Jeannie Sayers

OK - no expert here , but seems like you have two separate but related problems going on.

First handling the "intermittent " huge runoff that the clay creates in southern soils and second doing something to create a better soil environment. ?

Swales work , but involve knowing your land- walking it , feeling the contours and mapping it out- where are the areas the run off travels.? What can you do to send it where you want it to go? Why do you want to go it to that location?

Sit down where you want a swale and really look around.. think about it. Don't be in a hurry... If you don't like drawing it out - build a model - use your steps to measure approx. where things are - reduce it down- one step =one finger width .. LOL People learn in different ways...trust your land and your eye...

Our soil is clay base with sandy loam on top- have a similar problem. Our solution has been to build diversion swales into our pond and use raised beds until we can build enough good soil to help hold it- Winter rye has deep roots , that loosen the clay and add nitrogen to the soil. it can be cut and turned under in the spring.
We break the surface just enough to allow the good bio to contact the compost and soil we lay down- and let nature do her job. It is labor intensive and takes a period of time, but it makes your soil better, reducing the amount of runoff

We used metal roofing for rainwater cachement- and even though it tests "Drinkable" we till use it for household and garden only- our drinking water comes from our cave spring and is tested twice yearly--gravity flow to it's own spigot in the house. There are so many good filter concepts out there, read and read some more.. talk to people- see what has worked for them.

for us , the 24 inch snows we get and our desire to catch water steered us into the metal roofing. I would really like to do a living roof on our next building project.. wonder how well it would do at filtering toxins?

old timers here in the Ozarks used to always add a extra piece of pipe about four foot long , with a screw cap at the bottom for cleaning-which filled first catching the dirt/ trash and pollen , then the overflow- ie clean water - would go on into the barrel or tank... ?

Wow! have rural friends ho are loggers who can do that , but it is amazing nonetheless- good job,, but scary.. wow