We may well have an underground spring we are not aware of feeding additional flow into it. The geology of the area is quite interesting with an area between West Branch and Rose City that is ripe with many artesian springs and oil wells. We have a brook running through the property that is spring fed as well as the watershed feeding it.
The rainbows were a blast for everyone fishing and a great draw for the family. I like your suggestion to mix it up a bit and add some brooks and browns to it. I have a fishery 90 minutes away, Cedar Brook Farms who has all of these and more. I contacted him today about a possible early April delivery.
Oh you are that side of the state! I don't know why I was thinking you were on the other side. I'm familiar with Cedar Brook and Jerry Kahn. When I studied fisheries way back in 76-78 at Alpena Community College we got our brook trout eggs from Jerry for the college hatchery.