Not sure exactly what type erosion control problem / issue you are facing, but there is also a tool, (and dang if I can remember the name at the moment) that looks like a serrated disc, but the discs are all straight, and run in a straight line.
It is for use on slopes and "staples" or "punches" your straw down into the ground. I have only seen one or two of them out, fortunately, a guy that works with us has one and we share implements back and forth.
Anyway, if you are having an erosion problem (and I am guessing that you are from the 3" statement) then this is a way to get your straw to stay in place on a slope.
I can get the name off the side of it if you are interested.
Thinking about it, it may be called a Krimper, but maybe not.