Seeking advice about high groundwater levels and how to mediate them

clay if you could dig down, deep topsoil in many places...rock everywhere.

" The soils in Webster County formed in material weathered from limestone, dolomite, shale, and sandstone, in alluvium, in loess, or in a combination of these.
    Most of the soils formed in material weathered from limestone or dolomite, both of which tend to weather to clays. "

From... http://soils.missouri.edu/HTML_manuscripts/soilsmdb/intro.asp?x=f_parent&series=MO225

[problems of pines and such that they have some pretty inflamable type saps that can poison soils combined with the fact that they are planted in such great numbers, so close together.
      Saps that when the wood burns evaporate creating inflameable gas clouds above the woods . We do always do our best to find big trouble, like planting lots of pines in climates with hot dry summers.    

- Rose - its important that you realize Travis is talking about Canada, specifically Ontario Canada where forest fires are not a major issue, and pine is a native species, making up the majority of our forests.

Travis, If you have apples naturally, other fruit will do fine... Apples seem to be the most finicky in our climate. (disease, and need for spray)... If you want to stay organic, stay away from planting apples, and go with Asian Pear, pear, and plums.... - Talk to Steve at the greenbarn nursery, his knowledge and advise is really work a few minutes on the phone!

  I once looked up canadian forests i can't remember why and fires, the interestong thing is that most of the fires in canadian forest take place around cities.

i was forgetting about travis being from canada, it seems that forums often get on to a opoint when they are not longer about the ouint the person who started them meant so i was not really thinking of relating what i said to travis.

      The truth is there are mediterenan pines too, ones that are natural to the mediterenan.  El pino pinonero the umbrella pine that produces pine nuts, el halpensis, that is used to stop deserts and others forest of them for instance the in gredos in Ávila. I don't know if they form very big woods naturally.  still iit si not a good idea to let them in hot climates.
  Here, traditional woods are kept open and thats the reason i suppose for the silvo pastoral tradition if you have open woods then you need to produce somthing else bwcauase not aenough wood a hectare is produced to be profitable.

      I was talking of planted woods i suppose. i have photos of pines and next to them bits of land that have been left to their own devices and these bits of land that were no t planted have filled up with autoctonouse trees and are a demonstration of how uneccessary it was to plant pines however much the government like to pretend that pines were necessary to better the soil they plant them because they are profitable. i have been looking for the photo and have not found it but i will find it in the end.

  How thickly do  the natural pines in woods in Canada grow? Here they are planted woods and so they grow straight they are thickly planted  there are a few natuarl woods and they aren't thickly planted and they have pasture at their feet which means they don't cause resentment among the villagers . and there are ot fires in them. The one i know is that of Navarredonda de Gredos. agri rose macaskie.

  jennifer smith, paul wheaton's recipe for landcowpeas and buckwheat and i can't remember what probably works.
i have just read
i found some really good articles with the words pasture grasses clay soils permaculture. I thought that combi9nation of so many words would not work but it  did. agri rose macaskie.

I looked up th e words pasture grasses clay soils permaculture in google and found some good articles.
    One called mimicking microclimate (story) that comes from a magazine called Future Designers Permaculture it  talked of a place called Jimbour plains said these plains are black alluvial lcracked clay and used to be rolling rather than flat. They have been ploughed flat They used to have sweet grasses so tall that you could tie a knot above your saddle with them. The ground used to be soft and absorb enormouse quantities of water,  and the carriage wheels used to sink in it. It nowadays no longer takes much water and the clay has turned hard rather than soft  and the sweet grases have been replaced by low tough grass and in the end by just a few tufts of grass. because of heavy livestock loads and cereal farming 
    The article includes lots of detailed inrformation about the degradation of clay soils and how to restore them. She dug pàns, shallow rip lines and coutour trenches taking the water to a damn that that held the water in  abig pond and fed out of it by granvity into deep channels, but it is the grasses and bushes she has planted and the wild plants grown that she hopes will better the drainage of the soil and its water uptake and storage.. The article is not very long but it is dense.
  The other interesting article animal fodder and pasture plants for year round green fodder is full of usefull information about plants .
  The most usefull bit of information in it maybe was  that perrenial grasses though maybe providing less fodder have deeper roots than annuals and so are better for breaking up soils and filling them with organic matter in the form of dead roots as they die back in off seasons and grow back in good seasons.
  The grass i had and have on my land which helped the clay, though it did not become good fertile soil immediately did stop being heavy clay very quickly was oats. In one place rae ? ray grass? had been planted, the clay is still clay there. Oats have long roots though they are i think annuals.
Also they say that that all poplars make good forage so cotton woods would do for forage . agri rose macaskie.

Being in Louisiana we have a problem with standing water. I've found the best tree to use in my area for soaking it up is the willow. It's a beautiful tree (especially the weeping willow). 

We have roughly the same problem, only that we don't have the luxury of loam but fill over swamp.
From what I would imagine is, that swales do make the soil only very wet in the swale itself and that it otherwise distributes the water evenly over dry spells. I might be wrong though.
The bushcare ladies told me not to dig ponds on the lower land where the swamp begins, but on the upper land. A pond can somehow dry out a swamp.
I still ponder around what to plant in our miniature paddock (400 m²).Maybe a walnut but I'm not sure if you can mound that much. And the tree gets very big.
I would always stay away from gum trees, unless you live in Australia. They have all the negative qualities you can think of. They are allopatic to most other plants, shed whole branches when it's dry or break in strong winds and are very bad in fires.
Do trees really drain land? I have my doubts, don't they rather hold a lot of water in the roots?

Swales are made for dry soils they have  a wider base than a ditch that has been dug to drain water off the land so as to increase the area in which the water is in contact with the ground and so increase the water that will seep in to the ground. In wet areas you have ditches to drain off the water.
 Trees all behave differently willows and poplars, are poplars called cotton woods in north America,? take up a lot of water ,other trees don’t take up so much, so it depends on your tree.
    Some trees have pores that will carry air down to water logged roots or even sticking out knees with pores on them  that take oxygen down to water logged roots, mangroves and such.
      What about swamp cypresses they are pretty trees, they make a exciting atmosphere to a landscape, they probably take up a lot of water and they are American. We have one in the Madrid park of the Retiro.
       Some trees bring up and evaporate a lot of water and others less, dry country trees are made to loose less water than willows say.
      Willows will kill willows planted at their side, in a garden say, were there is not much water, it is only along a stream you can have a line of them.

     I have a pot of papyrus. a sort of reed from Egypt , on my balcony and in summer i give it enormous quantities of water. I have the pot in a bowl and fill up the bowl with water. The papyrus don’t look sweaty they have a heard shine and look dry but they don’t half loose water, Maybe its all taken up to allow them to grow, they grow like crazy as long as they have a lot of water.  So some plants do evaporate off or lose a lot more water than others. Poplars grow like crazy too.

Cattails loose a lot of water too. They can be used to take arsenic out of water which they will absorb, plants can block out things they don’t want to absorb so itis not all plants that will take up and store things like arsenic..  Some soils contain arsenic and so the ground water is poisonous.
  The trouble with cattails for taking arsenic out of water in a dry place, the place i have heard of where they have a lot of arsenic in the water is parts of India, is that the cattails evaporo.-transpire off so much of the water that they can't afford to lose in this dry country. Maybe you need them in a green house where the water they sweated off would condense on the roof and return to the ground.

 Rocks and soils usually come in layers, with some permeable layers that water can sink in to and go through, so the land does not get water logged, like sand and some more impermeable layers  that the water cannot traverse and so sits on top of.
   Wet clay is pretty impermeable, just try making a pottery bowl and filling it full of water before  the clay bowl dries out, it will hold the water . If you get vegetable matter in clay roots, dead roots and bits of plant material, it could help the water sink through the soil and into other and maybe more porous layers of the earths crust.  
   Tree roots might widen cracks in impervious rocks like granite, making it easier for water to drain into the ground.

     People put drains under their fields if they live in very wet places and have undulating feilds with drains under the trough of the wave of the undulations to catch water and take it off to ditches.

 I suppose the whole body of the tree holds water but i don’t think they hold much around their roots.
 I have a photo of the roots of an oak in a quarry and they  have made their way through the rock and made what looks like earth in the space they have created in the rock a crack like that might hold water, the soil that has developed in the crack would.
 It has been proved recently that trees do hydraulic redistribution in the ground. When the ground is very dry the superficial roots and trees and bushes have a lot of roots that run  horizontally just below the ground lose water instead of picking it up and then the tap roots supply them with water . They have put instruments on roots that measure water flow to discover this and prove it . The flow of liquids reverses in a shower then the shallow roots take up their usual function of absorbing water again and the water is passed down to the tap roots. So they do store water to a certain extent in the soil. Look up hydraulic redistribution trees in google. The article I have on it, that I printed from a google article, has been shorten as I last saw it and is harder to understand.  
 I took a photo of willow roots, when a bit of the stream bed fell downstream, because they made such a tight mesh that it looked like they would mat up anything, I don't know what for  Trees by rivers are meant to keep the river flowing, I don’t know why. They shade it but they also transpire, do evaporatranspiration, so they lose water as well as stopping loss by shading rivers, so it would need a lot of experiment to find out how that all came out. Whether the shade that reduces the evaporation of the water in the river saves more or less water more than the tree loses transpiring.
 that the land around rivers is wooded does increases the amount of rivers around. They say that if you cut down the trees the rivers dry up. Wangari Mathai is one of the people who talks of this So does the Spanish writer Jesius Charco
  Mediteranean trees shut off their stomata at midday in summer so as to prevent too much water loss in the heat of the day. Agri rose macaskie.

what about chinampas? does any one have any experience making chinampas? it is a very interesting way of working in wetlands, but I have no idea about how are those made

webpage this is a link to very ineteresting info about chinampas and permaculture

Not all trees are suited to wet locations.  Look for trees that normally grow in riparian areas that are used to having their roots wet.  Many trees will not take this sort of abuse but trees from riparian areas are the exception.  I will strongly second the recommendation someone made to look at willows.  If you are trying to lower the water table I will suggest looking at golden willows.  Because of their mature size and the amount water they use they are the best choice I am aware of for this sort of thing.  Along areas like canals where seepage out into the fields raising the water table is a problem they are sometimes used reduce the water making it.  The other answer is a clay dike between the water source and your area.  Basically a long trench is dug and filled with packed clay to act as a barrier.  Be aware that if you are a long way from the water source the water may be low oxygen and even riparian area trees may have trouble with it.

As for the outhouse question having lived with an outhouse the flooded at times while growing up I will strongly second Pauls comment about avoiding outhouses but I will clarify.  Avoid dry sump type outhouses.  Wet sump style would be fine.  It is just a different system design.(a methane generator design would be fine too here)  In a dry sump outhouse it makes what is a slightly smelly thing into a stinky thing with a bug problem.  It is unpleasant.

For pasture grass in such an area I will suggest Garrison Foxtail.  It is hard to get established but where it has plenty of good water once establish it makes a good pasture grass.  We use it at the bottom end of flood irrigated fields here to prevent other weeds from taking over.