Planned renovations for the recreation center in Louisville, Colo., were complicated by a soil report, released Friday by Ground Engineering of Denver, that outlined the potential for significant subsidence and shifting soil on the chosen site.
The 45,000-square-foot project is to be built on ground with a mining history, where unknown fill soils along with high moisture levels could pose a long-term risk to the structure, making the process both more difficult and more expensive than expected.
The soil report states that any structure positioned "directly on the existing site soils are subject to likely, post-construction, vertical movements of eight to 10 inches as a result of heave and consolidation.” The potential for damage is a risk to all of the planned renovations.
In a staff report, Louisville director of parks and recreation Joe Stevens described a possible way of mitigating the problem by digging ventilated crawl spaces underneath reinforced flooring. The fix could drive the estimated $2.8 million construction cost up by an additional $1.3 million.
On Monday, Louisville city manager Malcolm Fleming told the Daily Camera that the report came as a surprise. "I don't consider it a setback," he said, "but it is new information that we have to respond to."
City officials are considering multiple ways forward, including shifting funds to cover mitigation from the city’s general fund, scaling back on other project features or applying for a grant from the Department of Local Affairs (DOLA).
Each of these options puts the city at a disadvantage by stretching the city budget or causing project delays. The final option would be to take the risk and hope shifting ground does not manifest in any major structural problems.
"It's a question of how much risk and liability the city wants to assume as the owner," Fleming told the Daily Camera. "We either mitigate it up front or say that we think, based on the conditions and experience and multiple opinions, it's a reasonable risk to assume."
In 1989, council members received similar soil reports concerning the construction of the original center. At that time, the city chose not to mitigate, and the structure remained sound for almost 30 years.
"It's an uncertain future," said Fleming. "We don't know that the soil is for sure going to move — the last time around, council decided to assume the risk and that judgment has paid off." The Louisville city council will make a final decision on how to proceed at their Tuesday meeting.