WEBVTT - Can Beaches Be Saved by Adding Sand? 0:00:02.040 --> 0:00:07.040 Welcome to brain Stuff from How Stuff Works, Hey, brain Stuff, 0:00:07.080 --> 0:00:10.479 Lauren Vogel bomb Here in summer, there's nothing like feeling 0:00:10.480 --> 0:00:12.840 the sun on your face and the sand between your toes. 0:00:13.400 --> 0:00:16.960 But the rising sea levels and stronger coastal storms associated 0:00:17.000 --> 0:00:19.520 with climate change pose a threat to the sands that 0:00:19.560 --> 0:00:22.720 make up our beaches. A common approach to combating erosion 0:00:22.760 --> 0:00:26.040 at u S coastlines is beach nourishment, which is literally 0:00:26.120 --> 0:00:28.760 taking sand from one place off and off shore and 0:00:28.800 --> 0:00:32.760 pumping it onto a sand depleted beach. The question is, 0:00:33.000 --> 0:00:36.240 can beach nourishment keep up with the ever increasing forces 0:00:36.240 --> 0:00:39.680 of climate change, or, like Sisyphus forever pushing his boulder 0:00:39.720 --> 0:00:42.640 up the hill, is adding sand to beaches an expensive, 0:00:42.840 --> 0:00:46.519 temporary fix to a long term problem. We spoke with 0:00:46.600 --> 0:00:50.120 Bonnie Lutka, a post doc at Scripps Institution of Oceanography 0:00:50.159 --> 0:00:53.480 at the University of California in San Diego. She said, 0:00:53.880 --> 0:00:56.400 I think there's reason to be concerned, but I also 0:00:56.440 --> 0:00:58.720 think there's still a lot we don't know about how 0:00:58.760 --> 0:01:01.680 long the sand stays where it goes, and how much 0:01:01.720 --> 0:01:04.120 sand you need to place on a beach to be effective, 0:01:04.560 --> 0:01:08.000 or learning as we go. A study published by Luca 0:01:08.080 --> 0:01:11.880 in the June issue of the journal Coastal Engineering examines 0:01:11.959 --> 0:01:15.039 exactly what happened to sand deposited on four beaches in 0:01:15.080 --> 0:01:18.720 San Diego County in California. She and her colleagues used 0:01:18.800 --> 0:01:21.000 jet skis, a t v s, and other tools to 0:01:21.080 --> 0:01:24.400 continuously monitor sand levels and sand movement at the beaches 0:01:24.680 --> 0:01:27.800 over a period of about ten years. The research received 0:01:27.800 --> 0:01:30.240 funding from the U. S. Army Corps of Engineers, the 0:01:30.319 --> 0:01:33.920 California Department of Parks and Recreation, the National Science Foundation, 0:01:34.120 --> 0:01:37.839 and the California Sea Grant. Among their findings, the team 0:01:37.920 --> 0:01:40.360 learned that the entire amount of sand added to San 0:01:40.360 --> 0:01:43.440 Diego's Tory Pines in two thousand one was washed away 0:01:43.480 --> 0:01:46.840 during a single storm. At another beach, the addition of 0:01:46.840 --> 0:01:49.480 a hundred and thirty eight Olympic swimming pools worth of 0:01:49.480 --> 0:01:52.560 sand contributed to the clogging and eventual closure of a 0:01:52.600 --> 0:01:56.680 nearby estuary. Among the team's more positive findings was that 0:01:56.840 --> 0:01:59.640 larger grained sand appeared to have better staying power than 0:01:59.720 --> 0:02:03.080 fine grained sand, and in some cases, the amount of 0:02:03.080 --> 0:02:06.360 sand deposited to a beach by natural forces was comparable 0:02:06.440 --> 0:02:10.880 to any mechanically added sand Luca said, there is quite 0:02:10.880 --> 0:02:13.359 a bit of natural variability, so it's hard to pick 0:02:13.360 --> 0:02:16.200 out trends, but at our longest recorded site, we did 0:02:16.280 --> 0:02:20.400 see an overall pattern of erosion. The pattern of erosion 0:02:20.400 --> 0:02:23.280 that Luca's team observed at ground level is what's alarming 0:02:23.320 --> 0:02:26.600 to researchers assessing the long term future of US beaches. 0:02:27.520 --> 0:02:30.119 With climate change, sea level has risen by about eight 0:02:30.160 --> 0:02:34.560 inches that's twenty since nine, according to the Intergovernmental Panel 0:02:34.600 --> 0:02:37.480 on Climate Change, and could rise three to five feet 0:02:37.560 --> 0:02:40.399 higher that's point nine to one point five meters by 0:02:40.440 --> 0:02:43.960 the end of this century. More frequent coastal storms, also 0:02:44.000 --> 0:02:47.120 associated with climate change, take a further toll on beaches 0:02:47.160 --> 0:02:49.760 by unleashing rough waves that eat away at the shore. 0:02:50.720 --> 0:02:53.440 We also spoke with Michael or Back, Professor Emeritus of 0:02:53.480 --> 0:02:57.320 Marine Affairs and Policy at Duke University. He said, any 0:02:57.360 --> 0:03:00.840 beach nourishment is forever. It's like painting house. Once you 0:03:00.919 --> 0:03:03.760 start it, you have to keep doing it forever to maintain. 0:03:04.400 --> 0:03:06.919 The problem is with climate change, in rising sea levels, 0:03:07.080 --> 0:03:09.640 there's going to be even more demand by orders of 0:03:09.680 --> 0:03:13.320 magnitude because the beaches are going to erode more and faster. 0:03:14.040 --> 0:03:17.560 Western Carolina University's Program for the Study of Developed Shorelines 0:03:17.680 --> 0:03:20.920 hosts an interactive database of beach nourishment projects across the 0:03:21.000 --> 0:03:25.000 US and their costs. As the data show, beach nourishment 0:03:25.040 --> 0:03:28.560 today is not cheap. Or Bach estimates the average cost 0:03:28.639 --> 0:03:31.560 of supplementing sand at beaches comes out between one and 0:03:31.639 --> 0:03:35.400 two million dollars per mile of sand. As the demand 0:03:35.440 --> 0:03:38.440 for sand four beach nourishment increases, the cost will rise 0:03:38.480 --> 0:03:41.520 even higher. Or Bach predicts. He said, in the end, 0:03:41.640 --> 0:03:44.720 there may not be enough sand that's economically recoverable to 0:03:44.840 --> 0:03:48.360 nourish every beach that people want to nourish. There's also 0:03:48.400 --> 0:03:51.840 an ecological cost. Studies have shown that dredging and depositing 0:03:51.880 --> 0:03:54.480 sand is disruptive to creatures living in the sand and 0:03:54.640 --> 0:03:57.839 the animals that eat them. While the research suggests those 0:03:57.880 --> 0:04:00.680 animals tend to recover after eighteen months to two years, 0:04:01.000 --> 0:04:04.440 beaches that undergo repeated nourishment to see significant declines in 0:04:04.480 --> 0:04:09.640 animal life. Despite the economic and ecological costs of beach nourishment, 0:04:09.880 --> 0:04:12.640 it may be among the few available options for preserving 0:04:12.680 --> 0:04:16.720 beaches in the future. Sean Vita, sec and engineer specializing 0:04:16.760 --> 0:04:19.640 in ocean modeling at the University of Illinois and Chicago 0:04:19.960 --> 0:04:23.159 points out that natural sources of beach sand, including rivers 0:04:23.160 --> 0:04:26.200 and eroding cliffs, have been suppressed by human built dams 0:04:26.200 --> 0:04:29.760 and protective coverings. Vita Sex served as lead author of 0:04:29.760 --> 0:04:33.320 a March seventeen modeling analysis from the U S Geological 0:04:33.320 --> 0:04:36.480 Survey that concluded that if no measures are taken, up 0:04:36.480 --> 0:04:39.880 to sixty seven percent of California's beaches could be completely 0:04:39.920 --> 0:04:43.000 eroded back to sea, cliffs or coastal infrastructure by the 0:04:43.080 --> 0:04:47.040 year twenty one hundred. The U S Geological Survey models 0:04:47.080 --> 0:04:49.839 showed that beach nourishment could protect some larger beaches that 0:04:49.880 --> 0:04:53.640 have undergone nourishment for decades, but that overall beach nourishment 0:04:53.640 --> 0:04:55.640 will have to be stepped up to a much faster 0:04:55.720 --> 0:04:59.200 pace to continue to be at all effective. Vita Sex said, 0:04:59.560 --> 0:05:01.839 if you dump sand on a beach, that sand is 0:05:01.880 --> 0:05:04.800 not going to stay there forever, the current methodical rate 0:05:04.839 --> 0:05:08.440 of beach nourishment is insufficient against the coming sea level rise. 0:05:09.560 --> 0:05:12.640 Ludca said there is quite some debate about how climate 0:05:12.720 --> 0:05:15.960 change will influence the frequency and intensity of storms, and 0:05:16.000 --> 0:05:18.920 these storms will be more responsible for beach evolution than 0:05:19.040 --> 0:05:22.400 sea level rise in the next few decades. It may become, 0:05:22.480 --> 0:05:25.279 she says, a matter of choosing between investing in ever 0:05:25.400 --> 0:05:28.760 pricier efforts to preserve beaches or standing back and allowing 0:05:28.800 --> 0:05:31.680 nature's forces to redraw the lines of where the ocean 0:05:31.839 --> 0:05:39.640 meets the land. Today's episode was written by Amanda Onion 0:05:39.680 --> 0:05:42.240 and produced by Tyler Clang. For more on this and 0:05:42.400 --> 0:05:46.000 lots of other alarming but important topics, visit our home planet, 0:05:46.120 --> 0:05:58.640 how stuff Works dot com.