Flood plain may differ from that on FEMA map

#Middlebury #FEMA #FloodPlain

David Battista, a project engineer from Lenard Engineering, discusses the results of his firm’s initial study of the Porter Avenue/Regan Road area affected by FEMA’s revision of its 100-year flood plain map. (Marjorie Needham photo)

 
By MARJORIE NEEDHAM

A July 24 presentation on the Regan Road/Porter Avenue/Shadduck Road flood plain has raised the hopes of some homeowners in that area. Lenard Engineering’s preliminary look at the area in question found significantly reduced flooding from Skunk Hollow (off Porter Road) down to Route 188 on both Regan Road and Porter Avenue. This indicates the current Federal Emergency Management Agency (FEMA) 100-year flood plain map may be incorrect.

A redefined map, if accepted by FEMA, could save money for the affected homeowners, some of whom currently pay flood insurance premiums as high as $3,000 a year. About 40 homes were affected by FEMA’s 2010 revised mapping that suddenly placed them in a 100-year flood zone and made federal flood insurance mandatory for those still paying mortgages on their properties.

Based on the results presented Monday night, it seems 24 of those 40 homes may, in fact, be clear of the flood zone. Even the homes that aren’t completely clear of the zone may benefit from revised mapping.

Porter Avenue resident Greg Cyr said it’s important to remember that a requirement to have flood insurance isn’t just that you have to have it or you don’t have to have it. He said the cost of the insurance varies with the risk, which is calculated based on the elevation of the home’s lowest floor, the lowest adjacent grade and more. So if the study showed flooding would be a foot or two less than FEMA had estimated and FEMA accepted the results, homeowners could end up with significantly lower flood insurance premiums even if they still had to buy flood insurance.

Standing in front of an aerial map that covered roughly Regan Road, Porter Avenue and Shadduck Road from Route 64 down past Route 188 (for the Shadduck Road portion), professional engineer David Battista explained the firm’s methodology and the results of the study.

He said the firm obtained data from FEMA, including its 1977 flood plain study, to use as a reference point. He noted that mapping methods and computer methodology used at that time are now 40 years old and have been replaced with newer methods.

Lenard Engineering also obtained data such as aerial photos and elevation and contour information in the public domain and created its own model. They then calculated the water flow rates using newer methods. Battista said their model showed a water flow rate 25 percent smaller than FEMA calculated.

The lower flow rates were then plotted on the map, which used dashed light blue lines to show the FEMA-defined flood zone and solid black lines to outline the flood plain areas defined by Lenard Engineering’s calculations.

On the Route 64 end of the map, Lenard Engineering’s results were fairly close to FEMA’s. But from Skunk Hollow down to Route 188, its results define much narrower areas of flooding along Long Swamp Brook and Hop Brook.

Battista said of the study results, “I think we can make some hay for the town.”

He said the next step, if the town chooses to take it, will be to present the new flow rates to FEMA and ask FEMA to approve their use in further studies. If FEMA approves the new flow rates, Battista said, “Then we dive in the deep end. We send surveyors out to do 50 to 60 cross sections on the river channels. That is very expensive.” Those new cross sections would then be compiled into a new hydraulic model to present to FEMA.

First Selectman Edward B. St. John suggested Lenard Engineering include in its report to the Board of Selectmen both the results of the company’s work to date and a proposal for the next step, presenting flow rates.

Catherine Gay of Porter Avenue said after the presentation, “I think we are making some progress.” Lainie McDermott of Regan Road described her feelings as “cautiously optimistic.”

Cyr said he found the study results encouraging and optimistic. His back yard backs up to Long Swamp Brook, and his home is among those Lenard Engineering did not include in the flood zone. He said even when there was a 100-year flood, the water didn’t get up to his house. He said it got up to the apple tree towards the rear of his back yard, and he and his wife could look out and watch ducks swimming by the apple tree.