craigdailypress.com

The evidence is in.

Colorado Northwestern Community College is planning to spend about $29,000 to remove subsurface water from the site of a proposed road extension on its Craig campus site west of Craig, CNCC president John Boyd said.

Plans to remove the water include installing a sub-surface drainage system and replacing wet soil with dry material. Together, the work is projected to cost about $10,000 less than estimated.

At a special meeting Thursday, CNCC board members approved a change order, or supplemental funding, for the work.

Last week, CNCC officials were waiting for further geotechnical studies before making a decision on a possible change order to its project that would extend Ninth Street to the western-most edge of the property.

Previous reports from NorthWest Colorado Consultants indicated that subsurface water on the site could negatively affect the proposed street extension. That risk still remains, said Hal Schlicht, NorthWest Colorado Consultants senior project engineer.

"If you don't take care of the groundwater situation, you could have some pavement failure," he said.

However, recent studies on the site indicate the situation may not be as dire as officials once thought.

"We came back from an extra week or two of drying time, just to see how the soils were doing, and convinced ourselves that some of the soils looked like they had dried out," said Dan Giroux, project engineer for the street extension. "They're probably more stable than originally it looked when everything was pretty wet."

"That's where the cost reduction came from," said Giroux, who is also land division manager for Diversified Consulting Solutions.

Some ground areas, however, will require more work.

A subsurface drainage system, measuring about 750 feet long and 6 inches in diameter, will be installed alongside part of the proposed roadway. Half of the plastic piping making up the system will be perforated, Giroux said, to collect water from beneath the thoroughfare and carry it to a nearby storm sewer.

About 300 tons of dry, stable soil will replace wet earth beneath the proposed road, he said.

Twin Peaks Utilities and Infrastructure will complete the additional work on the street extension. The Memorial Hospital contracted the Lafayette-based company to complete infrastructure work for a proposed new hospital facility, which is slated for construction on the same property where CNCC plans to build its new Craig campus.

CNCC has agreed to repay the hospital for construction costs collected during the street extension.

A drainage system can mitigate the subsurface water that engineers currently observe on the site, Schlicht said.

However, he cautioned that predicting future below-ground water levels at the site could be difficult.

"Subsurface conditions in general can be highly variable," he said, adding that moisture levels can fluctuate depending on the season and precipitation levels.

"When we see a problem, we make our best attempt to fix it," he said. "It doesn't mean that there might not be some other ground water that pops up."

A possibility exists that the drainage system could fail to remove all the subsurface water. In that case, Schlicht said, future below-ground drainage systems may become necessary.

"In general, you try to design for the worse-case scenario," he said. "You can't clearly define exactly what the conditions are because you never really know."

Still, Schlicht expressed confidence in the planned system's performance.

"If we didn't think it was going to be successful, we wouldn't have recommended it," he said.

Bridget Manley can be reached at 875-1795 or bmanley@craigdailypress.com.