Joan Pope. Goals of the CEM. Expand, update, and replace the SPM Practical and easy to use State-of-the-art technical guidance document for coastal flooding, navigation, and shore protection projects Include basic principles of coastal processes
Goals of the CEM • Expand, update, and replace the SPM • Practical and easy to use • State-of-the-art technical guidance document for coastal flooding, navigation, and shore protection projects • Include basic principles of coastal processes • Include methods for computing coastal planning, design, construction, and maintenance parameters • Integrate computer-based and field data collection tools with the fundamentals of good engineering practices • “…..written at a level suitable for USACE District, BS-level engineering graduate who has no advanced academic training in coastal engineering.”
What’s new? • Spectral waves • Harbor and navigation design • Coastal geology • Dredging and disposal • Sediment prediction and management • Structure inspection, repair, and rehab • Wetlands and protected locations • Environmental enhancements • Monitoring and maintenance • Risk and uncertainty • Numerical simulation and modeling technology • Beach fill design • Functional design emphasis • Project development process, ………etc…….etc…..etc.
OUTLINE • PART I: Introduction • PART II: Coastal Hydrodynamics • PART III: Coastal Sediment Processes • PART IV: Coastal Geology • PART V: Coastal Project Planning & Design • PART VI: Design of Coastal Project Elements
Water wave mechanics • Meteorology and wave climate • Estimation of nearshore waves • Surf zone hydrodynamics • Water levels and long waves • Hydrodynamics of tidal inlets • Harbor Hydrodynamics • Hydrodynamic analysis and design conditions
Linear Wave Principles Other Wave Theories Korteweg and deVries and Boussinesq Fourier Approximation – Fenton’s theory Irregular Wave Analysis Directional Wave Spectra Random Wave Simulation Water Wave Mechanics Part II-1
Meteorology and Wave ClimatePart II-2 • Estimating Marine and Coastal Winds • No significant changes, as per SPM 1984 • Winds from near-surface observations • Winds from pressure fields and weather maps • Modification for • Level • Duration • Overland or overwater • Air-sea temperature stability
ESTIMATION OF NEARSHORE WAVESPart II-3 Refraction, diffraction, shoaling, breaking, dissipation due to friction, dissipation due to percolation, additional growth due to winds, wave-current interactions, wave-wave interactions
1. A large storm generates deepwater waves that propagate across shallow water while the waves continue to grow due to wind 2. A large storm generates waves in a remote area and as they cross shallow water with negligible wind they propagate to the site as swell 3. Wind blows over a shallow water fetch and as the waves grow they interact with the bottom Types 1 and 3 require numerical model whereas 2 can be approximated using a monochromatic wave Three Classic Cases of Wave Transformation
RCPWAVE • Based on Mild-Slope equation • Includes wave breaking (first occurrence) • Consistent with theories used in calculation of longshore sediment • transport and shoreline change • Suitable for regions: 10’s of km • Grid resolution: fractions of wave lengths (1/10 or smaller) • Solution technique: finite difference • Neglects reflections off of structures and rapid changes in bathymetry • Output gives wave height and direction variability with changing • water levels
REFDIF • Based on Mild Slope – wave current model (Kirby (1984)) • Simple breaking criteria (H = 0.78 d) • Includes damping due to Bottom boundary layer; Sand-bed percolation; Turbulent bottom boundary layer • Wave non-linearity • Smooth correction to Stokes for shallow water • Numerical noise filter • Suitable for regions: 10’s of km • Grid resolution: 5 to 6 grid points per wavelength (optimum) • Solution technique: finite difference • Neglects reflections off of structures and rapid changes in bathymetry
Steady state Spectral Model • Solves complete radiative transfer equation and includes • Propagation Effects – refraction, diffraction, shoaling, wave-current • Source term effects – breaking, wind, wave-wave • Deals with stochastic wave components so suitable • over very large distances • Can also incorporate phase information over short distances • near discontinuities such as structures • Assumptions • Nearshore transformations dominated by conservative processes • (refraction, shoaling and diffraction) • Predictions based on uni-directional monochromatic wave theories • Can provide solutions equivalent to behaviour of directional spectra STWAVE
Advanced Model Limitations Almost all of these models are regularly used to simulate conditions outside a strict interpretation of the limits, with the results often effectively accurate CEM specified Major Limitations RCPWAVE – inaccurate for wave crossing behind shoals or in the vicinity of structures. Wave approach not too OBLIQUE REFDIF– should not be used with highly oblique waves STWAVE – under-represent wave focusing for narrow swell
SURF ZONE HYDRODYNAMICS Part II-4 Breaker Criteria – Irregular Waves H rms = 0.42 d or Hmo = 0.6 d
Water Levels and Long Waves Part II-5 • Water Surface Elevation DatumNEW • Seiches - as in SPM 84 • Modeling of Long Wave HydrodynamicsNEW • Physical Models • Numerical Models (ADCIRC)
Hydrodynamic Analysis and Design Part II-8 • Analysis of Key Meteorological and Hydrodynamic Processes • Extreme wave analysis • Storms • Persistence • Long Waves • Water Level Climate
Sediment Properties • Longshore Transport • Cross-shore Transport • Wind-blown Transport • Cohesive shores • Outside the Surf Zone (Shore-face)
Terminology • Environments • Classification and Morphology • Morphodynamics
How the CEM will be used… Part II – Hydrodynamics Part III - Sediments Part IV - Geology (Part V) Problem Identification Engineering Process Alternative Solutions Site Characterization Design Conditions Project Development Part VI Design Components Structural Elements Materials Construction O&M
Engineering Parts V and VI Include: • Planning and design process • Problem definitions • Site characterization and design conditions • Functional performance • Risk and uncertainty • Empirical design techniques • Analytical procedures per design element • Case examples
Planning & Design Process • Site Characterization • Shore Protection Projects • Beach Fill Design • Navigation Projects • Inlets/Harbors • Environmental Enhancement • Federal Role in Hazard Mitigation
Part V.1 – Planning and Design Process Six Major Planning Steps Generic Design Chart Planning Coordination Requirements Design Constraints Data Needs & Sources The process of developing a coastal project must be iterativeto ensure that the final product is optimumfrom both the technical and economic viewpoints acceptable to the various levels of decision makers and all project partners.
Getting Started • “What is the problem?”*** • To achieve a successful coastal project plan and design requires that the engineer must start with a completely open mind, one without preconceived notions of the ultimate solution or a specific solution to advocate. ***“What is the project trying to accomplish?”(Quantify expectations!)
Project Need Project Problem Statement CP Module Damages Quantify w/o Project Condition Is the Problem Statement Still Valid Yes Abandon Project Exit CP Module Simple Functional Analysis and Identification of Alternatives No Yes Environmental Economic, Political, Aesthetic Constraints Yes Did You Fulfill All of Problem Statement? No No Modify Project Problem Statement Yes Is Federal Participation Justified? No Yes Economics Select Alternative Generic Project Development Chart
Breakwater Non-Structural Seawall Other Dredging, etc. Do Nothing Environmental and Economic Constraints Modify Functional Design? Select/Modify Functional Design CP Module Test Functional Design Is Functional Design OK? Continue to Figure V-2-2
Design Constraints • Scientific and Engineering Understanding of Nature • The CEM emphasizes the understanding and ability to analytically and numerically model nature. • 2. Economics • 3. Environmental • 4. Institutional, Political (Social), Legal • 5. Aesthetics
The “CP Module” SBAS ADCIRC Coastal Process Module, is defined as a repository of physical data and analysis tools relevant to the coastal problem. Wind, waves, currents, water levels, bathymetry, geomorphology, stratigraphy, sediment characteristics, sediment transport processes, etc. and the analysis tools (mainly numerical models) make up the CP Module. A fully 3D, dynamic model to simulate coastal processes at different scales for different settings does not exist. STWAVE GENESIS SBEACH ETC.
Costs Initial Costs Maintenance Costs Alteration/Removal Costs Total, Life-Cycle Cost Design Life Interest Rate Damage Failure Balanced Design Storm damage reduction & mitigation Ecosystems restoration. Recreation and tourism benefits Waterfront property (greater value and generates higher tax revenue). Coastal, beach related travel and tourism industry. Costs and Benefits
Storm Damage Reduction Benefits Methodology • Inventory structures. • Calculate depreciated replacement cost of the structures and content value. • Obtain the water level, storm frequency-of-occurrence data for the site and accompanying wave and shoreline erosion data. • Obtain and run storm damage calculation models. • Apply the models for without project conditions and for considered alternatives and sub-alternatives.
Sea Level Rise • Over the last 100 years – 30 cm (3mm / yr) on the East Coast and 11 cm (1.1mm / yr) along the West Coast. • Gulf of Mexico coast is high variable – 100 cm in the Mississippi delta plain to 20 cm along Florida’s West Coast. • Statistics related to and impact of sea level rise are debated regularly in scientific circles. • Existing rates of mean sea level rise have not been a severe economic constraint in shore protection design. • Anthropogenic effects (ie; jettied tidal inlets) causing downdrift, beach erosion have resulted in larger impacts. • Long-term, relative changes in sea level can be incorporated into storm surge analysis.
Data Needs and Sources …etc.
(A) CHANGES TO THE NATURAL, PHYSICAL SYSTEM APPROACH Class 2. Beach Stabilization Structures & Facilities Sills& (Vegetation) Groundwater Drainage Type Breakwaters Groins Headland Detached Single System Tuned Shoreline Normal Angled Single System Notched Permeable Adjustable Shaped (T or L) Geometry (Configuration) or Location Shoreline Submerged Perched beach (Submerged Aquatic Vegetation) Beach drain Bluff dewatering Interior drainage Rock Precast concrete units Sheet-pile (steel, timber, etc.) System of pipes, pumps with sumps Construction Material Geotextiles bags
APPROACH (A) CHANGES IN MAN’S SYSTEM Class 4. Adaptation & Accommodation Flood Proofing Zoning Retreat Type Elevated Structures Raise Grade Sandbags Flow Diversion Individuals Communities Infrastructure Move Structures Geometry (Configuration) or Location Setbacks Land use restrictions Public Lands (Institutional) Construction Material Single-Family homes on timber piles
Types & Functions of Structures • Site Specific Conditions • Materials & Construction • Fundamentals • Reliability • Case Examples • Repair/Rehab & Modification
Fundamentals of Design Part VI-5-2 • Wave Runup and Overtopping • Wave Reflection and Transmission
Wave Runup- Smooth Impermeable Slopes gr - Influence of surface roughness gb - Influence of fronting berm gh - Influence of shallow water gb- Influence of approaching wave angle
Runup on Rock Armored Slopes Impermeable Rock Slopes Coefficients Permeable Rock Slopes
Wave Overtopping Definition of freeboard Wave Overtopping... • Occurs where the highest runup levels exceed the freeboard • Unevenly distributed in space and time • Usually expressed as time-averaged overtopping discharge • Discharge from a single wave can be 100 times average
Wave Reflection Seelig Equation Structure a b With
Wave Transmission Transmission Coefficient
FORMS OF RELEASE • USACE ENGINEERING MANUAL • Official EM on Corps website • Non-interactive PDF version • Currently older-versions of Parts III and IV only • INTER-ACTIVE ELECTRONIC VERSION • Developed by non-government partner (Veri-tech) as commercial product • Parts I-IV newly released • PUBLISHED HARDCOPY • Government Printing Office • Entire document to be released at one time (2002) • Limited updates
STATUS • PART I: Introduction ON WEB • Includes definitions, history, diversity • PART 2: HYDRODYNAMICS ON WEB • EC-1110-2-289 Released 9/96 as hardcopy • PART 3: SEDIMENT PROCESSES • EC-1110-2-292 Released 3/98 on web as PDF file • Revised and in final format • Minor figure improvements • PART 4: GEOLOGY ON WEB • EM 1110-2-1810 released 1/95 as hardcopy Glossary of Terms –in draft form, under review
PART V:Project Planning and Design DONE: CH 1, 2, 3, 4, 5 & 7 FINAL REVISIONS 6 (Inlets) 8 (Federal Requirements) PART VI: Design of Project Elements DONE: CH 2, 3, 4, & 5 FINAL REVISIONS 6 (Risk/Reliability) SOME WRITING LEFT 7 (Case Examples) 8 (Repair & Rehab) 1 (Intro) STATUS (continuing)
FUTURE INITATIVES • FINISH THE darn THING! • RELEASE USACE ON-LINE VERSION • PUBLISH GPO HARD-COPY VERSION • CONTINUING TECHNICAL SUPPORT AND UPDATES • COORDINATION WITH CRDA PARTNER • USER WORKSHOPS/CLASSES • EDITORICAL CORRECTIONS • INCORPORATE R&D ADVANCES • APPENDICES & NEW SECTIONS AS REQUIRED