The Town of South Bethany may have some homework to do, if it follows the advice of an independent consultant who recently recommended new studies be made on coastal flood hazards.
The Town commissioned an independent study regarding its flood plain maps, the results of which will be discussed at the July 10 town council meeting, set to begin at 7 p.m. The Town paid about $10,000 for Taylor Engineering to examine the data Federal Emergency Management Agency (FEMA) used to create the new preliminary Flood Insurance Rate Map (FIRM).
“Given my understanding of the data reviewed, I recommend that the Town of South Bethany … perform its own calculations of coastal flood hazards,” wrote Guillermo J. Simón, senior engineer. “A revised analysis would include different and — in my opinion — more current assumptions regarding beach erosion and overtopping conditions during storms.” (Overtopping is when ocean waves surpass the dune height and flood the opposite side.)
Those assumptions could potentially lower South Bethany’s base flood elevation (BFE), although that’s not guaranteed.
Oceanfront residents have been particularly upset that FEMA decided to increase the BFE to 13 feet, after initially planning to lower their longtime 12-foot base flood elevation to 10 feet — until a council member submitted more information that caused FEMA to increase the BFE to 13 feet instead.
BFE is the elevation to which floodwater is expected to rise during a 1-percent-annual-chance (100-year) flood. Houses have to be built at that elevation or higher, or pay high flood-insurance premiums.
The consultant didn’t publish an official opinion on the BFE. However, “He told me verbally that he thought the 10 [feet] was wrong … and that he thought it worth further study,” Mayor Pat Voveris said.
The consultant was hired to attend the May 21 pre-meeting that FEMA requested to discuss the maps and to plan the June 12 public meeting. His report was dated June 16.
“Why the rush to finalize?” resident Ed Bintz had asked at the June 25 town council workshop.
“No rush. It’s what we contracted for,” and the job was completed, Voveris said.
Voveris noted that she had already forwarded the results to the property owners’ own consultant.
Bintz asked why the Town’s consultant didn’t first discuss the issues with the residents’ consultant.
“It’s a report as to what we contracted for… It was general information for our use,” Voveris said.
“I compiled and reviewed a significant amount of information, including, but not limited to, LiDAR (topographic) data, overland wave models, wave run-up calculations and beach erosion assumptions,” Simón wrote.
He did not personally recalculate any of FEMA’s numbers in his limited, five-page report, but he had studied the technical merit of the flood hazard designations.
He pointed out that the Light Detection and Ranging (LiDAR) used as part of the data has a blurry spot, but “no specific mention as to why the resolution of this area differs from the rest of the LiDAR.”
Although he noted that FEMA does not consider beach replenishment projects, he also questioned FEMA’s calculations for dune erosion within South Bethany. It appears that both a 2014 method and a 2015 method were used in different places.
“In general, the Preliminary study followed FEMA’s guidelines for coastal analyses,” Simón wrote. “We recommend, however, the introduction of two changes that, in our opinion, would improve the identification of the Town’s flood risks.”
Simón suggested that FEMA do the following: develop a new South Bethany erosion profile “using FEMA’s methodology for dune removal with a 1:50 slope”; calculating wave run-up using the appropriate method based on FEMA guidance, then adjust using another handbook; and update Sussex County’s guidelines “to describe more accurately the engineering analyses, methods and assumptions applied in the study for future reference.”
“Right now, we’re not taking any action,” Voveris said on June 25.
If the property owners ask the council to take action, the council would consider the request.
“We want to be open,” Voveris said.
The appeals process is expected to begin as early as this autumn. Residents will first submit appeals to the Town of South Bethany. The Town will forward any appeals to FEMA but can also weigh in if it feels an appeal has merit. After FEMA resolves any appeals (which could take months), it will issue a new Notice of Final Determination. Six months later, the new maps could be enacted (as early as the summer of 2016).