Author(s): Rafael O. Tinoco; Salman Alkhidhr; Kamil Czaplinski And William Nardin
Linked Author(s): Rafael Tinoco
Keywords: Living shorelines oyster reefs nature-based solutions coastal morphodynamics
Abstract: Oyster reefs are an increasingly used type of living shoreline used to address threats due to coastal erosion and flooding. The complex geometry of such reefs creates flow-structure interactions at multiple scales, which can alter the short- and long-term morphodynamic evolution of the shoreline. To begin investigating these effects, we conducted a series of laboratory experiments on a small-scale stream table using 1:7 scale 3D-printed oyster reef blocks on a beach made of lightweight sediment (SG=1.5). Free surface elevation, bed evolution, and net sediment transport were characterized using acoustic wave gages, time-lapse photography, and lidar scans, respectively, for waves of 2 and 4 s periods. We tested 4 spatial arrangements for each wave case to investigate the effect of space between oyster blocks, d_g. Data showed clear differences in shoreline evolution driven by localized regions of high shear between the shortest gaps which defined areas prone to erosion, while recirculation areas due to wider gaps and shorter structures allowed us to identify deposition-prone zones. Wave period and wave excursion also affected the shoreline evolution, resulting in limited areas impacted by the reef wakes, and showing clear patterns of sediment sorting past the reefs. While the data presents clear patterns driven by gap size and wave excursions, scale limitations of the experiments limit generalization of the findings, such that larger-scale experiments are needed to fully characterize the effects of oyster reef geometry and layout on shoreline evolution.
Year: 2025