BajaNomad - Flood dynamics

Flood dynamics

Sharksbaja - 9-14-2006 at 03:09 PM

The theory of flash flooding is somewhat complicated as the water runs off the desert w/o soaking it and holding it. You hydrology folks may be helpful here.

Will the next evnt or heavy rains soak in now better because of capillary action and wicking or will it be the same. Completely dry and runs-off?

[Edited on 9-15-2006 by Sharksbaja]

Cypress - 9-14-2006 at 03:28 PM

Not a hydrologist, but steep slopes without much vegetation such as the areas surrounding Mulege will not soak up very much rainfall if it fall's in volumes over 2+ inches /hour. Called such events "waterspouts" in northeast Oregon, the resulting floods, while only affecting small drainade areas, would bounce boulders the size of VW's down thru the creek bottoms

Big Rain

Sonora Wind - 9-14-2006 at 03:52 PM

Heavy Rain + Big drainage + small outlet + Steep Topo= FLASH FLOOD. Part of Einstines theroy of S--T flows down hill + Payday Friday. You can count on flash floods every time the rain exceeds .5" over 1/2 an hour, over 1/2 the drainage. Everything else less is just auga in the road. :coolup:

Everything more is some form of nature changing the way earth looks. Not good for the lower parts of the drainage.

[Edited on 9-14-2006 by Sonora Wind]

[Edited on 9-14-2006 by Sonora Wind]

Bruce R Leech - 9-14-2006 at 03:57 PM

with rainfalls in the range of the last storm it wont make much deference ether way. but the puddles will stay around longer after it is over. but I really don't want to test my theory. :light:

Al G - 9-14-2006 at 05:17 PM

IMHO
Dry will always absorb faster thew wet.
Soil density makes a world of difference.
Pee on the beach and it is hard to make a puddle.
Pee on ground you cannot put a shovel in and you get your sandals wet.
Sharksbaja, You are also right about "capillary action and wicking" some water will change the surface density and the soil below may be less dense.
Not a hydrologist, but it makes sense to me.

EngineerMike - 9-14-2006 at 05:39 PM

The hills around Mulege are more porous than the soils of the floodplain, but much shallower to bedrock or the equivalent.
After John, the hills will accept less water because they now have some in they. The clayey soils of the floodplain wouldn't have absorbed much in John, and now that they are pregnant w/precipitation, will accept less.

The big problem is always rainfall intensity. Too much to soak in or be contained in existing flow channels. And of course those idiot humanoids build in the floodplain, so Man-A-Bunga, here comes the flood. (Oops, guess I'm one of the idiots)

sunchaser - 9-15-2006 at 05:04 AM

Quote:

Originally posted by Al G
IMHO
Pee on the beach and it is hard to make a puddle.
Pee on ground you cannot put a shovel in and you get your sandals wet.

where else but on this forum can we find these pearls of wisdom? Thanks Al G! I'll pass this on to my g'kids!

:spingrin:

toneart - 9-15-2006 at 10:03 AM

Quote:

Originally posted by Al G

Pee on the beach and it is hard to make a puddle.
Pee on ground you cannot put a shovel in and you get your sandals wet.

At my age I've peed in a lot of places, and ya know what?
He's right! :lol:

FARASHA - 9-15-2006 at 11:28 AM

There we go, so much on FLOOD DYNAMICS :lol:

quite educative AND FUN this thread, best way to attain knowledge.

That's right Farasha

Sharksbaja - 9-15-2006 at 11:34 AM

you can learn a lot from children.

FARASHA - 9-15-2006 at 12:14 PM

I wonder as to where all the HYDROLOGY experts have disappeared, to fieldtest their puddle theory? :lol:

or to compete

okay now seriously:
If it is true what has been said on the previous posts - then next heavy rainfall will maybe cause more damage.
Speaking out of experience - Austria had and still has repeatedly floods- if the soil is already soaked, then expect troubles.
Depending on underground: mudslides, rockslides,etc....are creating new riverbeds etc. Reshaping the landscape.

Sharksbaja - 9-15-2006 at 12:28 PM

Totally different here in the soggy NW. Our organic laden soils here hold a tremendous amount of water. So much so that the water tables can run from very deep to close to the surface thu wicking. It takes a lot of rain to flood here and it's amazing how fast that water soaks in.
I have heard that your region has been dealing with receding glaciers. Less snow, more rain?

FARASHA - 9-15-2006 at 01:53 PM

Last years winter was extremely cold and lot's of snow, even Danube River was frozen for some weeks -no shipping possible.
Suddenly temperatures went up, all snow and ice started thawing, rivers filled quickly, as the undground was still frozen and wouldn't take up any water, and in the Mountains - solid Rocks, then it started to rain, p'ng down for days. Result : flooded areas left and right of the river, over 20 square kilometers in some regions. Regions which never had floods before, or not for the last 100 years
Mother Nature gave us another lesson, within 2 years it was another disaster to suffer, for the same people.
So most did consider to leave the area, after second time.
You can't fight a Mother - certainly not Mother Natur.