RiverGuide for Kayakers (link opens iTunes), by developer Wayne Daley, provides real-time streamflow information throughout the U.S. The app has a very logical layout -- the first screen you see breaks the country into seven regions. Tapping on the appropriate region shows a list of states, and then tapping on the state displays an alphabetized list of rivers or river segments. For each river, RiverGuide for Kayakers displays the time and date that the streamflow information was recorded, the cubic feet per second (cfs) that the river is running, and a wave icon signifying high, medium or low relative water level.
That's enough information to make sure that you don't arrive at a river with your kayak only to find that the water level is at a trickle. However, RiverGuide for Kayakers also has a built-in newsreader for getting the latest scoop on general topics (whitewater, Olympic, or sea kayaking, and American rivers), or regional kayaking news.
At $1.99, RiverGuide for Kayakers is an absolute bargain for kayakers, rafters, or even fishermen who can use the up-to-date info. Be sure to check out the gallery! And be sure to keep your iPhone dry while you're out there on the river with an OtterBox or AquaPac.