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Hydraulics Engineering


Tidal Hydrology, Hydraulics, and Scour at Bridges

Hydraulic Engineering Circular No. 25

First Edition

Publication No. FHWA-NHI-05-077 December 2004
PDF Version (4.7 mb)

Table of Contents

List of Figures
List of Tables

Technical Report Documentation Page
Chapter 1 - Introduction
1.1 Purpose
1.2 Background
1.2.1 Previous Studies
1.2.2 Tidal Waterways
1.3 Manual Organization
1.4 Dual System of Units

Chapter 2 - Tidal Hydrology and Boundary Conditions
2.1 Introduction
2.2 Astronomical Tides and Tidal Currents
2.2.1 Tide Types, Periods, and Levels
2.2.2 Tidal Days
2.2.3 Tidal Epochs
2.2.4 Tidal Predictions
2.2.5 Tidal Range and Variability
2.2.6 Simulating Tide Constituents
2.2.7 Tidal Currents
2.3 Storms and Other Climatologic Conditions
2.3.1 Tropical Storms and Hurricanes
2.3.2 Extratropical and Nor'easter Events
2.3.3 Tsunamis, El Niño, and Winter Storm Events
2.4 Storm Surges
2.4.1 Factors in Surge Formation
2.4.2 Surge Constituents
2.4.3 Surge Configuration
2.5 Predicting Storm Surge Hydrology
2.5.1 Issues in Selection of Storm Surge Hydrology
2.5.2 Probabilistic Approaches for Surge Prediction
2.5.3 Deterministic Approaches for Surge Prediction
2.6 Storm Tides
2.6.1 Combining Storm Surge and Astronomical Tides
2.6.2 Single Design Hydrograph Approach
2.7 Wind Considerations
2.8 Upland Runoff
2.9 Other Considerations
2.9.1 Sea Level Changes
2.9.2 High-Velocity Flows
2.10 Tide and Storm Surge Example Problems (SI)
2.10.1 Example Problem 1 - Tide Heights (SI)
2.10.2 Example Problem 2 - Simple Tidal Constituent Equation (SI)
2.10.3 Example Problem 3 - Complex Tidal Constituent Equation (SI)
2.10.4 Example Problem 4 - Storm Surge Hydrograph (SI)
2.11 Tide and Storm Surge Example Problems (U.S. Customary)
2.11.1 Example Problem 1 - Tide Heights (U.S. Customary)
2.11.2 Example Problem 2 - Simple Tidal Constituent Equation (U.S. Customary)
2.11.3 Example Problem 3 - Complex Tidal Constituent Equation.(U.S. Customary)
2.11.4 Example Problem 4 - Storm Surge Hydrograph(U.S. Customary)

Chapter 3 - Basic Tidal Hydraulic Methods
3.1 Introduction
3.2 Tidal Prism
3.3 Orifice Approach
3.4 Routing Approach
3.5 Method Selection

Chapter 4 - Tidal Hydraulic Modeling
4.1 Introduction
4.2 Model Extent
4.3 One-Dimensional Modeling
4.4 Two-Dimensional Modeling
4.5 Model Selection
4.6 Model Calibration and Troubleshooting
4.6.1 Model Calibration
4.6.2 Model Troubleshooting
4.6.3 Evaluating Results
4.7 Physical Modeling in Coastal Engineering
4.7.1 Coastal Engineering Models
4.7.2 Advantages and Limitations of Physical Models
4.7.3 Types of Physical Models in Coastal Engineering
4.7.4 Modeling of Estuary Processes
4.7.5 Modeling Coastal Erosion and Coastal Structures
4.7.6 Modeling Tidal Inlets
4.7.7 Physical Model Facilities

Chapter 5 - Tidal Scour
5.1 Bridge Scour Analysis for Tidal Waterways
5.1.1 Overview
5.1.2 Level 1 Analysis
5.1.3 Level 2 Analysis
5.1.4 Scour Equations
5.2 Time Dependent Contraction Scour
5.3 Time Dependent Local Scour
Chapter 6 - Data Requirement and Sources
6.1 Introduction
6.2 Tide Gages
6.3 Tidal Benchmarks and Vertical Datums
6.3.1 Tidal Datums
6.3.2 Fixed Datums
6.3.3 Datum Conversions
6.4 Hurricane Surge Data
6.5 Wind Data
6.6 Bathymetric and Topographic Data
6.7 Aerial Photography and Mapping

Chapter 7 - Other Considerations
7.1 Coastal Zones and Beach Dynamics
7.1.1 Introduction
7.1.2 Coastal Zones
7.1.3 Pacific Coastlines
7.1.4 Dynamic Beach Processes
7.1.5 Longshore Current and Sediment Transport
7.2 Wave Analysis
7.2.1 Wind Waves
7.2.2 Wave Height Computations
7.3 Shore Protection Countermeasures
7.3.1 Seawalls
7.3.2 Revetments
7.3.3 Riprap Shore Protection
7.3.4 Jetties
7.3.5 Groins

Chapter 8 - Literature Cited 8.1

Appendix A Metric System, Conversion Factors, and Water Properties
Appendix B Our Restless Tides
Appendix C Hurricane Frequency
Appendix D NOAA Hurricane Properties
Appendix E ADCIRC Surge Estimates

List of Figures

Figure 1.1 Estuary
Figure 1.2 Bay and inlet
Figure 1.3 Passages
Figure 1.4 Barrier Islands forming complex tidal systems
Figure 2.1 The principal types of tides
Figure 2.2 Tide levels terminology
Figure 2.3 NOAA predicted and observed tide for Annapolis, Maryland
Figure 2.4 NOAA predicted and observed tide for Anchorage, Alaska
Figure 2.5 Example harmonic constant data from NOAA
Figure 2.6 Example of predictions from harmonic constant data
Figure 2.7 Tide levels in the Chesapeake Bay
Figure 2.8 Tide levels along the James River, Virginia
Figure 2.9 Tide translation on the James River, Virginia
Figure 2.10 Storm Tracks along the North American Coastline (1984-2003)
Figure 2.11 Coastal water levels during El Niño event
Figure 2.12 Coastal water levels following El Niño event
Figure 2.13 Alternative synthetic storm surge hydrographs
Figure 2.14 Observed storm tides for Hurricane Gordon
Figure 2.15 Comparison of observed and synthetic storm tides for Hurricane Gordon
Figure 2.16 Example surge design hydrographs
Figure 2.17 Schematic of hurricane windfield with a forward speed "f"
Figure 2.18 Ratio of wind speed for duration t to the 2-hour winds speed
Figure 2.19 Wind speed adjustment for nearshore terrain
Figure 2.20 Yearly sea level, Atlantic Coast
Figure 2.21 Solution to Example Problem 4 (SI)
Figure 2.22 Solution to Example Problem 4 (U.S. Customary)
Figure 3.1 Estuary
Figure 3.2 Simplified tidal hydrograph
Figure 3.3 Typical tides in an estuary
Figure 3.4 Typical storage relationships for tidal prism method
Figure 3.5 Bay and inlet
Figure 3.6 Typical tides in a bay
Figure 3.7 Factors influencing the selection of a tidal modeling approach
Figure 4.1 Illustration of 1-D model geometric layout
Figure 4.2 Example of 2-D model layout and results
Figure 4.3 Columbia River estuary model
Figure 4.4 Typical 2-dimensional coastal structure model
Figure 4.5 Details of jetty plans, Shrewsbury Inlet
Figure 4.6 Photograph of hydraulics laboratory with river model during testing
Figure 4.7 Typical laboratory wave tank
Figure 4.8 Typical laboratory wave basin
Figure 5.1 Typical surge hydraulic conditions
Figure 5.2 Time dependent scour results
Figure 6.1 Definition sketch for tide level terminology
Figure 6.2 Tidal benchmark datum comparison, from NGS web site
Figure 7.1 Beach profile terminology
Figure 7.2 Nearshore wave processes terminology
Figure 7.3 Schematic diagram of storm wave attack on beach and dune
Figure 7.4 Indian River Inlet, Delaware
Figure 7.5 Wave characteristics
Figure 7.6 Wave height plus surge
Figure 7.7 Definition sketch for wave calculations
Figure 7.8 Seawall at San Francisco's Great Ocean Highway
Figure 7.9 Seawall at Galveston, Texas
Figure 7.10 Stone revetment
Figure 7.11 Riprap rock shore protection - typical design configuration
Figure 7.12 Jetty entrance for navigation channel
Figure 7.13 Core-loc armor units on Manasquan Jetties being placed over dolos
Figure 7.14 Schematic showing effect of a single groin on the shoreline and the effect of a continuous groin field
Figure 7.15 Concrete groin constructed with precast units
Figure 7.16 Timber pile groin

List of Tables

Table 2.1 Tide Predictions (High and Low Waters) January 2004, NOAA
Table 2.2 Tidal Differences
Table 2.3 Mean Tidal Ranges (ft)
Table 2.4 Saffir-Simpson Hurricane Scale
Table 6.1 Internet Sources of Relevant Data for Storm Surge Modeling
Table 7.1 Suggested KD Values for Different Armor Types

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