A surprise discovery on Third Street Thursday afternoon resulted in the closure of all four lanes in front of the courthouses and county administration building Friday.

Traffic was detoured all day so that the two blocks between Main and Coombs streets could be reconstructed with a more solid rock and asphalt foundation, said Barry Martin, the city’s outreach coordinator.

A contractor was in the process of grinding down three inches of asphalt Thursday in preparation for repaving when it was discovered that a portion of Third didn’t have three inches to grind down, Martin said.

A decision was made to reconstruct the entire two-block section of Third, Martin said. By closing all four lanes, the job could be done in a day rather than stretching out over multiple days, he said.

While vehicles had to be detoured onto nearby streets starting at 6 a.m., traffic was much lighter than normal Friday because of the three-day Memorial weekend, he said.

Third reopened late Friday afternoon. This weekend motorists will be traveling on a new layer of asphalt, with base rock repaired as necessary, Martin said.

Next week, the contractor will complete the job with a 11⁄2 inch top coat of rubberized asphalt, Martin said.

Also, grinding, patching and repaving will occur on the remainder of Third from downtown to California Boulevard and between Burnell Street and Silverado Trail./Register