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Flood Maps

flood.firetree.net

45 pointslelf27 comments

I assume for the San Francisco Bay, if sea levels rose enough to be a serious problem, they could just build some kind of dam or something across the Golden Gate. Is that correct?

Where would the water from all the rivers that empty into the bay go?

The worlds only 1m high hydroelectric dam.

Alas, since you want to keep the water level lower inside, that means you'd have to pump the incoming flow up to get it into the ocean. Rather than generating electricity, it would consume vast quantities of it.

The tide moves 6ft+ from high to low. As long as the flow rate is less than 3ft/day then you can just wait for low tide.

I'm not sure if this is feasible and certainly it would be more of a process than 'building some kind of dam'. A few reasons:

- The bridge spans 2700m and the channel is 350+ feet deep in some spots. For scale, the Three Gorges Dam is 2300m long

- Sea levels will rise so incrementally that a massive public works project might seem unnecessary or hard to get support for

- Shipping traffic needs to be able to pass through to get to the port of Oakland, Richmond, Stockton, etc...

This map is simply based on sea level and totally ignores sea force. If the sea were 10' higher, it would probably erode most of San Francisco within 50 years.

What's up with these odd diamonds? Graphical artifact? http://i.imgur.com/uPxPPI1.png

Probably has to do something with google maps elevation value for those coordinates. https://developers.google.com/maps/documentation/javascript/...

nope it's the SRTM itself. It's a quite low quality data, or more exactly, it's not meant to be used directly, you theoretically need some post-precessing and cross check of this data before use.

Of course normal people don't have the means to do that so we use them directly. I have not personally checked it, but this guys offers something that seems higher quality than the raw SRTM (in particular in the mountains): http://www.viewfinderpanoramas.org/dem3.html

Those are swaths that the SRTM was unable to survey before its mission ended. There are only a few of them and luckily they're all inside the US where there is already higher quality elevation data available from the USGS to fill them in.

http://en.wikipedia.org/wiki/Shuttle_Radar_Topography_Missio...

Is there a reason behind "+60m" being the maximum the map displays? I tried to change the url [0] directly but it's not working that way. I want to know how much the sea level needs to rise so we have direct access to the sea in Austria.

[0] http://flood.firetree.net/?ll=47.1210,11.2395&zoom=7&m=60

yes, it's pre-computed I guess.

The blog talks about it:

http://blog.firetree.net/2006/05/18/more-about-flood-maps/

The elevation data was processed to fit into 4 bits (so the server has 16 values available, "No Data" + 15 elevation levels).

Here's a site that lets you use any arbitrary height: http://www.heywhatsthat.com/sealevel.html

Austria can get a shallow water port on the Black Sea, in Vienna, with a rise of ~500ft.

It's fairly close to the maximum theoretical rise, if all the ice melted (~80m, apparently)[0]. Also, here are some interesting maps, including Earth with 66m rise, Mars with oceans, and more[1].

[0] http://pubs.usgs.gov/fs/fs2-00/ [1] http://www.johnstonsarchive.net/spaceart/cylmaps.html

At 60m, what's with the diamond areas in the eastern Carolinas and northern Florida?

At 60m a considerable portion of the Brazilian amazon would be invaded by the sea.

Being from the Netherlands, albeit not living there, this is kinda worrying..

Your nation is literally built on contempt of sea levels. Using only renaissance technology.

Even if the rest of the world is submerged, I imagine a single Netherlands-shaped island in the vast sea, populated by unmoved people not sure exactly what the fuss is all about.

Indeed, about 20% of the Netherlands are already beneath the sea level. Sea levels rise slowly and the Netherlands are rich. I expect the Dutch to simply build bigger dikes.

In fact maybe they will not even have to. The current installations are probably already designed to hold even at a noticeably higher sea level for safety reasons. At least I cannot remember ever hearing about flooding disasters in the Netherlands during my lifetime, despite the fact that the land is coastal, flat, and beneath or close to the sea level.

Kind of embarrassing actually. I am sitting in neighboring Germany and we seem to have a major flooding disaster every couple of years.. and just because of the natural water level fluctuations in the rivers!

I do not mean to say that rising sea levels are not a serious problem.. just probably not for the Dutch.

In fact, I'd bet the rising sea levels will enrich the Dutch even more through expansive, international public works projects. Those need engineering firms with extensive experience with water, dikes, dams, storms, etc: something the Dutch should excel at.

New Orleanian here, and we're in the same boat. Except that we don't even need rising seas.

What this map doesn't show is the land uncovered by melting ice. Something a Canadian or Russian might be thinking about.

I remember hearing when I was growing up how we're going to "run out of oil." Haven't heard anything about that lately.

Is there an agreed upon max if both poles melted?

60-70 meters, but melting the poles would thousands of years. In the next century, worst-case estimates put the rise in sea level at around 1 meter: http://en.wikipedia.org/wiki/File:Ipcc_proj.jpg

If the polar ice caps were to melt away entirely:

http://boards.straightdope.com/sdmb/showthread.php?t=697242

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