We have a river that feeds our lake here at home, I would call it an avg sized river. 70-80 yards wide in most places and averages 6-10 ft in depth until you get farther up river where it starts to turn rocky and impassable. At most any time of the year you can catch nice smallmouth farther up river but for some reason you cant catch them until it gets colder down around the mouth of the lake and they do not venture into the lake except for maybe a handful. Big debate among us that chase them is do they migrate up and down the river, I believe they do but there are many that believe they don't. Do you have smallmouth that you believe to migrate up or down a river system or do you believe they are resident to an area year around??