Contamination raises costs of Valpo’s Thorgren Basin project
By James D. Wolf Jr. Post-Tribune correspondent October 24, 2012 5:36PM
Updated: November 26, 2012 7:15AM
VALPARAISO — Workers dug up a purplish soil with magnetic bits that stuck to construction machines while terraforming the Thorgren Detention Basin. The discovery of that industrial contamination raised costs on the project intended to help the environment.
The city employed a cost-effective method of containing high levels of arsenic, lead and chromium in the soil near the Canadian National tracks.
On Tuesday, the Valparaiso City Utilities Board approved the unexpected costs of handling the matter.
One was putting the contaminated soil into a planned berm — a soil barrier — near the tracks with a clay cap, similar to how landfills are sealed. That raised the $514,905 contract cost with contractor G. E. Marshall, of Valparaiso, by $22,063.
The other expense was hiring Amereco Inc. of Valparaiso as environmental consultants for basin area testing and to work with the Indiana Department of Environmental Management. That cost is not to exceed $18,466.
Deputy city engineer Adam McAlpine said because the original project came in less than engineering estimates, the project is still under budget.
“This is the perfect situation for berm material,” Amereco owner John Blosky said to the Utility Board. Unlike with chemical contamination, metals stay put when buried, Blosky said.
Amereco’s testing showed the contamination is high for a residential area but acceptable for an industrial area.
“To actually dig this out and haul it away is highly unlikely,” Blosky said, citing expenses.
His company is providing a remediation plan to IDEM and will work with the agency.
It’s possible that IDEM will want more testing, but Blosky said it’s more likely IDEM will simply categorize it and put restrictive covenants on the land should Valparaiso sell it.
McAlpine told the board that an older man watching the dig said the place had been used for dumping long ago, but no one knows where the material came from.
Terraforming the basin — reconstructing the land — is to protect the water quality of Salt Creek as it drains into Lake Michigan.
The former ditch now is two ponds that will hold storm water for it to cool and for plants to absorb pollutants.