The Cupertino city council unanimously approved an emergency response plan to respond to a full or partial failure of the Stevens Creek Dam on Oct. 16.
Jim Yoke of the Santa Clara County Fire Department said the public education campaign that is part of the plan will tell people who live in areas that could be flooded in the case of a complete dam failure to immediately move to higher ground if there's an earthquake.
"You don't need to wait for someone to tell you there's a problem with the dam," Yoke said. "And it's our belief that the odds are that there won't be, but better to find that out from high ground than find out otherwise."
Yoke said in the case of a complete failure, water would move along a narrow channel north before hitting Highway 280 and spreading out.
Councilmember Gilbert Wong expressed concerns over how well informed the public is at present, directing his concerns toward Yoke.
"If it were to happen tomorrow, there would be problems," said Yoke. "Because the general public has not been provided any educational information yet."
Addressing Wong's concerns, director of administrative services Carol Atwood said the city already has a system to alert people in the inundation area and will run a drill on Oct. 27 to test its effectiveness.
Cupertino resident Cathy Helgerson urged the council to distribute maps educating the public about where high ground is.
"I don't know if I'm high ground," she said. "I'm behind Target, I always assumed I was high ground, but we need to start putting maps out so people know where high ground is."
She also brought up concerns about mercury pollution in the Stevens Creek Reservoir from Stevens Creek Quarry and the Lehigh cement plant. She said the pollution contaminates drinking water and has resulted in sores on the top of her head.
Frank Maitski, deputy operating officer of the Santa Clara Valley Water District, said heavy metals like mercury and bacteria get filtered out as the water makes its way to the aquifer below.