Maximum Slope and Flood Plains

Hi!  I have some property near a river basin on the south side of the property and along  the side of this which has initially something like a 15% slope and then a 4% slope higher away from the basin.  This area has clay soil in zone 7 and was planted in pines and should be timbered soon.  Knowing this, I am trying to think of ways to make use of this space ideally with something edible.  Plants in the flat portion of the river basin would need to be able to withstand a bit of flooding once or twice a year or if a hurricane came and so would not be suitable for livestock because of potential damage or grounding of fencing.

My goals are eventually to have some apple trees, grape vines, elderberries, blackberries, a garden, and one day later a cow.  At least that is my dream even though it is far off.

I am trying to think of ways to fit these things and use what is usable of the river basin as well as the slope.  My initial thought is that perhaps trees would be more suitable for a steeper slope, with the vines, etc being better for a lesser slope.   But then that would put the trees more south than the vines and they may shadow the vines, but maybe it wouldn't be so bad because they would be growing starting at a lower elevation...

1. What is the recommended and maximum slope for orchard (apple trees) or vines (blackberries/grapes/elderberries)?  And why is that recommended?  
2. What would you recommend given the things I would love to do someday?

I dont have an answer to your questions so I thought I would bump your topic to see if others might have answers.

I would suggest the use of swales, berms or terraces to keep the trees from washing away in the event of heavy rains.

Hi Tee,
I'm all for planting trees on slopes. The trouble with clearing all the existing trees is the risk of erosion. Hopefully you will be able to mitigate this somehow.
I believe a North facing slope is ideal in some climates for top fruit, especially if you are liable for late frosts. I understand the cooler aspect delays flowering, so damage is less likely.

At my place in northern Utah, the sun rises in the north during the summer, and sets in the north. Therefore, every side of a plant receives sunlight during mid-summer.

Tee,

I have seen very steep vineyards and have not encountered steep orchards yet, but it does not mean they do not exist.
There exists grape rootstock Vitis riparia or its hybrids that will stand the flooding and the high clay. The rootstock can be grafted with most available grape varietals.
The number of fruit tree species that will tolerate wet, clay conditions is quite limited.
Where are you located?

Thanks for all of your ideas.

I am in NC piedmont zone 7.  This area is the south edge of the property and the slope also faces south.  

My thoughts were that the main troubles would be maintenance of mowing (future planted grass in an orchard or vineyard) if the slope was too steep and the ability to dig in that area.  

That is a very interesting thought about the rootstock.  I hadn't considered grafting grapevines!