Council briefed on unexpected soils, debris at Ridgeview Estates; change orders possible

Fort Atkinson city engineer Bert updated the City Council on construction problems at the Ridgeview Estates subdivision on Banker Road, saying crews discovered large areas of nonstructural fill and debris during early grading that were not identified in pre-construction soil borings.

Bert said the initial set of roughly 25 soil borings indicated suitable structural material beneath topsoil, but excavation found “nonstructural material, almost like a topsoil type material” that cannot be used under roads, driveways or utility backfill. He said crews also encountered “tree stumps, just trees in general, chunks of concrete” and even a loader tire pulled from the excavation.

The finding forced additional test pits and a search for cost-effective disposal or reuse. Bert told the council that designers found at least one parcel within the development with good structural material that could be used, and that landscape contractors have agreed to remove up to about 12,000 cubic yards of excess material at no charge.

“No action is requested tonight,” City Manager Hausman told the council, but he warned there “may be a change order or two relating to this.” Bert said the team is exploring on-site design changes to incorporate some of the nonstructural material (for instance altering grades or storm-basin locations) and is also evaluating whether some excess must be hauled off-site. He said the precise volume of nonstructural material is still being determined as excavation continues.

Council members asked practical questions about the location of the junk material, whether tires and other refuse would be buried, and whether work would continue during cold weather. Bert said the heavier “junk” items, including the loader tire, will not be buried in areas intended for infrastructure and that some loads were already taken to the city dump or to a site in Cambridge. He said most organic / soil-type material mixed with stump debris could be designed into an outlot or easement area near the northeast stormwater detention basin, but there still may be material that must be removed.

Bert estimated crews had hauled a small number of loads to the city dump and Cambridge and said stockpiling on-site remains under study; he described the situation as a mix of partial on-site reuse and some off-site disposal.

The council received the update; no formal vote was taken. Staff said they will return to the council if and when change orders are required.