i am assuming that you are joking. Plenty of stuff will be running in may. especially southern colorado and New mexico. It all depends on weather of course.
There is a sweet new guidebook that covers colorado, new mexico, arizona, wyoming, and Utah that will be available in may. It is called "Whitewater of the Southern Rockies". Go to http://www.coloradokayaking.com
for more info.
if you need a book sooner than that, get "Colorado Rivers and Creeks"