Consider that in order for enough things to be deposited to make it worthwhile, then a lot of people needed to have visited your "hole." I know they did...I take Sandmans advice and ask anyone with silver hair.
But, keep in mind that for the deposits to be there, the people had to GET there.
Ergo, look for road crossings, bridges, where roads ended at the water, ferry crossings, etc. And remember that where todays road runs isnt neccessarily where the older ones went. If you read pld newspapers, youll find that they often made the trip by bus, truck, etc in groups and went to places near the road, or not far from it.
You should search out wide spots to the side of the watercourse, accessible from the road where people could have parked buggy or car, picnic'ed and/or set up camp. Try also to envision the area without all of todays foliage. It would not have been there to hamper the earlier generation of water goers.