Workers will place two dams in a section known as Lambert Beach, once a swimming hole in a crook of the river held up by a 1930s stone wall.
The garage is one of the few proposed changes to the park that survived a contentious public debate in 2016.
Mayor Ivy Taylor will host Tom Bacon, chairman of the Houston Parks Board, at Alamo Brewery on Thursday.
To the citizens who attended one or more of the eight public input meetings for the Brackenridge Park Master Plan: it seems your voices were heard loud and clear.
The Brackenridge Park Master Plan draft was presented and discussed at several public meetings across San Antonio over the last few months, but some community members fear implementation of the plan will forever change the essence of the city's largest urban core park.