Mid summer is here, and changes happen on many small waters. On streams where flows drop to the point of little overhead cover and higher in-stream temperature, fish move usually downstream to seek more cover and cooler flows in a main stem water. A good example is that fabulous little brook trout stream, Rock Creek off the Cave Falls Road. Here as waters drop and warm with mid summer, many resident brookies move down into Robinson Creek. The same also happens on lower Willow Creek. This part of the creek provides good early season fishing when flows between 50 and 100 cfs offer better living conditions than much lower summertime flows and warmer in-stream temperatures. So many fish move down into Ririe Reservoir. Streams with a more constant flow such as from springs (Birch Creek, Big Elk Creek, Henry’s Fork above Island Park Reservoir) or with upstream lakes that add sub-surface water(Palisades Creek, Fall River in Yellowstone Park) will not be impacted as much this time of year.