Officials say traffic headed south on Broadway between Hildebrand and Groveland, near the AT&T building, will be reduced to one lane beginning Saturday.
Construction crews will begin trench work, which will require two lanes to close as a safety precaution.
The work is scheduled to finish in approximately one week, authorities said.
The open southbound lane will be shifted east toward the center of the roadway.
According to the City of San Antonio CIMS, electronic message boards have been in place during the week to notify motorists of the upcoming change. Area businesses and residents have also been notified.
Authorities said northbound traffic will continue to have two lanes open.
The Broadway Corridor Phase IIIA (Broadway-Hildebrand) project will provide a drainage system designed to convey a 100-year storm event across Broadway Street, improving driving conditions and safety along Broadway Street and Hildebrand Avenue.
The city said the project also includes reconstruction of Broadway and Hildebrand with curbs, sidewalks, driveway approaches, addition of turn lanes and traffic signal improvements.
SAWS and CPS Energy will be replacing and adjusting the water, sewer and gas facilities throughout the project area.
In addition, officials said the project includes the construction of the approved Broadway Street/Hildebrand Avenue underground conversion project as part of the CPS Energy CIED Program to bury all overhead utility lines at the four corners of the intersection.