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Living with Dams: Extreme Rainfall Events | 2015
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Ka Loko Case Study
Failed on March 14, 2006.
Killed 7 people with
considerable property
damage.
Privately owned dam on the Big
Island of Hawaii. Height 40 ft.
Storage 1200 acre ft. The owner
filled the auxiliary spillway
with soil. There was a lack of
maintenance, the crest was
uneven and there were trees on
the dam which hid the erosion
of the dam that had taken
place. The reduced capacity of
the spillway caused the dam to
overtop and fail during a large
rainstorm.
Boulder, CO Case Study
Flash Floods of 2013 -
More
than 200 dams were identified
as having been exposed to
rainfall with return frequencies
from the 50-year to over the
1000-year event. Nearly all of
those dams withstood the
event because they were held
to high standards.
Florida, 2013: A radar estimated that approximately 20 inches of
rain fell in the area in just 24 hours, with rates in Pensacola at one
point on Tuesday night reaching an incredible 6 inches in one hour.
Pensacola, Florida 2014
Case Study
One week in April, 2014.
The same widespread storm
system that set tornadoes
spinning across the landscape
from Arkansas to North Carolina
this week also deluged the Gulf
Coast from Mobile to Pensacola
with more rain falling in a
single day than both locations
usually see in March and April
combined. A radar estimated
20 inches of rain fell in the area
in just 24 hours, with intensities
in Pensacola at one point on
Tuesday night reaching an
incredible 6 inches in one hour.
Above: Upgraded dam with spillway operating
correctly.
Below: Inadequate dam design resulted in
devastating failure.