Dredging Guidelines Development
The projected long-term demand for sand for beach nourishment and restoration projects is growing. To help protect the ocean ecosystem, offshore dredging guidelines were needed to protect the morphologic integrity of the ridge and shoal features. These important features which are being targeted as sand borrow sites.
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An improved understanding of the morphologic evolution of ridge and shoal features was required to develop and support the offshore shoal dredging guidelines. Highlights of the findings include:
- The relative shoal height is the most important parameter for shoal assessment.
- Waves and subtidal currents from nor’easters are the primary environmental factors.
- Dredged shoals will typically reform into smaller shoals and under certain conditions can reform topre-dredged shoal height.
- Classify the most important parameters in assessing shoal geomorphic integrity.
- Identify the most important environmental factors affecting shoal morphology.
- Determine what will happen to the shoal once it is dredged.
- Establish how a shoal should be dredged to protect its geomorphic integrity.
- A unique morphometric analysis of key shoal parameters was developed.
- Extensive field data for more than 180 shoals was analyzed, including mapping, sediment sampling and wave and current measurements.
- Numerical model was used to analyze a number of dredging scenarios.
- Detailed dredging guidelines were developed identifying techniques that would promote reformation of shoals to pre-dredged heights.