Yet another coastal city that’s looking for a way to “avoid the unmanageable and manage the unavoidable.”

By Elizabeth S. Padjen

Can Boston take action—enough action—to protect itself from rising waters before the next big storm? Or will the city tragically require its own Katrina or Sandy in order to muster the will to protect itself against repeated catastrophe?

Those were the questions in play at the “Sea Change: Boston” symposium on April 26, cohosted by Sasaki Associates and the Boston Architectural College. Sea-level rise is no idle threat in this city: If Superstorm Sandy had hit five hours earlier, at high tide, flood waters could have extended to City Hall. Boston is vulnerable to storm surges of both hurricanes and nor’easters, which could hit on top of sea levels that are projected to rise 1 to 2 feet by 2050 and 3 to 6 feet by 2100.

Conferences about sea levels in Boston are increasingly frequent and intense—much like the storms expected in coming years—and often revisit familiar issues. The “Sea Change” gathering and accompanying exhibition, which originated in research led by the Sasaki principals Gina Ford, ASLA, and Jason Hellendrung, ASLA, brought new depth to the discussion.

Robert Nairn, a director of the global water engineering firm Baird & Associates, used a wharf project in Australia to stress a need for greater attention to risk evaluation, or “risk-based planning.” Coastal designers and planners focus on 100-year storms, a shorthand way of indicating flood severity (Sandy produced 700-year flood levels in New York); only rarely do they analyze risk in terms of the cost of severe destruction against the costs of preemptive construction. The Australian project was designed for a 1,000-year storm—part of a risk assessment for a mile-long wharf that accounts for 2 percent of the Australian GDP.

As Nairn suggested, we live in a statistics-illiterate society. Terms such as “100-year storm” have ill served both the public and planners; recasting the definition as a 1 percent chance of occurring in any given year is not much more useful. But as the popularity of lotteries shows, an understanding of probability theory remains one of the great challenges in communicating sea-level risks to the public and to policy makers.

There are people, however, who thrive on risk assessment: insurance executives. As Robert Culver, the managing director of Sasaki, pointed out, that industry, specifically the secondary and reinsurance segment, is an increasingly powerful hidden player in coastal design and planning decisions. Many developers hope to cash out in a few years after construction, but the cost of insuring risk at the time of sale becomes a significant factor in a project’s financial profile. “The secondary insurer may in fact end up being the real judge,” Culver said.

Compensation for either possible or actual losses remains one of the thorniest aspects of sea-level rise. Jerold Kayden, a planning professor at the Harvard Graduate School of Design, described the legal and ethical conundrum by pointing to the concept of the common law of nuisance. “As harsh as it may sound,” he said, “one may ask whether building or staying in harm’s way in vulnerable areas may be understood as some type of land-use nuisance.” There has been a tighter focus generally on what economists call moral hazard, the tendency to pursue risks without having to pay for the consequences.

Amid this theoretical groundwork, design—the design of buildings, either new or retrofitted, and of blue-green infrastructure—seemed the easy part; one panelist, Robbin Peach, program manager for resilience at the Massachusetts Port Authority, even called it the low-hanging fruit.

Barbara Wilks, FASLA, an architect and landscape architect, presented work from the Red Hook proposal for the Rebuild by Design initiative that demonstrated how well-designed barriers and protections can also create new economic and social opportunities for devastated communities—the sort of “multivalent” projects that address disparate issues at once.

The landscape architect Walter Meyer provided a science-based approach to resilient design, applying “forensic ecology” to a seaside park in Puerto Rico. For a dune construction project in the eastern end of the Rockaways  in New York, Meyer similarly looked at larger systems related to Sandy, presenting underreported aspects of the storm—wind fetch, bathymetrics, wave refraction, groundwater liquefaction, dune formation—and their implications for design.

Both Wilks and Meyer suggested that site-specific resilient design is achievable in Boston. But talk of the larger regional picture was more discouraging, particularly for the smaller communities outside the symposium’s focus area. Brian Swett, Boston’s chief of environment and energy, stated the challenge succinctly: “We need to avoid the unmanageable and manage the unavoidable.”

The accompanying exhibition, Sea Change: Boston, will be up at District Hall, 75 Northern Avenue, Boston, from April 16 through early June. The online version of the interactive touch screen created for the event can be seen here:  seachange.sasaki.com/map