Big fan of this thing. It's one of my favorite places to take friends who visit the Bay Area.
Something that's not mentioned in the article is that the building they occupy is a former warehouse of Marinship, a World War Ⅱ shipyard that made Liberty Ships and T2 oil tankers used to supply fuel in the Pacific Theater: https://en.wikipedia.org/wiki/Marinship
The Bay Model building has a Marinship museum in a front room. For anyone who wants to see Marinship's full story in motion, here's my HEVC encode of ‘“Tanker” — 1942–1945 War Time History of Marinship Corporation’ https://mega dot nz/file/lgtmlKIA#asrzuwGOxi6l8I5BmgyAxfKkm1zFcxvY4SYS1SxqtZk
e: the Bay Model building is the big square one that is center-frame starting at 04:30 in the video, Marin City at 09:23, and some beginnings of modern-day international oil politics at 12:28.
I went to SF once for a few days and this is one of the things my friend showed me in my limited time there. I remember it from time to time. It's pretty cool.
Im trying to reflect on why it was so memorable. I thought it was interesting at the time but it wasnt mind-blowing or something. I think it is just just such a unique oddity and a relic of the past. There was so much effort and space devoted to this. You'd never do something like that today.
I used to live in Tam Junction, close to Sausalito. I had lived there at least a year before I discovered the Bay Model and was amazed when I visited it. It is huge.
The real question is would a Godzilla incursion be good for property values (novelty, tourism attraction, remove some housing stock) or decimate them (safety concerns, change the spirit of neighborhoods).
It's a shame that there isn't a series of articles on such models --- saw the Chesapeake Bay model (mentioned in a footnote) on a field trip when I was much younger (and it was still in active use for research I believe, yes, as my kids constantly tell me, I'm old).
Simulation used to be essentially impossible, something one dreamed of, or had to pay for time on a Cray or similar supercomputer/cluster.
Apparently, the Chesapeake Bay model was built just as that was becoming feasible:
I highly recommend a visit. It’s only a beautiful ferry ride and nice walk along the waterfront away from San Francisco. A refreshingly retro and analog experience.
John McPhee talks about a similar model for the Mississippi River in “The Control of Nature” Well worth a read. Fun stories about Hawaii and Los Angeles too, iirc.
This is neat to see. US army crops of engineers is a negative “word” to me after growing up in FL and they destroyed so many ecosystems. And the entire Everglades. They’re still at it now. My family has basically spent the past 30 years fighting a ware they put in on our natural creek. It killed the creek, it shrunk the flow to the size of the culvert.
So, It’s neat to see something competent! Imagine if they modeled what cutting off the natural draining to the Everglades would do :p
The existence of negative externalities or tradeoffs does not inherently imply incompetence.
I remember reading that the USACE said the NOLA levees would not adequately protect against a category 5 hurricane but the powers that be didn’t think the added cost for a more robust design was worth the risk. If true, it doesn’t imply USACE was incompetent but that we live in an uncertain world with tough tradeoffs.
Was it displayed at the Civic Center or did Autodesk have an office location in Sausalito? I had never heard of this Bay Model and believe to only have seen a model at the (new location) of the Exploratorium - this was over a decade ago so don't quite recall
The distortion is interesting and something I didn’t realize the model included. I assume that it’s necessary because the effects of surface tension and the viscosity of water (and other effects?) change its behavior at this scale relative to the features of the model?
If I recall correctly, at an undistorted scale, the water would be so shallow that surface tension and viscosity would dominate, so the depths are exaggerated to keep the flow realistic.
More specifically, tidal flow obeys Froude similarity, not Reynolds. Matching the model's Froude number to the real Bay's requires enough depth for gravity waves and tides to scale correctly, which the vertical exaggeration provides.
But the distortion makes the flow too efficient, so copper strips are added throughout to achieve the right frictional resistance.
Have you ever watched a movie with a fire or explosion just didn't look right because it was a scale replica? At a subconscious level, you may have picked up on how the dynamics of the smoke or debris didn't fit right with the scale. It's because the fluids in the model lacked "similitude" at the adjusted scale.
When building scaled models, adjustments have to be made to create that similitude, usually done by comparing some dimensionless number at the real scale and model scale. If you're using water, maybe you can't adjust the viscosity, so you may you have to adjust the velocity to get the same dimensionless number. Everything doesn't just scale linearly; you tweak the variables to achieve the dimensionless value so the whole system dynamics remain faithful.
Yes. Another technique was to use alcohol rather than water since it has lower surface tension, but that was only workable for smaller models (which were usually enclosed).
Even if it wasn't a large size, it likely wouldn't be great. During my PhD on sprays, I did some (unpublished) experiments using isopropyl alcohol to reduce the surface tension. The nozzles I used were around 1 mm in diameter as I recall. I did not anticipate that the room would fill up with isopropyl alcohol vapor and (probably) tiny droplets. I wore a mask and maybe left the room while each trial was running. Breathing that likely wasn't great for my lungs.
These are the kinds of interesting engineering challenges that were solved with human ingenuity and grit; I wish we were talking more about them to our youth to inspire imagination about what's possible.
In addition to sibling comments for intent, the book Cadillac Desert documents how this government agency can be used to further moneyed interests, ie subsidize developments that would otherwise not be economically viable from local funding but become viable when federal taxpayer foots the bill. (The big examples in the book is building cities and farmland in deserts.)
Not sure about the exact thrust of your question but a few points:
- flood management is not easy to monetize so there is not much incentive for private industry. The timelines for design decisions (100 year, 500 year) often don’t mate well with private incentives
- it crosses many property boundaries which makes it hard to manage unless you have the rights of a government
- much of the work is still done by private companies but managed by the government, just like other infrastructure works like roads, bridges etc.
The US did not have a civilian engineering school for a few decades after the founding. West Point was the only institution creating engineers. Given they had responsibility for port defenses the civil engineering of waterways was an easy addition.
The fellow who lived next door to me told me of a similar model system used to model Sydney Harbour which he worked on in the 1970s. IIRC it was instrumented with electronics and linked to a VAX or similar early machine.
The Aus Navy had a computer simulation of Sydney Harbour, dating from the 70s or maybe 80s. One particular feature of the system was a disk drive about 1m in diameter with about 12 heads. Cost a bomb, but I guess it was worth it.
When I saw a demo, they had an easter egg of a Loch-Ness type monster in it.
There's also a topographical map of the harbour at St Ives showground but it's purely non-hydrographical.
But it's almost disappeared now through neglect.
>The Aus Navy had a computer simulation of Sydney Harbour, dating from the 70s or maybe 80s. One particular feature of the system was a disk drive about 1m in diameter with about 12 heads. Cost a bomb, but I guess it was worth it.
Meanwhile the Soviets probably found a little inlet somewhere that was "close enough", evicted anyone who lived there and excavated it to match.
Some junior engineer probably had to wake up at 1am to take a kayak out to "Little Kotlin Island" to change the tape in the recording equipment in time for the tide change.
Something that's not mentioned in the article is that the building they occupy is a former warehouse of Marinship, a World War Ⅱ shipyard that made Liberty Ships and T2 oil tankers used to supply fuel in the Pacific Theater: https://en.wikipedia.org/wiki/Marinship
The Bay Model building has a Marinship museum in a front room. For anyone who wants to see Marinship's full story in motion, here's my HEVC encode of ‘“Tanker” — 1942–1945 War Time History of Marinship Corporation’ https://mega dot nz/file/lgtmlKIA#asrzuwGOxi6l8I5BmgyAxfKkm1zFcxvY4SYS1SxqtZk
See also Marin City, which is the remains of Marinship's on-site worker housing: https://en.wikipedia.org/wiki/Marin_City,_California
e: the Bay Model building is the big square one that is center-frame starting at 04:30 in the video, Marin City at 09:23, and some beginnings of modern-day international oil politics at 12:28.
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