How do you drain a swamp?

Factual Questions
1

In doing some reading of my pioneer ancestors, and in reading about the construction of Washington DC, I note several accounts of people draining the swamp. So I am curious: how do you go about draining a swamp?

I tried google, but only got a bunch of political commentary on fighting terrorism, but here are my thoughts:

  1. Dig out a deep channel through the middle of the swamp. (How deep? How steep?)

  2. Put a whole lotta rrocks and soil over the top of the swamp. (Seems kind of hard for a pioneer to do).

  3. Buy a really big wet/dry vacuum and have at it!

Any one out there have some ideas? For the PC / Environment types on the board, no, I am not planning on doing this myself. So the waterfowl are not in danger, no one is going to suffer from any habitat changes, and the world will not increase any in global warming or CO2 production. I just want to know how they did it back in the day.

Thanks!

2

I would go for the clearing a channel. Find the swamp’s outlet (it pretty well has to have one) and widen it out. Wait. Let it drain. Then find the next bottleneck in the drainage and clear it. Continue for a long time.

Depth and steepness do not overly matter. Water flows down any hill, no mater how slight. Flowing water will carve out a channel to the required depth.

3

You drain a tub from the bottom, but you drain a swamp from the top. Swamps get swampy because groundwater flows in faster than it flows out. So, you dig trenches along the contour lines above the place you want to dry out, and lay drains in them, that direct the water around your currently saturated land.

Now the natural drainage of the swamp continues at its normal pace, but the inflow is drastically reduced. Time passes, and the ground becomes much drier. How much drier? Depends on how you place your drains, and how deep the inflow is. Engineering has dealt with the hard numbers fairly often, now, and you can pretty much plan for your desired reduction.

No actual waterfowl were killed or displaced in the preparation of this answer.

Tris

4

Down here in south florida they used dredge and fill. First, dig some nice deep, wide canals which lowers the water table. Then use the dredged up material to raise portions of the land on which you can build. On the coast, this method is used to turn mangrove islands into expensive neighborhoods with canals and streets alternating. Matlacha Island in my county looks like a fish bone pattern because of this.