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University of Iowa News Release


March 2, 2007

UI To Dam Iowa River For Chilled Water Project

The Iowa River will soon be parted, but Charlton Heston has nothing to do with it.

Half the river will be dammed for about two months while work crews connect the University of Iowa's east and west chilled water plants so buildings on the UI's east campus can remain cooler in the summer.

Preliminary work is expected to begin on the North Chilled Water River Crossing Project on Thursday, March 8, and wrap up in early May. Information about the project, including a Webcam, is available online at

Currently, the east and west campuses are served by separate chilled water plants. The west campus plant recently increased its capacity to 35,000 tons of water. But the east campus plant's capacity is only 7,000 tons, a number the UI came close to exceeding during last year's especially warm summer.

"If it weren't for the energy curtailments last year, we probably would have exceeded our capacity, and air conditioning systems would have had trouble keeping up with demand," said Chris Varo, an engineer with Facilities Management and manager of the project. "The further out buildings are from the plants, the less able they are to maintain cool temperatures when we're at peak capacity."

With more UI offices moving into the University Capitol Centre and the upcoming completion of the UI Chemistry Building renovation, demand for chilled water is only going to increase, Varo said.

To meet that demand, crews plan to connect the east and west plants with pipes that run underground, beneath the Iowa River. But to excavate the river bottom, they first must stop part of the river.

Using sheet steel pilings, workers will form a horseshoe-shaped barrier - called a "cofferdam" -- on the east side of the river between the Iowa Avenue bridge and the CRANDIC railroad bridge. Once the cofferdam is enclosed, crews will drain the interior water so they can dig into the riverbed and begin laying the two 36-inch pipes that will connect the two chilled water plants. The cofferdam will then be dismantled and relocated to the west side of the river for work to commence there.

In preparation for the project, UI contractor Helms & Associates surveyed the river bottom to ensure that no endangered mussels would be disturbed. Amid the broken bottles, rocks and other detritus, the consultants found four pistol-grip mussels and moved them out of harm's way, about 100 feet upstream.

Although traffic on the river is light in the winter and early spring, Varo said boaters should avoid the area of construction while the barrier is up. The presence of the barrier means the current will flow that much faster in the undammed part of the river and could catch boaters off-guard.

Varo said the entire project should be completed before summer, ensuring that all campus buildings have adequate chilled water.

"With this connector we can export chilled water from the west campus to the east campus to meet demands," he said. "This should solve the problem for the next 10 to 12 years, at least."

The chilled water project is part of a long-term, campus-wide commitment to ensure reliable and adequate energy for effective university operations.  That commitment was summarized in the recently released UI Energy Plan, which focuses on reliability, conservation and sustainability. The plan calls for sharply reducing the UI's reliance on non-renewable energy sources by 2013, unprecedented campus-wide participation, and a direct tie-in with the UI's research and educational missions. Under the plan, the UI Iowa is on track to save more than $5 million in reduced energy expenditures for the 24-month period ending in June 2007.

More information is available at

STORY SOURCE: University of Iowa News Services, 300 Plaza Centre One, Suite 371, Iowa City, Iowa 52242-2500.

CONTACTS: Project: Chris Varo, 319-335-5496,; Media: Stephen J. Pradarelli, 319-384-0007,