CRISP Type 1: Protecting Coastal Infrastructure in a Changing Climate by Integrating Optimization Modeling and Stakeholder Observations

Columbia University, New York NY

Investigators

Abstract

Infrastructure - such as roads, bridges, railways - is the backbone of a functional and healthy community. When parts of this infrastructure are threatened, it is critical for society to respond to that threat or risk loss of life and property. One of the most significant threats to our infrastructure in recent U.S. history has been as the result of hurricanes, most memorably Hurricane Katrina, which devastated New Orleans, and Hurricane Sandy, from which the infrastructure of New York City is still recovering from. Addressing these threats requires a multi-pronged approach that takes into account how infrastructure is connected and how failures in one type of infrastructure can impact the other. Questions then arise as to how we can protect ourselves from these threats. This Critical Resilient Interdependent Infrastructure Systems and Processes (CRISP) project develops a methodology that can answer questions related to protecting infrastructure. For instance, if a community wanted to build a sea-wall, questions such as "how high should it be?" and "where should it be placed?" must be asked. Other important questions compare a sea-wall with other protective options, such as: "Is a sea-wall the best protective measure?", "What about artificial sand dunes?", or "What about raising the infrastructure to a higher elevation?" And a related critically important question should be "Can adopting this option for protecting one community be detrimental to the safety of a neighboring community?" In addition to questions about the efficacy of protective measures, there are questions about how coastal protection may impact other coastal uses including recreational, cultural, and economic activities, and how negatively impacting these uses can be reduced while still maximizing protection. Resource constraints are also important to take into account and the question of how to optimally protect a community given constrained resources is critical. Such questions require the combination of advanced computing, mathematics and social science approaches to design tools to address these complex intersecting problems and placing these tools in the hands of decision makers that need to make these types of critical decisions. This is the goal of this project. Interdependent critical infrastructure in coastal regions has long been threatened by storm-induced flooding. Events such as Hurricanes Sandy and Katrina punctuated the need for plans to protect our infrastructure, but these events only reflect a possible future threat and do not fully address the unknown probability and impacts of a future threat. This uncertainty is only made more critical by the addition of climate change to exacerbate and amplify impacts, in particular sea-level rise. The goal of the proposed work is to address the threat from storm-induced flooding to interdependent infrastructure, including transportation and power systems and emergency services, by developing a methodology that can test various adaptation strategies. Strategies in this context include, but are not restricted to, building sea-walls or other physical, protective mechanisms. The proposed methodology would optimize strategies to maximize their protective abilities over time and space constrained by budgetary considerations. To accomplish this the methodology will contain four conceptual steps: (1) formulate a new strategy for adaptation, (2) computationally determine flooding levels given an ensemble of storms representing the likely threat and future sea-level rise, (3) estimate the damage over the ensemble to the infrastructure considered, and (4) using appropriate metrics evaluate the relative suitability of a given strategy including cost and social acceptability. This process would repeat iteratively until a sufficiently optimal strategy is found. Developing such a methodology will be challenging however. The magnitude of the computational effort needed is significant. Using a set of computational models that vary in accuracy and speed, the methodology will swap between models appropriate for the optimization stage. The methodology will also not be successful without stakeholder engagement. For this reason, interviews with key stakeholders will be an important component of the methodology design and implementation. Interviews will inform the identification of critical components of infrastructure and the interdependencies among them that could be affected by coastal flooding, assist in the design of the optimization metrics, and assess how well the output of the methodology matches stakeholder expectations. Community meetings will also be held to introduce and discuss the results of the methodology with local communities who would potentially benefit from the adaptation strategies. Finally, using New York City's complex infrastructure and recent events, the methodology will be validated.