Following devastating floods of 1935, when Houston’s population was about 400,000, city leaders constructed two large reservoirs outside the city to act as detention ponds for future events. In the decades that followed, however, different leaders—more interested in capitalizing on the oil and gas boom—encroached upon these reservoirs, even permitting development within the basins them- selves. Predictably, when Hurricane Harvey blew through Harris County in 2017 (Houston’s population at the time was 2.3 million), the reservoirs and the surrounding area filled with water, displacing thousands and causing more than $125 billion in damage and economic loss. The New York Times wrote, “Resettling neighborhoods, making certain places off-limits to development, creating dikes and reservoirs is difficult, both financially and politically. It takes longer than most election cycles … . Politicians want votes, not trouble.”
When the 1994 Northridge Earthquake struck, Santa Monica, Calif., avoided a direct hit. Nonetheless, many unreinforced masonry, steel and multistory wood-framed buildings were damaged. Aware that it was only a matter of time before one of the faults under or nearer the city ruptured, Santa Monica’s leaders passed regulations requiring the mandatory retrofit of the community’s most vulnerable buildings. This culminated in a 2017 ordinance considered one of the nation’s most extensive. Mayor Ted Winterer, said at the time, “We want to do as much as we can to limit the loss of life and infrastructure, so in the event of a disaster, we bounce back strong.”
Leaders often focus on addressing chronic stresses because the return is more immediate and the benefits accrue to them. Great leaders, however, know their lasting legacy will be in part measured by how they thought about the long-term—and the economic and social security of future generations.
Resilience Is Sustainability
It is a common misconception that modern buildings will be “proof” against natural disasters. Modern building codes, typically those enacted in the mid 1990s and later, are intended to prevent collapse in the largest events, not to minimize damage and recovery time. It is also a common misconception that cities wouldn’t allow potentially unsafe buildings to remain in use. In fact, in most cities, the overwhelming percentage of the building stock was built well before modern life safety codes were adopted. The image above shows the age of buildings in Los Angeles. Most were built prior to the advent of modern building codes.
Events like Hurricane Harvey, the California wildfires and the Napa Earthquake have made it painfully clear it is not enough for our buildings to have a low impact on the environment; the environment must also have a low impact on our buildings. In other words, true sustainability requires both green and resilient design. Individuals and companies who have lost their most valuable assets or their businesses in natural disasters—and cities like New Orleans that have seen their social and economic vitality diminished or destroyed—realize they must implement long-term resilience strategies.
Building Rating Systems
Cities seeking support from their residents and businesses for retrofit incentives and ordinances must raise awareness about the risks they face and the ways in which these risks can be mitigated. Already part of our everyday lives, ratings communicate the quality and expected performance of a product or service. We have ratings for car crash performance, hotel quality, restaurant cleanliness and financial transactions that enable users to compare investment options and quantitatively assess their risks.
The U.S. Resiliency Council, located in the San Francisco Bay area, was established to increase awareness of the benefits of resilient design and to develop rating systems for earthquakes and other natural hazards. The rating systems credibly and consistently communicate building performance in ways that are meaningful to stakeholders across the built environment: owners, lenders, insurers, designers, tenants, risk managers, governments and the public. USRC’s Earthquake Performance Rating System was developed with the collaboration of more than 40 of the nation’s leading engineering companies and earthquake professional organizations. USRC is currently developing rating systems for wind and wildfire.
One of the most important benefits of a building rating system that is able to quantify performance across dimensions of damage and recovery time, is the ability to perform benefit-cost and return-on-investment studies when evaluating retrofit options. Researchers at the California Institute of Technology, Pasadena, recently determined that for every dollar spent in retrofitting soft-story structures, property owners could expect to save up to $7, even without considering the reduction in contents losses, alternate living expenses, or deaths and injuries. (Read more in “Soft-Story Residential Buildings in Earthquakes–Risk Management and Public Policy Opportunities”.)
IMAGES: U.S. Resiliency Council