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22
Jul
2011

By JON ERICSON, jonathan.ericson@wcfcourier.com | Posted: Sunday, June 19, 2011 4:00 pm

CEDAR FALLS — The University of Northern Iowa is the most conspicuous and largest landowner in Cedar Falls. The college is also the leader in attempts to reduce effects on the Dry Run Creek watershed.

UNI has completed a dozen projects designed to improve water quality. Two of the largest were under construction last week.

The latest effort includes installing asphalt and paving bricks in two large parking lots to allow water to soak into the soil rather than rush into the creek and wetlands.

The massive lot north of the UNI-Dome and Wellness and Recreation Center represented a perfect place to try permeable asphalt. For one, the sheer size of the area — eight acres — means copious amounts of water run off when it rains.

Secondly, the area drains directly to a new wetlands project and ponds to the north. The area is intended as a prime spot for learning and recreation, in addition to holding floodwaters along the University Branch of Dry Run Creek.

The other project is in the parking lot of the towers dorms downstream along the same creek. In that case, the permeable surface is paver bricks.

UNI first worked with the permeable pavement in a parking lot outside the McLeod Center back in 2007. In that case, the material was concrete, and the results have not been what officials hoped.

Paul Meyermann, head of facilities planning at UNI, explained the situation.

“It performed well in terms of infiltration, but we’re not real happy with it because the surface deteriorated,” Meyermann said. “We’re a victim somewhat of being one of the first to try it.”

Monica Smith, manager of transportation engineering at Robinson Engineering, is dealing with the asphalt project. She said the asphalt is much easier for construction crews to work with and does not require special techniques to apply, unlike pervious concrete.

The asphalt relies on a different mix, one without sand that binds small rocks that make up asphalt. As a result, the pavement has small crevices water can infiltrate and sink through to layers of gravel and rock under ground.

“It kind of has a Rice Krispie treat texture,” said Phil Schuppert, watershed conservationist with the Black Hawk County Soil and Water District.

For decades, the goal of engineers was to get storm water off properties as soon as possible. For nearby waterways, like Dry Run Creek, such philosophies led to erosion, elevated temperatures in the water and a hostile environment for wildlife because of lower water quality. Projects like these at UNI are designed to gradually make Dry Run Creek healthier.

The asphalt strips in the parking lot are designed to capture all the water from a 1 1/4-inch rain event in a 24-hour period. Total cost for the two parking lot projects amounts to about $350,000, with 75 percent paid through a Department of Natural Resources grant.

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