Residents concerned about the possible poisoning of Orange County waterways with herbicides have been making their voices heard on Instagram and pressured the county into holding a meeting on the issue. Their effort has exposed tensions between people who see the waterways as natural creeks and county officials who see them as flood channels. Brent Linas, a 41-year-old tech sales director in San Juan Capistrano, launched the Creek Team OC Instagram account after seeing changes on his runs along San Juan and Trabuco creeks. Lush green reeds in the channel had suddenly turned brown and lifeless, and birds had disappeared. Linas said when county officials ignored and brushed aside his complaints, he and others turned to social media. “We want an end to the use of herbicides in our creeks,” Linas said. “This idea that we’re just going to spray, hose down these creeks and leave them dead is unacceptable.” Brent Linas walks through foliage along the Trabuco Creek where no herbicide was sprayed. The account has gained more than 4,600 followers in three weeks. …