Just to emphasize the high variability in our area, just 1 mile from my pond in seemingly the same geology is a sand and gravel pit.(Bloomfield, NY). That sand and gravel goes seemingly on forever in all directions. Actually there are several pits right along rt5&20 very near me we order our driveway stone from. Somehow, at my house there is barely enough clay/pulverized limestone to dig a pond. It wasn't close to the house where I would have liked, but I got really lucky it held water at all further away (and yet I still complained that it leaked!).
The top of the hill near the house, the previous owners had a test hole dug, and I am told it was nothing but mixed cobbles under 2ft of light gravel mixed soils. a 5gal bucket of water would leave a wet spot the size of the rim of the bucket.
Anyhow good luck. TJ made a lot of useful suggestions with Soilfloc which slowed my seeps considerably when I applied it. Take advantage of his great advice!
If you have a variety of glacial stone types in your basin, quick get yourself a small 365nm UV flashlight with a filter for rock hounding. There are soda-stones (sodalite) in our glacial debris, and is actually worth a few bucks to rock hounds. Quarter-sized stones are selling for $45. Easy to find as they glow very brightly orange with UV, very cool rocks and the time to do it is at night after a light rain.
