BrainStuff Classics: Can Beaches Be Saved by Adding Sand?

Beaches are eroding faster than we've ever seen. Some efforts to save them involve adding more sand from offshore -- but can that really work? Learn more in this classic episode of BrainStuff, based on this article: https://science.howstuffworks.com/environmental/green-tech/remediation/adding-sand-not-enough-to-save-beaches.htm

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff production of I Heart Radio. Hey
brain Stuff, Lauren Vogel Bomb here with a classic episode
from the podcast archives. Some of the effects of human
induced climate change are pretty familiar and obvious, changing temperatures
and weather patterns, But of course those effects have other effects,

(00:23):
and this episode is about one of them. More storms
means more sand is getting pulled from some beaches. Here's
one of the things that researchers are trying to do
about it. Hey brain Stuff, Lauren Vogel bomb Here. In summer,
there's nothing like feeling the sun on your face and
the sand between your toes. But the rising sea levels

(00:45):
and stronger coastal storms associated with climate change pose a
threat to the sands that make up our beaches. A
common approach to combating erosion at US coastlines is beach nourishment,
which is literally taking sand from one place off and
off shore and pumping it on to a sand depleted beach.
The question is can beach nourishment keep up with the

(01:05):
ever increasing forces of climate change, or, like Sisyphus forever
pushing his boulder up the hill, is adding sand to
beaches an expensive temporary fix to a long term problem.
We spoke with Bonnie Lutka, a post doc at Script's
Institution of Oceanography at the University of California in San Diego.
She said, I think there's reason to be concerned, but

(01:26):
I also think there's still a lot we don't know
about how long the sand stays where it goes, and
how much sand you need to place on a beach
to be effective or learning as we go. A study
published by Luca in the June issue of the journal
Coastal Engineering examines exactly what happened to sand deposited on
four beaches in San Diego County in California. She and

(01:48):
her colleagues used jet skis, a t v S, and
other tools to continuously monitor sand levels and sand movement
at the beaches over a period of about ten years.
The research received funding from the U. S. Army Corps
of an Engineers, the California Department of Parks and Recreation,
the National Science Foundation, and the California Sea Grant. Among
their findings, the team learned that the entire amount of

(02:09):
sand added to San Diego's Tory Pines in two thousand
one was washed away during a single storm. At another beach,
the addition of a hundred and thirty eight Olympic swimming
pools worth of sand contributed to the clogging and eventual
closure of a nearby estuary. Among the team's more positive
findings was that larger grained sand appeared to have better
staying power than finer grained sand, and in some cases,

(02:33):
the amount of sand deposited to a beach by natural
forces was comparable to any mechanically added sand. Luca said,
there is quite a bit of natural variability, so it's
hard to pick out trends, but at our longest recorded site,
we did see an overall pattern of erosion. The pattern
of erosion that Luca's team observed at ground level is
what's alarming to researchers assessing the long term future of

(02:56):
US beaches. With climate change, sea level has risen about
eight inches that's twenty since nine, according to the Intergovernmental
Panel on Climate Change, and could rise three to five
feet higher that's point nine to one point five meters
by the end of this century. More frequent coastal storms,
also associated with climate change, take a further toll on

(03:17):
beaches by unleashing rough waves that eat away at the shore.
We also spoke with Michael or Back, Professor emeritus of
Marine Affairs and Policy at Duke University. He said, any
beach nourishment is forever. It's like painting a house. Once
you start it, you have to keep doing it forever
to maintain. The problem is, with climate change and rising
sea levels, there's going to be even more demand by

(03:39):
orders of magnitude because the beaches are going to erode
more and faster. Western Carolina University's Program for the Study
of Developed Shorelines hosts an interactive database of beach nourishment
projects across the US and their costs. As the data show,
beach nourishment today is not cheap. Or Bach estimates the
average cost of supplementing, saye that beaches comes out between

(04:01):
one and two million dollars per mile of sand. As
the demand for sand four beach nourishment increases, the cost
will rise even higher. Orbach predicts, he said, in the end,
there may not be enough sand that's economically recoverable to
nourish every beach that people want to nourish. There's also
an ecological cost. Studies have shown that dredging and depositing

(04:22):
sand is disruptive to creatures living in the sand and
the animals that eat them. While the research suggests those
animals tend to recover after eighteen months to two years,
beaches that undergo repeated nourishment to see significant declines in
animal life. Despite the economic and ecological costs of beach nourishment,
it may be among the few available options for preserving

(04:43):
beaches in the future. Sean Vita, sec, and engineer specializing
in ocean modeling at the University of Illinois and Chicago,
points out that natural sources of beach sand, including rivers
and eroding cliffs, have been suppressed by human built dams
and protective coverings. Vita Sex served as lead off of
a March seventeen modeling analysis from the U S Geological

(05:03):
Survey that concluded that if no measures are taken, up
to sixty seven percent of California's beaches could be completely
eroded back to sea cliffs or coastal infrastructure by the
year twenty one. The U S Geological Survey models showed
that beach nourishment could protect some larger beaches that have
undergone nourishment for decades, but that overall beach nourishment will

(05:24):
have to be stepped up to a much faster pace
to continue to be at all effective. Vita Sex said,
if you just dump sand on a beach, that sand
is not going to stay there forever. The current methodical
rate of beach nourishment is insufficient against the coming sea
level rise. Ludca said there is quite some debate about
how climate change will influence the frequency and intensity of storms,

(05:46):
and these storms will be more responsible for beach evolution
than sea level rise. In the next few decades. It
may become, she says, a matter of choosing between investing
in ever pricier efforts to preserve beaches or standing back
and allowing nature's forces to redraw the lines of where
the ocean meets the land. Today's episode is based on

(06:09):
the article can adding sand to beaches save them? On
how stuff Works dot com written by Amanda Onion. Bran
Stuff is production of iHeart Radio in partnership with how
stuff Works dot Com, and it is produced by Tyler Klang.
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