A picture of Keawaʻula Bay with a clear sky, light blue water and green mountains of the Waiʻanae range is on the screen as Kammie Tavares began her presentation at the Global Environmental Sciences ( GES ) Symposium, the culminating event of her bachelor’s of science degree at the University of Hawaiʻi at Mānoa. She described her favorite memory there—watching sunsets and playing in the sand with her brothers while her parents prepared dinner on the grill. She grew up in Waiʻanae and always felt a deep connection to the Mākaha-Keawaʻula coast.

After starting her degree program, Tavares realized beaches are important not just personally but also ecologically, culturally and economically. Despite the importance of beaches, coastal development is an ongoing major issue. Shoreline hardening, the construction of seawalls to protect beachfront development from erosion, paradoxically causes narrowing and loss of beach in adjacent areas.

For her project, Tavares and her advisor, Department of Earth Sciences Professor Chip Fletcher, hypothesized that the number of coastal structures considered threatened by coastal erosion, and whose owners may consider hardening the shore, will increase as sea level rises. She used a computer model to project the erosion risk with a sea level up to three-feet higher than present day, and then calculated the length of developed shoreline on Oʻahu that will be considered threatened based on current state policies.

Initial results show that just one foot of sea-level rise has drastic implications for the future of beaches on Oʻahu and coastal development. Tavares’ findings accentuate that the time to act is now.

“Beaches are dynamic environments, and most beaches in Hawaiʻi, especially here on Oʻahu, are trapped by development near the shore,” said Tavares. “Retreating from the shore provides the space needed for natural coastal changes and provides our best chance for beach preservation. Let’s free the beach.”

To conclude her presentation, Tavares takes the audience back to Keawaʻula except, this time, her niece and nephew are playing in the sand. They and future generations are her motivation in this project. For her, protecting beaches is important to ensure that future generations have the opportunity to make memories of their own.

For the full story, see the School of Ocean and Earth Science and Technology website.

—By Marcie Grabowski