Works involve widening 52km of roads between the city's northern access highway and Carrera Séptima avenue.
As the Brazilian government creates a new sector watchdog, it also sets up mechanisms to keep political influence at the entity at bay.
President Vázquez also promised that the project will achieve its financial closure next month.
For decades, authorities have announces plans to clean up the highly polluted bay but with no success to date.
The two Chinese bidders want to avoid competing against each other while pursuing a bridge contract in Brazil's northeast.
City hall in Santa Marta and the country's housing ministry will instead focus on a series of short-term investments to expand the capacity of the existing water system.