Katherine E Brutsche

Evolution of a Swash Zone Berm Nourishment and Influence of Berm Elevation on the Performance of Beach-Nearshore Nourishments along Perdido Key, Florida, USA

ABSTRACT Brutsché, K.E.; Wang, P.; Rosati, J.D., and Beck, T.M., 2015. Evolution of a swash zone berm nourishment and influence of berm elevation on the performance of beach-nearshore nourishments along Perdido Key, Florida, USA. A nourishment was placed within the swash zone along eastern Perdido Key, Florida, in 2011–2012 using maintenance-dredged material from nearby Pensacola Pass, referred to here as a “swash zone berm nourishment.” The study area was divided into three sections, the swash zone berm project and two adjacent areas to the west and east, and was monitored with time series beach surveys. The performance of the 2011–2012 nourishment with a constructed berm elevation of +0.91m North American Vertical Datum 1988 (NAVD88) was compared with two previous nourishments in 1985 and 1989–1991, with +3.0 m NAVD88 and +1.2 m NAVD88 elevations, respectively. The low elevation for the 2011–2012 nourishment allowed natural overwash processes to occur frequently, which resulted in net onshore sediment transport and growth of the active berm. The swash zone berm evolved back to the natural equilibrium profile shape maintained in the study area within 8 months. The high–wave energy conditions associated with the passages of Tropical Storm Debby and Hurricane Isaac accelerated the equilibrium process. Sediment volume gain west of the project area due to longshore spreading of the nourishment occurred mostly in the trough between the shoreline and the bar, rather than on the dry beach. In terms of rate of shoreline retreat, the short 1.2-km 1985 nourishment performed the poorest with a rate of 40 m/y. The long 7.3-km 1989–1991 nourishment performed the best with a retreat rate of 11 m/y. This suggests that high berm elevations do not necessarily lead to better nourishment performance. Instead, longshore extent of a nourishment may dominate project performance. Furthermore, the very high nourishment density of 1550 m3/m did not improve nourishment longevity.

Long-Term Morphology Modeling for Barrier Island Tidal Inlets

The U.S. Army Corps of Engineers, Coastal Inlets Research Program, conducted at the U.S. Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory, 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. DESTROY THIS REPORT WHEN NO LONGER NEEDED. DO NOT RETURN IT TO THE ORIGINATOR. ERDC/CHL TR-18-12 iii

Physical monitoring methods for the nearshore placement of dredged sediment

PURPOSE: This Regional Sediment Management Technical Note (RSM-TN) provides an introduction to equipment and methods for monitoring the nearshore placement of dredged sediment. Topical information regarding instrumentation, physical monitoring techniques, and field operations planning is included and closes with an example monitoring plan from Ogden Dunes, IN. This overview is intended for U.S Army Corps of Engineers (USACE) District Project Managers, Planners, and Engineers tasked with developing a plan to monitor the evolution of a nearshore placement and its impact to adjacent beaches.

User’s guide for the Sediment Mobility Tool web application

INTRODUCTION: As part of regional sediment management, dredged sediment is commonly placed in the nearshore for beneficial use. A simple web application has been created that can rapidly produce a preliminary assessment of sediment mobility at prospective nearshore placement sites. This web application is ideal for preliminary or reconnaissance engineering studies to evaluate the potential mobility of sediment grain sizes and volumes placed in the nearshore and for comparison between multiple placement sites. This user’s guide is intended to describe the function and steps to use the web application. Currently, the web application can be found on the Navigation Portal (http://navigation.usace.army.mil) under the Sediment & Ecosystem Management tab. Additional details about the sediment mobility calculations are detailed in the Coastal and Hydraulics Engineering Technical Note (CHETN) Evaluating Sediment Mobility for Siting Nearshore Berms by McFall et al. (2016), and the depth of closure calculations are detailed in the CHETN Calculating Depth of Closure Using WIS Hindcast Data by Brutsché et al. (2016).

Engineering with Nature: Nearshore Berm Placements at Fort Myers Beach and Perdido Key, Florida, USA

Abstract : Two nearshore berm nourishments were placed at Fort Myers Beach and Perdido Key Florida, USA, as part of Regional Sediment Management practices. At Fort Myers Beach, a bar-like berm was placed offshore, while at Perdido Key a swash-zone berm was placed approximately half-way between the mean water line and berm crest to maximize the potential for mobilization. Themorphologic and sedimentologic evolution of both study areas was documented based on beach profile surveys and sediment sampling. Both projects were successful in that they added sediment to the littoral system and dry beach, protected the natural beach from storm impacts, and equilibrated with the natural system making the placement site sustainable for future projects. The nearshore berm at Fort Myers Beach contained mixed sediment and fine material initially located in the trough landward of the berm migrated offshore, while coarser beach quality sediment moved onshore. Sediment at Perdido Key was beach-quality sand slightly finer than the native sand on the subaerial beach, and was successfully integrated over the two-year monitoring period.