Starting a 5 acre forest garden - need advice on earthworks

Hey I am new to this forum.  So hello.  So I have lots of questions.  A bit of background on me.  I am a grower of produce.  I supply 4 restaurants, 2 farmers markets and a recently opened farm market.  I work at it full time.   I have 25 sheep and have 75 egg layers currently.  I have a greenhouse and I am putting in 4 cold frames this year.  I have a 5 acre pasture beside my house that has a limestone shelf that runs through it.  The dirt is thin and the rocks are plenty.  My plan is to convert this 5 acres to a thriving food forest over time.  
     I have attached a topograph map, a rough lay of the land of my farm, and roughly the way I anticipate my contour Swales to go in the third picture.

My goal this year is to install Swales on contour over this 5 acre parcel of land so that I can modify the flow of water next year before doing anything else. Things like changing Swales and putting in a pond or depression if there is standing water.  My question about this is where do I put my swale over a limestone shelf with not much dirt.  Above the thin soil, below it or right on top?  My goal is to build the topsoil over time In These areas.  They are. Fairly visible in my birds eye view photo.
     My short term goal for this area is to have pasture in between my Swales to run my sheep in contained with electric fence and to have chicken tractors following the sheep on a rotation through the pasture.  I want to then start planting fruit trees, nut trees and fruiting bushes.  I also want to plant a lot of nitrogen fixing trees near the start of this.  This is my roughly 5 year timeline.
     Long term as trees mature and pasture strips become not as good I plan to let it fill in and add trees and shrubs to grow at different stages as a true forest.  I will likely be dead or an old man before my vision is more or less recognized.
     Currently I need advise on Swales and holding water on my land.  Down the west fence there is a drainage ditch that runs  all the uphill water off into the road ditch.  I could build a dam to either run that water onto my land or have it run as it is depending on the precipitation amount of each year.  This year there is so much rain that my field would be flooded like no other.  Another consideration I have to think about is that all my fields have big O pipe installed to drain water off as fast as possible.  This may be an issue to hold water on my land.  Thanks in advance for any input.

The flow of water on my property is this.  Along the west side is a ditch that drains water from north and west of here.  Following the lane out back there is a limestone shelf that cuts diagonally across my property.  The water follows the lane on the left mostly to a ditch which runs water off the property.  It needs to be able to drain in the spring but I want to be able to collect water through the rest of the year.

My other photo shows my loose vision of what I want my forest to look like in the near term.