The July 2015 issue of Architectural Record features three articles on “Water and Resiliency”: one on a city (New Orleans) and its coastal neighbors, one on buildings (NYC) and one on an urban park (China). While uber-protection against severe weather and rising sea levels may make sense for an art museum in a dense urban environment, most owners cannot afford the extreme measures undertaken for the new Whitney Museum of American Art located on the Hudson River in downtown Manhattan. More often than not, the owners we work with must “learn to live with water” as is being modestly introduced in post-Hurricane Katrina New Orleans and perhaps even going so far as to follow the model of the 50-acre Yanweizhou Park in Jinhua, China, that quite literally “befriends the flood”.
This set of articles examines strategies for dealing with severe weather and flooding in the built environment. It describes some of the measures implemented or planned for New Orleans, both in terms of traditional hard infrastructure and so-called "green infrastructure." It explores a new park in Jinhua, China, that is designed to thrive even when inundated. And it discusses the flood-prevention tactics used at two recently completed waterfront art museums.
Architectural Record, July 2015
The federal and state agencies that QEA works with are responsible for extensive coastal and other properties that are prone to flooding, storm surges, flash flooding, and other ravages of storm events. For example, at the Gateway National Recreation Area, the National Park Service is the steward of more than 600 historic structures located in two states (New York and New Jersey). These coastal properties include a multitude of decommissioned U.S. military bases located by design on barrier islands that are in-escape-ably also in flood hazard areas. “Learning to live with water” has been a default design criteria for these facilities, and these properties have weathered many a storm over the past 100+ years. Nonetheless, after each event, the military had to undertake a certain amount of repair work. Since the mid-1970’s, the National Park Service has inherited this responsibility without the resources historically available to the military.
When Hurricane Sandy “landed” at Gateway NRA in October 2012, the summer beach season was long over and many buildings were buttoned up for the winter. More importantly, many of the historic buildings remained vacant and in a stabilized condition, waiting for the wherewithall to transform them for current generations of public users. The load-bearing masonry and wood-framed buildings of Fort Tilden in NY and Fort Hancock in NJ relied on the intelligence of their original design to survive Hurricane Sandy, although not without injury.
The National Flood Insurance Program and FEMA propagate two time-tested strategies to reduce damage to buildings from storm events: (1) dry or (2) wet floodproofing strategies. Dry floodproofing works to raise a building out of the flood design elevations – including raising an entire building or moving it to higher ground. In the context of historic buildings, extreme examples of dry floodproofing include the successful relocation of the 1870 Cape Hatteras Light Station (seven historic structures) by the National Park Service in 1999.
Can you imagine the impact if an entire city elected to do this? Imagine the colonial brick masonry and wood framed rowhouses of Annapolis, Maryland, elevated – or moved to a new location. This is not a future I would wish upon Annapolis.
Wet floodproofing strategies are much more realistic for the average city, building or site. Many historic buildings located in the flood plain have survived numerous storms and have much to teach us. What can we learn from these historic buildings and similar water management strategies being introduced in post-Hurricane Katrina New Orleans and by the National Park Service at Gateway NRA?
- Plan on “getting wet”: move essential functions to floors above flood levels; relocate utility service entrances and critical equipment above flood levels; and use or re-use non-porous, closed-cell construction materials and assemblies that can repeatedly get wet and dry out without reducing their integrity.
- For potential inundation with “black water” or polluted waters, use the least absorptive materials.
- Don’t rely on mechanical solutions: allow stormwater and storm surges to move through buildings.
- Plan for sea level rise: After Hurricane Sandy, flood insurance maps were revised to raise the base flood elevations. Code makes some accommodate for the combinations of high tides and storm surges. Be conservative and learn about sea level rise predictions for your location and set design flood elevations accordingly.
- Develop a holistic strategy. In New Orleans, this means establishing systems that will slow the flow of storm waters, store it, and encourage infiltration into the ground – and that works “from the scale of the city to the individual lot”.
- Be pragmatic, but don’t be afraid to think big.