Assessment of Wave Attenuation, Current Patterns, and Sediment Deposition and Erosion During Winter Storms by Living Shoreline Structures in Gandys Beach, New Jersey

Open-File Report 2021-1040

Prepared in cooperation with the U.S. Fish and Wildlife Service and The Nature Conservancy
Prepared in collaboration with Northeastern University

By: , and 

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Abstract

This study was conducted by the U.S. Geological Survey and Northeastern University in cooperation with the U.S. Fish and Wildlife Service and The Nature Conservancy. This report summarizes field investigation and analysis of waves, current patterns, and sediment deposition and erosion along the Gandys Beach, New Jersey, salt marsh vegetated shoreline and mudflat, where living shoreline structures (for example, oyster reefs) were constructed to protect the marsh shoreline and enhance habitat for oyster and other species. Constructed oyster reefs (CORs, also known as oyster castles) provide shoreline protection and habitat for fish and shellfish communities via wave energy attenuation. However, the processes and mechanism of CORs on wave attenuation and current circulation remain unclear, thus limiting the assessment of COR effectiveness for shoreline protection. This report presents the results of the field investigation on wave characteristics, current patterns, and marsh edge erosion along a shoreline with CORs in Delaware Bay. To measure the effectiveness of these CORs, six pressure transducers, six tilt current meters, multiple sediment traps, and marsh edge erosion pins were deployed from February to April 2018 in Gandys Beach in upper Delaware Bay. The spatial variations of wave heights measured on both sides of the CORs indicate a strong dependence of wave attenuation on the ratio between the freeboard of the CORs and the offshore wave heights. It was found that swell energy originating from the Atlantic Ocean can penetrate the CORs without any dampening even when the CORs are emergent, whereas the wind seas are more impacted by the CORs. Tidal current velocity and circulation patterns near the CORs (for example, the current velocity was higher than 10 centimeters per second [cm/s] and even up to 30 cm/s in the gaps between the CORs compared to less than 10 cm/s in the control area) differ from those in the control area without protection from the CORs and are greatly affected by the surrounding bathymetry. The combined effect of living shoreline structures on wave attenuation and changes in circulation patterns over the study period resulted in the reduction of shoreline erosion both vertically and laterally compared to that in the control area and also resulted in changes in the grain size distribution in both the water column and the salt marsh and mudflat areas.

Suggested Citation

Wang, H., Capurso, W., Chen, Q., Zhu, L., Niemoczynski, L., and Snedden, G., 2021, Assessment of wave attenuation, current patterns, and sediment deposition and erosion during winter storms by living shoreline structures in Gandys Beach, New Jersey: U.S. Geological Survey Open-File Report 2021–1040, 37 p., https://doi.org/10.3133/ofr20211040.

ISSN: 2331-1258 (online)

Study Area

Table of Contents

  • Abstract
  • Introduction
  • Methods
  • Results
  • Discussion
  • Summary
  • References Cited
Publication type Report
Publication Subtype USGS Numbered Series
Title Assessment of wave attenuation, current patterns, and sediment deposition and erosion during winter storms by living shoreline structures in Gandys Beach, New Jersey
Series title Open-File Report
Series number 2021-1040
DOI 10.3133/ofr20211040
Year Published 2021
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) New Jersey Water Science Center, Wetland and Aquatic Research Center
Description Report: ix, 37 p.; 2 Data Releases
Country United States
State New Jersey
Other Geospatial Gandys Beach
Online Only (Y/N) Y
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