Todd Barneck crouches near a trickle of storm water deep within the bones of the concrete Los Angeles River and gently lays in a thermometer. “That’s 16 degrees C, or about 60 degrees Fahrenheit,” he announces to the group. Wearing a knit cap and cargo pants, he moves from task to task, scooping water samples and snapping photos of trash, including a gold, high-heeled shoe found floating amidst a week’s worth of run-off surprises.