Comment by freeopinion | Hacker News Reader

Comment by freeopinion | Hacker News Reader

I get that is isn't always obvious when you're in a flood plain, but... Some years ago I visited a home in the U.S. southwest where the owner complained that they were the surprise victim of a flood within a year of purchasing the house. It seems that they had no idea that their house was positioned in the dead center of a wash. I don't think they even knew what a "wash" was. Even after the flood.

I took them outside and pointed to the road coming to their driveway.

Me: "See that embankment you come down about 40 feet from your driveway?"

Them: "Uh-huh."

Me: Turning to the left, "See that embankment that goes up about 50 feet past the other side of your house?"

Them: "Yeah..."

Me: "Doesn't it kind of look like two river banks with no water in between?"

Them:"Umm... But there _is_ no water."

Me: "That's because it hasn't rained in over 100 days. 360 days a year, this will be dusty dry."

Them: "Exactly"

Me: "There are more than 360 days in a year."

Sometimes, nobody thought to warn you because it was painfully obvious. Like the rattles on a snake. Unless you've never heard of a rattlesnake before.

Assuming what’s painfully obvious to you is painfully obvious to everyone is how major accidents and mistakes happen.

What you have described is an indictment of our educational system on several different fronts, and a testimony of the need for broad education not just giving people enough to know a narrow field where they can earn money but be ignorant and uniformed of everything else.

Their inability to see what seems like common sense to people familiar with washes is one example. Your inability to see that people without any background knowledge on a topic will have trouble understanding the topic is another example.

> What you have described is an indictment of our educational system on several different fronts, and a testimony of the need for broad education not just giving people enough to know a narrow field where they can earn money but be ignorant and uniformed of everything else.

this is a bit much. all you need to understand to recognize the potential problem is the basic fact that water flows downhill. this is sort of like buying a house right next to a college dorm during the summer break and complaining that no one warned you college kids like to party.

Dialing down the blast radius on your comment, imagine if homebuyers were required to pass the same sort of locally-tuned competency test on houses and real estate that new drivers must pass to get their driver’s license. No need to restructure the educational system.

Imagine a “renter’s/buyer’s” general ED course in high school, and requiring the passing of a local “buyer’s test” prior to signing. It would be prudent from an investment standpoint and a “Welcome to the neighborhood” for newcomers who have never lived in a flood plain, experienced a tornado, etc. or even owned a home.

You seem to imply that this story shows how obvious it is for people to know when they're in a food plain.

I think it shows the opposite. This person bought a house, was a victim of a flood, and still didn't realize they were in a flood plain.

I'm just curious, I live in the Midwest U.S. and here if you live in a designated flood plane, you have to buy flood insurance. There is no way to not know you are in a flood plane. I think the rule is that if it flooded within the last 100 years, it is automatically designated a flood plane too. Is this not how the rest of the U.S. operates? (within some variation of course)

Does that 100 year rule apply to undeveloped areas? My neighborhood is 20 years old and before it existed, it was wilderness in the middle of nowhere. I wonder how well flood data is tracked for that type of land.

From what I remember (where I am obviously), the Department of Water division of the Department of Natural resources surveys pretty much all of the area of the state. When someone builds something in a new place, there is quite a bit of research that goes into water tables, flood zones, etc. I would assume they map that out, but honestly I can't say for certain. I do know that it's occurred on occasion that rules get "bent" to make certain things happen. It's politics and money, and permitting is a high visibility job.

It depends!

I used to do permitting for construction of aerial and buried fiber networks.

Typically if you're doing some sort of thing where floodplain data is needed, you'll start by finding the dataset from USGS/FEMA/USGIS/etc. Import that in, you'll get a whole bunch of data that depending on package (i.e. if you are doing stuff in AutoCAD instead of working with real GIS software) you might have to shape to get more proper information; floodplain data looks like a bunch of contoured lines (often semiparallel to each other.) based on the survey, and have different embedded metadata accordingly.

So you'll do your drawing based on that, and ideally at some point, a Surveyor goes out and will Verify the map. They'll do this by probably re-pulling the original survey data, going out to the site, and basically making sure you didn't lie in your map.

This last part BTW is an important check&boundary, and IMO the more important one than municipal approval. A good professional surveyor knows that if he does the wrong (i.e. potentially harmful) thing, he could lose his license and livelyhood forever. Professional Seals are something that I have a lot of respect for.

FWIW, this is often the easier part of getting a permit as long as you are building sanely. The city is where politics, money, and process gets broken.

It's also based on simulations. They army corp of engineers runs simulations to figure out where the flood planes are and also where they can dump water in the case of flooding. Saved new orleans about 10 years ago from being completely underwater.

There is no 100 year rule. To the extent that "N-year floods" exist, or their hypothetical water levels, that is all more of an arbitrary label than a scientifically-valid designation.

realistically they're measuring "big floods" and "bigger floods" in a way that is consistent, however the stated time frequency with which they supposedly occur is so extremely inaccurate that it does not rise to the level of 'science.'

There's a -little- more nuance to it.

Private Mortgages may require flood insurance depending on factors, depends on the bank and their rules. Govt Backed mortgages (i.e. FHA) will require for 'high risk' areas. However you can still have a flood within 100 years in your area but not be required to have insurance (I live in such an area.) Typically this is for cases where flooding is going to be very minor; i.e. in this area it can happen but it's a small enough flood both in size and depth it doesn't meet the criteria. As a result, savvy folks just make sure not to keep anything expensive out of their basements. Less savy folks take extra trash out after a bad rain.

FEMA flood maps, which are used to determine flood insurance requirements as part of a mortgage origination, are woefully out of date. It doesn’t take a lot of water to cause damages exceeding the resources of your average homeowner.

To the savvy real estate buyer, I recommend https://floodfactor.com to accurately quantify the flood risk of a potential property. They have stepped in where FEMA has dropped the ball.

My point was that something blatantly obvious to one person is not necessarily so to another person. I know not to play with rattlesnakes, but if I went to Georgia and saw a snake swimming through the water, I might assume that it was perfectly harmless because it wasn't a rattlesnake. But a Georgian might think me a complete idiot.

USA is all about personal freedoms, including the freedom to be stupid about things and shooting yourself in the foot.

People ignore inconvenient facts all the time.

I'm sure we've all talked ourselves into a stupid decision or two because you really wanted something.

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