Boston Harbor Flood Protection Projects

JeffDowntown said:
F-Line, Doesn't 2 ft of water at the Community College portal mean that the North Station Orange Line under gets flooded out severely as well? The Charles River tunnel and the station look like big "drains" to me.
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Since the superstation is connected to the basement of the Garden (an oasis of dry) and Green Line passes through said basement, the Garden pump rooms will bail out a breach from the street and the Science Park portal on Green. Orange just needs basic flood doors at the CC portal to prevent a longer-distance drain effect. The actual incline from NS to CC isn't very steep at all because the Charles is so shallow by the dam, so gravity doesn't overpower everything way down the tunnel in an unstoppable torrent like you could get with the steeper portals (e.g. the Kenmore trio).

0-2 feet at a tunnel portal 'drain' is akin to what we see at Fenway on the D every couple years when the Muddy River gets angry and they bust out the wooden boards and sandbags. You're not talking very much necessary stoppage to protect that CC portal. Flood doors are just obviously a lot less manpower-intensive than building up a sandbag barrier like they currently do at Fenway.
 
These are from Long Wharf at high tide about noon on Saturday. Needless to say, we dodged a bullet with this storm, big time:

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And this is at fan pier - this must have been a little hairy at the next high tide @ midnight:

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Didn't know where else to put this:

I went to a community meeting the other day for a small infill hostel building proposed in the Bulfinch Triangle, and the architect kept emphasizing how the new FEMA flood maps prohibit any new building in that area from having a basement. At one point an abutter asked if the building would have an excavated foundation or sit on piles, and the architect went as far as saying something to the effect of "It'll be on piles; FEMA doesn't allow excavation any more". My BS sensors went off every time she said this, as I know for a fact that tons of new buildings built in that area (Hub on Causeway) or in similarly flood-prone areas (the entire Seaport) have excavated basements.

Could somebody in the know explain to me how this works or point me to a good resource? Is it that FEMA guidelines don't allow habitable basements or essential mechanicals stored sub-grade, but do allow underground parking? Or is it that basements are allowed as long as certain precautions are undertaken, and it's not worth it for smaller buildings? Thanks...
 
That's amazing. i had thought about a barrier there as a possible solution some time back,

As they're blessed with the island chain.

never thought anyone would actually propose it!!
 
JumboBuc said:
Didn't know where else to put this:

I went to a community meeting the other day for a small infill hostel building proposed in the Bulfinch Triangle, and the architect kept emphasizing how the new FEMA flood maps prohibit any new building in that area from having a basement. At one point an abutter asked if the building would have an excavated foundation or sit on piles, and the architect went as far as saying something to the effect of "It'll be on piles; FEMA doesn't allow excavation any more". My BS sensors went off every time she said this, as I know for a fact that tons of new buildings built in that area (Hub on Causeway) or in similarly flood-prone areas (the entire Seaport) have excavated basements.

Could somebody in the know explain to me how this works or point me to a good resource? Is it that FEMA guidelines don't allow habitable basements or essential mechanicals stored sub-grade, but do allow underground parking? Or is it that basements are allowed as long as certain precautions are undertaken, and it's not worth it for smaller buildings? Thanks...
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Seems odd to me but I think this is filled tideland. It is also on the former Middlesex Canal, I think. So it is very low and presumably floodable.

In any case, the pile vs. basement thing is usually a concern of the Groundwater Trust. If the surrounding buildings are on wooden piles like in the Back Bay, a lot of excavation could jeopardize their structure. Driving piles for a new building rather than excavating would likely cause less disruption to nearby building.
Anybody else want to take a guess?
 
I don't think FEMA can prevent you from doing what you want, -- if you want to excavate, go ahead.

However, its quite probable that if you did excavate, you wouldn't get insurance, and without insurance, you won't get financing (unless, of course, you self-finance and self-insure).

(I believe the city of Boston now generally prohibits placing mechancials / electricals etc, on the ground floor, or below the ground floor, in a flood zone.)

This is similar to FAA declaring a structure, e.g., a building, to be a hazard. You can build it, but you can't insure it. And if a plane were to subsequently hit an air hazard building, you'll wind up being ridden on a rail to the poor house.

The Federal government will indemnify against an un-insurable structure; if the Federal government weren't willing to indemnify, there would be no nuclear power in the United States. (The Federal government also indemnified after 9/11.)
 
stellarfun said:
I don't think FEMA can prevent you from doing what you want, -- if you want to excavate, go ahead.

However, its quite probable that if you did excavate, you wouldn't get insurance, and without insurance, you won't get financing (unless, of course, you self-finance and self-insure).

(I believe the city of Boston now generally prohibits placing mechancials / electricals etc, on the ground floor, or below the ground floor, in a flood zone.)

This is similar to FAA declaring a structure, e.g., a building, to be a hazard. You can build it, but you can't insure it. And if a plane were to subsequently hit an air hazard building, you'll wind up being ridden on a rail to the poor house.

The Federal government will indemnify against an un-insurable structure; if the Federal government weren't willing to indemnify, there would be no nuclear power in the United States. (The Federal government also indemnified after 9/11.)
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But that would imply that all the dozens of buildings with significant excavations and large underground garages being built in flood-prone areas of the city right now aren't insured. This is clearly not the case, so something doesn't compute here.
 
I think the difference lies in whether they were built on fill. The aforementioned Bulfinch Triangle is located on the former Mill Pond, and therefore would have extra hurdles for basements than just being on a flood prone area.
 
bigeman312 said:
I think the difference lies in whether they were built on fill. The aforementioned Bulfinch Triangle is located on the former Mill Pond, and therefore would have extra hurdles for basements than just being on a flood prone area.
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But in the seaport is 100% former bay, and right now there are buildings with 3-level deep below grade pits (like the one going in on the northeast tip of Fan Pier (which is only a grassy field in Google Earth bu has a basement similar to the apartment building being then built.).

I"m not saying there isn't a FEMA policy, but whenever its effective date is the whole Seaport seems to have beat the buzzer and the Bullfinch building would be the first to have been bitten by whatever cutoff there turns out to be.
 
You're talking about 234 friend st? Here's my theory on what the architect was trying to say but failing to do so clearly:

It's a small parcel - like 25 feet of frontage. On that footprint, almost impossible to do an underground garage, let alone do it economically, and not necessary anyway for a hostel/low end hotel. And fema means no mechanicals in basement. They probably are going to contract laundry offsite, and the kitchen is going to be a microwave in the lobby.

So with nothing to put in the basement, no reason to dig one.
 
^ Yup, that's the one, and this sounds right to me.

So FEMA doesn't prohibit digging basements, they just prohibit storing essential equipment in the basement. And since this is such a small site there's no use in digging a basement if you can't use it to house your necessary equipment.

This sounds completely reasonable, but the architect was definitely framing it as "we'd love to build a basement but Big Government Overreach tells us that we don't have the freedom too". It was kind of strange...
 
Cool.

In other barrier-related news: CLF is going to sue ExxonMobil because the terminal faciliities in Everett are not adequately protected against flooding.

https://www.bostonglobe.com/busines...tt-terminal/N0YoUgUZx8LlI08Jl0oXZP/story.html

I think this represents a very plausible strategy for getting a barrier built - i.e. if the full costs for all parties of an increasingly-likely bad storm flood are pulled forward, then a barrier etc. looks cheap by comparison. (And who better than this gaggle of earnest lawyers to do the pulling-forward?)

(And if you add some other value-capture strategies, like increasing the value of city / state / federal real estate on Long Island and elsewhere and - maybe - throwing some tidal electricity generation into the mix, then you might have a hell of a business case for starting work on this like yesterday)
 
JumboBuc said:
^ Yup, that's the one, and this sounds right to me.

So FEMA doesn't prohibit digging basements, they just prohibit storing essential equipment in the basement. And since this is such a small site there's no use in digging a basement if you can't use it to house your necessary equipment.

This sounds completely reasonable, but the architect was definitely framing it as "we'd love to build a basement but Big Government Overreach tells us that we don't have the freedom too". It was kind of strange...
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There really is no such overreach. For FEMA to dictate what can or cannot be built would mean the Federal government is the ultimate land use / zoning authority, which isn't the case.

I was being too shorthand earlier.

FEMA 'sells' flood insurance for properties in a flood zone that cannot secure private insurance. To obtain insurance, FEMA has set out certain conditions / requirements that must be met. For example,

If a proposed building site is in an Special Flood Hazard Area (SFHA), the building support utility systems for all new construction and substantial improvements shall:

(1) Be constructed with electrical, heating, ventilation, plumbing, and air conditioning equipment and other service facilities that are designed and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding;

(2) Require within flood-prone areas new and replacement water supply systems to be designed to minimize or eliminate infiltration of flood waters into the systems;

(3) Require within flood-prone areas new and replacement sewage systems be designed to minimize or eliminate infiltration of floodwaters into the systems and discharges from the systems into flood waters; and

(4) Require onsite water disposal systems be located to avoid impairment to them or contamination from them during flooding.
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From a definitions page at: http://www.fema.gov/flood-insurance-rate-map-firm

If the Federal government is the insurer of last resort, it is unlikely a private insurer would accept less. And without insurance, a developer will not obtain financing to construct a building, or be able to sell it for anything near full value, because a new owner(s) also could not obtain insurance.

In flood-prone areas, buildings are being designed and built so that the building can be insured.
 
^yeah, understood. I was using shorthand too. Yes you can put shit in the basement. You'll pay through the nose for insurance, if you can get it at all. FEMA has a prominent role in defining the geography of risk that determines how much you'll pay for that insurance and even whether it makes sense for any competently managed insurer to offer it in the first place.

Seems settled.


In other news, I think the Clf / xom lawsuit is potentially a big deal. You all k ow that I think this barrier should be an urgent priority for the region. Boston has been building dikes for flood control, water power, and land reclamation for 400 years, and this could be a natural extension of that legacy. If strategies like this can get big private players to actually recognize the currently-unfunded risk on their balance sheets, the math could make sense sooner rather than later. I.e in insurance terms, we're all bearing an unaccounted risk cost every day with regard to flooding and slr, and the sooner we bring it into the formal accounting the more rational our collective planning and decision making will be.
 
Re: Storm surge in Boston

Is that silly photoshop in the article? We're talking about a 5-foot flood, not a disaster movie. 5 feet of water is disaster enough.
 
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