Yep, Joe; I would MUCH rather have only a sealed bowl that catches rain. That's what the majority of ponds are. If you think about it, it is the same concept as a swimming pool; just a different input source. However, you are working with what you have. If the guy is right, and it certainly sounds plausible, you will probably be OK.
Gotta admit, during our last 8 years of drought, I would really like some handy groundwater. Especially flowing into the impoundment rather than out of it.
