The sinkholes opened up a few months ago, condemning some of the homes on the 1400 block.
The report comes from engineering firm Gannett Fleming. It shows there are several fault lines under the street, and the area surrounding that block is also fragile, but stable.
The city says it will cost $4 million to fix the problem.
In the meantime, crews are monitoring the area. They paved the road last week to keep rain and snow off the sinkholes, which could aggravate them. But it's too dangerous to drive on the street and it remains closed.
"With the heavy rain, the road is doing exactly what we intended it to, and that is carrying the storm water off the road and into the inlets," says city engineer Wayne Martin.
The city is applying to the county, PEMA and the federal government for emergency grants to cover the cost of the repairs.