Publications:CHETNs

Coastal Hydraulics Engineering Technical Note (CHETNs)

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For a full and more working listing, please go to the CIRP Website Tech Notes page.

2010

A Review of Coastal Navigation Asset Management Initiatives within the Coastal Inlets Research Program (CIRP) Part 1: Coastal Structures

Purpose: This is the first Coastal and Hydraulics Engineering Technical Note (CHETN) in a series summarizing research initiatives underway since fiscal year (FY) 2007 within the Coastal Inlets Research Program (CIRP) concerning asset management of coastal navigation structures and channels. This CHETN describes the Coastal Structures Management, Analysis, and Ranking Tool (CSMART), a decision-support package for prioritizing coastal structures for annual maintenance funding that has been developed within the CIRP’s Coastal Navigation Portfolio Management (CNPM) work unit.

Concepts and Applications of Water Transport Time Scales for Coastal Inlet Systems

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) reviews concepts describing water transport time scales – flushing time, age, and residence time – and illustrates their use for coastal applications. As an example, a methodology to estimate residence time is presented for a constructed wetland cell in Chesapeake Bay, MD with the output of the Coastal Modeling System (CMS) and the CMS-driven Particle Tracking Model (PTM).

Grid Nesting and Application Example for Rhode Island South Shore Regional Sediment Management Study

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) describes the grid nesting capability of the Coastal Modeling System (CMS) wave model CMS-Wave availa-ble in the U.S. Army Corps of Engineers (USACE) Surface-water Modeling System (SMS). The grid nesting for wave transformation is useful in applications where a smaller computational domain resides fully or partially inside a larger grid domain. The theoretical background and user’s manual for CMS-Wave are provided by Lin et al. (2008). CMS-Wave is part of the CMS developed under the Coastal Inlets Research Program (CIRP) for simulating combined waves, currents, sediment transport and morphology change at coastal inlets, estuaries and river mouths (Lin et al. 2006; Demirbilek et al. 2007).

Proactive Strategy for "Dredge-Ready" Operation and Maintenance at Low-Use Navigation Projects

Purpose: This Coastal and Hydraulics Engineering Technical Note describes a collaborative strategy with a Federal navigation project sponsor for conducting operation and maintenance (O&M) dredging and disposal activities. A collaborative strategy increases opportunities for securing funding to conduct maintenance dredging and promotes responsiveness to local sponsor needs and capabilities. Dredge-ready or shovel-ready maintenance dredging plans compete well and may possibly be more competitive for future Federal funding presently unavailable through U.S. Army Corps of Engineers (USACE) for low-use navigation projects.

2009

Concepts for Functional Restoration of Barrier Islands

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) presents guidance for functional restoration of barrier islands. The concept of functional restoration is introduced here as an engineering and ecological design such that a barrier island can perform as a wave attenuator, storm surge buffer, and ocean boundary for an estuary, bay, and mainland over the defined project lifetime. Ecological design is required as part of the restoration to minimize initial nourishment losses and to ensure that environmental goals are met. Functional restoration allows for the possibility that a restored island could migrate alongshore and cross-shore, and possibly overwash to some extent as long as it continued reducing the risk of damage to the estuary, bay, and mainland. This CHETN reviews existing knowledge on the benefits of barrier islands and presents guidance for functional restoration.

Regional Morphology Analysis Package (RMAP), Version 3: User's Guide and Tutorial

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) serves as a user’s guide for the Regional Morphology Analysis Package (RMAP) Version 3, a modernized version of the Beach Morphology and Analysis Package (BMAP). A revised interface facilitates assembly, quality control, manipulation, analysis, visualization, and archiving of geospatial shoreline positions, beach profiles, and channel cross-sections. The interface, options, data import and export, and data analysis routines are described within this CHETN. A step-by-step tutorial is also provided to familiarize the user with selected features of RMAP Version 3.

2008

A GIS Based Tool for Extracting Shoreline Positions from Aerial Imagery (BeachTools) Revised

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) presents BeachTools, an ArcView™ 9.1 Geographic Information System (GIS) extension designed to identify and quantitatively establish the postition of shrelines and other coastal features from aerial imagery. This CHETN is a revision of the original BeachTools extension produced in ArcView 3.2 (Hoeke et al. 2001). Interactions Between Wetlands and Tidal Inlets Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) presents numerical simulations investigating how the loss of wetlands in estuaries modifies tidal processes in inlet navigation channels. The implications for wetland loss and construction of wetlands to tidal inlets and navigation channels are discussed, and hypotheses are presented for possible engineering approaches to mitigate wetland loss and improve the sedimentary sustainability of constructed wetlands.

Particle Tracking Model (PTM) in the SMS10: IV. Link to Coastal Modeling System

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) describes the coupling between the Particle Tracking Model (PTM) and the Coastal Modeling System (CMS). It familiarizes users with the PTM-CMS coupling interface as implemented inside the Surfacewater Modeling System Version 10 (SMS10). The steps necessary for preparing solutions of two-dimensional CMS-Flow and CMS-Wave models for input to the PTM are described, and two examples are given.

Estimation of Combined Wave and Storm Surge Overtopping at Earthen Levees

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) provides empirical equations for estimating several parameters of unsteady flow resulting from the combination of steady storm surge overflow and overtopping of irregular waves at a trapezoidal-shaped earthen levee. Equations are given for the average overtopping discharge and the cumulative probability distribution of instantaneous overtopping discharge. On the landward-side slope, empirical equations can be used to estimate the mean flow depth, mean flow velocity, root-mean-square wave height, and velocity associated with the overtopping wave front. Worked examples illustrate application of the empirical equations.

Interaction of Shore-Parallel Geotextile Tubes and Beaches along the Upper Texas Coast

Purpose: This Coastal and Hydraulic Engineering Technical Note (CHETN) summarizes initial lessons learned about ongoing field monitoring of shore-parallel geotextile tubes (GTs) constructed as beach dune cores in Galveston County, TX. Beach profile data and aerial photography collected between 1999 and 2007 are examined to evaluate the interaction of the GTs with beaches and the protection provided to public infrastructure and other landward improvements. Specific goals of the monitoring are to determine (a) if the GTs have exacerbated erosion of adjacent beaches by preventing release of littoral sediment or by increasing wave reflection and scour and (b) if GTs hinder post-storm beach recovery.

Estimation of Overtopping Flow Velocities on Earthen Levees Due to Irregular Waves

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) provides empirical equations for estimating several parameters of unsteady flow resulting from the combination of steady storm surge overflow and overtopping of irregular waves at a trapezoidal-shaped earthen levee. Equations are given for the average overtopping discharge and the cumulative probability distribution of instantaneous overtopping discharge. On the landward-side slope, empirical equations can be used to estimate the mean flow depth, mean flow velocity, root-mean-square wave height, and velocity associated with the overtopping wave front. Worked examples illustrate application of the empirical equations.

2007

Tips for Developing Bathymetry Grids for Coastal Modeling System Applications

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) gives practical advice and guidance on development of numerical model bathymetry grids for Coastal Modeling System (CMS) application. These tips can improve accuracy of simulations, make modeling more efficient, and help avoid common pitfalls that degrade simulation results. Most tips are applicable to other types of numerical models of nearshore hydrodynamics. Emphasis is given to the complex morphologic and hydrodynamic environment of coastal inlets.

Infra-Gravity Wave Input Toolbox (IGWT): User's Guide

Purpose: This Coastal and Hydraulic Engineering Technical Note (CHETN) is a user's guide for the Infra-Gravity Wave Toolbox (IGWT) developed as an activity of the Coastal Inlets Research Program (CIRP) of the U.S. Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory. Predicted infra-gravity (IG) wave input is required in modeling of long-waves affecting harbors. IG waves may also influence navigation, coastal inlets, and coastal structural design projects. The IGWT has been implemented in the Surface-water Modeling System (SMS) of the U.S. Army Corps of Engineers (USACE) to establish a link between CGWAVE and BOUSS-1D numerical wave models.

WABED Model in the SMS: Part 2. Graphical Interface

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) describes the graphical interface for the Wave-Action Balance Equation Diffraction (WABED) model that has been added to the U.S. Army Corps of Engineers (USACE) Surface-water Modeling System (SMS). The theoretical background and user's manual for WABED are given by Lin et al. (2006) and Demirbilek et al. (in preparation). WABED is intended for application in calculating wave transformation at coastal inlets and is part of the Coastal Modeling System (CMS) developed under the Coastal Inlets Research Program (CIRP) for simulating combined waves, currents, sediment transport, and morphology change.

Irregular Wave Forces on Heavily Overtopped Thin Vertical Walls

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) provides empirical equations to estimate irregular wave forces and overturning moments on thin, vertical walls extending from the sea floor and having a top elevation that is below the still water level. In this situation the majority of the wave crest passes over the vertical wall. A worked example illustrates application of the empirical equations.

2006

Sand Waves That Impede Navigation of Coastal Inlet Navigation Channels

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) discusses large bed forms, such as dunes or sand waves, that can pose a navigation hazard for inlet channels (Pope 2000). Understanding the conditions causing their formation can be an aid in navigation channel management. This CHETN is concerned with large bed forms that chronically or periodically encroach on the authorized navigation depth. Smaller bed forms have been observed in many (perhaps most) other inlets, but because they do not hinder navigation, they are not discussed in this CHETN. Navigation channels with reported sand waves include the Columbia River, WA/OR; East Pass, Panama City, Fort Pierce, and St. Marys Entrance, FL; Merrimack River, MA, and Kennebec River, ME. This technical note discusses the characteristics of the bed forms found in those areas and conditions responsible for their development.

Wave-Action Balance Equation Diffraction (WABED) Model: Tests of Wave Diffraction and Reflection at Inlets

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) demonstrates the numerical modeling capability to represent wave diffraction and reflection available in the WABED (Wave-Action Balance Equation with Diffraction) model. The WABED model is available as a nearshore wave transformation model in the Coastal Inlets Research Program's (CIRP's) Coastal Modeling System (CMS). Performance of the model is examined in this CHETN with two physical model data sets. The first data set pertains to a detached semi-infinite breakwater in front of a natural inlet, and an inlet with dual jetties. The second data set pertains to an inlet protected either by reflecting or absorbing jetties. Wave diffraction, wave reflection, and consequences of these processes on numerically simulated currents are examined with the two-dimensional (2-D) circulation model M2D. Future technical notes in this series will describe the interface and report additional validation and enhancements of WABED.

Jetty Spur Functional Design at Coastal Inlets; Effects on Nearshore Circulation and Potential Sediment Movement

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) discusses the effects of connected and detached spurs on sediment transport and circulation in the vicinity of a coastal inlet jetty. The influence of spur orientation on the magnitude and pathways of these processes is detailed based on observations in the field and comprehensive laboratory measurements. A companion technical note, CHETN-IV-61 (Seabergh and Krock 2003), discusses existing jetty spurs in the United States and presents initial Coastal Inlet Research Program (CIRP) physical model jetty spur results.

Uses for Marine Mattresses in Coastal Engineering

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) provides basic information on the Triton Marine Mattress System, describes potential applications for marine mattresses in coastal engineering, and summarizes previous successful deployments of marine mattresses in projects by the U.S. Army Corps of Engineers and others.

Frequently-Asked Questions (FAQs) About Coastal Inlets and the U.S. Army Corps of Engineers' Coastal Inlets Research Program (CIRP)

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) provides answers to Frequently-Asked Questions (FAQs) about coastal inlets and about the Coastal Inlets Research Program (CIRP). The FAQs are grouped in the following categories: a) General questions about coastal inlets, b) Coastal inlet hydrodynamics, c) Coastal inlet morphology, d) Coastal inlet channels, e) Coastal inlet structures, f) Coastal Inlets Research Program, g) Available tools for solving coastal inlet problems, and h) Miscellaneous inlet topics.

2005

Particle Tracking Model (PTM) in the SMS: I. Graphical Interface

Purpose: This Dredging Operations and Environmental Research (DOER)Technical Note describes the graphical interface for the Particle Tracking Model (PTM). The Coastal Inlets Research Program (CIRP) and the DOER Program are jointly developing the PTM. The PTM is described in a series of three technical notes. This technical note, Part I, describes the graphical user interface of Version 1.0 of PTM. The PTM has been developed for application to dredging and coastal projects, including dredged material dispersion and fate, sediment pathway and fate, and constituent transport.

Particle Tracking Model (PTM) in the SMS: II. Overview of Features and Capabilities

Purpose: This Dredging Operations and Engineering Research (DOER) Technical Note (TN) is the second in a series. It describes the features and capabilities of a new Particle Tracking Model (PTM) for analysis of sediment transport and sediment pathways in coastal waters, estuaries, rivers, and waterways. This note is applicable to Version 1.0 of PTM. Examples are presented that illustrate key features of the PTM s application in coastal and estuarine environments.

Particle Tracking Model (PTM) in the SMS: III. Tutorial with Examples

Purpose: This Dredging Operations and Engineering Research (DOER) Technical Note (TN) is a tutorial with examples of the PTM, developed jointly by the Coastal Inlets Research Program (CIRP) and DOER Program. This note is applicable to Version 1.0 of PTM.

Estimating Irregular Wave Runup on Rough, Impermeable Slopes

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) describes a new formula for improved estimation of irregular wave runup on rough, impermeable slopes. The runup guidance is based on the wave momentum flux parameter described in CHETN III-67. Sample calculations illustrate application of the formula.

Coastal Barrier Island Breaching, Part 2: Mechanical Breaching and Breach Closure

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) describes case studies of the mechanical closure and creation of coastal barrier island breaches. Emphasis is on breaches that form near inlets, with examples also given of breach opening for environmental enhancement. Part 1 in this technical note series reviews the causes of breaching and measures to prevent breaching (Kraus and Wamsley 2003). Subsequent technical notes will describe models under development in the Coastal Inlets Research Program for predicting the inception and evolution of breaches.

Tidal Inlet Shoal and Channel Change Analysis from Aerial Imagery Using Inlet, Nearshore, and Littoral Enhancement Tool for Geographic Information Systems (INLETGIS)

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) presents Inlet, Nearshore, and Littoral Enhancement Tool for Geographic Information Systems (INLETGIS) and describes a methodology for an objective, rapid inlet shoal and channel analysis through classification schemes using aerial photography and the INLETGIS extension for ArcViewTM 3.x Geographic Information System (GIS).

Coastal Inlet Navigation Channel Shoaling with Deepening and Widening

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) presents the response of six inlet navigation channel projects to deepening and widening. In all cases, deepening and/or widening of these channels increased the dredging rate. The post-dredging rate has a good correlation with the deficit of sediment in the channel (defined as the difference between the natural and dredged channel volumes), as compared to the natural (non-dredged) channel.

Representation of Nonerodible (Hard) Bottom in Two-Dimensional Morphology Change Models

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) describes a methodology for representing nonerodible substrates in a two-dimensional (2-D) coastal morphology change models, with emphasis on coastal inlets. The calculation procedure is described, followed by examples showing the functioning of the method.

2003

SMS Steering Module for Coupling Waves and Currents, 2: M2D and STWAVE

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) provides guidance on coupling the two-dimensional (2-D) circulation model M2D (Militello et al. in preparation) with the steady spectral wave model STWAVE (Smith et al. 2001) through the Surface-Water Modeling System (SMS) (Zundel 2002). Coupling of models is an efficient and accurate means of calculating wave-driven currents, setup and setdown, and wave-current interaction in nearshore regions, including tidal inlets. Procedures and options for coupling M2D and STWAVE within the SMS are described and an example application is provided.

Wave Momentum Flux Parameter for Coastal Structure Design

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) provides new formulas for improved estimation of irregular wave runup on smooth impermeable slopes. The runup guidance is based on the recently introduced wave momentum flux parameter. Sample calculations illustrate application of the formulas.

Estimating Irregular Wave Runup on Smooth, Impermeable Slopes

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) provides information about a new wave parameter for characterizing wave processes at coastal structures. A description of the parameter is given along with sample calculations for periodic waves and solitary waves. The first application of this physically relevant parameter has been development of new empirical relationships for irregular wave runup on smooth, impermeable slopes.

Uncertainties in Bathymetric Surveys

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) presents a statistical methodology for assessing the uncertainty of bathymetric analyses. The uncertainty assessment is based on the reported accuracy of a bathymetric survey.

Application of an Artificial Neural Network to Predict Tidal Currents in an Inlet Purpose: This Coastal and Hydraulics Technical Note (CHETN) describes application of an Artificial Neural Network (ANN) that can be trained to predict currents at an inlet located within a larger regional system, based on water level measurements at a different and possibly distant location. Once developed, ANNs reduce the need for field gauging, and information may be hindcast for sites where data do not exist, or which have gaps in the historical record.

Human-Induced Changes in Back-Barrier Environments as Factors in Tidal Inlet Instability with Emphasis on Florida

Purpose: This Coastal and Hydraulics Technical Note (CHETN) provides general information about the consequences of human alterations of back-barrier environments on tidal inlet stability, including several examples from the Gulf Coast of peninsular Florida.

Coastal Barrier Breaching, Part 1: Overview of Breaching Processes

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) provides information about the causes of breaching of coastal barrier islands and spits, with emphasis on breaching near inlet navigation projects and measures to prevent breaching. Subsequent technical notes in this series will present case studies and models under development in the Coastal Inlets Research Program (CIRP) for predicting the inception and evolution of breaches.

CHL Precision Flow Table - Description and Applications

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) provides information about the new precision flow table experiment facility located at the U.S. Army Engineer Research and Development Center, Coastal and Hydraulics Laboratory (CHL). The precision flow table can examine complex steady flow problems rapidly and at low cost. This capability is useful for understanding complicated flow problems and deciding on whether to pursue more elaborate modeling technologies. A description of the flow table capabilities is given along with an example application related to flow at a tidal estuary.

2002

Weir Jetties at Coastal Inlets: Part 1, Functional Design Considerations

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) provides information on the performance of selected weir jetty systems constructed in the United States and discussion of their functioning. A companion CHETN (Seabergh 2002) presents the design elements of weir jetty systems.

Weir Jetties at Coastal Inlets: Part 2, Case Studies

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) provides information on the function and experience of weir jetty systems and discusses introductory design considerations. A companion CHETN, Weir Jetties at Coastal Inlets, Part 2: Case Studies, summarizes selected weir jetty systems.

Inner Bank Erosion Processes and Solutions at Coastal Inlets

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) described herein provides information on erosion which occurs on the banks (or shoulders) of tidal inlets stabilized with jetties. The causes for initiation of this erosion area are discussed and potential solutions for reducing/preventing the erosion are presented.

Inlets Online: A Tutorial for Evaluating Inlet/Beach Processes Using Aerial Photography

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) describes a web-based information and analysis resource on tidal inlets and adjacent beaches, Great Lake entrances, navigation channels, and U.S. Army Corps of Engineers (USACE) Operation & Maintenance activities at these sites. All of the information presented in this CHETN may be accessed at: http://www.oceanscience.net/inletsonline.

Quantifying Potential Measurement Errors and Uncertainties Associated with Bathymetric Change Analysis

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) describes procedures for quantifying error and uncertainty estimates in volume change calculated from comparison of bathymetric surveys from two different times.

Video-Based Wave Direction Measurements in a Scale Physical Model

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) describes a method for video-based measurement of wave direction in an idealized coastal inlet physical model. This method may be applied in other physical model settings or extended to field measurement applications.

Estimating Along-Channel Flow and Sediment Transport at Tidal Entrances - Ebbjet Calculator

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) described herein describes the EbbJet Calculator, a utility of the Analytical Toolbox of the Diagnostic Modeling System (DMS) (Kraus 2000). The EbbJet Calculator estimates depth-averaged velocity and sediment transport rate at an inlet from established analytical and empirical equations. (This Windows-based Visual Basic application is available for download on our <a href="file:///D|/Website/products/products.html"> Products & Tools </a>page.

Tidal Velocity Asymmetry at Inlets

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) herein discusses selected factors responsible for controlling tidal velocity asymmetry at tidal inlets with implications for maintenance of navigation channels and sediment bypassing to the adjacent beaches.

Deployment of Oceanographic Instruments in High-Energy Environments and Near Structures

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) describes methods and techniques for acquiring measurements of waves, currents and suspended sediment from high-energy wave and current environments. The case study described herein involved measurements obtained in proximity to a large jettied inlet. Two techniques are described:

• Deployment of instrumented platforms in a high-energy surf zone.
• Deployment and recovery of instrumented tripods near a submerged structure using a Sikorsky HH-60J Jayhawk helicopter.

Inlet Spits and Maintenance of Navigation Channels

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) provides information on the formation and behavior of sand spits at inlets. Their interaction with navigation channels and possible consequences for water exchange are discussed. A mathematical model is presented to estimate spit development, and an example of physical modeling of spit evolution is given to illustrate properties of spit growth at inlets and model capabilities.

SHOALS Toolbox: Software to Support Visualization and Analysis of Large, High-Density Data Sets

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) outlines the capabilities of SHOALS Toolbox, a stand-alone software package designed to facilitate the use of SHOALS (Scanning Hydrographic Operational Airborne Lidar Survey) and other high-density survey data in engineering analyses. The SHOALS Toolbox comprises a suite of tools with which to visualize, manipulate, and analyze SHOALS data, and it is available free to all US Army Corps of Engineers elements and their contractors.

Coupling of Regional and Local Circulation Models ADCIRC and M2D

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) described herein provides guidance on coupling the regional circulation model ADCIRC with the local circulation model M2D. Coupling of models is an efficient and accurate means of calculating water level and current on a local domain, such as at and around an inlet. This CHETN also serves as a tutorial for coupling the two models within the Surfacewater Modeling System (SMS).

SMS Steering Module for Coupling Waves and Currents, 1: ADCIRC and STWAVE

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) describes the purpose and functionality of the steering module in the Surface-Water Modeling System (SMS). The steering module was developed to automate repetitive user tasks and required data sharing between circulation and wave propagation numerical models. Procedures and processes for operating the steering module are summarized, and an example demonstrates hydrodynamic coupling within the steering module.

Wave Transmission at Detached Breakwaters for Shoreline Response Modeling

Purpose: This Coastal and Hydraulics Engineering Technical Note (CHETN) evaluates selected available formulas for predicting wave transmission at rubble mound and armor unit structures, leading to recommendations for the most appropriate formulas for shoreline-response modeling. The GENESIS shoreline response numerical model is modified to allow for automated time-dependent calculation of the wave transmission coefficient, and a case study is presented to illustrate the new predictive capability.

Guidelines for Using the Eastcoast 2001 Database of Tidal Constituents within the Western North Atlantic Ocean, Gulf of Mexico and Caribbean Sea

Purpose: This Coastal and Hydraulic Engineering Technical Note (CHETN) describes the Eastcoast 2001 computed database of tidal elevation and velocity constituents. This database was developed to allow surface water elevation and currents to be quickly and easily defined in open waters within the Western North Atlantic Tidal (WNAT) domain. The WNAT domain encompasses the Western North Atlantic Ocean, the Gulf of Mexico and the Caribbean Sea. This CHETN summarizes the development of the Eastcoast 2001 tidal constituent database, presents global, basin specific and site specific error estimates, and discusses exactly what is computed, where it can be applied, and how it can and should be used. Limitations of the database are also described.

Reservoir Model for Calculating Natural Sand Bypassing and Change in Volume of Ebb-Tidal Shoals, Part I: Description

Purpose: This Coastal and Hydraulic Engineering Note (CHETN) provides information on a mathematical model developed to calculate natural sand bypassing and change in volume of ebb-tidal shoals. Subsequent CHETNs in this series will describe the interface and generalizations of the model to cover flood-tidal shoals, inlet-entrance channel, and other morphologic features at inlets.

2001

Beach Erosional Hot Spots: Types, Causes, and Solutions

Purpose: This Coastal and Hydraulic Engineering Technical Note (CHETN) discusses the types, causes, and example solutions of erosional hot spots (EHSs; singular EHS) by which they can be identified and measures that can be taken to prevent or cope with the erosion in an effective way. An EHS is an area with high erosion rate as compared to the adjacent beach or to expectations for the behavior of the beach. EHSs located adjacent to inlets can compromise beach nourishment performance or performance of the site as a placement area for beach-quality dredged material. Possible types of EHSs are extended to cover geologic or regional scales.

Field Data Recovery in Tidal System Using Artificial Neural Networks (ANNs)

Purpose: This Coastal and Hydraulic Engineering Technical Note (CHETN) describes how artificial neural networks (ANNs) can be used provide reliable estimates of missing values in a measured data set. The method is illustrated using data for a tidal lagoon, Biscayne Bay in Florida, USA.

A GIS Based Tool for Extracting Shoreline Positions from Aerial Imagery (BEACHTOOLS)

Purpose: This Coastal and Hydraulics Technical Note (CHETN) presents BeachTools, an ArcView TM 3.x Geographic Information Systems (GIS) extension designed to identify and quantitatively establish the position of the shoreline and other coastal features from aerial imagery.

Chronic Beach Erosion Adjacent to Inlets and Remediation by Composite (T-Head) Groins

Purpose: Beaches located directly down drift of inlets may become isolated from sediment sources and experience chronic erosion. Because shore-protection actions taken on a beach isolated from sediment sources may not significantly disturb the down-drift beach, highly efficient sand-retention structures such as T-head and L-head groins may be considered as a remediation measure. This Coastal Engineering Technical Note gives an overview of the performance and functional design procedures for T-head and similar composite groins.

Mathematical Model for Rapid Estimation of Infilling and Sand Bypassing at Inlet Entrance Channels

Purpose: This Coastal Engineering Technical Note describes a mathematical for rapid estimation of rates of infilling and bypassing at inlet entrance channels located on sandy or gravel shores. Infilling is assumed to occur by cross-channel transport. The calculation procedure requires information typically available or estimated in coastal navigation projects and is intended to provide guidance for projects where detailed studies cannot be performed. The procedure can be applied to any channel that meets the basic assumptions.

Estimation of Suspended Sediment Trapping Ratio for Channel Infilling and Bypassing

Purpose: This Coastal Engineering Technical Note describes a method for estimating the percentage of sand-sized material placed in suspension by breaking waves and carried by a cross-channel current to either fall into a navigation channel or travel across it. Required inputs are channel width and depth, depth in the vicinity of the channel, depth-averaged current velocity perpendicular to the channel, and sediment fall speed. The procedure is applicable to inlet entrances that experience breaking waves.

Morphological Asymmetries at Entrances to Tidal Inlets

Purpose: This Coastal Engineering Technical Note discusses selected morphologic symmetries of ebb shoals and channels at tidal inlets with implications for maintenance of navigation channels and sediment bypassing to the adjacent beaches.

Leaky Internal-Barrier Normal-Flow Boundaries in the ADCIRC Coastal Hydrodynamics Code

Purpose: This Coastal and Hydraulic Engineering Technical Note (CHETN) describes the methodology and input requirements for the leaky-barrier boundary feature in the Advanced Circulation (ADCIRC) coastal hydrodynamics code versions 40.02 and higher. This feature calculates flow over and through structures such as levees and jetties.

2000

Database of Inlet Navigation Projects and Structures Purpose: This Coastal Engineering Technical Note provides information about the online database of tidal inlet navigation projects and structures that is available on the World-Wide Web. This Note describes the database content, overviews how to access the database with a web browser, and explains how to extract information from the database.

Natural Mechanisms of Sediment Bypassing at Tidal Inlets

Purpose: This Coastal Engineering Technical Note describes mechanisms by which sediment bypasses both natural and improved tidal inlets. The note pertains principally to inlets on alluvial or sandy shores.

Where and Why Inlet Channels Shoal: A Conceptual Geomorphic Framework

Circulation Patterns at Tidal Inlets with Jetties

Purpose: This Coastal Engineering Technical Note provides guidance on interpreting horizontal circulation patterns at inlets.

Simulation of Current-Induced Scour in Movable-Bed Inlet Models

Purpose: This Coastal Engineering Technical Note provides guidance on using movable-bed physical models to predict erosion and deposition caused by currents in tidal inlet channels. A scaling relationship based on equilibrium scour depth allows observed model scour depths to be quantitatively scaled to full-scale dimensions. Appropriate situations are listed for which this mod- eling guidance can be applied.

Enhancements of the Numerical Model of the Longshore Current NMLONG to Include Interaction Between Currents and Waves (NMLong-CW)

Purpose: This Coastal Engineering Technical Note describes the Numerical Model of the Longshore current for Current and Waves (NMLong-CW) that accounts for the interaction between a current and surface waves. NMLong-CW can simulate wave transformation, the steady-state wave-generated longshore current, and change in water level at an inlet by waves and wind. NMLong-CW is a one-dimensional model and is limited to situations were longshore uniformity applies.

Field Data Collection at Coastal Inlets

Purpose: This Coastal Engineering Technical Note provides overview guidance on the collection of field data at coastal inlets. It contains a method for planning a data-collection program and identifies parameters, methods, and equipment useful for analyzing conditions at the site.

Hydraulic Processes Analysis System (HyPAS)

Purpose: This Coastal Engineering Technical Note describes a PC-Windows-based system for analyzing, visualizing, and archiving hydrodynamic and related field data taken at inlets and related estuarine and coastal waters. The Hydraulic Processes Analysis System (HyPAS) is also applicable to riverine and laboratory application.

1999

Shoal-Reduction Strategies for Entrance Channels

Purpose:This Coastal Engineering Technical Note (CETN) presents several methods for reducing sediment shoaling in navigation channels at coastal inlets and entrances.

Surfacewater Modeling System Tidal Constituents Toolbox for ADCIRC

Purpose: This Coastal Engineering Technical Note provides guidance on specification of tidal boundary conditions for the ADCIRC circulation model within the Surface-Water Modeling System (SMS). This technical note is one in a series prepared by the Coastal Inlets Research Program documenting specific features of the SMS developed for ADCIRC applications.

Sediment Budget Analysis System (SBAS)

Purpose: This Coastal Engineering Technical Note presents the Sediment Budget Analysis System (SBAS), a PC-based method for calculating sediment budgets at single or multiple inlets and at the adjacent beaches. The SBAS runs on the Windows 95, 98, and NT platforms. This CETN is a companion to CETN-IV-15, which presents sediment budget theory and methodology, and CETN-IV-16, which discusses uncertainty in sediment budgets. This Coastal Engineering Technical Note provides information about the potential use of a physical model facility dedicated to the study of inlets and equipped to represent the most significant physical processes at and around inlets.

Physical Model for Coastal Inlet Entrance Studies

Purpose: This Coastal Engineering Technical Note provides information about the potential use of a physical model facility dedicated to the study of inlets and equipped to represent the most significant physical processes at and around inlets.

Equilibrium Scour Depth at Inlets

Purpose: This Coastal Engineering Technical Note introduces a simple expression relating maximum discharge per unit width at a location in a tidal inlet to the depth of scour at that location. Application of this provisional guidance is illustrated by three examples.

Wave Breaking on an Opposing Current

Purpose: This Coastal Engineering Technical Note provides a method to estimate wave breaking on an opposing current, such as at coastal inlet entrances.

1998

Techniques for Measuring and Analyzing Inlet Ebb-Shoal Evolution

Purpose: This Coastal Engineering Technical Note provides techniques to measure and analyze the evolution of ebb shoals associated with tidal inlets.

Estimation of Uncertainty in Coastal-Sediment Budgets at Inlets

Purpose: To provide information and procedures for estimating uncertainty in coastal-sediment budgets at inlets. Incorporation of uncertainty provides bounds for the sediment budget and serves as an indicator of reliability and possible variability in a sediment budget.

Formulation of Sediment Budgets at Inlets

Purpose: To discuss the steps involved in developing a sediment budget in coastal reaches that include inlets. The types of data sets and analysis procedures useful in formulating sediment budgets, as well as a methodology for incorporation of both quantitative and qualitative data, are addressed.

Grid Development for Modeling Two-Dimensional Inlet Circulation

Purpose: To provide guidance for developing computational grids for numerical modeling of water level and current in and around inlets. This CETN applies to grid development for two-dimensional triangular finite-element and rectilinear finite-differnece models.

1997

PC Program for Coastal Inlet Stability Analysis Using Escoffier Method

Purpose: To provide information for determining coastal inlet stability using a personal computer program which is a tool in the Coastal Inlet Management Package of the Coastal Inlets Research Program.

Interpretation of Shoreline-Position Data for Coastal Engineering Analysis

Purpose: To provide background information and guidance for interpreting shoreline-position data. Such data are analyzed for assessing historic and recent shoreline change, estimating impacts of jetties and navigation channels on adjacent shorelines, formulationg sediment budgets, and calibrating and verifying numerical models of shoreline response. This Technical Note reviews definitions of the shoreline, their relation to the data sources, and characteristics of the observed shoreline shpae or signal that reflects the acting processes and measurement procedure.

Even-Odd Function Analysis of Shoreline Position and Volume Change Data

Purpose: To present the background and methodology for separating shoreline position and volume change data into symmetric (even) and anti-symmetric (odd) functions. Applicability and interpretation of the even-odd function analysis for engineering application is also discussed.

One-Dimensional Wave-Current Interaction

Purpose: To describe the theory and a computer program for calculating the wave height, wavelength, and wave steepness for monochromatic waves interacting with a uniform current for a one-dimensional channel.

Estimating Scour Caused by Deflected Ebb Flows

Purpose: To estimate maximum scour potential when tidal ebb flow is deflected by an inlet navigation jetty.