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

Storm surges are among the deadliest and most costly natural disasters. Increased damage from flooding related to storm surges is one of the most certain impacts of climate change along the coastal NEUC, through storms that carry more intense rainfall and higher storm surges caused by sea level rise. Even conservative sea level rise projections triple the frequency of current 1 in 10 year coastal floods in many areas.

We propose to advance the understanding of effective adaptation to coastal flooding in close collaboration with decision makers in NYC and Boston. We will design and evaluate adaptation blueprints for types of neighborhoods, informed by a multi-dimensional analysis of vulnerability. (1) We will produce maps of probability of coastal flooding for the 2010s, 2050s and 2080s, using a new framework that integrates multiple sources of risk: storm surges, rainfall, flash flooding, waves, sea level rise and effects of climate change on rainfall. (2) We will create dynamic maps that represent multiple components of vulnerability to coastal flooding for the areas at risk. (3) We will produce a typology of adaptation blueprints that specify decision and implementation processes for well-defined types of neighborhoods and that are based on the vulnerability analysis and contingent on new information about flooding risks. (4) We will provide a guide to conditions under which each blueprint may be effective in other coastal urban areas based on likely impacts on resilience and costs of approaches proposed in each blueprint.

Adaptation in coastal zones that are vulnerable to storm surges is one of the highest priorities along the NEUC. However, adaptation planning and understanding what adaptation approaches are effective under different conditions are in early stages of development. Coastal NYC and Boston provide a setting that enables learning about adaptation strategies because cities can marshal resources to gather and analyze information, conduct studies, and experiment with solutions in ways that smaller entities cannot match. Solutions that address the complex challenges typical in city neighborhoods will serve as good models in other urban locations and smaller municipalities that face similar coastal storm threats as affect the entire NEUC.

The proposed work is directly relevant to NOAA's goal of long-term climate adaptation and the goals of CSI-COCA, and supports three out of the four 5-year climate objectives in NOAA's Next Generation Strategic Plan. We will improve the understanding of decision makers' needs by building partnerships with decision makers to provide key science and data that they help to identify as necessary to support adaptation to coastal flooding. We will improve the understanding of the current and future coastal flooding threat and respond to demand from decision makers by producing flooding predictions that integrate effects of several sources of risk. We will improve the understanding of vulnerability to coastal flooding in NYC and Boston and respond to demand from decision makers by producing dynamic maps that represent several dimensions of vulnerability and that enable decision makers to quickly analyze the implications of new data for adaptation decisions. We will advance the understanding of effective adaptation strategies supported with climate information by producing a typology of blueprints for adaptive responses to coastal flooding risk. We will extend the usefulness of the blueprints for improving decision making by producing a guide that other coastal, urban areas can use to identify

blueprints that meet their needs, based on an analysis of impacts on resilience and costs that the approaches proposed in the blueprints are likely to have under different conditions.