Weather, temperature, seasonal fishing patterns, forage availibility, light levels, and fishing pressure seem to be the most important factors in determining when and how fish bite in river systems, however if you have a stable weather pattern for 3-4 days then the Solar Lunar tables can come into play. The solar lunar effect seem to have more of an influence in salt water bays, lakes, and reservoirs than it does in rivers. I have noticed that I have caught many of my biggest trout during the prime times in the tables during a prolonged stable weather period.
Not all of the published tables are the same or are accurate. It took a while for me to figure that out.
Rivers and streams are unique systems and fish differently than other bodies of water. I think it has to do with fishing feeding during periods of stable water temperatures like in the morning when the river has stopped cooling from the lower night temperatures and has yet to start heating up from the warmer day time temperatures and the reverse in the evening when the river has stopped being warmed by the sun and has yet to start cooling down from the lower evening temperatures.