They will absolutely relate to cool water running into the lake. Doesn't have to be up the river either. Can be something as simple as a drain from a road or neighborhood rushing water into a lake. This is especially true in a situation like right now where we are getting rain water coming into lakes that are really warm. One of may biggest bags ever was on Granbury running areas that had water rushing into the lake after a big rain. Not sure if those fish are there for the cooler oxygenated water or for food but it really doesn't matter as long as they are in a feeding mood. Same concept is true up the rivers it just lasts longer and the inflow is on a larger scale. You do get to a point that the inflow may muddy up the water to a point that it shuts the bite off for a spell though. Timing is everything.