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44-3 Quantifying Post-Dredge Refilling at Pohoiki Bay Following the 2018 Kīlauea Lower East Rift Zone Eruption Using kGPS and Photogrammetry

Session: Recent Advances and New Voices in Marine and Coastal Geoscience (Posters)

Poster Booth No.: 220

Presenting Author:

Lucas Chinchiolo

Authors:

Chinchiolo, Lucas¹, Lundblad, Steven Paul², Rodriguez, Roberto³, Decker, Meghann F.⁴, Gallant, Lis⁵, Lee, Thomas A.⁶, De Torres, Cristina⁷, Richfield, Susan Marie⁸, Goehring, Brandon⁹, Debsky, Tom¹⁰, Adams, Raymond Gumercindo¹¹, Kohagura, Nanako¹³, Gerasimof, Caitlin¹⁴, Forster, Lichen¹⁵, Chun, Nikolas¹⁶, Dilley, Analeise¹⁷, Blankenship, Ethan¹⁸r> (1) University of Hawaiʻi at Hilo, Hilo, HI, USA, (2) University of Hawaiʻi at Hilo, Hilo, HI, USA, (3) College of Agriculture Forestry and Natural Resource Management, University of Hawaiʻi at Hilo, Hilo, HI, USA, (4) University of Hawaiʻi at Hilo, HIlo, HI, USA, (5) University of Hawaiʻi at Hilo, Hilo, HI, USA, (6) University of Hawaiʻi at Hilo, Hilo, HI, USA, (7) University of Hawaiʻi at Hilo, Hilo, HI, USA, (8) University of Hawaiʻi at Hilo, Hilo, HI, USA, (9) University of Hawaiʻi at Hilo, Hilo, HI, USA, (10) University of Hawaiʻi at Hilo, Hilo, HI, USA, (11) University of Hawaiʻi at Hilo, Hilo, HI, USA, (12) University of Hawaiʻi at Hilo, Hilo, HI, USA, (13) University of Hawaiʻi at Hilo, Hilo, HI, USA, (14) University of Alaska Fairbanks, Fairbanks, AK, USA, (15) University of Hawaiʻi at Hilo, Hilo, HI, USA, (16) University of Hawaiʻi at Hilo, Hilo, HI, USA, (17) University of Hawaiʻi at Hilo, Hilo, HI, USA, (18) University of Hawaiʻi at Hilo, Hilo, HI, USA,

Abstract:

The Lower East Rift Zone (LERZ) eruption of 2018 at Kīlauea volcano was one of the most destructive on Hawaiʻi Island in recent memory. Lava flows destroyed nearly 2000 structures, isolated 9.3 square miles (24 square kilometers) of land by cutting off road access, and displaced over 5,500 people temporarily or permanently. At the end of the eruption, flows came within 230 feet (70.1 meters) of Pohoiki Boat Ramp, a critical piece of infrastructure for the lower Puna District. Sediment from eruptive fragmentation at the ocean entry and erosion of the new coastline filled the bay that housed the boat ramp, cutting off its access to the Pacific Ocean within a few days. Sediment transport modeling was conducted by the US Army Engineer Research and Development Center (ERDC) Coastal and Hydraulics Laboratory (CHL). Modeling indicated that maintaining a navigable channel would require an initial dredge of approximately 42,000 cubic yards (32,000 cubic meters), followed by maintenance dredging of at least 5,500 cubic yards (4,200 cubic meters) three times per year. In July 2023, five years after the eruption ended, a plan to dredge the sediment and reopen the boat ramp was approved. Dredging began in July 2025 and finished that October. Three days after dredging was completed, sediment began rapidly refilling the dredged channel, once again cutting off access to the boat ramp. The University of Hawaiʻi at Hilo's Departments of Geology and Aeronautical Sciences performed several geodetic surveys using uncrewed aerial systems (UAS) and kinematic GPS (kGPS) before dredging began and after refilling occurred. Structure-from-Motion (SfM) photogrammetry was used to create high-resolution digital elevation models (DEMs) from these surveys. This study quantifies how much sediment refilled the channel and how the dredge scar has evolved over time. These results can be used to validate and inform models for future dredging projects, or help guide discussions on building a boat ramp in a new location less prone to dramatic sediment transport.

Quantifying Post-Dredge Refilling at Pohoiki Bay Following the 2018 Kīlauea Lower East Rift Zone Eruption Using kGPS and Photogrammetry

Description

Session Format: Poster

Presentation Date: 10/11/2026

Presentation Room: CCC, Hall F

Poster Booth No.: 220

Author Availability: 2:00 to 4:00 p.m.

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