Kevin,
I think you've hit the soft underbelly with many of us. We're just glad this didn't happen to us. It is a nervous moment when the earth moving equipment arrives, you are now committed, and you just hope the hole holds water when they get done.
I sent you a PM with some additional ideas and contacts.
As for using concrete or and EPDM liner versus clay, the big issue would be cost. If you can't determine where the water is leaking out, you will have to line the entire 3/4 acre area. IMO, concrete or an EPDM liner, for that size area would be quite expensive. You may be able to find clay for free or very inexpensively. Even if you have to pay for it, it would probably still be far less expensive than the other two alternatives.
Regarding the sheepsfoot roller -- where I've lived for the last 40 years, it is not necessary. Heck, tractor ruts in my fields, after I bushhog, will hold water for a couple of weeks. Instead of your problem, getting a conventional septic tank and drainfield approved is rather difficult. Our land just doesn't perc -- in most places.
We put in two ponds on our place this past year. The 1/4 to 1/3 acre pond was compacted with a road roller after the dozer and trackhoe were done. It filled up a week later after a storm, and has stayed at full pool throughout this summer. The other pond was much smaller and will be used as a koi pond, maybe 20 x 50, and about 3-4 foot deep. It was excavated with a backhoe and small excavator. The pond itself was not compacted at all. The dam was compacted with the excavator tracks. It too has been near full pool since last spring.
So, as our good friend Bill Cody always says .... "it depends."
Good luck,
Ken
