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The US Army Engineer District, San Francisco (SPN) and the Coastal Inlets Research Program conducted a pilot study to consider various placement locations for dredged material in vicinity of Noyo Harbor, CA. Approximately 30,000-40,000 cu yd/yr of beach-quality sediment is dredged from the navigation channel and the lower Noyo River, located on the north central California coast. The pilot study investigated several potential locations for placement of dredged sediments in one of two areas north of Noyo Bay. The investigation included field data collection and numerical modeling of near-field sediment transport and suspended sediment concentration during and after placement of the dredged sediments under combined wave and current conditions. The numerical model provided the technical information necessary for SPN and Noyo Harbor stakeholders to evaluate a location site that is economically feasible for the optimum sediment placement. Upon acceptance by the stakeholders and receipt of additional funds, a demonstration project will be conducted, and the Dredged Material Management Plan (DMMP) for Noyo Harbor will be updated to include a beneficial use site for nearshore placement.

The harbor structures/shoreline armoring on the southern Lake Michigan shoreline interrupt sand migration. Ogden Dunes, Indiana, and the nearby Indiana Dunes National Lakeshore observed shoreline erosion due to engineered structures associated with Burns Waterway Harbor (east of Ogden Dunes) impeding natural east-to-west sediment migration. To remedy this, USACE placed over 450,000 cubic meters (m 3) of dredged material post-2006 in the nearshore of Ogden Dunes. However, the effectiveness of nearshore placements for shoreline protection and littoral nourishment is not fully established. To improve nearshore placement effectiveness, USACE monitored the June/July 2016 placement and subsequent movement of 107,000 m 3 of dredged material in the nearshore region at Ogden Dunes. This involved an extensive monitoring scheme (three bathymetry surveys, and two acoustic Doppler current profiler deployments), a Coastal Modeling System (CMS) numerical model of the changes following placement, and a prediction of sediment transport direction using the Sediment Mobility Tool (SMT). The SMT-predicted sediment migration direction was compared to observations. Observations indicated that between 10/11/2016 and 11/15/2016 the centroid of the sediment above the pre-placement survey moved 17 m onshore. These observations agreed with SMT predictions-onshore migration under storm and typical wave conditions. CMS accurately reproduced the hydrodynamic features. 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.

has developed the Coastal Modeling System (CMS) as a coupled wave, hydrodynamic, and sediment transport numerical modeling system. The primary focus of this study is to validate CMS for long-term applications through simulations of tidal inlet evolution and verify the results against established theoretical and empirical formulations that describe the stability and equilibrium conditions of tidal inlets. A wide range of conditions are chosen to test the breadth of model applicability including varying waves, tide and inlet geomorphic characteristics. The model is run for 100 years and the resulting morphological state is gauged in terms of inlet stability theory. Overall, CMS compares well to theoretically and empirically predicted inlet cross-sectional areas with some noted deviations due in part to the artificial nature of the idealized inlet geometry. The sharp spatial transition at either end of the inlet throat leads to artificially large gradients that may increase erosion and associated cross-sectional area. The results suggest that CMS can efficiently and accurately, to the degree of available empirical information, quantify long-term evolution of barrier island tidal inlet systems. 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.

This report documents a field data collection program, including the sediment tracer study, and numerical modeling investigation for dredged material placed in the nearshore area of an ocean dredged material disposal site (ODMDS) adjacent to Coos Bay Inlet, OR. The collected data around the inlet system were assembled, analyzed, and used to calibrate and validate the Coastal Modeling System (CMS) and the Particle Tracking Model (PTM). Sediment transport pathways and fate of placed material were evaluated. The model and sediment tracer study results indicate that the tracer placed within the nearshore ODMDS primarily moves alongshore towards the inlet at the initial stage of the release. Material arriving at the inlet channel and ebb shoal is jettisoned offshore by strong ebb currents. The results also show that the sediment tracer spreads northward alongshore due to strong dominant southerly wind across the inner continental shelf. At and outside the inlet, finer particles are transported the farthest offshore and away from the navigation channel and nearshore ODMDS area. A new sediment mapping technique applied in model simulations demonstrates migration and burial for sediments placed in the nearshore ODMDS. Both CMS and PTM results compare well with those of the sediment tracer study. 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.