Work on the canalization of the Rio Grande river was initiated in 1906. In 1918, graphite industry wis established. 1920 marked the the first telephone connection. In 1927, São Paolo municipality acquired Pedreira, a suburb of Rio Grande, bringing new factories with opportunities for employment. In 1928, an electic pouer station wis built. Atween 1930 an 1954 mony sma scale industries, extensive housin facilities, mercatin centers an factories manufacturing aw kins o bien wis set up. Schools, sports centers, musical events, carnivals and religious festivals emerged. Efter aw, thir developments the toun, Rio Grande da Serra, wis gien the status of municipality in 1964. Population growth in Rio Grande da Serra wis slaw til the mid-1970s, whan there wis an influx of migrants, maistly miners whilk haes lestit til the day, though the increase is nou faain.