Massachusetts Port Authority Resiliency Program and Floodproofing Design Guide
In 2014, the Massachusetts Port Authority (“Massport”) began the Massport Resiliency Program to protect Massport transportation facilities from flooding hazards caused by extreme storms and rising sea levels as a result of climate change. The program seeks to better prepare for the impacts of climate change by incorporating resilience principles into Massport’s business strategy and operations. As a part of this program, Massport created a Floodproofing Design Guide (“Guide”) that will help make the built environment resilient to sea-level rise and major flood events.
Massport launched its Resiliency Program to help ensure that its assets and the region as a whole are more resilient to increasing threats from climate change. As part of this program, Massport has conducted a high-level analysis to look at its vulnerabilities and risks related to climate change and other threats, and is developing a framework for enhancing resilience of its critical infrastructure. So far, the program is focusing on increased physical threats from sea-level rise and storm surge, but Massport recognizes the need to link short- and long-term decisions, considering other factors like social and economic resiliency. Massport is incorporating resilience into five key strategy areas: strategic convening; research and planning; design; education and training; and operational preparedness. The Floodproofing Design Guide was developed as part of this program to help increase asset resilience through design requirements.
Massport’s Floodproofing Design Guide takes into account future flood risks, setting minimum design requirements for new and substantially repaired or retrofitted Massport facilities (including at Logan International Airport and the maritime facilities in South Boston). The Guide estimates maximum flood elevations for existing critical infrastructure under different model scenarios, and shows at what elevations Massport should expect interior flooding. It assigns different “design flood elevations” (DFEs), which represent the maximum level of water a structure is designed to withstand and other design standards based on a variety of factors.
The Guide separates existing facilities from new facilities. For existing facilities, the DFE is the predicted elevation of a flood in 2030 with a 0.2% chance of occurring within a given year, plus 3 feet of freeboard. For new facilities, the DFE is the predicted elevation of a flood in 2070 with a 0.2% chance of occurring within a given year, plus 3 feet of freeboard. At Logan Airport and in South Boston, this translates to 13.7 feet for existing facilities, and 17.0 feet for new facilities. Appendix B presents this data graphically and highlights the facilities where the First Floor or Lowest Critical Elevation is below different flood scenarios. Where structure elevation is not possible, the Guide allows Dry and Wet floodproofing under certain circumstances. Table 4 lists the floodproofing performance standards for substantial repairs and improvements to existing facilities and floodproofing projects. Table 5 lists the floodproofing performance standards for new facilities. The main difference between the two tables is that the guide allows for more instances of dry floodproofing for existing structures than for new structures.
The Guide also outlines the floodproofing design-implementation process (Table 6). It includes four design stages. Specifically, it emphasizes 1) Schematic Design/Pre-Design, 2) 30% Design, 3) 90% Design, and 4) Final Design. During the first stages, new construction and improvement projects must identify the flood maps and assess the site. As a project progresses, it must update and finalize those maps and complete the FEMA NFIP floodproofing certificate. This process should identify floodproofing-related issues early on in the life of a project so that Massport implements the appropriate floodproofing strategies.
In 2013, prior to developing the Guide, Massport retained Kleinfelder Northeast to perform a Disaster and Infrastructure Resiliency Planning Study (“DIRP”) to produce climate hazard analyses, vulnerability assessments for critical infrastructure, and resiliency recommendations for capital improvements and programming. One of DIRP’s high priority recommendations was to create guidelines for flood resiliency, including DFEs that consider future flood scenarios and are more stringent than the current building codes require.
The DIRP study first utilized the Sea, Lake, and Overland Surge from Hurricanes model (“SLOSH”) from the National Weather Service to predict worst-case flooding conditions for Massport facilities. MassDOT developed a more realistic flood map utilizing their Boston Harbor Flood Risk Model (“BH-FRM”). The BH-FRM integrates probabilities so that Massport understands the worst likely scenario, rather than SLOSH’s worst possible scenario. Massport first incorporated the SLOSH flood models into their Guide in the November 2014 version, but revised the plan in April 2015 based on the BH-FRM recommendations.
The Guide is intended to assist Massport staff, tenants, third-party developers, design professionals, and contractors with substantial improvements to existing structures and new construction. The guidelines do not apply to routine maintenance. The Guide also includes general information about project objectives, vulnerable Massport facilities, and the process that Massport has taken to ensure future flood resiliency. Massport undertook this initiative to maximize business continuity in light of recent extreme storms and other human and natural threats to their air and maritime transportation infrastructure.
This Adaptation Clearinghouse entry was prepared with support from the Federal Highway Administration. This entry was last updated on January 26, 2016.
Publication Date: April 2015
- Massachusetts Port Authority (Massport)
- Agency guidance/policy
- Case study