# Dam Safety Terminology - Don't Panic: "Dam Spilling" vs "Dam Breaking"



## Andy H. (Oct 13, 2003)

*Dam Safety Terminology - Don't Panic: "Dam Spilling" vs "Dam Breaking"*

Hey Folks, I haven't been glued to the sensationalvision watching the reports of the Front Range getting washed away, however I've heard that the media is, as they like to do, getting the situation incorrectly out there. So some folks we may know and love are probably starting to freak out thanks to idiots on camera with microphones in hand.

As water rats, we may be asked by our friends what we think about the "dam breaking" up above town, or the possibility this may happen.

Sooo.... here's a note from the Deputy State Engineer about what to tell folks who may not understand the difference between a "Dam Spilling" vs a "Dam Breaking."

Takehome: Everything's OK so far with all the major dams.

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email from 9/13/13 to DWR staff:

It will help the public to understand dam safety terminology with
respect to a dam spilling and a dam failure:


When a dam fails, it is due to an uncontrolled breach, or break in the
body of the dam; we've had a few small dams fail causing only very
minor impacts; the large dams are all operating as designed at this
point.


A dam has an "emergency spillway" for just the current set of
circumstances: i.e. the reservoir is full, but more water is coming
into the reservoir than the outlet works can release. In this
condition, the dam begins to "spill", meaning water is being released
from the emergency spillway so that the dam will not be compromised by
the excessive inflow. This condition is a fairly infrequent, even
rare, event for most dams - so when it happens, the public generally
interprets it as a dam "failure". Just the opposite is true. This is
the condition that has prompted most of the media reports of dam
failure.


Scott C. Cuthbertson, P.E.
Deputy State Engineer


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