My professor told me to always check the local bedrock before digging a pond
He said, 'The map says sandstone, but go look at the creek bank first,' and I'm so glad I did. I was planning a small pond on my property near Lexington, Kentucky, and a quick walk showed fractured limestone everywhere, not solid sandstone. That would have leaked like a sieve. Anyone else have a story about a geology tip that saved a project?
Dug a test hole for my garden pond a few years back and it was a total game changer. I was sure the soil was mostly clay but after digging down a couple feet I hit a layer of gravel that would have drained all the water out in hours. Ended up moving the whole pond ten feet over to where the clay was actually thick enough to hold water. Saved myself a world of hassle and probably a hundred bucks in liner materials too. The ground really does tell you everything if you just take the time to look at it.
@maxw34 your buddy dodged a bullet with that clay warning. I had a neighbor who built a garden shed on a clay layer and it shifted six inches after one wet spring. With ponds you can get away with a liner if the bedrock is wrong, but then you're fighting roots and freeze thaw cycles forever. The real trick is to dig a test hole and fill it with water overnight to see the actual seepage rate. I always keep a 5 gallon bucket and a shovel in the truck for that reason. You can read all the maps you want but the ground tells the real story once you get below the grass.