All six lanes of the Septima Clark Parkway will be open to traffic Thursday morning.

Two of the lanes have been closed for about six months for the initial phase of a $154 million project to improve Crosstown drainage. The inner lanes going in both directions were shut for the work.

The project includes building a tunnel more than 100 feet underground to handle stormwater runnoff from the parkway that will be pumped into the Ashley River. All of the work is scheduled to be complete in 2020.