View Full Version : Swamp draining
08-21-1999, 05:55 PM
How do you go about draining a swamp?
So many ancient civilizations did it so I'm assuming it doesn't require highly advanced technology. Maybe just tremendous slave labor.
So how did they do it back then and how is it done now?
08-21-1999, 06:30 PM
WAG: They dig a ditch to let the water flow away to somewhere else, a canal or river.
08-21-1999, 07:10 PM
Ok. They dig a ditch. Forget pumps, etc. MOST swamps ARE swamps, not because they are on the top of a freaking mountain, but because they are in low-lying areas. Fine, I wanna build Xanadu, I buy some land, I gotta swamp problem. I dig my ditch, as only a true ditch-digger can. HOW does the water flow UPWARDS???? This low-lying swampland of mine, it's gonna ruin my Mansion. How does one get water to flow uphill, out of the swamp, to the culver/stream/river/ocean ?
( Don't talk to me about the Nile, here, I am talking about flowing UPhill, not North opposed to South. ) :)
------> up to his eyeballs in swampgas,
08-21-1999, 07:46 PM
ok swamps are low lying, but there is a slope and there is a flow very slow maybe but a flow. Other wise if there is no drainage at all you wind up with a lake that eventually becomes putrid lifeless water or a salt sea if evaporation is high enough. You dig a series of channels deeper than the original bottom, the water drains into them,drying out the swamp.Instead of a wide shallow swamp, you got a few DEEP channels holding the same amount of water.Connect all those channels to one canal at the low end. Still not draining fast enough?Keep extending and deepening the canal till it reaches a place that is naturally lower than the swamp.might have to cut through some rises even hills but it's been done and by human and animal power alone. Now that you know how to do it, I got this chunk of land,don't look like much now,but...
"Pardon me while I have a strange interlude."-Marx
08-21-1999, 11:12 PM
A combination of draining, and filling low-lying areas with dirt is common. The water table in such areas is generally high, and sometimes it's necessary to fill it several times, because the water might come back.
But, if you're eying the swamp on the back 40 of your property, picturing condos and a golf course, I wouldn't try it. The EPA frowns on such things, son. And they're not known for their leniency.
08-22-1999, 12:43 AM
Toledo, Ohio (my hometown) was built on what was called the "Black Swamp." Most days I wish they never drained the swamp. Some days it feels as if they never drained it.
"I'm not dumb. I just have a command of thoroughly useless information."
-- Calvin and Hobbes
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According to Pliny
08-22-1999, 01:13 AM
Wasn't Mexico City and the original Aztec city before that built in the middle of a swamp?
08-22-1999, 05:13 AM
Papabear, swamp and lake depending on season and drought conditions.
Not only do you use ditches and canals but some of the wet lying farmland around here was "tiled". This was basically just running drainage pipe a couple of feet below the surface through a wet area and downhill to pond, ditch etc. In the old days it was down with interconnecting clay(?) piping that just loosely fit together easily letting water flow in in wet spots and out in dry spots. The same stuff was used in old septic/ leach fields. Nowadays you can get a variety of both flexible and stiff piping to do the same thing, you still have to dig the ditch though.
08-22-1999, 01:21 PM
The short-term answer ? You got 'em already. By the way, it isn't usually the EPA, but generally either the state or the US Army Corps of Engineers that manages wetlands rules, aka "swamps".
The long-term answer ? Ask the Army Corps, or anyone living in the Mississippi basin, etc... You can't really do it. You can:
- hope for relatively useful draining, with continual maintenance;
- use fill and concrete to make a floating substrate to build upon;
- apply for Federal aid every rainy season;
- wait for Mother Nature to do the job right.
Mme. Nature takes her time, though. Geologically, dried-up swamps become soft basins: Mexico City, LA, Seattle, et al. [these at varying stages]. The swamps are not only related to relative depression, but often also to fault lines; a brief trip to Joshua Tree Nat'l Park will show this. A good quake returns the "dried-up" substrate to a near liquid consistency, and Blammo ! Structures sink, albeit a little faster...
"Proverbs for Paranoids, 1: You may never get to touch the Master, but you can tickle his creatures."
- T.Pynchon, Gravity's Rainbow.
08-22-1999, 09:04 PM
Tenochtitlan was actually built on a small island in the middle of the now mostly dry lake in Mexico Valley. The Aztecs actually didn't drain the lake, they would build reed rafts with piles of lake mud on top, plant water loving trees, and these trees would anchor the floating patches of mud with their roots. I think that as the city grew, they filled in the lake to accomodate the growing city. This page i am reading states that they even had to bring water in from the mainland (meaning the lake must have shrunk considerably at the peak of Aztec civilization).
John W. Kennedy
08-24-1999, 10:26 AM
Sufficiently large quantities of water can also be drained over hills to lower terrain by use of a syphon, provided that the hills are no more than about 32 feet high.
I only just learned that Canal St. in New York commemorates a now-forgotten swamp-drainage canal. (I always used to wonder why a canal would be built on an island in the middle of the greatest natural harbor in the world.)
John W. Kennedy
"Compact is becoming contract; man only earns and pays."
-- Charles Williams
A good quake returns the "dried-up" substrate to a near liquid consistency, and Blammo ! Structures sink, albeit a little faster...
That gives me a chance to cite one of my favourite words: thixotropic. It describes materials (usually clay or silt, but it can refer to yogurt :)) that turn liquid when they're disturbed, and solidify when left alone. Parts of Vancouver, B.C., are built on thixotropic clay, and will sink out of sight, I'm told, when a big earthquake hits.
Bob the Random Expert
"If we don't have the answer, we'll make one up."
08-24-1999, 01:46 PM
"A good quake returns the "dried-up" substrate to a near liquid consistency, and Blammo ! Structures sink, albeit a little faster..."
Ah yes, liquefaction. Unfortunate real-world example: the Marina neighborhood in San Francisco in the 1989 quake.
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