Being a river smallmouth bass addict, I chase the "pound-4-pound" champ more than most guys. I'm blessed to live in a place that has several quality smallie rivers around me that affords me the opportunities to chase them with a passion.
While I enjoy trout fishing, no fish compares to the grit and sport of a river smallmouth bass on the fly rod (to me).
I've taken several friends who were great trout fishers on float trips for smallies only to have them almost strike out while I was smackin `em. Not that I am a better fisherman than anyone I've ever fished with but over the years, I've learned where to find the fish at certain times of the year, what techniques work for that time frame and what flies to toss. It's just experience, not talent...LOL. I've read several comments that smallie fishing isnt much different than trout but I gotta disagree. Effectively fishing a smallmouth bass river takes a different mind-set and outlook on targeting the river. Yeah, some of the same techniques are used but more differences than so.
I agree with what someone above wrote, most rivers are better fished from a drift boat, pontoon boat, cataraft, etc. However, I have seen so many guys approach the river in a toon just like they would while trout fishing and continously spook off fish, or float into areas too close with the mindset that bass are not spooky like trout. I tell my friends new to smallie fishing "always be looking ahead, never float too close into a section you think holds fish until you cast to it first!" Simple but common mistake I see often.
Structure! Structure!! Bass love structure. Not just structure you can see sticking out of the water either. Look for cover underwater, anything that will break the current and offer an ambush spot for the fish to dart out and grab food.
Early spring, slower water, deeper. Summer, warm water time, think disolved oxygen, like riffles and faster, shallow water. Still searching for structure too.
Big flies too. Guys new to smallie fishing are "usually" undergunned in flies and rod weights. The heavier rod weights are not necessarily needed for fighting the fish but for tossing the big, wind-resistant and heavy flies to the fish. I carry nothing smaller than a 6wt, and fish a 8wt probably more. I've had friends show up to fish with their 4wt and a box of trout flies. They had fun with panfish but had a hard time enticing a smallmouth bass. When I gave them a #2 Clouser, they got binged in the back of the head a couple times while "chuckin-n-duckin" trying to cast a heavy fly on their 4-5wt.
River smallies are a blast, an itch I can never seem to scratch and dont want to.