^Do that. You can do this yourself, it's a very simple test. Get a handful of soil and roll it between your hands like play dough. It needs to be wet and have the consistency of play dough. Roll it between your hands and make a "snake". If it breaks off, it's sand. If it makes a big snake, it's clay. The more it smears on your palms, the more clay you have as well.
I have worked on some EPA wetland projects, so I can possibly help. I don't mean this in a condescending way, but "marsh" is a meaningless word, the same as swamp, slough, etc. The hydrogeomorphic (HGM) classification system
is the preferred way to classify wetlands, because it actually gives an impression of what's going on in the wetland. It sounds like you have a slope wetland or a "wet meadow
". I can tell you more about your options with more information:
1. Does the wetland occur on an incline, i.e. is there water seeping out of the side of a hill or sloping pasture? You've described this as occurring in an upland habitat, does it occur in a small basin or on the side of a hill?
2. If you PM me the coordinates in google maps I can tell you quite a bit more.
3. Which HGM classification would you give the wetland?
In OK, a lot of wetlands have been modified to hold more water or less water, which is a shame. A pond is not the same as a wetland, and ducks will prefer a wetland over a pond. I visited a pond down by the Red River where the owner had created a "duck wetland" (it was actually an impoundment, aka pond). He had the necessary modifications to control the water, and he planted some sort of exotic vegetation (milo, I believe). 200 meters away, there was a sand mining operation uphill which inevitably filled in his pond on a regular basis. He griped about the beavers "ruining" his pond (and he shot them), when he in fact ruined a perfectly good wetland that would have supported waterfowl. The absolute best small wetlands (<20-30 acres) are created by beavers because ALL of the water is ~2 feet deep which is perfect for dabbling ducks. They create tiered pools that are perfect for smartweed and duckweed (lemna). That landowner was throwing money and effort away, if he had just let it be it would have been perfect.
That's my word of warning/advice for this project. They seem great beforehand, but trying to create a wetland where it's not supposed to be usually doesn't work out. It won't work without a regular source of water and/or a high water table. Also, there are legal ramifications to modifying a wetland that is in the National Wetland Inventory. The Swampbuster program looks at aerial photography to see if people are illegally modifying/destroying wetlands without a proper permit (404 permit from the Army Corps of Engineers). Admittedly, that permit is fairly easy to get in OK.