Interactive map to view risk of flooding from dam failure in Los Gatos

The risk of flooding from dam failure in Los Gatos appears to be mainly from four reservoirs, all tying into the Los Gatos Creek at some point or another. Recently Clair found a great resource for better understanding this risk, and we wanted to share it with our readers.

The usual home seller disclosures include a natural and environmental hazard report, but the info does not go into deep detail. For instance, it may state that a location is in a zone of potential flooding from dam failure, but it does not tell the reader which dam it is. At times I’ve sold homes that were in that designated area but wondered whether the dam was a smaller or larger one (my concern being how much water could come through).

Now, more of those questions can be answered by visiting the state of California’s Dam Breach Inundation Map Web Publisher.

Dam failure flood zones in Santa Clara County

 

This site is very easy to use and to understand. The dams are marked with colors to indicate the downstream risk. Larger dams that spill into more populated areas appear to be those at higher risk, but perhaps they have a different formula for that designation.

Once you zoom in to your desired area (most counties appear to be participating, and MOST dams appear to be included in this publication), just click on the colored box and wait for the information to populate. It is sometimes a little slow, but after a few seconds it will appear.

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Is Your Home in a Dam Failure Inundation Area?

Vasona Lake dam in Los Gatos
Vasona Lake dam in Los Gatos

When Los Gatos, Monte Sereno or other Santa Clara County residents buy or sell homes here, one of the reports provided by the sellers is the Natural Hazard Report.  In it, there’s a statement as to whether or not the subject property is in an area of potential flooding if a dam were to give way.

In Los Gatos, most of the zones marked as potential flooding from dam failure are along the path of the Los Gatos Creek. Lexington is a good sized reservoir, so most of the risk comes from there.  Vasona Lake is far smaller, but there are a number of houses just below the dam (which, by the way, sits atop the apparently dormant county mapped Shannon Fault).

Most of us are somewhat “downhill” of a reservoir or two, but not everyone is in an area that would be flooded should the dam burst.

Town of Los Gatos Flood ZonesThe town of Los Gatos has a flood evacuation map and identifies a number of different zones. This map does not show ALL of the town, but presumably all of the areas at risk from flood from dam failure. To view it, click on on this link: Town of Los Gatos Flood Zones

There are maps for the county, as well. It takes some digging to find these things, and the best one I have found so far is not very easy for seeing the details, but it becomes clear that the largest risk is Anderson Dam, and after that it’s Lexington. Santa Clara County Dam Failure Inundation zones – go to page 95 of 223 

Santa Clara County Dam Failure Inundation zones