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Contaminated soil floods stormwater-basin project with cost increases

A budget originally calling for spending $14.1 million on a pair of stormwater drainage basins in a Milwaukee industrial corridor has lately increased to around $15.2 million.

On Monday, members of the Milwaukee Metropolitan Sewerage District gathered for a special session to approve a second contract modification related to the construction of a new stormwater-management system in the city’s 30th Street Industrial Corridor. The 30th Street Industrial Corridor is an 880-acre area on the north side of Milwaukee that is bordered by West Hampton Avenue to the north, West Highland Boulevard to the south, North 27th Street to the east and North 35th Street to the west.

Among other things, the MMSD contract calls for the construction of two new stormwater basins, 5,400 feet of storm sewers and a large box culvert. A separate contract will have a third stormwater basin built farther east of the other two, just across a set of railroad tracks.

Altogether, the basins will be able to hold 40 million gallons of stormwater.

MMSD officials this summer tapped Menomonee Falls-based Super Excavators to build the two drainage basins. With its offer coming to a little more than $14.1 million, the company submitted the lowest of the four bids received for the project contract in July.

Yet, since the sewerage district awarded the contract, an unforeseen need to dispose of contaminated soil has helped push up the project’s budget by $1.1 million. The MMSD found that building both the basins and box culvert would require crews to excavate and dispose of large amounts of soil. The soil being removed from the site has been classified by the Wisconsin Department of Natural Resources as being either “impacted material” or “non-impacted material,” depending on how contaminated it is.

Any soil deemed “non-impacted” can be safely reused. “Impacted” soil, though, must be taken to a licensed disposal site, said Jerome Flogel, a project manager at MMSD.

“Impacted material is required to be placed at a licensed facility, generally a landfill, and therefore is a significantly higher per unit cost,” he said in an email. “Non-impacted material can be re-used as fill material.”

The cost to transport and dispose of non-impacted material is $2.25 a ton, according to the MMSD report. For impacted material, it’s $30 a ton.

As Super Excavators started working on the two basins, they discovered that much more of the soil was impacted than MMSD officials had originally thought.

The first resulting cost increase totaled nearly $330,000 and was the result of the need to both remove contaminated soil and to move various utility equipment. Kevin Shafer, executive director of MMSD, was able to sign off on that cost increase without the approval of the commission because he has the authority to make contract modifications of up to $400,000.

The second contract modification, though, couldn’t go ahead without the commission’s approval.

The second change will cost no more than $774,000, and comes largely from the added costs associated with removing contaminated soil from the construction site, according to the MMSD report.

Since both the city of Milwaukee and the sewerage district are paying for the project, the two will also divide the bill for the cost increases. MMSD is responsible for all construction costs related to the stormwater basins, and the city is responsible for the rest of the stormwater infrastructure, Flogel said.

Of the $1.1 million in increased project costs, the city would be responsible for about $740,000, according to the report. The remaining roughly $360,000 would be paid for by the MMSD.

The new basins and other stormwater-system improvements are part of a plan to help prevent flooding during what’s known as a 100-year storm in the industrial corridor. A 100-year storm is one in which so much rain falls within a 24-hour period that it has a 1 percent chance of happening in any given year.

The last time Milwaukee saw a 100-year storm was in July 2010. The storm dropped about 7 inches of rain in a 24-hour period. The flooding caused about $32 million worth of damage, MMSD officials said.

Work began on the two basins began in August, and crews have since made “substantial progress,” according to the MMSD report. The project is expected to finish in July 2018.

About Alex Zank, [email protected]

Alex Zank is a construction reporter for The Daily Reporter. He can be reached at 414-225-1820.

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