Doctoral Candidate Designs Artificial Reefs for Coastal Protection




   Story by Schaefer School of Engineering & Science

November 9, 2011

Spicer Bak, PhD CandidateFor Spicer Bak at Stevens Institute of Technology, being a beach bum and a PhD candidate go hand-in-hand. That is because this Ocean Engineering graduate student studies beach erosion to better understand how we can protect America's coastlines. He's also using support from a unique National Science Foundation graduate student scholarship program to share his excitement for both science and the sea with New Jersey high school students.

Coastal protection is a major topic for government agencies, ocean scientists, and beach bums around the world. It's also a big issue among surfers, one of the most vocal and engaged groups among beach users. As an avid surfer himself, Spicer makes it a personal mission to discover new ways to preserve beaches without reducing the chance of catching a wave.

"There is a great need today for a solution that preserves beachfront without damaging recreational value, and does so in a relatively natural and more permanent way," reports Dr. Thomas Herrington, Spicer's advisor and Assistant Director of the Center for Maritime Systems.

The solution proposed by Spicer and Dr. Herrington is the installation of artificial reefs designed to advantageously influence waves to protect seaside property yet maintain surfing potential. To develop these reefs, Spicer works on computer models and scale physical demonstrations of artificial reef schemes that will one day became permanent fixtures along popular New Jersey beaches. He is also one of several doctoral students who survey New Jersey beaches to better understand current erosion processes and how they are affected by storms, tides, and human activity.

Artificial reefs are meant to assist the common response to beach erosion today, called beach replenishment or beach nourishment, which is simply the adding of sand to widen or restore a beach. This relatively straightforward approach has its advantages: it starts working immediately and causes no problems to marine life as long the sand is mostly mud-free.

Despite these benefits, "beach replenishment can ruin waves and regularly takes beaches out of commission because new sand has to be added again and again," Spicer states.

A fundamental problem in nourishing beaches is that imported sands often have a different grain size than native sand. Adding sand with smaller grains causes sand to be easily swept off the beach, creating a mellow slope that requires the appliation of more sand to appropriately widen the beach. Larger grains cause steep slopes, which make waves break too close to shore creating dangerous shore break.

"There are only so many waves out there," Spicer says, so when beach replenishment cuts waves in one part of the beach, surfers must jostle for smaller and smaller surfing spots. This isn't only a concern for surfers, but also for businesses at destinations where visiting surfers and other beachgoers are a major economic factor.

Regardless of these disadvantages, beach replenishment is the only proven method for widening beaches. Artificial reefs that change beach conditions are a relatively new concept, but have become a hot topic in the surfer community after previous projects in Australia and southern California. Spicer is building on the data from those successes to create his own reef designs.

Spicer also takes his passion for the ocean to area high schools as part of the National Science Foundation GK-12 Fellow program. As a Fellow, Spicer receives NSF support for his PhD studies and research in return for teaching tenth graders basic engineering and science principles through lessons about the sea.

"I would always start broadly by relating scientific principles to something in the ocean," Spicer recalls. Waves alone can fuel many discussions. Gravity, the electro-magnetic spectrum, light, refraction/diffraction—all are principles that can be visualized and explained through the behavior of waves at the beach.

To make chemistry more appealing, Spicer brought in scuba gear to demonstrate the importance of chemistry in scuba diving. As the kids got to kick around in his flippers and wear oxygen tanks, he went to the board to explain how divers must monitor the nitrogen concentration in their tanks to avoid the bends. He also used diving as an entry point to discuss pressure changes underwater and how deep light travels in the ocean.

Spicer also brought in a small wave tank and let the students set up their own experiments. With sand, rocks, and a little water, they could see how small changes in the orientation of an artificial reef or jetty can make big differences in how a beach erodes or builds up.

The GK-12 Fellow program is designed to enhance STEM education among American youth, but it can also be fun for the Fellows. "It was really rewarding. The kids were fun and I could see how excited they were. It was like taking them on in-class field trips."

Spicer says he is "stoked" that he gets to combine engineering and a love for ocean in a career. "It's almost like a romantic fantasy that I get to do research related to surfing."

Learn more by visiting the Department of Civil, Environmental and Ocean Engineering.


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