sedimentary evidence of hurricane strikes in western Long Island, New York, Geochemistry, Geophysics, Geosystems, 8(6), DOI: 10.1029/2006GC001463.

Taylor, D. I. (2010), The Boston Harbor Project, and large decreases in loadings of eutrophication-related materials to Boston Harbor, Marine pollution bulletin, 60(4), 609-619.

USACE (1963), Interim Survey Report, Morgan City, Louisiana and Vicinity, in serial no. 63, edited, U.S. Army Corps of Engineers District, New Orleans, LA.

Zu Ermgassen, P. S. E., et al. (2012), Historical ecology with real numbers: past and present extent and biomass of an imperilled estuarine habitat, Proceedings of the Royal Society B: Biological Sciences, 279(1742), 3393-3400.

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Hudson River floodplain mapping with surge, rain and sea level rise

The Hudson River Flood Hazard Decision Support System – Accurate Modeling of Flood Zones for Combined Sea Level Rise, Storm Surge, and Rain

PIs:  Philip Orton, Alan Blumberg, Kytt MacManus (Columbia CIESIN), Mark Becker (Columbia CIESIN; 1961-2014), Upmanu Lall (Columbia University)

Funding agency:  New York State Energy Research and Development Authority (NYSERDA)

Project period:  May 2013 – April 2015

 

Abstract

This project will create an easy to use, free, online mapping tool that lets users assess the impacts of flood inundation posed by sea level rise, storm surge and rain events on communities bordering the lower Hudson River.  The project will utilize state-of-the-art flood models and will adhere to or improve upon the latest FEMA coastal flood mapping techniques. The study area for this project is the coastal zone area for all counties adjacent to the Hudson River from the southern border of Westchester County to the Federal Dam at Troy.  Flood simulations will merge all sources of flooding water with a single model, so they will not rely on linear superposition of tides, surge and tributary flooding, which is inaccurate along the Hudson [Orton et al. 2012].

The resulting 5-year to 500-year flood zone maps will be applied to newly-created social and critical infrastructure vulnerability layers to measure and map flood risk for the Hudson River coastal region.  The customized mapping tool will allow users to select a particular region of interest and predicted flood scenarios and then visualize the impact on community resources.  Users will also be able to download maps and summary statistics on structures, populations, and critical facilities affected by specific predicted flood events.  The mapping tool along with additional project related information will be available from a publically accessible website developed and hosted by the Center for International Earth Information Network (CIESIN).  This website and the featured mapping tool will be a valuable resource for public officials, resources managers and others looking to assess risk, identify areas suitable for tidal wetland migration, and evaluate the cost/benefit of proposed climate change mitigation options.

 

References

Orton, P., N. Georgas, A. Blumberg, and J. Pullen, 2012. Detailed Modeling of Recent Severe Storm Tides in Estuaries of the New York City Region, J. Geophys. Res., 117(C9), doi:10.1029/2012JC008220.  web | PDF

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Climate Reconstruction for Long Island Sound Fisheries

Analyzing History to Project and Manage the Future: Simulating the Effects of Climate on Long Island Sound’s Physical Environment and Living Marine Resources

Lead PI:  Nickitas Georgas, Stevens Institute of Technology

Co-PIs:  Philip Orton, Alan Blumberg, Stevens Institute of Technology

Co-PI:  Penelope Howell, Connecticut Department of Energy and Environmental Protection

Associate Investigator:  Vincent Saba, Geophysical Fluid Dynamics Laboratory and NOAA National Marine Fisheries Service

Funding:  EPA Long Island Sound office, New York and Connecticut Sea Grant programs

In this project, we will a) conduct a multi-decadal three-dimensional hindcast of Long Island Sound (LIS) to study hypothesized linkages between the Sound’s physical climate and its recent ecological response and b) project future impacts of climate change and variability on the LIS ecosystem and its living marine resources over the span of the 21st century through model development and synthesis.

NYHOPS 3D model domain showing simulated SST, surface currents, and wind barbs. From the Google Earth viewer of the NYHOPS operational forecasts www.stevens.edu/NYHOPS

Figure 1: NYHOPS 3D model domain showing simulated SST, surface currents, and wind barbs. From the Google Earth viewer of the NYHOPS operational forecasts.

Specifically, our objectives are to:

  1. Address the paucity of physical environmental data during Long Island Sound’s (LIS) observed warming trend and accompanying fisheries shift since the 1970s by running a hindcast of the LIS circulation using the New York Harbor Observing and Prediction System (NYHOPS), an operational, comprehensive, high-resolution, three-dimensional, numerical model (Figures 1-2).
  2. Explore climate-forced links between the physical and ecological environment of the Sound by studying the statistical correlations of historic ecological data (such as the fish trawl survey data) to the physical environmental data from the NYHOPS model with a goal to explain the recent ecological regime changes and,
  3. Project the impacts of climate change and variability on the Sound’s ecosystem and its living marine resources until the year 2100, by forcing NYHOPS with Intergovernmental Panel for Climate Change (IPCC)-class global climate models, creating NYHOPS-based predictions for LIS to the end of this century, and deducing future changes to the LIS ecological regimes.
Figure 2. A zoom of the NYHOPS domain that covers the Long Island Sound. Shown is simulated SST (colored background and legend on the upper left), a popup with data from a UCONN buoy used in the NYHOPS model, and instantaneous surface current vectors also from the NYHOPS model. Screenshot taken from the NYHOPS google earth viewer 9/26/2012 1900Z.

Figure 2. A zoom of the NYHOPS domain that covers the Long Island Sound. Shown is simulated SST (colored background and legend on the upper left), a popup with data from a UCONN buoy used in the NYHOPS model, and instantaneous surface current vectors also from the NYHOPS model. Screenshot taken from the NYHOPS google earth viewer 9/26/2012 1900Z.

Justification

Over the last few decades, the LIS ecosystem has undergone profound changes. Water temperature measurements at a LIS long-term station frequently used in ecosystem assessments (LISS 2010, Howell and Auster 2012, among others) have recorded a significant warming trend (1.46ºC increase from 1976 to 2010; Dominion Resources Services 2011). Concurrently, substantial changes have occurred in the community structure and abundance of living marine resources in LIS (Howell et al 2005; Howell and Auster 2012). A dramatic example is the American lobster (Homarus Americanus) collapse, initiated by the major die-off in 1999.  Although multiple factors may have been synergistically responsible for this collapse, the increase in bottom temperature was likely the major factor that caused an increase in the mortality rate of lobsters, especially egg-bearing females (Howell et al 2005). Interestingly, the lobster collapse was exclusive to southern New England waters south of Cape Cod. The lobster stocks and fisheries further north, particularly the Gulf of Maine, are thriving. Reported landings have been at record highs over the past decade (Thunberg 2007). Based on the CT DEEP trawl survey, there seems to have been a shift in adult lobster population (ALTC 2010), that has altered the area where young lobsters recruit (Kim McKown, pers. comm.).

Fisheries-independent trawl surveys in LIS have reported substantial changes in finfish community structure and abundance (Howell and Auster 2012). Correlated with the increase in the bottom temperature of LIS from 1984 to 2008, the seasonal mean catch of cold-adapted finfish [i.e. windowpane flounder (Scophthalmus aquosus), spotted hake (Urophycis regia)] has significantly decreased, while warm-adapted species [i.e. butterfish (Peprilus triacanthus), striped sea robin (Prionotus evolans)] have increased (Howell and Auster 2012). There appears to have been a cold to warm species regime shift in the 95 finfish species examined statistically separating the community seen in 1984-1998 compared to 1999-2008 (Howell and Auster 2012). Although this time-period may be too short to attribute to climate change, it is apparent that the ecosystem of LIS may have responded to a climate perturbation.

The aforementioned reports suggest a regime shift in both the climate and ecosystem of LIS occurring around 1998. Remarkably, there have been increasingly more studies reporting a 1998 regime shift in the climate and living marine resources of coastal and pelagic marine ecosystems in vastly different parts of the world. To name a few, these include the Bering Sea (Rodionov and Overland 2005), the North Pacific (Overland et al 2008), and the North Sea (Weijerman et al 2005). Therefore, there may be a large-scale climate teleconnection between the local LIS climate and the global climate, whether due to natural or anthropogenic climate perturbations.

The apparent sensitivity of LIS to climate warrants research that elucidates the specific processes that are associated with the ecosystem’s response to climate perturbations. This is especially critical for projecting the impacts of global climate change on the LIS ecosystem given the 2-3ºC increase in surface air temperature projected by climate models included in the IPCC fourth assessment report (Christensen et al 2007). In order to assess, understand, and project the biophysical and mechanistic underpinnings between climate and living marine resources of  LIS, a detailed, historical analysis of climate and living marine resources is first required. However, the historical three-dimensional physical data of LIS is very sparse and only provides a general warming trend based on a few stations (one of which is near a power plant) without details on the relationships between circulation, hydrology, high-resolution depth-profile data covering the entire area of LIS, and interaction with the shelf-waters outside of LIS. Our proposed research will attempt to fill in these gaps.

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Building resilience to storm surges and sea level rise

Building resilience to storm surges and sea level rise:
A comparative study of coastal zones in New York City and Boston

Lead-PI:  Malgosia Madajewicz, Columbia University Center for Climate Systems Research

Co-PI: Alan Blumberg, Stevens Institute of Technology

Co-Investigators:  Philip Orton, Stevens; Mark Becker, Columbia CIESIN

Statement of the problem
Large proportions of the United States’ population, infrastructure, and economic wealth are vulnerable to flooding caused by storm surges along the coastal north-eastern urban corridor (NEUC)1 (Frumhoff et al. 2007). In 2003, 53% of the population of the United States lived in coastal counties, with 34% of that 153 million residing along the northeastern Atlantic coast, which has 4 out of 10 of the nation’s largest cities (NOAA 2004). The population pressure along the coastal NEUC has eroded coastal ecosystems and their role as protective buffers against storm surges, compounding the vulnerability of society and nature (Frumhoff et al. 2007).

Storm surges are among the deadliest and most costly natural disasters (Parker 2010). In New York City (NYC) and Boston, billions of dollars of urban infrastructure lie less than 4 meters above mean sea level. Hurricane Irene was only a tropical storm when it made landfall in NYC, and it only caused a modest storm surge of 1.4 meters. However, this storm caused estimated damages totaling at least $55 million in NYC (The Associated Press 2011), flooded waterfront highways, and came close to damaging major electrical and transportation infrastructure. Hurricane Irene was preceded by a mandatory evacuation order affecting 370,000 people in NYC (Bloomberg 2011). Three hurricanes in or near NYC in 1788, 1821 and 1893 had storm surges of 3 – 4 meters and flooded about half of Manhattan below 34th Street and large swaths of East Harlem, Queens, Brooklyn and Staten Island (Scileppi and Donnelly 2007).

Increased damage from coastal flooding related to storm surges is among the most certain impacts of climate change along the coastal NEUC (Frumhoff et al. 2007). Climate change has a two-fold impact on coastal storms. First, storms are likely to bring more intense rainfall (see for example Trenberth et al. 2003; Rosenzweig et al. 2010). Second, sea level rise will raise the height reached by storm surges (e.g. Solomon et al. 2007). Even conservative sea level rise
projections triple the frequency of current 1 in 10 year coastal floods in many areas (Horton et al. 2010; Horton et al. 2008). The increased flooding risk could greatly impact NYC’s and Boston’s coastal communities, critical infrastructure, and major urban transportation routes, as well as compound development pressures from anticipated population growth (Kirshen et al. 2004; Rosenzweig et al. 2011). In NYC, for example, Rosenzweig et al. 2011 estimate that “a direct hit from a major hurricane would cause $100s of billions in damage, with economic losses accounting for roughly two times the insured loss” (94). In metropolitan Boston, sea-level rise of about 20 inches will increase the value of assets exposed to damage by coastal storms from less than $100 billion today to about $500 billion (Climate Action Leadership Committee 2010).

Summary of proposed work

In this project, we will seek to advance the design of effective approaches to adaptation to coastal flooding associated with storm surges, based on research in two cities, NYC and Boston. We will work with decision makers in NYC and Boston to design and evaluate adaptation blueprints for different types of neighborhoods. We will inform the design with a multi-dimensional analysis of vulnerability to coastal flooding.  We will produce probabilistic predictions of coastal flooding for the 2010s, 2050s and 2080s, in the form of spatial maps of inundation probability per year. We will combine the inundation maps with dynamic maps of a vulnerability index that combines information about several dimensions of vulnerability as represented by land use, characteristics of infrastructure, and socioeconomic data. We will work with decision makers to use the vulnerability maps to develop blueprints that specify adaptive decision and implementation processes for adaptation in different types of neighborhoods. We will assess the likely impacts on vulnerability and costs of approaches proposed in each blueprint, and we will determine under what conditions each blueprint may be effective in other coastal urban areas.

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Coastal-Urban Microclimates (2010-2012)

Weather and wind forecasting typically relies upon low-resolution computer simulations, with no more detail than a 12-kilometer grid.  Also, these model simulations virtually never incorporate urban features such as pavement and skylines.  As a result, they cannot accurately predict how temperature varies over city neighborhoods during a heat wave, nor can they always tell what direction wind will be blowing an atmospheric contaminant.  In the end, weather forecasters do an amazing job with mediocre weather models by using their long-term knowledge of what works for various situations and locations.

Air temperature measurements at 1:15 AM during a recent heat wave.  The 240 weather stations demonstrate how some neighborhoods around New York City were as much as 15 degrees warmer than rural areas.  Data credits given below.

Sometimes this isn’t good enough, so a goal of a research collaboration between our research group and collaborators at the Naval Research Laboratory and City College of New York was to push the boundaries of dealing with these shortcomings in atmospheric prediction.  Our research aimed to help improve prediction capabilities for weather and atmospheric transport, as well as the scientific understanding of urban weather features such as the urban heat island, which often keeps temperatures 10-15 degrees (F) warmer than rural areas at night, as shown above.  The influence of the ocean and sea breezes on weather is also captured much better by COAMPS than by most weather models.  Previous results and publications from similar research are summarized on Julie Pullen’s webpage.

We worked with the Navy’s Coupled Ocean-Atmosphere Mesoscale Prediction System (COAMPS) computer model, and using grids as high as 333 meters resolution.  For checking the model results with actual weather observations, we used the usual airport and city weather stations, maintained by NOAA, but also hundreds of civilian-run weather stations — all these are conveniently merged in City College’s NYC Met Net.

A student publication resulting from this research is:

Meir, T., Orton, P.M., Pullen, J., Holt, T., Thompson, W.T., Arend, M.F., 2013. Forecasting the New York City urban heat island and sea breeze during extreme heat events. Weather and Forecasting.  doi: 10.1175/WAF-D-13-00012.1.  webPDF

 

[Temperature figure data credits:  NOAA (NOS-PORTS, NWS-ASOS, NWS-HADS, Urbanet), Rutgers NJ Weather and Climate Network, APRSWXNET, AWS Convergence Technologies, Inc. (WeatherBug), and Weatherflow, via Mark Arend (NYCMetNet).]

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