Living with Dams: Extreme Rainfall Events | 2015
The risks associated with dam
failure and flooding in the US
continue to increase dramatically
as a direct result of the occurrence
of extreme rainfall events, local
land development and a failure to
adequately maintain or upgrade
Extreme rainfall events happen
almost every day, somewhere–
maybe not in your backyard or
above a dam in your community,
but around the country and the
world. Sometimes we see them
in the news on TV and sometimes
these extreme rainfall events get
names like Katrina, Irene, and Sandy
Can extreme storms happen?
or are referenced by location,
like Boulder, Colorado (2013) or
Pensacola, Florida (2014).
Climate experts put all the historical
extreme rainfall events into a
database to determine how often
they happen, how big they can
get and what the threat is for
individual communities. Experts
consider hundreds of years of data
at thousands of locations and
have a broad understanding of
the climate and the potential for
extreme rainfall events. They know
that extreme rainfall happens and
may be happening more often.
This booklet was prepared by the DamOwner Outreach Committee
of the Association of State Dam Safety Officials.
What Should Dam Owners Do?
• Follow proper Industry, State and Federal Guidelines.
• Have your dam inspected.
• Invest in routine maintenance and repair.
• Adhere to regulations (no shortcuts or exemptions).
• Don’t let short term band aids become long-term fixes.
• Have a plan for emergencies.
What Should Policymakers Do?
• Promote proactive dam safety programs that balance sound science and economics
with risk reduction and public safety.
• Recognize that adequately funding dam safety programs is the most cost effective
hazard mitigation available for private and public dams.
• Recognize that public welfare and safety supersedes individual hardships and ability
to afford the proper level of protection for dam safety.
• Provide funding mechanisms. Storage of water is a personal responsibility but often
requires public assistance due to the benefits realized by all.
Dam engineers use this climate
database to predict the extreme
rainfall events they use in dam
design. Mother Nature very often
surprises us with the unexpected
ferocity of her storms. Climate data
helps engineers to anticipate these
This publication will help explain
and justify the engineering
principles involved with predicting
the extreme rainfall events and
how they are used to design safe,
functional and economical dams.
It will connect the concepts of rain
to floods to dams to failure and the
flooding impacts downstream.
WHAT SHOULD DOWNSTREAM
• Know Your Neighborhood:
Who is at Risk?
• Ask: Is the dam upstream safe?
• Ask: Has it been inspected?
• Know who your emergency manager is.
• Work cooperatively to minimize the
risk to the public.