A Campus Stream Finds a New Way

The noise of the buses and cars driving down Campus Drive are a constant reminder of Duke's urban setting, but a few steps away there's a quieter sign of nature.

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An unnamed stream slowly meanders under and along Campus Drive. Filled with water from 141 acres of watershed, the stream during a fall day is surrounded by the sounds of crickets, crows and a hawk in the sky above. The shoots of baby sycamores, dogwoods, maples, birches and ashes take root along its banks.

A year ago, before a five-month restoration effort of a 3,200-foot section of the stream, the scene was very different.

Years of fast-moving water sweeping off of roads and parking lots fed the stream, eroding it into a deep, narrow and fast-moving channel disconnected from its flood plain, said Ryan Lavinder, a civil engineer with Duke Facilities Management who supervised the restoration project. The stream was caught in a vicious circle in which the fast-moving water scooped out sediment as it traveled, incising the stream even deeper and ultimately leading to greater pollution of Lake Jordan, the end point of the stream bed.

The steep banks were an eyesore, filled with trash and concrete. They were also fodder for invasive species such as kudzu and Chinese privet, which adapt well to such environs but do a poor job of erosion control.

The stream's degradation might have continued except for a different project: the new Reclamation Pond near Erwin Road. That project, one of several that will boost Duke campus sustainability efforts, involved disruption of several streams. To win state approval, the university needed to either pay a large fee or earn mitigation credits by restoring streams elsewhere on campus.

"For years, the huge urban watershed compromised the stream," said Lavinder, as he walked along the central section of the stream.  Around him new grasses and plant life were taking hold in soft land that had been clear-cut last year to create a floodplain.

"In an urban setting, the velocity of the water coming off of roads and parking lots increases. The stream was never meant to cover this kind of velocity.  The water eroded the channel, and at the edge of the bank there was a sharp drop-off.

"Now along the stream we see a gentle slope, a slow, winding course, with the water spilling out into the floodplain.  We've had a year of heavy rain, and we've had to make a few modifications, but essentially the stream has successfully handled it."

Duke contracted with the local firm McAdams Co. to manage the project and to oversee the seven-year monitoring effort required by the state.  Josh Allen, McAdams project engineer, said the stream is in constant change, but the positive reaction of the stream bed to the heavy rains and the early success of the native plantings are positive signs.

"Streams are living things; they move around flood plain. Our goal in design is to account for that change and improve soil habitat and water quality," Allen said. "The state requires five to seven years to account for all this change before it declares the project a success.  But I think what we're seeing so far is great."

October is prime time for the annual monitoring effort done by McAdams in coordination with Duke Facilities.  Engineers from both units regularly check the land plots during the fall for the health of the planted trees and to remove invasive species, which grow faster than native plants and threaten to choke them off.

For amateur botany succession scholars, the stream will be something to watch.  Over the next five years, Allen said he expects small plants to dominate along the stream bank, while the tree samplings grow slowly.  Beyond five years, the trees will be large enough to tower over the plants and their growth will be secure.  Ultimately, ferns will likely take root in the ground underneath.

For now the wildlife activity in the water is limited to insects and water spiders.  But again, within five years Allen said he expects to see minnows returning.

"Part of the beauty is that you can come into an urban setting like this and create something that is beneficial to the environment," Allen said.

One beneficiary, Lavinder said, will be Jordan Lake.  With erosion carrying away less sediment, water quality from the stream to the lake should improve.

"The project's goal is water quality and protecting Jordan Lake downstream," Lavinder said. "Anything that helps water quality and reduces the sedimentation rate is a great benefit to the public."