SIOUX CITY -- Beyond the traffic of Hamilton Boulevard and the winding roads leading up to Briar Cliff University, the tall grass drifts in the breeze like waves lapping against a shore. Out there on a high plain above the city, the wind blows and the sun shines along a ridge of the Loess Hills. 

This land just northwest of Sioux City is quiet, going unnoticed by many each day, explained Graham McGaffin, The Nature Conservancy of Iowa's associate director of conservation and Loess Hills programs. And that land that's deep with fine silt soil known as the Loess Hills just got larger. 

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The Nature Conservancy recently acquired the Hummel Acquisition, a parcel of land previously owned by Gordon "Curly" Hummel. The land stretches across a wide range of earth, 834 acres to be exact, of unbroken tallgrass prairie and dense woodland. 

"This project ... is one we've been working toward for quite a number of years," McGaffin said. "But it's done one project at a time."

The Hummel Acquisition is sandwiched between Stone State Park to the south and the Heendah Hills to the north, both of which are protected in part by the Iowa Department of Natural Resources. According to The Nature Conservancy, the three properties will now "create a complex of almost 3,000 acres of contiguous conservation land in an area of the Loess Hills facing increased development pressure."

"This is a tremendously important piece of ground that we know there's pressure to subdivide," McGaffin said. "Sioux City's growing ... we know there's pressure to excavate dirt for construction projects ... but it'd be a tragedy to lose precious, remnant Loess Hills prairie to do that."

Given the delicate structure of the area acquired by The Nature Conservancy, McGaffin explained that it is incredibly important that nature is given the space it needs to keep the hills and surrounding area preserved. 

"We're part of nature," McGaffin said. "What nature does is not disconnected to what we do. So we shape that story."

The Loess Hills are home to a trove of history. The soil has been accumulated over millennia from strong eastward winds blowing across the Missouri River. 

After the glaciers receded following the last ice age, large beds of mud were left in the area that is now the northwest region of the Midwest, the soil ground to a fine silt.

The strong winds dried out the mud and began to create giant dust clouds that swept the region. The heavier particles fell to the ground just east of the river. In time, that wind created what is now known as the Loess Hills. 

Because of this, the Loess Hills are extremely fragile and prone to erosion year after year.

The Loess Hills of western Iowa are so unique, in fact, that there is only one other area in the world with similar soil: the Loess Plateau in China.

For thousands of years, farmers in China have attempted to till the fine soil of the Loess Plateau hills in north central China. The result has been devastating, McGaffin said.

In fact, the Yellow River got its name from the soil erosion that polluted the river years ago. Now, scientists, like McGaffin who traveled to China with scientists from Iowa State University earlier in June, are aiming to change the tide in China and preserve what is left of the loess soil there. In the process, McGaffin said he's learning more about how to save the soil he works with back home.

"It's daunting, the challenges we face," McGaffin said. "But it's still done an acre at a time."