Bivalve Colonies as a Self-sustained Scour Mitigation Method: Assessing their Effects on Sediment Erodibility

Joanna Quiah

North Carolina State University

Co-Authors: Celso Castro-Bolinaga, Steve Hall, Nina Stark, Grace Massey, Melody Thomas, Sam Consolvo

Sediment erosion and scour have led to major societal challenges across the globe including scour around bridge piers, infrastructure collapse, and poor ecological function in streams and along the coast. Many engineering techniques employ the use of gravel and rock deposits to mitigate scour and erosion; however, these techniques are subject to frequent maintenance because coarse particles are prone to dislodge during strong velocities and storm events. Bivalve aquaculture (mussels, clams, oysters) has been identified as a promising long-term solution for coastal scour and erosion protection due to its resiliency, environmental impact, and contribution to the economy. The morphology and self-sustainability behaviors of these colonies have the potential to reduce the applied boundary shear stress of the flow on shoreline sediment. Bivalve colonies also produce adhesive proteins, which might be capable of increasing soil resistance to erosion through soil cohesion. This presentation will provide insights into a novel method of scour and erosion prevention using the Jet Erosion Test (JET) around three intertidal oyster reefs in the Rachel Carson Reserve, NC. I will also discuss the intrinsic value of bivalves and their potential to reduce coastal scour.

Please post comments and questions for the author below.

5 thoughts on “Bivalve Colonies as a Self-sustained Scour Mitigation Method: Assessing their Effects on Sediment Erodibility

  1. Hi Joanna!

    Looks like a fun project!

    Did you see any patterns in Tc? It seems like A1 and A2 have similar Kd but very different Tc-is there a reason for this? Also how much did these values change after the Cd calibration?

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    1. Hi Whitney, thank you! Great questions.

      Oyster reefs with more pronounced flow conditions (such as Site 2 compared to our other two sites) seem to show that Tc is primarily influenced by grain size while Kd is primarily influenced by location relative to the oyster reef. But as you pointed out, A2 has a very different Tc, even while sharing the same d50 with A1. I think this is because A2 is more directly exposed to flow and the fact that there are fewer oyster fragments and shells in A2 to challenge Tc.

      I haven’t applied the Cd variation to this Site yet, but I have applied it to a sample JET dataset from another project. There, depending on the grain size distribution, Cd was underestimated by up to 0.04 due to temperature, which underestimated Tc by about 0.4 Pa and overestimated Kd by about 30 cm/Ns.

      Thanks for watching and please let me know if you have any further questions!

      Like

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