Editor's note: Summer is one of the best seasons to float a river, whether you do it by raft, kayak, or canoe. Greg Breining, author of Paddle North: Canoeing the Boundary Waters-Quetico Wilderness, and his wife, Susan, discovered that to be true while exploring the St. Croix National Scenic Riverway.

Paddling and drifting down the St. Croix, we came upon a group of three kayaks. Two were in an eddy, where a man gave advice to a woman whose boat teetered on a rock. Not far away, Peter Schofer, a retired French professor from the University of Wisconsin at Madison, paddled a kayak with not one, but two, rods — a fly rod and a spinning rod — sticking upright like masts, and such an array of gear lashed to his deck that his boat looked like a world-traveling sailboat.

This was his first trip down the river, he said. “We’re pleasantly surprised. You’re the first people we’ve seen.”

We were pleasantly surprised as well, for Schofer and his crew were among the few people we had seen — even though it was a weekend in mid-July, the peak of the season, when I feared the river might be overrun.

We might as well have been on a river far to the north. But we weren’t. My wife, Susan, and two friends had slipped our canoes into the river at Highway 70 east of Grantsburg, Wis., just an hour and a half north of the Twin Cities. We had spotted our friends’ car at the Nevers Dam Landing on the Wisconsin shore, 26 miles downstream. We planned to float and fish a few miles, camp overnight along the river, and reach their car the next day.

The St. Croix and its Wisconsin tributary, the Namekagon, are the only components of the national wild and scenic rivers system in either Minnesota or Wisconsin. Over the years, I had paddled the swift rocky reaches of the St. Croix near Gordon Dam, and the roller coaster waves of the river near the confluence with the Kettle River. I had floated on the near-continuous current of the Namekagon near Trego, Wis. Under other circumstances, we might have chosen one of those swift sections of stream to test our rock-dodging skills. But with the water at its midsummer low, those steep stretches promised to better hikes than paddles, so we opted for this deeper, slower section of the river.

It had been 20 years since I had paddled this stretch of the St. Croix, and I had forgotten how pretty it was. We bobbed down broad riffles through clots of islands. We saw hardly any cabins or homes, or any other development, just a solid screen of pine and hardwoods. Occasionally we scrubbed against rocks, usually because we were fishing and not paying attention. And the fishing was better than I remembered. As we paddled and drifted, Susan and I laid fly-rod poppers and streamers along the bank and in the deeper runs in the riffles, where smallmouth bass hammered them and tail-walked on the water.

Through the afternoon, overcast turned to sprinkles. Then the sky opened. Lightning, thunder and strong winds drove us to an island, where we rushed to set up a tarp to shield us from some of the heaviest rain I’ve endured. As the tarp strained against the wind, a stake occasionally flew from the soft sand, and I’d scramble around to find it and sink it again into the ground. A small group of the wettest kayakers I had seen paddled by and disappeared again into the gray rain. After an hour, the rain abated, the clouds broke apart, and the sun shone.

Back on the river, we floated through the afternoon. A pair of fishermen, each scooted around on inflatable one-man pontoons, as if they were giant water striders stroking over the glassy reflection of the evening sky. Then we found a campsite, a grassy opening beneath a spreading oak where we set our tents and roasted bratwurst over a campfire.

* * *

Beginning a lifetime ago, when I worked for the Department of Natural Resources on the state’s wild and scenic rivers program, I’ve try to spend as much time as possible on a river of some kind — kayaking, canoeing, usually fishing. I can’t think of anything like a river for personality, its ever-changing moods, and the suggestion that everything is somehow connected to everything else, that the rain in the forest links us to the sea.

And it is special to camp on a river. As bad as the mosquitoes can be — and this evening they were bad — sitting on the bank after dinner offers a chance to watch the river fade to night and to feel not the least bit rushed or worried.

To run a river is to feel freedom, and the ability to paddle back in time, to imagine the St. Croix the Ojibwa and Dakota and fur traders saw — that is, a river not so much different from how it appears today. It was 40 years ago this year that the St. Croix upstream from St. Croix Falls and the entire Namekagon were included among the original eight national wild and scenic rivers. The designation protected the rivers from further dam building and brought considerable federal resources in managing endangered species and developing recreation. (Not that Minnesota and Wisconsin should feel too congratulatory. Oregon leads the nation with 48 streams in the federal system, and Alaska has the greatest length — 3,210 miles.)

The designation of St. Croix does mean the river, compared with others in the nation, exists much as it did in centuries past. Even though loggers pulled tremendous volumes of white pine from the valley more than a century ago, the native vegetation has returned. The river looks wild and, well, scenic.

“There are a lot of rivers where you just don’t see that anymore,” said Kate Hanson, resource management chief for the National Park Service. Another sign of an intact natural ecosystem — more than 40 species of native mussels, including the rare Higgins eye pearly mussel and winged maple leaf.

As far as aquatic life goes, paddlers are less likely to notice mussels and more likely to see the river’s game fish, including walleyes, northern pike, even muskies. For me, nothing rivals the smallmouth bass in this broad, rocky stream. In two days, Susan and I had caught more than two dozen, though the largest ran only 15 inches. Among several northern pike, the largest ran about 4 pounds.

In our final hours on the river, the sun shone, illuminating the riverbed through the shallow water. As we drifted, we watched minnows in the shallows. Occasionally we occasionally surprised a big bass behind a boulder or a redhorse bulling up the current. Bald eagles, ever so much more plentiful now than when the river was designated, loafed in trees, looking for fish. Along shore, we spotted herons and kingfishers. On such a warm summer’s day, everything seemed humid, humid, verdant, and fecund.

As we paddled past Wild River State Park on the Minnesota shore, we finally saw more people — families along shore and out in canoes. Below Nevers Dam, a flood-destroyed relic of the logging days, we pulled ashore. The reveries of day and night on a river vanished to the mundane chore of loading canoes and gear aboard a waiting car.

If You Float the St. Croix

Planning: St. Croix National Scenic Riverway, National Park Service, www.nps.gov/sacn; 715-483-3284 or 715-483-2274.

Water level: Before you go, check river levels at www.nps.gov/sacn/planyourvisit/riverlevels.htm. The upper reaches of the St. Croix (Gordon Dam to CCC Bridge) and the rapids near the confluence with the Kettle River (Nelsons Landing to Soderbeck Landing) may be too low to run with normal midsummer flows. Downstream from Soderbeck Landing, the St. Croix is nearly always passable.

Upper reaches of the Namekagon may also be too low to run in low water.

Permits and fees: None needed to paddle or camp along the Namekagon or the St. Croix north of St. Croix Falls. (That’s even true of river campsites in state parks such as Wild River, though you need a vehicle permit to drive into a park.) Downstream of St. Croix Falls, stringent new regulations for 2008 require each group to get a yearly camping pass and bring in their own portable camp toilets or use on-board facilities on boats. See the National Park Service web site for details.

More Area Floats

While the St. Croix is the only Minnesota stream in the national wild and scenic rivers system, several state streams offer a pleasant multi-day float through rural and wild surroundings. Try these:

Kettle River: The Kettle, the first state wild and scenic river, flows through the forestland of east-central Minnesota. Points of interest include the ledges and rapids of Banning State Park. (Don’t run these with a canoe full of gear — or even an empty canoe if you don’t know what you’re doing!) Hiking trails through the park’s abandoned quarries is fascinating. Best stretch: Start at Highway 48 bridge east of Hinckley. Take out at Snake River Landing on the St. Croix. The most interesting parts of the Kettle — sections with rapids — aren’t much fun when the water is low. Check water levels at www.dnr.state.mn.us/river_levels.

Vermilion River: Running the Vermilion in remote northeastern Minnesota is a lot like tripping in the Boundary Waters. Short intense rapids, many requiring portages, punctuate long stretches of flat water. Some of the rapids are runnable when water is moderate to high. Several, for all practical purposes, are unrunnable. Fishing can be good for walleyes, northern pike, and smallmouth. Best stretch: The whole thing! It’s only 40 miles. Put in just below the dam at Lake Vermilion. Take out on Crane Lake.

Big Fork River: The Big Fork courses through forests of north-central Minnesota. Widely separated rapids and falls vary in difficulty from easy to unrunnable. Fishing can be good for the usual suspects — walleyes, northern pike, and smallmouth bass — as well as the occasional big muskie. Best stretch: town of Big Fork to the first Highway 6 bridge. In low water, try a stretch farther downstream.

Little Fork River: The Little Fork is in many ways the riverine twin of the nearby Big Fork — similar size, territory, rapids, and muskies. It does tend to run a bit more turbid and bog stained. Best stretch: Linden Grove (Highway 73 north of Hibbing) to Dentaybow near Highway 65. The route passes through a really wild section of river in Nett Lake Indian Reservation.

Crow Wing River: A clear, sandy tributary of the Mississippi, the Crow Wing flows through the farms and woodlands of central Minnesota. It has a few easy rapids, but is mostly placid — a terrific trip for inexperienced canoeists. There are plenty of accesses and campsites along its length. Best stretch: Mary Brown Landing southwest of Huntersville to Motley.

Zumbro River: The Zumbro carves a deep valley through the bluff country of southeastern Minnesota. Limestone outcrops and hills flank the stream. Fishing can be good for walleyes, catfish, and smallmouth bass, especially in the riffly upper and middle reaches. Best stretch: Highway 7 north of Zumbro Lake to Funk Ford.

Greg Breining writes about travel, science, and nature for The New York Times, Audubon, and other publications. His books include Super Volcano: The Ticking Time Bomb Beneath Yellowstone National Park, and Paddle North: Canoeing the Boundary Waters–Quetico Wilderness.