Tag Archives: flood

Compound Fluvial-Coastal Flood Adaptation

PI Philip Orton, Stevens Institute of Technology

Co-PI Franco Montalto, Drexel University 

Co-PI Marc Cammarata, Philadelphia Water Department 

Additional team members: Julia Rockwell (PWD), Korin Tangtrakul (Drexel), Kazi Mita (Stevens)

Funding agency/program:  National Oceanic and Atmospheric Administration, Climate Program Office, Coastal Ocean Climate Applications (COCA)/Sectoral Applications Research Program (SARP)

Project Period:  September 2019 to August 2021


Compound flooding is the combination of rainfall-induced flooding with storm surge induced flooding, and is currently inadequately considered nationwide in both flood risk assessment and forecasts. It is well-established that coastal floods are becoming more frequent, and the U.S. Northeast has seen a substantial increase in intense rainfall events in recent decades, likely as a result of climate change. In many U.S. cities, coastal and fluvial floods merge in estuaries, causing a compounded problem, and the coincident occurrence of extreme rain and surge is growing at many locations. However, little research has been performed to improve our understanding of compound flooding.

An ideal location to investigate this problem, Eastwick is a low-lying neighborhood in South Philadelphia situated near the Delaware River at the confluence of Darby and Cobb’s Creeks. It is in close proximity to the 1.2 km2 John Heinz National Wildlife Refuge, two federal Superfund sites, a series of oil refineries, and the Philadelphia International Airport, and meets the EPA criteria for an Environmental Justice community, with a majority (76%) of its population being African American, and pockets of low income residents. Triggered by rainfall, coastal surges pushing up the tidal portion of the Delaware River, or some combination of the two, flooding has long been one of the biggest problems facing this community.

The proposed research will inform climate risk management and adaptation decision-making regarding flooding in Eastwick, and will be performed by researchers from two universities and the Philadelphia Water Department (PWD). The project will include four core areas of science, as well as a community engagement process, strong coordination with decision makers and a specific focus on two ongoing city planning initiatives. The core compound flood science research areas include flood modeling, extreme value analysis, climate-impact assessment, and adaptation benefit-cost analysis. The engagement process will consist of two community workshops, including collaborative design of flood adaptation scenarios and a socially-sourced validation of the flood modeling. Coordination with decision makers will occur through an advisory panel, project webinars, and the activities of our team members at the PWD.

The proposed research will strongly further NOAA and COCA/SARP interests relating to climate change. It presents a framework and detailed technical approach for addressing both the communication of risk and the economics of adaptation to compound flooding and climate change. An important additional component of the planned research is to compare our detailed analyses to simplified approaches, to improve the transferability of the work to other communities with similar challenges. The advancement of scientific understanding, prediction and communication of compound flooding will help enable effective decisions, and our development and dissemination of modeling, statistical hazard analysis and benefit-cost analysis tools will have a nationwide impact on resilience.


Eastwick is a low-lying community in South Philadelphia that floods frequently yet lacks sufficient information on flood risk or adaptation. It meets the EPA criteria for an Environmental Justice community, with a majority (76%) of its population being African American, and pockets of low income residents. The community is situated near the Delaware River at the confluence of Darby and Cobb’s Creeks, and in close proximity to the 1.2 km2 John Heinz National Wildlife Refuge. Unfortunately, Eastwick also happens to be located next to portions of the Lower Darby Creek Superfund Site, increasing the health risks posed by any flooding that occurs in this area.

Flooding has long been one of the biggest problems facing Eastwick, the lowest-lying community in Philadelphia (University of Pennsylvania, 2017). Eastwick’s floods can be purely due to rainfall, purely due to high coastal sea levels pushing up the tidal Delaware River, or they can be compound flooding (Moftakhari et al., 2017; Wahl et al., 2015), the merger of the two (U.S. Army Corps of Engineers, 2014).  As such, the community exemplifies a common problem faced by low-lying coastal neighborhoods located at the downstream end of coastal urbanized watersheds found across the nation. Eastwick has been designated by FEMA as a Special Flood Hazard Area. In 1999, for example, Hurricane Floyd deposited 25 cm of rain in the Darby Creek watershed and pushed a 0.85 m surge up the Delaware River, creating such severe flooding that residents had to be rescued by rowboat.  After Hurricane Irene’s (runoff-induced) flood and just before Hurricane Sandy’s (surge-induced) flood, the Mayor called for a comprehensive solution to Eastwick’s flooding problems, yet to date no comprehensive mitigation plan for the neighborhood has been developed.

Compound flooding is currently inadequately considered nationwide in both flood risk assessment and modeling activities. Neither FEMA’s maps, nor NOAA’s forecasts address compound flooding because they address runoff-induced or surge-derived flooding separately (e.g., Corelogic, 2017a; Moftakhari et al., 2017; Orton et al., 2012). For example, Philadelphia is ranked as being the metro area with the 11th-highest hurricane storm surge risk in the US (Corelogic, 2017b), but that study did not account for rainfall. Flood modelers often either assume constant stream flow, if they are simulating surge-derived floods, or a static coastal water level if they are simulating runoff-induced riverine floods (e.g., U.S. Army Corps of Engineers, 2014). Holistic simulation and probabilistic assessment of compound flooding is thus essential to “risk characterization” and to “the development of innovative, applicable, and transferable approaches for decision making” in urban coastal communities across the nation (two key goals of the CSI program).

Proposed study and objectives

The overriding objective of the proposed research is to inform climate risk management and decision-making regarding flooding in Eastwick. The proposed research activities will be integrated into two ongoing community planning initiatives: (1) the City-wide Flood Risk Management Task Force which was first convened in 2015 “to address the circumstances of flooding as it impacts various Philadelphia neighborhoods” including Eastwick (PWD, 2017a) and (2) the Lower Eastwick Public Land Strategy (LEPLS), a planning effort that has developed and will now begin to implement a vision for Eastwick’s vacant and publicly-owned land (RDA, 2017). Our interactions with the Task Force will be facilitated principally by project partner Philadelphia Water Department (PWD) with Co-PI Joanne Dahme and PWD project manager Julia Rockwell, while our interaction with the LEPLS (Figure 1) will be through our partners at Keystone Conservation Trust and the Eastwick Friends and Neighbors Coalition.

Flow Chart 3a

Figure 1:  Diagram of the proposed COCA/SARP project (top) as well as the timeline of projects with which the study would connect or leverage (bottom).


The research team will improve an existing dynamic model of compound flooding in Eastwick developed by the project team and use it in conjunction with ongoing and proposed new stakeholder activities in several inter-related ways. The land use strategies developed by the LEPLS team will be incorporated into the model domain, ensuring that future climate impacts and adaptation scenarios respond to the community’s expressed aspirations and goals regarding local land cover and land use. New workshops planned by the project team will be used to validate retrospective model simulations with local knowledge regarding the location, timing and severity of historical flooding in the community (a “social validation”).  These workshops will also source community-guided green and grey flood adaptation measures across the watersheds and waterfronts (e.g. Figure 2). The efficacy of these measures for mitigating flooding will be quantified with dynamic flood modeling of historical and synthetic flood events across a wide range of return periods (e.g. Figure 3). Damage computations for flooding and benefit-cost ratios will be computed using improved city data within FEMA’s HAZUS software.


Figure 2:  Co-PI Montalto and his students listening to community leaders with Eastwick Friends and Neighbors Coalition (EFNC) at last year’s flooding workshop.

These activities will be coordinated through and at times conducted during regularly scheduled meetings of the City-wide Task Force, minimizing the time commitment that our engagement activities will have on local stakeholders, while also ensuring participation of a diverse and representative group of intended beneficiaries in the research. This synchronization will ensure that the research outputs are both timely and germane, given other planned activities in this dynamic community.

In this way, we will test innovative, broadly applicable approaches for flood modeling, flood risk assessment, benefit-cost analysis of compound flood risk reduction scenarios. Key contributions of the research to the science of climate adaptation and engagement will be: a) an evaluation of the proposed stakeholder-engaged modeling approach as a means of communicating complex probabilistic, multi-source flood risks to a vulnerable community, b) development of a workshop framework that can be used to explore the advantages and disadvantages of alternative adaptation strategies under a wide range of compound flood risk scenarios.


Figure 3: Example of modeled flooding (shaded water depth in feet) for a synthetic storm event with Hurricane Sandy’s Delaware River water levels combined with Hurricane Irene’s Cobbs-Darby streamflows.  Eastwick spans the top-right to the center-right.



Corelogic. (2017a). Storm Surge Inundation vs Freshwater Flooding Report.   Retrieved August 8, 2017, from http://www.corelogic.com/about-us/researchtrends/storm-surge-inundation-vs.-freshwater-flooding-report.aspx?WT.mc_id=crlg_170601_97ewN#.WYt9kVF95PY

Corelogic. (2017b). Storm Surge Risk Report.   Retrieved August 9, 2017, from http://www.corelogic.com/about-us/researchtrends/storm-surge-report.aspx?WT.mc_id=pbw_170530_iRNG1

Moftakhari, H. R., Salvadori, G., AghaKouchak, A., Sanders, B. F., & Matthew, R. A. (2017). Compounding effects of sea level rise and fluvial flooding. Proceedings of the National Academy of Sciences, 114(37), 9785-9790.

Orton, P., Georgas, N., Blumberg, A., & Pullen, J. (2012). Detailed modeling of recent severe storm tides in estuaries of the New York City region. Journal of Geophysical Research, 117, C09030. doi: 10.1029/2012JC008220

PWD. (2017a). Citywide Flood Risk Management Task Force.   Retrieved August 9, 2017, from http://www.phillywatersheds.org/category/blog-tags/citywide-flood-risk-managment-task-force

University of Pennsylvania. (2017). Researchers and Residents Explore ways Eastwick Floods and Ideas for Mitigation.   Retrieved May 19, 2017, from https://www.sas.upenn.edu/urban/news-events/news/researchers-and-residents-explore-ways-eastwick-floods-and-ideas-mitigation

U.S. Army Corps of Engineers. (2014). Eastwick Stream Modeling and Technical Evaluation Philadelphia, Pennsylvania, Philadelphia District, North Atlantic Division.

Wahl, T., Jain, S., Bender, J., Meyers, S. D., & Luther, M. E. (2015). Increasing risk of compound flooding from storm surge and rainfall for major US cities. Nature Climate Change, 5(12), 1093-1097.



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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 2017 (Completed)


Primary Research Products

Fischbach, J., H. Smith, K. Fisher, P. Orton, E. Sanderson, R. Marsooli, H. Roberts, and others (2018), Integrated Analysis and Planning to Reduce Coastal Risk, Improve Water Quality, and Restore Ecosystems: Jamaica Bay, New York. Final project report for The Rockefeller Foundation.  web open access

Marsooli, R., P. M. Orton, J. Fitzpatrick, and H. Smith (2018), Residence time of a highly urbanized estuary: Jamaica Bay, New York, Journal of Marine Science and Engineering, 6(44), doi:10.3390/jmse6020044.   web open access

Marsooli, R., P. M. Orton, G. Mellor, N. Georgas, and A. F. Blumberg (2017), A Coupled Circulation-Wave Model for Numerical Simulation of Storm Tides and Waves, J. Atmos. Oceanic Technol.(2017), doi:http://dx.doi.org/10.1175/JTECH-D-17-0005.1.  web open access

Marsooli, R., P. M. Orton, and G. Mellor (2017), Modeling wave attenuation by salt marshes in Jamaica Bay, New York, using a new rapid wave model, Journal of Geophysical Research – Oceans, 122, doi:10.1002/2016JC012546.  PDF web

Marsooli, R., P. M. Orton, N. Georgas, and A. F. Blumberg (2016), Three-Dimensional Hydrodynamic Modeling of Coastal Flood Mitigation by Wetlands, Coast. Eng., 111, 83-94. web open access

  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.


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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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, Kytt MacManus (Columbia CIESIN), Alan Blumberg, 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

Webtool created under project: Hudson River Flooding Decision Support System.  Also, here’s a nice project webpage from my collaborators at Lamont-Doherty.


Under this project we created 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 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 merge all sources of flooding water with a single model, so they do 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 1000-year flood zone maps are 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 allows users to select a particular region of interest and predicted flood scenarios and then visualize the impact on community resources.  Users can 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 are hosted by the Center for International Earth Information Network (CIESIN), and is available following this link.  This website and the featured mapping tool will be a valuable resource for public officials, resource managers, and others looking to assess risk and evaluate the cost/benefit of proposed climate change mitigation options.

Resulting Publications

Orton, P. M., F. R. Conticello, F. Cioffi, T. M. Hall, N. Georgas, U. Lall, A. F. Blumberg, and K. MacManus (2018). Flood hazard assessment from storm tides, rain and sea level rise for a tidal river estuary, Natural Hazards, 1-29, doi:10.1007/s11069-018-3251-x.  web | PDF.

Orton, P. M., Hall, T. M., Talke, S., Blumberg, A. F., Georgas, N., & Vinogradov, S. (2016). A Validated Tropical-Extratropical Flood Hazard Assessment for New York Harbor. J. Geophys. Res., 121. doi: 10.1002/ 2016JC011679. unformatted PDFweb


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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