Why were combined sewer overflows started so early in the evening of July 22?
A. As heavy rains poured down, MMSD Executive Director Kevin Shafer decided he’d need to reserve even more space for the sanitary sewer area in an attempt to prevent basement backups. He started combined sewer overflows around 6:10 p.m. when there were only 150 million gallons in the tunnels, not the usual threshold of 200 million gallons. Sanitary sewer flows filled the tunnels later that night. This in turn started overflows from district-controlled sanitary sewers. Why did a large volume of water come into the tunnels after the district closed gates to the combined sewers? “Because water is getting into the separate sanitary sewers,” he said. Q. Is the deep tunnel system a success? A. “We’ve captured 86.8 billion gallons (of wastewater) since the tunnels came on line,” Shafer said. “All of that would have gone to the rivers and lake without the tunnels.” Studies show there have been dramatic improvements in water quality since the tunnels opened. In 1975, overflows from combined sew
