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View Full Version : Salt marsh bayou delta dohicky



Jaxilon
09-10-2011, 07:37 AM
I wanted to get additional thoughts on this as well as share a bit more of what I've been working on. I was attempting to create a salt marsh type area along the lines of Louisiana and the delta on the Nile.

I have to say the images from Google earth for Louisiana are a mess as far as colors go...it's all over the place so I had a bit of a time figuring out exactly how it all worked. It seems like a bunch of marshy lakes connected by rivers that don't move a lot unless the tide is moving?

Also, this may yet change entirely.

Ascension
09-10-2011, 02:04 PM
I'd make all of those rivulets thinner. It may not be technically right to do so but the way it looks is more important sometimes and thinner streams connecting the shallow pools would enhance the effect...in my opinion. Looks pretty good, though.

Midgardsormr
09-10-2011, 02:26 PM
I think the hard black line around the coast is spoiling the effect somewhat. I've never been in one of these kinds of salt marsh, but I expect that they probably merge pretty smoothly with the sea, so a sharp delineation between ocean and marsh may not be appropriate. Also, that line is a little at odds with the painterly look of the rest of the piece.

waldronate
09-10-2011, 02:31 PM
Those areas have formed by a succession of deltas that overlap each other and slowly subside. The extremely tattered look of the Mississippi delta is due in large part to canalization of the main river channel and loss of new sediments over the continental shelf edge. The old sediments are subsiding, leaving just the natural levees and the man-made road systems.

As Ascension pointed out, your channels are much too large compared to the incoming river. The active delta regions should have distributaries (the split-apart end of the river) that carry as much water as the incoming river. Those channels would have to be extremely shallow and the incoming one extremely deep to get the effect that you have there. A delta forms where a river slows down dramatically and drops sediment. This slowdown can be due to a sudden change in the slope of the land (your typical alluvial fan or the Okavongo Delta in Africa) or where a river enters a very flat body of water such as a lake or the ocean. If the land is relatively flat and the river's sediments are in steady-state between erosion and deposition, the river will expend its energy cutting side-to-side, forming meanders.

The colors look reasonable, though. One thing to watch out for on the Nile delta coloration is that it's pretty much all farmland that's giving it that bright green color. There aren't too many wild deltas left that are above water. The main reason that the Mississippi delta wasn't overly farmed is that it was a bit too swampy. However, those strips of farmland on either side of the river show that people did what thye could to farm it.

It's hard to say too much without a scale, though.

Jaxilon
09-10-2011, 05:26 PM
Sorry about the scale I should have thought of it...I think it's about 225 miles across at the widest part.

@Waldonrate - thanks for the breakdown on how the system works.
@Mid - I know I have been looking at the black line as well. I guess I'm going to have to do something about it.

Thanks for all the comments, they help me to do a better job.

Jaxilon
09-10-2011, 09:31 PM
Ok, I thinned out the connecting areas. Looks like I will be adding some more rivers above this as well which will help fill the basins. As for the black coastline I did tone that down a bit and I still have to work over the Ocean so I will leave it until then.

I will post more and see about posting up a WIP for the whole thing.

Hugo Solis
09-10-2011, 10:59 PM
I've seen few swamp maps, and those I have, are always alike. This one looks quite different and is looking very good. I'm eager to see its scale and ho you throw the rest of the details in.

The green areas looks nicely marshy and I like that ss greener at the center. I see the rivers very wide, specially at the "entry" point, but that may be a matter of scale or simply that's the way it is. I don't have much experience on marshes.

Anyways, great start!

Ascension
09-11-2011, 12:56 AM
I like it, dude. Could use some more thinning in a few places but I dig it.

Steel General
09-16-2011, 08:06 AM
Coming along nicely Jax, I always found swamps, etc. one of the harder things to do.

paulbhartzog
11-19-2011, 01:15 PM
Great idea. Looking good!

The quintessential (standard?) delta has always been the Nile, and there are good pics of it online.

NASA images:
http://earth.eo.esa.int/cgi-bin/satimgsql.pl?ids=1899,121,98

Google Earth:
http://www.narg.org.uk/africandatabase/

RobA
11-26-2011, 06:02 PM
For really large, undeveloped deltas, Canada's Mackenzie Delta is a massively good example for the geology of a delta, as there is little heavy forestation affecting it:

http://maps.google.com/?ll=68.765589,-133.530458&spn=3.540453,16.907959&t=w&z=7&vpsrc=6
http://en.wikipedia.org/wiki/Mackenzie_River

-Rob A>

Lukc
12-01-2011, 06:49 PM
It's a fascinating delta ... but ... zoom into Great Bear Lake and you can see it at the resolution where you get individual TREES!!! E.g.: http://maps.google.com/?ll=66.278521,-117.928609&spn=0.00262,0.009903&t=h&vpsrc=6&z=17 ... drool! :O

jesuisbenjamin
12-06-2011, 06:12 PM
You should take a look at the Ganges' mouth too http://maps.google.com/?ll=21.955783,89.579773&spn=0.352812,0.617294&hnear=Europe&t=h&z=11&vpsrc=6

atpollard
12-06-2011, 11:18 PM
If I might suggest ...

http://www.bing.com/maps/?v=2&cp=25.32834390588812~-81.08638510091164&lvl=20&dir=0&sty=h&form=LMLTCC

(If the image is blurry, zoom out a little and zoom back in.)

Lukc
12-07-2011, 03:55 AM
Bing has a really nice font on their maps. What is that? Anybody know?