I have only seen crawdads in the water. Caught them all the time when I was kid.
That's how I grew up too - going out to the river to go "crawdaddin' " and then having a boil right there on the river bank. In fact, one of my most distinct childhood memories would be from just such a family outing (big outing - we're talking aunts, uncles, cousins - the whole fam-dam-ily) -- well, after the boil was over I was running around with some of the cousins and managed to run right through the hot coals that I forgot were there --- burned the snot out of my feet!