The Yadkin River produced wide and rapid turbidity swings that regularly challenged the city of King Water Treatment Plant operators. Turbidity on dry days averaged 6 to 8 NTU, but heavy rains could raise levels to 800 NTU or higher within 30 minutes.The operators at the plant in northeastern North Carolina ran six-beaker jar tests and then waited for the results, which could take an hour or so. “By then, the water we were testing had passed through the flocculators and was on its way to the filtration basins,” says Ben Marion, plant supervisor. “During storms, we fed alum as
