Small Stone Dams Built on Mountain Brook Trout Streams

I see some small stone dams built on mountain brook trout streams. I assume the intention is to provide extra depth for the trout or a swimming hole for children. Actually, these dams can cause problems for the trout. They can block the free movement of the trout up and down the stream. I even saw several trout blocked in one pool last fall that were trying to spawn but the pool was all ledge bottom. I tore the lower dam out. The trout were spawning in the next pool downstream the following week. Just do not monkey with nature!