A map from 1968 shows the six-acre cemetery that could be disrupted by the rebuilding of Oak Park Avenue. [Northwest Chicago Historical Society/Matt Schademann)(left); DNAinfo/Heather Cherone]

DUNNING — Oak Park Avenue will be moved east to avoid unearthing thousands of bodies buried in a long-forgotten Dunning cemetery that holds the remains of Chicago's poorest and sickest residents who died between 1890 and 1912.

While preliminary work to rebuild the road began last week, construction will start in earnest July 11, and Oak Park Avenue will be closed to all traffic between Irving Park Road and Forest Preserve Drive, city officials said.

The project was postponed last year after DNAinfo reported warnings that the planned work could unearth thousands of bodies buried in a long-forgotten Dunning cemetery. As many as 10,000 bodies are under what is now Oak Park Avenue in Dunning.

Heather Cherone on the cemetery that will alter the look of Oak Park Ave.

Plans approved by Illinois Historic Preservation Agency, in compliance with the Illinois Human Skeletal Remains Protection Act, call for the roadway to be moved east — outside the cemetery — onto property owned by the city, according to plans released by the state agency.

The new storm sewer being installed for the road will now go around the cemetery, according to a statement from the Chicago Department of Transportation.

In addition, new lights will be installed on bases that are wider than they are deeper to avoid disturbing any remains, officials said.

The other planned improvements — including new pavement and sidewalks — will not extend more than a meter below the ground's surface and are not expected to interfere with any remains, according to the plans approved by the agency.

In addition, an archeologist will be on hand throughout the construction to monitor "unanticipated discoveries" as the work progresses. That person will have the authority to halt the work, according to the plans approved by the agency.

If human remains are discovered during the road work, they will be reburied in the Read Dunning Memorial Park after being examined and cataloged, according to a recommendation from Chicago Department of Transportation officials.

An exploratory dig carried out by a team of archeologists in July "confirmed a section of Oak Park Avenue built in the 1930s crossed a portion of the unmarked" cemetery, according to a statement from CDOT.

Starting in the 1850s, poor and indigent Chicagoans were buried by the county on 20 acres near Berteau and Narragansett avenues near the county poorhouse. The six-acre portion of the cemetery opened in 1890 near Irving Park Road and Oak Park Avenue, and about 17,000 people were buried there.

The cemetery stopped accepting most new burials after the state bought the 320-acre property in 1912 and built a mental institution.

It wasn't until March 1989 that construction workers building what is now the Dunning Square shopping center found "the top half of a remarkably well-preserved 19th century man, complete with a handlebar mustache and muttonchops," according to the Reader.

That led to the rediscovery of the cemetery — and ultimately the creation of the Read-Dunning Memorial Park to honor those who were buried there.

The rebuilt road will have three 10-foot travel lanes and a striped median to allow cars to make left turns. New sidewalks, lighting and buffered bike lanes will be built, along with curbs and gutters, paid for with $5 million from the Dunning Tax Increment Financing District.

[Chicago Department of Transportation]

A storm sewer system and vegetated swale will be built to handle flooding.That part of the project will be funded by Mayor Rahm Emanuel's $50 million Green Stormwater Infrastructure Strategy, officials said.

Torrential rains in April 2013 turned streets in Dunning into gushing rivers and left two to three feet of water in residents' basements for weeks.

The project is expected to be completed by the end of the year, officials said.

For more neighborhood news, listen to DNAinfo Radio here: