Resilient design trend? Modern floodgates appear in vulnerable areas.

Posted by on Oct 31, 2012


Walking along Flat Street in Brattleboro, Vermont this morning before businesses opened, I saw a sign that an important lesson about resilience had been learned over the past year.  The floodgates were up in numerous doorways.

Flat Street, as some readers may recall, lies in the floodplain of the Whetstone Brook, which angrily overflowed its banks in August 2011 during Tropical Storm Irene and created havoc for the small businesses, artisans, and restaurants located there.  That event is pictured in a previous RDI post here.

No one expected that flood.  Yet, somewhat remarkably, the New England Youth Theatre had had the foresight to equip its recently renovated building with aluminum floodgates in every entrance – simple plates that are inserted in tracks attached to the doorjambs and screwed tight against rubber gaskets.  And building manager Rick Barron had the presence of mind to put them in as Irene’s rains started to fall.

The result – celebrated by Vermont’s governor Peter Shumlin in many speeches and noted by The Weather Channel in a video documentary on Tropical Storm Irene – was that the NEYT remained almost entirely dry, only shipping a small amount of water despite its unaccustomed 3-to-4-foot (90 – 120 cm) draft in the muddy torrent.  It was able to resume operation quickly after the catastrophe, and bore relatively light recovery costs.

What made this Tuesday morning’s discovery poignant was that it occurred just as the erstwhile Hurricane Sandy was subsiding into a post-tropical cyclone somewhere to the southwest in Pennsylvania, leaving numerous towns and city neighborhoods swamped and wrecked.  Brattleboro had been spared.  The Whetstone was merely swollen and rushing.  But some Flat Street businesses were ready with new floodgates this time, as the following photos from the CF Church Building show.  New knowledge led to new practices.  This is a trend to watch.

The floodgates are expensive, so not every business had been able to install them.  Lynde Motorsports resorted to oriented strand board sealed with tarpaper.  But the NEYT considers them worth every penny.  In fact, for 2012, new gates about eight inches higher had been budgeted, but not yet ordered.  When 200-year weather events seems to be arriving almost annually, one can’t be too careful.

An additional lesson on NEYT’s part, learned from last year’s maiden voyage, is that a bead of silicone caulk between the bottom edge of the floodgate and the (ungasketed) floor solves the problem of the missing seal that allowed some moisture to seep through during Irene.

How many other resilience trends are emerging as we learn from the design thinking of our neighbors?  The aftermath of Sandy will surely offer many examples…


New floodgates prove their mettle at the CF Church Building on Flat Street in Brattleboro, Vermont.

More floodgates at the CF Church Building. Notice how one has already been removed so the entrance is unobstructed.


Lynde Motorsports on Flat Street, severely impacted by Tropical Storm Irene in 2011, uses tarpaper, OSB, and nails or screws to greet Sandy, but it’s hard to blame them because a quality aluminum floodgate for just one of those large garage door openings would cost thousands of dollars, at last check.



  1. Ralph, the OSB design for the garages makes several interesting points. Many engineers if given the task to design a floodgate would without much thought start with an aluminum structure such as the ones shown for some of the business in the photos, however some considerations come to mind. These floodgates will be used once in a blue moon, be uses for only a few days when used, have several hours to be set up, and most importantly must have a cost that can be afforded by the small shop owner. For this as the design engineer I would start by using some technology from the concrete industry. Forming for pouring concrete is often custom built of plywood, and lumber. It must hold back concrete with a weight of about 150 lb./ft^3 about 2.4 times that of water alone. Plywood, and lumber are available locally everywhere, can be worked by most people, no mig welder needed, and is low cost. When completed you can hang the floodgates from the shop ceiling, and wait for the next 100 year flood, probably next year :).

  2. Yeah, I’d think plywood and lumber would be a lot more durable and reusable than osb, which performs very poorly when immersed.


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