A key part of the effort to control flooding in Terrebonne Parish began operation Thursday. The Petit Caillou Lock Structure in Chauvin includes a 56-foot lock that allows boats to travel along Bayou Little Caillou even when the tide is abnormally high. And its floodgates can be closed during storms or strong Gulf of Mexico tides to prevent water from rushing in and flooding nearby homes and businesses. The structure, near Boudreaux Canal, will also help prevent saltwater from the Gulf from killing vegetation in surrounding freshwater swamps and marshes. Construction, which began in October 2018 and took 515 days to complete, is part of the long-running efforts to help control flooding in Terrebonne, Parish President Gordon Dove said during a ribbon-cutting ceremony hursday.