The Associated Press | A sign marks Good Earth State Park at Blood Run Creek in southeast Sioux Falls, S.D., Tuesday, June 9, 2015. An estimated 6,000 to 10,000 people lived 500 years ago in a vast complex of villages along Blood Run Creek and the Big Sioux River, the largest known in the Oneota cultural tradition and larger than any Lyon County town today. (Emily Spartz Weerheim /The Argus Leader via AP)

ROCK RAPIDS, Iowa (AP) — The planned route of the Bakken oil pipeline in northwest Iowa would lie near an area in Lyon County that archaeologists say was essentially the state capital for native populations from 1500 to 1700.

It's also near what state officials hope is Iowa's newest state park — and the nation's first bi-state park, managed with South Dakota.

The Des Moines Register (http://dmreg.co/21a5FBh ) reports that the issue draws attention to a little-known area of rich historical and cultural significance in Iowa's history.

An estimated 6,000 to 10,000 people lived 500 years ago in a vast complex of villages along Blood Run Creek and the Big Sioux River, the largest known in the Oneota cultural tradition and larger than any Lyon County town today.

"It's an amazing number for its time, and is one of the biggest population aggregates in the Midwest," said John Doershuk, Iowa's state archaeologist.

A sovereign lands construction permit for Dakota Access LLC pipeline construction in the area was issued in March by the Iowa Department of Natural Resources. But a stop-work order followed, because of possible disruption of a sacred site of the Sioux tribe to the south of Blood Run. Officials with several government and tribal agencies conducted an on-site investigation last week.

The Ioway, Ponca, Omaha and Oto tribes, all descendants of the Oneota culture, shared the area that became a settlement for economic reasons near spring-fed Blood Run Creek, named for carrying the red pigment of iron oxide after heavy rains.

The tribes were fleeing pressure from the Iroquois from the east in the 1500s and found a place where water, game and trade was plentiful. The western state border here is often thought of as the ecological and symbolic area where the Western plains begin. Natives gathered the soft red stone from nearby Pipestone, Minnesota, that was easily carved and valued by traders in the Midwest and beyond.

The tribes constructed numerous burial and ceremonial mounds and storage pits on the landscape. Historical maps show up to 200 mounds, but only 85 are visible today, Doershuk said.

The Sioux entered the area by 1714 and used it primarily as hunting grounds, but they were the last tribe there before white settlement.

In the 1800s, the mounds began to be destroyed by railroads, agriculture and "pot hunters" who dug them up, according to the book "Blood Run: The 'Silent City'" by Dale Henning and Gerald Schnepf.

Some farmers would plow over mounds and find hundreds of artifacts.

Native groups were friendly with each other along Blood Run. It wasn't unusual for a family to move in with another family for purposes of trade, said Henning, a former Luther College professor and archaeologist who lives in West Des Moines.

Henning's excavation of 150 to 200 storage pits in 1985 and 1986 found that they once held stored crops and hides and bones that told a story. Bison likely were so numerous that they literally walked through the village, Henning said. Studying the remains showed that the bison had been killed so near the camp, they had not even been dissembled to carry long distances before storage.

The study of burial and ceremonial mounds revealed human remains, pottery, bison bone tools and other artifacts from far and wide, because it was a major trading area.

In 1970, the National Park Service designated 873 acres as the Blood Run National Historic Landmark. But most of the land within it is in private ownership and in many ways can't be protected. In 1987, the State Historical Society, with assistance from the Iowa Natural Heritage Foundation, acquired a 230-acre tract that is now managed by the Lyon County Conservation Board.

But a study by the National Park Service suggested that the significant cultural resources of Blood Run cover a much wider area, and the agency has listed it as threatened on the National Park Service's Landmarks of Risk.

Henning said that all along the Big Sioux River down to Sioux City are likely mounds and native sites. The planned pipeline would now run about 10 miles south of Blood Run.

"But there are probably hundreds of sites along that pipeline across Iowa," he said.

Dakota Access pipeline officials told The Des Moines Register last week that if archaeological sites are confirmed along the route, the company will work with appropriate agencies to make adjustments.

URL

The sites are valuable for their national historic and cultural significance, state officials say, and also are sacred to native populations.

"This consequence of the expedited project is representative of a tribal apprehension regarding the Dakota Access Pipeline: the destruction of important cultural and historic sites," Dave Archambault II, chairman of the Standing Rock Sioux Tribe, said in a prepared statement.

Doershuk said archaeologists from outside Iowa were brought in by pipeline officials to initially investigate the route through Lyon County.

"My first response was, 'You know about Blood Run, don't you?'" he said. "To my horror, I had to fill them in."

Blood Run is an area valued by Iowa officials. Two years ago, the Iowa Legislature allotted $2 million for a study of Blood Run and acquisition of land for a future state park. On July 15, the master plan will be unveiled in nearby Larchwood.

The plan will not only include the existing national landmark boundaries, but other land to the north and south, said Todd Coffelt, chief of the Department of Natural Resources State Parks Bureau.

"In the area under the scope of study, it won't be impacted by the pipeline," he said.

He said the state is working with landowners on acquiring land, but it will take more money. Iowa is also "four or five years behind South Dakota." The neighboring state, which would join Iowa in management of the planned park covering both states, has established Good Earth State Park at Blood Run across the border and is building a visitor's center.

It would be Iowa's first new state park since Summerset State Park near Indianola in 2004. Coffelt said state parks were first established to protect natural areas, then created for recreation and in later years to save "areas of cultural significance" to the state.

Archaeologists remain concerned about the pipeline's path. Original boundaries of national landmark properties were quickly drawn after the 1966 National Historic Preservation Act and may not include all sensitive areas.

"There is at least one mound group to the south of Blood Run," Henning said. "So they're getting close."

Doershuk said he expects that, after officials meet with tribal leaders, "we will probably ask them to reroute, which should not be a big deal. They do this all the time."