Town of Los Gatos Flood Evacuation Route Program
While the Lenihan Dam at Lexington Reservoir is considered to be structurally sound and is carefully maintained by the Santa Clara Valley Water District, the fact that the lake’s 19,000 acre feet of water is just minutes upstream from downtown Los Gatos, makes it a concern to Los Gatos emergency managers.
Built in 1952, the Lenihan Dam is an earthen structure that is designed to withstand earthquakes. Water District studies show that in the event of a catastrophic failure of the dam, with the reservoir at capacity, flood waters would reach Main Street in about six minutes, and would inundate nearly all of the area between Los Gatos Boulevard and North Santa Cruz Avenue/Winchester Boulevard.
Vasona Lake Dam
At 400 acre feet capacity, the Vasona Lake Dam represents less of a hazard to Los Gatos. Also an earthen dam, a catastrophic failure of Vasona would almost immediately inundate the portions of Los Gatos bordering Los Gatos Creek from the dam to the border of Campbell.
The Town of Los Gatos has developed a comprehensive program to address the threat to public safety that the possibility of dam failure poses. One of the final steps of that program is the installation of flood evacuation route signs, directing evacuees to the safe zones of Los Gatos Boulevard on the east, and N. Santa Cruz Avenue/Winchester Boulevard on the west.
The evacuation route signs have been posted on the east-west arterial routes of Main Street, Highway 9/Saratoga Avenue, Blossom Hill Road and Lark Avenue. In the event an evacuation is ordered, people and traffic west of Los Gatos Creek or Highway 17 would be directed to N. Santa Cruz Avenue or Winchester Boulevard. Those to the east of Los Gatos Creek would be directed to Los Gatos Boulevard. View Evacuation Map
After a significant earthquake the integrity of the dam would be evaluated. If the safety of the structure was in doubt, the evacuation of the flood inundation zone could be ordered. Evacuation announcements to the residents and business in the affected area would be made via the public radio and television Emergency Alert System (EAS,) Alert SCC reverse 911 system, by door to door contact by emergency response personnel, or by vehicle mounted public address systems. View from February 2, 2012.
In addition to evacuation route signage, the following other components of the plan have been completed:
- Training has been provided to Los Gatos/Monte Sereno Police by water district dam safety personnel on how to recognize and report post-earthquake damage to the dam.
- The Town of Los Gatos has incorporated a Flood Evacuation Plan annex which establishes evacuation zones and routes as well as incident command procedures.