It's fitting that Red enters Idaho waters at the base of Palisades Dam. Without the Snake River's dozens of impoundments, there'd be no Famous Potatoes on the state's license plates. For that matter, without the moderating effect Palisades has on river conditions, there'd be fewer trout in this section—at least of the nonnative brown and rainbow variety. Boasting 7,000 trout per square mile and the healthiest native cutthroat fishery outside Yellowstone, this stretch—known as the South Fork, Red's third leg on her survey of the Snake—is one of the reasons I settled here. In summer, people make pilgrimages to this river; I prefer the seasonal periphery, taking advantage of the fantastic spring and fall angling. So far the early spring had provided some excellent action, but thirsty spuds downstream now need water and the dam has started releasing 500 cfs nightly. As a result, the water is a turbid green, making fishing challenging. The canoeing, though, is fine.

The three of us—me, my partner Kat, and our canus domesticus, Luna—clamber aboard the stalwart 17-foot canoe. Red easily swallows our pile of camping gear, and we launch into the tailwaters. A few undaunted anglers in boats are out, rowing, casting, and drifting. We cruise past massive vacation homes, rarely ever occupied, many of them offering realty brochures from their lawns along the rivers edge ("Angle for a little solitude! 5 br., 3.5 ba., wine cellar, hot tub, wireless. $1.8 mil. Call Debi.").

Red, an explorer by nature, urges us past the usual fisherman's takeout and into the Canyon stretch. Gliding into quiet wilderness, we leave the road far behind, and the canyon walls grow steeper. We're in what the U.S. Fish and Wildlife Service rates the most critical remaining intact cottonwood forest in the West, home to 126 bird species, including the largest bald eagle winter roosting area in the greater Yellowstone ecosystem. We find camp and put Red up for the night. We place some barley pops in the river to cool, bracing them against rocks for safekeeping. Our gear unpacked, we return, parched, to find they've vanished. All of them. "An offering to the river gods," Kat, the perpetual optimist, puts it. My response is less than spiritual. I spot a moose across the river, trying just a little too hard to act innocent. It avoids my suspicious gaze—a sure sign of guilt.

Come morning, we launch in drizzle and low-lying clouds; the canyon walls fade in and out of view. Luna's nose is working overtime; she's shifting from one side of the boat to the other, making the concept of balanced packing academic. Opting for a side channel, we drift in six inches of water, gazing at the upper reaches of the canyon. Then the chase is on—a flash of white tails on shore followed by a bolt of black lab over the gunwale. Both parties disappear, erupt from the high grass downstream, and swim back across the channel. I leap out of the boat, collar the hound, and too soon the canyon is in the rear view.

The landscape reclines and we're negotiating a variety of irrigation diversions—from old, crude spillways to the "great feeder," a large, rectangular beast that slurps up half the river's flow, and on at least one occasion, unwary boaters. Old farmhouses, large silos, and brand new John Deere combines become the dominant features of the landscape. We watch a family of six, crammed into a workhorse pickup, fly by on the dirt road next to the river, blond pigtails flapping out the window. It'd be easy to fall into the trap of lamenting the human impact we see on this lower section of the South Fork after being spoiled by the remote canyon. Instead, ravenous, we buy a pound of fresh local potatoes in the first small town we pass through and head home.