Ashley E. Frey

Merrimack Estuary and Newburyport Harbor sediment management studies

This report documents a numerical modeling study investigating sediment transport and morphology change adjacent to Merrimack Inlet, Newburyport, and nearshore in the vicinity of Salisbury Beach and Plum Island, Massachusetts. Concerns at the site include beach erosion, shoreline retreat on Plum Island downdrift of and within the inlet, and reduced navigability of the inlet. The numerical modeling evaluation consists of two phases. The Phase I study was conducted with the damaged and partially rehabilitated South Jetty between 2012 and 2014, and the Phase II study was conducted with the fully rehabilitated South Jetty between 2015 and 2016. Historical hydrodynamic and sediment data in the study area were assembled, and a field data collection program was carried out. The datasets were used to develop a coastal wave, hydrodynamic, and sediment transport model. Different alternatives were developed to evaluate sediment management strategy and structure modification, and the calculated bed sediment volume changes of each alternative were compared with the results under base (existing) condition. Alternative simulations demonstrated the Coastal Modeling System capability in evaluating beach erosion, structure performance, sediment transport, and morphology change in the inlet and estuarine system. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents. DESTROY THIS REPORT WHEN NO LONGER NEEDED. DO NOT RETURN IT TO THE ORIGINATOR. ERDC/CHL TR-18-7 iii

Sediment Budget on the Indiana Shore at Burns Harbor, Lake Michigan

Abstract : Net sediment transport in the littoral cell extending from Michigan City Harbor, IN, to Burns Waterway Harbor, IN, USA, is from east to west. For the four decades following construction of the Burns Waterway Harbor, net transport averaged about 190,000 yd3/year. Of this amount, accumulation in the fillet east of the Arcelor-Mittel bulkhead was 106,000 yd3/year, while dredging from the Bailly Generating Station cooling water intake was 83,000 yd3/year. The total transport calculated in this study is higher than most published previous estimates. The volume of sediment now bypassing the lakeward end of the bulkhead and entering the Federal harbor is estimated to be 84,000 yd3/year. This value will have to be confirmed from dredging statistics in the future. An average of 61,000 yd3/year of sand has been placed both on beaches at the National Park Service West Beach Unit west of Portage/Burns Waterway and offshore at Ogden Dunes. Full bypassing should to be about three times this amount to equal the longshore transport value of about 190,000 yd3/year.

Sediment Management Options for Galveston Island, Texas

Abstract : Galveston Island is a major tourist and commercial center on the Gulf of Mexico at the mouth of Galveston Bay, Texas, USA. The shoreline along the Galveston Seawall regularly requires beach nourishment while the beach west ofthe Seawall has severely eroded. In order to protect the island and ensure it is available for generations to come, a 50-year sediment management plan was developed. A sediment budget using the Sediment Budget Analysis System was calculated and numerous alternatives were simulated with GenCade, a shoreline change and sand transport model. Finally, several alternatives ranging from no action to a comprehensive beach fill and backpassing system are presented as partof the sediment management plan.

CONCEPTUAL REGIONAL SEDIMENT BUDGET FOR THE U.S. NORTH ATLANTIC COAST

A Conceptual Regional Sediment Budget (CRSB) was developed for coastal beaches, bays and estuaries extending from Virginia to Maine, USA, as part of the North Atlantic Coast Comprehensive Study. Hurricane Sandy made landfall on October 30th, 2012 near Brigantine, New Jersey and generated severe beach erosion and property damage throughout this region. A CRSB is the first step in understanding sediment transport patterns and magnitudes, and aligning dredging and placement operations to take advantage of natural processes and identify sediment deficiencies in a regional system. Optimizing regional sediment management practices in this region is critical to (a) improve beneficial use of dredged sediments; (b) reduce the risks of future storm damage and enhance the environment; and (c) reduce costs in maintaining coastal infrastructure. Data from 1990-2013 indicated an average of 18.7 million cu yd/year was dredged within the North Atlantic region. The CRSB is accessible via a web portal.