I'm a RiverBrain fan too but just want to make a shout out for my fun side project Whitewater levels in the United States - Whitewater Map
It's a map with river sections color coded based on water levels. Orange = too low, blue = too high, green = just right. Click on a section and it brings up the link to the AW page.
Honestly though, in Colorado, gauges chosen by RiverBrain are much more accurate than the gauges chosen by AW. Go back east though and AW is the best source I know of (though kayak411.com was trying).