(March 8, 2013) Intended to be a self-explanatory term, the phrase “100-year-floodplain” — a common parlance for builders, insurers, and emergency planners — is beginning to lose its vogue faster than a Members Only jacket, thanks to global warming.
With the expectation that the next several decades of climate change will likely transform what were once termed “floods of the century” into an almost annual occurrence, the state of the Maryland is embarking on a long-range revision of its construction policies to accommodate higher waters.
Authorized this past December by an executive order of Gov. Martin O’Malley, the state has formed a so-called “Climate Change and Coast Smart Construction Working Group,” which contains a number of representatives from public and private agencies across the state, including Ocean City Councilman Dennis Dare as the representative for the Maryland Municipal League.
As stated in O’Malley’s order, Maryland has roughly 450 state-owned buildings and 400 miles of state highway in areas that are projected to be affected by sea level rise over the next 100 years.
“The whole idea is to look out for Maryland’s investment in these 400-odd structures that could be affected,” said Dare, who served as city engineer and city manager before coming to elected office.
“The state may also be participating in the funding for a county or a city-level project that are in this flood area.”
The only specific edict contained in O’Malley’s order, however, is that the state universally adopt a two-foot freeboard minimum for all new construction and/or significant renovations of structures in Special Flood Hazard Areas.
SHFAs were created as part of the National Flood Insurance system in 1968. At that time, the Federal Emergency Management Agency was directed to identify such flood prone areas and create maps to identify different tiers of damage risk, based on the estimated high water levels for “100-year” events. These schemes, known as Flood Insurance Rate Maps, were then used to determine the premiums charged to different areas under the federally sponsored insurance program.
For most extremely low-lying areas, including most all of Ocean City, FEMA recommended that buildings’ ground floors be constructed at least two feet above the 100-year flood level, leaving 48 inches of extra, just-in-case room know as freeboard. The federal government also offered steeper flood insurance rate discounts to areas where local governments had required additional freeboard.
“Ocean City, in the 1970s, did what was recommended by the governor’s order, which is raising the design level of these facilities two feet,” Dare said.
In fact, he explained, the city began to raise the height of its roads as it rebuilt and paved them. Since developers were required to build at a certain angle above the road height, to ensure proper drainage, the overall height of the town thus gradually increased as more lots were built and rebuilt.
“We really raised the height of the whole town, with the ocean side a little higher than the bay side,” Dare said. “In fact, on the ocean front, we’re probably five and a half feet higher than FEMA says it has to be.”
The convention center, Dare pointed out, was built under state supervision in the 1960s at a less than optimal flood height. The town’s own post-1968 additions were built to a higher code.
“When we built on to the building, we did it to our own Ocean City code, and that’s what you may see at other facilities that either belong to the state of Maryland or are rebuilding in cooperation with the state,” Dare said.
Seemingly minor inconsistencies or loopholes and codes, he noted, can have a significant effect on the functionality of a structure. The bridge recently built over the Indian River inlet in Delaware was washed out during Hurricane Sandy because – while the elevation of the bridge itself was sufficient – the approach road sections were too low.
“The solutions aren’t exotic, but what we’re going to do is make it logical and make it something that can easily be on the architect or the engineer’s checklist,” Dare said.
