Those who contemplate the beauty of the e ar ves of strength that will endure as long as life last th find reserarson s. ~R achel C
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The Dynamic Seashore The Shoreline Is a Constant Battle Between Mother Nature and Man
By Dr. Lenore Tedesco, Executive Director of The Wetlands Institute
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ndoubtedly, the love of our area is focused on the beaches of Seven Mile Beach. They are the cornerstone of so many memories, the provider of calm moments, and a keystone of the shore economy. When you spend time at the beach, it’s easy to notice the dramatic changes that take place constantly. Beaches have a seasonal rhythm that add to their mystique. Our beaches are also on a trajectory of change that is being driven by both the human engineering of the beach and dune system and Mother Nature’s will. As we welcome the promise of spring and the coming of another beach season, it’s fitting to talk about the patterns and rhythm of the beaches. The beach is a marker of sea level; think of it as zero elevation. It makes sense when you are measuring the height of a mountain relative to it but gets a lot trickier when you factor in the tides. A beach is also highly dynamic: Variability in the level of the water (tides) and the energy of the waves (seasonal and storm) means that the actual beach face is constantly changing. Wave energy moves beach sand – both onshore and offshore, depending on its strength. The higher the wave, the stronger the wave energy. During the winter, larger waves take sand from the beach. The beach is steeper, but the sand isn’t gone – it’s stored just offshore, often as a series of sand bars separated by deeper troughs. You can see them when waves break on them, even though they are submerged. During the spring and summer, when waves are gentle, the beach rebuilds itself. The sand stored in bars
Summer Profile High Tide Line
Wide Berm
Winter Profile High Tide Line
Eroded or No Berm Eroded Dune Scarp Sand Bar
Sand Bar
Steep Beach
Cross-section profile of the beach in summer and winter.
and troughs moves back and the gentle wave swash pushes the sand up onto the beach. Breezes blow the finer sand into the dunes, where vegetation traps it. Summer beaches are wide and relatively flat, and the bars and shallow pools make great places for kids to play – though the bars are constantly moving, so it is unlikely that they will be just where you remembered them. As sand moves onshore and offshore, it also moves to the south. Thus, rather than a zigzag pattern of sand moving on and off the beach, it is more of a sawtooth pattern, with sand moving offshore and south, and then back onshore even farther south. This is the repeatable rhythm of our beaches, creating narrow and steep beaches in the winter, and wide, gently sloping beaches in the
summer. If you only visit the beaches in the summer, you may not notice this. But for those who walk them year-round, this change is apparent. Superimposed on this regular rhythm of the seasons is the change caused by major storms – nor’easters, tropical storms, or hurricanes. During storms, the larger waves and storm surge push water higher onto the beaches and erode sand from both the beach and dunes. The beach works to protect itself by creating a broad, sloping ramp to spread wave energy, which again moves sand from the beach and dunes offshore into bars. However, these bars are usually farther offshore than the normal winter bars and can take longer to move back on to the beaches. During particularly large storms,
beach sand can also be pushed inland as overwash sand banks. Again, the sand also moves farther south with each cycle of offshore and onshore movement. You can feel this southward movement in the water that is carrying the sand when you swim or stand in the surf. There is a constant tug down beach; our beaches are actually like a river of sand. This is caused by how the waves break on the beach. They almost never break straight onshore, but rather at an angle, with the north end of the wave coming onshore and breaking first and the rest of the wave gradually breaking down beach. Thus, the sand (and water) on our beaches is constantly moving from north to south. This is one of the reasons the north end of Avalon is eroding and the south end of Stone Harbor at the Point is growing. The other big variable of our everchanging beaches is sea level. Remember, the beach elevation is a marker of sea level, and the tides rise and fall around this central point. Sea level has been rising since the end of the last ice age about 18,000 years ago. Along with this rise, the barrier islands – and their beaches – have been marching westward toward higher ground. When we established our communities on the barrier islands, our property ownership, homes, and infrastructure have effectively tried to set a fixed line with the beach. Our practices are trying to hold the beach in place. The problem is that beaches don’t behave this way. Sea level has risen nearly 1½ feet since the early 1900s and almost 7 inches since the 1980s – and it continues to rise. This is continued on page 72
Seven Mile Times
Spring 2021
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Study nature, love nature, sta y It will never fail you. ~Fra close to nature. nk Lloyd Wright
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Sand bars and troughs showing sand moving back on to the beach in the spring.
Storm waves eroding dunes that are protecting our community.
moving wave energy and the beach-shaping forces higher onto the beach – and because we are trying to hold the beach in place, it is getting narrower. Finally, with each beach replenishment project, we are intentionally shaping today’s beaches. These engineered beaches are shaped very differently than what Mother Nature would create. The flat beach is designed to be higher and the dunes much wider in an effort to
provide resilience. This design does provide resilience, but it does so on a relatively short-term basis. When storm energy has time to reorganize the beach to a configuration that matches current sea level and energy, it does. Thus, we find ourselves in a cycle where we have significant storm-driven beach erosion followed by repetitive beach replenishment projects. Every spring, the beaches reflect the natural cycle of sand depletion from
Winter beach showing eroded dune scarp and storm ramp. High tide will be at the base of the dunes.
winter storms, and the number and intensity of winter storms determines how much change the beaches will experience. Thus, the spring beaches are somewhat narrower, and await the calmer waves to help rebuild them with some of the sand held in offshore bars. Our beaches are wild and dynamic. For me, this is part of their beauty. I spend more time at the beaches when the energy is high and find my connection to that
APRIL TIDE CHART HIGH
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
Thu Fri Sat Sun Mon Tue Wed Thu Fri Sat Sun Mon Tue Wed Thu Fri Sat Sun Mon Tue Wed Thu Fri Sat Sun Mon Tue Wed Thu Fri
AM
FT
12:38 1:34 2:34 3:41 4:52 5:55 6:47 7:32 8:13 8:51 9:28 10:04 10:41 11:18 11:57 12:05 12:46 1:34 2:31 3:36 4:44 5:46 6:42 7:34 8:26 9:17 10:08 11:00 11:52
5.1 4.9 4.7 4.6 4.4 4.4 4.3 4.3 4.2 4.2 4.1 4.0 3.9 3.8 3.7 4.5 4.5 4.4 4.3 4.3 4.3 4.3 4.4 4.5 4.5 4.5 4.4 4.3 4.1
Seven Mile Times
PM 12:06 12:59 1:56 2:57 4:05 5:13 6:12 7:03 7:49 8:32 9:12 9:49 10:23 10:56 11:30 12:38 1:23 2:13 3:10 4:14 5:19 6:17 7:12 8:04 8:56 9:47 10:38 11:29
Spring 2021
MAY TIDE CHART
LOW
FT
AM
4.2 6:08 3.9 7:05 3.7 8:05 3.6 9:08 3.5 10:12 3.6 11:14 3.8 3.9 12:20 4.1 1:14 4.2 2:03 4.3 2:48 4.4 3:28 4.5 4:07 4.5 4:45 4.5 5:23 6:03 3.6 6:47 3.5 7:36 3.4 8:29 3.3 9:26 3.4 10:25 3.6 11:21 4.0 4.4 12:26 4.8 1:25 5.1 2:22 5.4 3:17 5.5 4:10 5.5 5:03 5:56
FT
PM
-0.3 6:11 0.0 7:04 0.3 8:02 0.5 9:05 0.6 10:12 0.6 11:19 12:10 0.4 12:59 0.2 1:43 0.1 2:24 0.0 3:01 0.0 3:35 0.1 4:08 0.2 4:39 0.4 5:10 0.6 5:43 0.7 6:21 0.9 7:07 1.0 8:04 1.0 9:08 0.8 10:17 0.6 11:23 12:14 0.0 1:05 -0.3 1:53 -0.5 2:41 -0.6 3:27 -0.6 4:13 -0.4 5:00 -0.2 5:51
FT -0.1 0.2 0.5 0.6 0.7 0.6 0.5 0.3 0.1 -0.1 -0.1 -0.1 0.1 0.3 0.5 0.7 0.8 0.9 0.9 0.8 0.6 0.3 0.2 -0.1 -0.3 -0.5 -0.5 -0.4 -0.2 0.1
energy reaffirming. Beaches are shaped by the awesome energy of the sea. They have a rhythm that matches the gentle lapping of the waves on the shore. They are also equipped to handle the ferocious pounding of the surf during the worst storms. Our desire to have the beach and dune fixed where they suit us most is what causes the challenges. A beach that is free to move landward, to higher ele-
HIGH SUNRISE 6:41 6:39 6:38 6:36 6:35 6:33 6:32 6:30 6:29 6:27 6:26 6:24 6:23 6:21 6:20 6:18 6:17 6:15 6:14 6:13 6:11 6:10 6:08 6:07 6:06 6:05 6:03 6:02 6:01 6:00
SUNSET 7:24 7:25 7:26 7:27 7:28 7:29 7:30 7:30 7:31 7:32 7:33 7:34 7:35 7:36 7:37 7:38 7:39 7:40 7:41 7:42 7:43 7:44 7:45 7:46 7:47 7:48 7:49 7:50 7:51 7:52
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Sat Sun Mon Tue Wed Thu Fri Sat Sun Mon Tue Wed Thu Fri Sat Sun Mon Tue Wed Thu Fri Sat Sun Mon Tue Wed Thu Fri Sat Sun Mon
LOW
AM
FT
PM
FT
AM
12:23 1:19 2:18 3:20 4:22 5:20 6:10 6:53 7:34 8:15 8:56 9:36 10:16 10:55 11:35
5.4 5.1 4.8 4.5 4.3 4.1 4.0 4.0 3.9 3.9 3.9 3.9 3.9 3.8 3.7
4.7 4.6 4.4 4.3 4.2 4.2 4.2 4.3 4.3 4.2 4.2 4.1 4.0 5.4 12:32 5.1 1:26
3.9 3.8 3.7 3.7 3.7 3.9 4.1 4.2 4.4 4.6 4.7 4.8 4.8 4.8 4.8 3.6 3.5 3.4 3.5 3.6 3.9 4.3 4.7 5.1 5.5 5.7 5.7 5.6
6:53 7:50 8:49 9:47 10:43 11:34
12:23 1:10 2:03 3:01 4:04 5:07 6:06 7:02 7:58 8:54 9:50 10:44 11:38 12:09 1:03
12:47 1:44 2:43 3:45 4:49 5:47 6:36 7:21 8:03 8:42 9:19 9:55 10:29 11:04 11:41 12:15 12:59 1:47 2:42 3:43 4:47 5:48 6:45 7:40 8:34 9:28 10:21 11:15
12:50 1:38 2:23 3:06 3:46 4:25 5:03 5:43 6:26 7:12 8:01 8:53 9:47 10:41 11:34 12:02 1:05 2:05 3:02 3:57 4:49 5:42 3.9 6:36 3.8 7:30
FT
PM
0.1 6:46 0.3 7:46 0.5 8:49 0.6 9:54 0.5 10:58 0.4 11:57 12:21 0.4 1:03 0.3 1:43 0.3 2:22 0.3 2:58 0.3 3:33 0.3 4:07 0.5 4:41 0.6 5:16 0.7 5:56 0.8 6:44 0.8 7:41 0.7 8:44 0.5 9:50 0.3 10:58 0.0 0.1 12:26 -0.1 1:18 -0.2 2:09 -0.3 3:00 -0.3 3:51 -0.2 4:41 -0.1 5:33 0.1 6:29 0.3 7:28
FT 0.4 0.6 0.7 0.7 0.7 0.5 0.3 0.1 0.1 0.1 0.2 0.3 0.5 0.6 0.7 0.8 0.8 0.7 0.6 0.5 0.3 -0.2 -0.3 -0.3 -0.3 -0.2 0.0 0.2 0.4 0.5
SUNRISE 5:58 5:57 5:56 5:55 5:54 5:53 5:51 5:50 5:49 5:48 5:47 5:46 5:45 5:45 5:44 5:43 5:42 5:41 5:40 5:40 5:39 5:38 5:38 5:37 5:36 5:36 5:35 5:35 5:34 5:34 5:33
SUNSET 7:53 7:54 7:55 7:56 7:57 7:58 7:59 8:00 8:01 8:02 8:03 8:03 8:04 8:05 8:06 8:07 8:08 8:09 8:10 8:11 8:12 8:12 8:13 8:14 8:15 8:16 8:16 8:17 8:18 8:19 8:19
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t h e re i s s o m e t h i n g I n a l l t h i n g s o f n a t u re A r i s t o t l e .~ of the marvelous
vation, to match sea-level rise, is a natural state that is incredibly rare. Moving beaches don’t fit into the community we have built, so we have set ourselves on a cyclic course of never-ending beach construction followed by erosion. I intention-
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ally didn’t use the word restoration, because we aren’t actually restoring the beach. We are constructing one to meet our needs. It is expensive and becoming more expensive every year, but is now a necessity of island life.
BOOK YOUR 2021 SUMMER RENTAL NOW
DON’T WAIT, the best properties always book the earliest! Whether you want weekly, half season, full season — we have over 550 properties in our rental inventory, from the bay front to ocean front and everything in between…call now!
~
Double the fun for Summer ‘21! This year, The Wetlands Institute has two great ways for you to enjoy a fun-filled summer of imagination and discovery. Take part in on-site events at the Institute or bring the programs home with our Adventure Chests. Whatever you choose, the summer is yours to explore!
July 5-9 June 30-July 2 Creation Nation: Crafting with Nature
Wild Walks: Explore the Shore
July 12-16 Nature’s STEAM, STREAMs & STEMs
July 19-23 July 26-30
Close Encounters with Micro-Macro Wildlife
Weather or Not Climate Science
Aug. 23-25 Aug. 2-6
Creation Nation: Seashells in My Pockets
Fins, Scutes, Scales & Tails
Aug. 9-13 Secrets of the Way Down Under
Aug. 16-20 Marine Mammals and the Sea Life Web
For more information or to register, visit wetlandsinstitute.org/education/summer-nature-program.
s e v e n m i le t im e s . com
CHRISTINE CORBO
Broker/Salesperson, BPOR Cell: (609) 412-5008
Long & Foster R.E.-Christie’s Int’l R.E. 2773 Dune Drive, Avalon, NJ 08202 | (609) 967-3001 AvalonStoneHarborResortHomes.com | ccor1@msn.com Spring 2021
Seven Mile times