History is showing its face along the Minnesota River, thanks to the driest fall on record in the Twin Cities.

The river is so low that it's exposing large sandstone ledges and rapids for the first time in many years at a couple of spots between the cities of Carver and Jordan.

The "Little Rapids," also known as "Carver Rapids," are rich in history and one of the main reasons why the riverfront towns of Chaska and Carver were founded in the 1850s.

Jerrod Larson, who runs and hikes in the Louisville Swamp area in Scott County, said the massive outcroppings of rock in the Minnesota are impressive. The more dramatic stretch of rapids requires a 3-mile hike to view, he said, but another set is easier to access.

"A lot of the rest of the season, the river's too high or it's swamped out," Larson said.

The rapids are more than just landmarks. They are an enduring but largely forgotten part of history in what is now the southwest metro area.

"In the early years, rivers were the only roads, and steamboats couldn't pass much beyond Carver because of the rapids there," said John von Walter, vice chairman of the Carver Heritage Preservation Commission.

Passengers and merchandise heading upriver from St. Paul to New Ulm and Mankato had to stop at the rapids and transfer to smaller boats, he said, or continue their journeys by horse, stagecoach or oxcart.

The rapids and huge exposed sandstone bars are covered with water during most years and are sometimes barely visible for only short periods.

Larson and others said this fall is different, with rocks or rapids showing nearly all the way across the river.

The two stretches of rapids are about one-quarter of a mile apart at a bend in the river. At one location, the river falls about 2 feet, and at the other it drops a foot.

The upper rapids are reached through trails in the Louisville Swamp Unit of the Minnesota Valley National Wildlife Refuge.

The smaller rapids can be seen from the Carver side of the river by taking a short hike near the refuge's Rapids Lake Education and Visitor Center.

"It's a nice, peaceful area away from traffic," park ranger Leanne Langeberg said. "There are no houses in view, so you feel like you're almost in a wilderness situation."

Prehistoric settlements

Von Walter said that the rapids were a busy trading center in the mid-1800s, and prehistoric people lived along the rapids intermittently for thousands of years before that.

"Last time the river was this low, my neighbor and his daughter were canoeing at the rapids and he found a stone spear point sitting right on top of the rocks," von Walter said. "I think they pegged that at 8,000 to 10,000 years old."

In the early 1800s, a Wahpeton Dakota village with about 325 people was thriving near the upper rapids, and early European settlers established a fur trading post nearby in 1802. The late University of Minnesota archaeologist Janet Spector wrote a book about the village's 1830s culture, "What This Awl Means."

When steamboats began cruising the river in the 1850s, they could go no farther than the rapids during summer periods of shallow water.

To accommodate the trade, settlers built a town called San Francisco on the Carver side of the river across from the Dakota village.

"The town was of use only when water was low and the steamboats had to stop, so it wasn't a commercial success," said Paul Maravelas, former director of the Carver County Historical Society.

While the flat area between the river and its bluffs seemed like a perfect place for a town, he said, pioneers learned the hard way about the river's seasonal power.

"There was a big flood in 1863, and it pretty much carried everything away," he said.

Tom Meersman • 612-673-7388