City of Ottumwa issued the following announcement on August 05.
This closure will allow for the replacement of settled brick pavers with new PCC Concrete. In addition to the intersection, the mid-block brick paver crosswalks too will be replaced.
Once the work has been completed in the Main and Market Street intersection, crews will move to the intersection of Main Street and Green Street. This intersection too, as well as the mid-block crosswalks, will undergo the same reconstruction.
During this work, motorists will need to seek alternate routes around the work zone. In total, this work is anticipated to take 3-4 weeks to complete, weather dependent.
Original source can be found here.