Colac population to hit 20,000 Share this:Click to share on Facebook (Opens in new window)Click to share on Twitter (Opens in new window) Contact the authorby Jennifer Chiu April 4, 2012 COLAC’S population could grow to 20,000 by 2050 under a plan for growth in the region. Unlock full access to Colac Herald - Subscribe today! Subscribe Now Share this:Click to share on Facebook (Opens in new window)Click to share on Twitter (Opens in new window) Tags: Business, Population