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Comment by criddell | Hacker News Reader

Don't lenders require flood insurance for high risk areas?

They do, but most people get their flood insurance through the National Flood Insurance Program, which makes determinations of risk based on data collected back in the 80s, and doesn't have premiums that cover the actual risk, which means it doesn't really dissuade people from building in flood areas.

My first job out of college was doing flood zone determinations with this data. FEMA updates their FIRM (Flood Insurance Risk Maps) flood zones in most places every few years.

Just checked here in Austin and it was last updated in 2016. https://msc.fema.gov/portal/availabilitySearch?addcommunity=...

In theory, but a) many properties are owned outright, for one reason or another, b) the flood maps assume flood control measures all work properly (e.g Harvey necessitated intentional release of water in order to prevent dams/levees from failing), c) over a 30 year mortgage you have a 26% chance of experiencing a "100-year flood", d) 100 year flood definition is inherently imprecise in the first place, not to mention climate change issues...

I could go on, not sure how much of this is really Houston's fault, the only flood insurance program is federal and they exert so much influence because they do establish the requirements for ~everyone who has a mortgage. Feds should probably take the lead on this.

Also Houston is just really flat to begin with, basically at sea level.

Houston is apparently sinking as fast as New Orleans. 2 inches a year in some places (up to 12 feet since 1920).

https://pubs.usgs.gov/circ/circ1182/pdf/07Houston.pdf

Venice isn't just dealing with sea level rise, it's also sinking into the sea due to ground water pumping.

As sea level rises we are probably going to have to find ways to get water back into the aquifers faster. Both to stop subsidence and to keep it out of the oceans. More the former than the latter, but here are some numbers:

The surface area of the oceans is about 361.9 million square kilometers. Since a millimeter is a millionth of a kilometer, every millimeter of sea level rise is over 361.9 km^3 of water. The USGS pegged our aquifers as down 800-1000 km^3 in 2008 an the rate per year is over 25 km^3, and different sources seem to say we're now globally somewhere around 300-400 km^3 net loss in ground water. Per year.

And in the worst places the ground is sinking 2 feet per year due to pumping.

"the worst places the ground is sinking 2 feet per year due to pumping."

Is that number accurate? Thats would be bonkers, any kinf of infrastructurr or houses would crumble it it's foundations move at that rate.

I don’t know, but that’s what the usgs doc said, and another list said Houston and New Orleans are tied for first place (in NA presumably). I saw a video the other day about subsidence in some valley in California that’s almost as nuts. Bridges that are now underwater during every rain because they’ve sunk, things of that sort.

Houston does have unique local situtations, such as "we're going to allow you to build homes inside of our flood management reservoirs [1] and not require you to disclose to buyers that they're in a flood management reservoirs."

[1] i.e., the land that is intentionally flooded to prevent worse floods from happening downstream.

I know that happens but I'm not sure this is really unique to Houston, it seems to be a problem throughout the US in low-lying and/or coastal areas.

https://www.governing.com/archive/gov-flood-zone-floodplain-...

"not require you to disclose to buyers that they're in a flood management reservoirs."

I live in Uk, and this sounds downright fraudulent. Its basically knowingly selling defective product.

Wouldn't the logical conclusion be to build the homes, but to build the foundation higher than the forecast flood line? Or even to build the house raised above the foundation?

Yes, they very much do. I'm not entirely sure how to square the GP's comment.

Most of the issues as-of-late have been areas that didn't previously flood. The areas which flood change as development increases.

Houston also has pretty substantial regulation around flood mitigation and such these days. I'm not sure how that relates to this article in any way, which is focused on zoning, minimum lot size changes, and neighborhood-based opt-out on loosened regulations.

>Yes, they very much do. I'm not entirely sure how to square the GP's comment.

It happened. Lots of the flood plain homes that were destroyed in Hurricane Harvey were not flood insured. One of the reasons cited was lax updating of maps, another was builders gaming the system, another was loopholes for land near flood management reservoirs, etc. Things that happen less often if the local government is active around land use regulations.

And, in fact, Houston and Harris county did enact a bunch of new ordinances around all of this after Harvey.

https://archive.is/XxhE

https://wga-llp.com/blog/city-of-houston-adopts-new-floodpla...

"I'm not sure how that relates to this article in any way, which is focused on zoning, minimum lot size changes, and neighborhood-based opt-out on loosened regulations."

Most flood mitigation regulations are essentially zoning/planning/building permit related. They include restrictions on impermeable surface area, lot grading, etc. Let's say you cut lot size in half and are essentially doubling impermeable surfaces. That water has to go somewhere. This can increase the amount of run off and the chance of flash flooding. It can also complicate grading since existing houses might have been graded on the assumption that their runoff can go to the other side of the lot... where the new house now exists.

So they are connected.

i’d vote enthusiastically for a superlinearly-escalating tax on impervious surface area as a percentage of lot size to counteract runoff and groundwater issues, as well as flood control. we have entirely too much concrete and entirely too little permeable ground with trees and plants in cities like houston and LA.

That's interesting, but I'm missing how that will help. Most people want their house, driveway, and patio. I don't know that the tax would change any behavior.

it would encourage developers to minimize those things. in LA, for example, the city had a subsidy to replace thirsty lawns with drought-tolerant landscaping. many property owners replaced lawns with fake plastic grass... that requires a concrete substrate. so we got more heat-concentrating surface and worse water/drought management. this kind of tax would have encouraged property owners to consider better alternatives.

It seems that's more of a poorly thought out policy that is being subsidized. It's focusing on removal of an attribute (grass) rather than an outcome (drought tolerant native plants replacing lawns to manage water requirements, tempature management, and rain water). A better option would be to fix the poorly implemented subsidy program to set specific criteria that creates a beneficial environment.

it's one example of a swath of problems that can be discouraged in one go, rather than having to mitigate each poor policy one at a time.

natural ground cover is beneficial in many ways over impervious surfaces so incentivize the former and disincentivize (rather than prohibit) the latter. if you want to cover your whole lot with concrete, go for it, but expect to pay for the negative externalities of that.

I really don't see a benefit to creating conflicting/competing policy. You have people who would rather keep their lawn than go to concrete based on the tax being more than the subsidy (assuming one time subsidy vs yearly tax). The policies undermine each other. You can't just slap a single policy over a multitude of others and think that's more beneficial, right? You have to look at it from a systems thinking perspective, which would require evaluating the interactions and n-order effects between that one police and all the others. If you're doing that work already (clearly politicians don't, based on the existing poor policies) then you might as well fix the underlying issues since it will allow the policies to function more effectively.

"but expect to pay for the negative externalities of that."

But what do you think that money will actually do? Is it going to prevent issues? I don't think so. It won't even cover the costs of actual damages in many cases.

The federal government provides flood insurance when private insurers won't.

The federal government requires flood insurance, even if you own your house outright. They also expanded those flood zones substantially over the past decade or so.

I’ve never heard of the federal government requiring flood insurance for your own property, house or otherwise. Is there a source where I can read about this?

All I can find is this:

https://www.floodsmart.gov/flood-insurance/requirements

>Homes and businesses in high-risk flood areas with government-backed mortgages are required to have flood insurance.

Which makes sense. I've never seen a government requirement for insurance for a loss only the asset's owner will incur.

I forgot the details. It's not a blanket requirement but has to do with FEMA money. Basically, they don't want people relying on FEMA instead of buying insurance.

"If you receive disaster relief funds following a disaster declared by the president, that money often comes with a caveat that you buy flood insurance to cover the cost of repairs or a replacement building if it is in a high-risk area for flooding. The Federal Emergency Management Agency requires that you maintain flood insurance on the property for as long as you own it. You’re also required to notify the next owner of the requirement if you sell the property. If you fail to cover your home with flood insurance after you receive federal disaster aid, you’re ineligible to receive future relief."

Interesting! That makes sense too.

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