buying land on a Flood plain?

We are moving out to Wisconsin and considering purchasing a property with 12 acres. However, every spring a few acres in the back flood. The 100 year flood plain shows about 9 acres that flood. I was thinking about starting a large food forest/u-pick service. Possibly using Sepp Holzer's style of raised beds to try to lift some soil up out of the water if needs be. If I give the land plenty of ground cover and try to build the soil quality up, how much of my efforts would be washed away should a large flood occur? The flooding is a pretty stagnant process. The water slowly rises and slowly lowers. No swift currents. Any experience with flood plains out there? I also worry about runoff from other farms should a flood occur. Should I worry about a Roundup cesspool invading my land?

We have a flood plain across a big chunk of our land, the entire front area has been under 2 feet of rushing water a few times. Personally I would tend to avoid disturbing a flood plain, though if it just burbles up and doesn't rush you might be able to plant some trees and things between floods. You just want to make sure not to disturb large areas of groundcover. If you're concerned about contamination from neighboring farms I would leave it alone as far as food production, maybe developing it as a natural area for wildlife. So, I guess it comes down to do you really need that land for your plans, or can you adapt the plans to avoid messing with the flood plain?

Paul, It sounds like potentially an awesome adventure, but you are wise to proceed with caution. Here's my 2 cents worth - If the water rises and lowers very slowly as you describe, you shouldn't have much erosion at all, in fact you may only get deposition. You should be able to tell by looking over the site - is it badly eroded or not? The deposition could be quite wonderful potentially depending on what's upstream. Floodplains tend to be some of the most fertile soils in the natural world. If you time your annual plantings after the floods, you may have an automatic soil replenishing service for free. The EPA tracks water quality for just about every flowing stream in the country, and you should be able to access that data. A quick and dirty assessment would be to see if there are any fish contamination advisories. If there are, it may be draining a superfund site or something of that nature with high levels of some toxic substance. If there are no fish contamination advisories posted, that's a good sign, but you may still want to take a good look at the water quality data, or have it analyzed by an expert. You may want to grab a few samples, especially during flood events and have them analyzed. Many rivers in America have local groups who advocate for the protection of their water. They usually go by the name "Friends of the _______ River". Find your group and ask them if what you want to do is safe. In the US today, our rivers and streams are in the best shape they've been in for decades, thanks to the Clean Water Act and better farming practices. Many of the places I've lived (28 different cities) are making a concerted effort to educate the public about reducing fertilizer and pesticide runoff, and I believe things are generally getting better and better all the time. So, I'm optimistic about your plans. Nature cleans up our messes amazingly well, meaning that a good bit of the pollution is chewed up by the microbes. For that reason, if it was me personally, I wouldn't be afraid to follow through just because of a small amount of urban runoff upstream. It's real hard to find places anymore that are pristine. Please keep us updated on your adventure.

Thanks for the replies. As to the condition of the land right now it is plowed and ready for use by a conventional farmer. They current owners rent it out. My biggest fear is planting dozens of trees, blueberries, raspberries and the like and them sitting in water for a month before dying. It only floods for a month or so in the spring dude to snow melt. I would like to use a no till/ruth stout/ Fukuoka/holzer style but again worried about soil drifting away. I will look intothe river and fish, though it id more of a little stream on most occasions

I am understanding it better now. Trees and shrubs will die if they are flooded for a month. The site is much better suited for annuals planted after the spring flood subsides. If there are higher parts that dont flood they would be good for perennials.