ENGR 691, Fall Semester 2010-2011 Special Topic on Sedimentation Engineering Section 73 Coastal Sedimentation. Yan Ding, Ph.D.
ENGR 691, Fall Semester 2010-2011Special Topic on Sedimentation EngineeringSection 73Coastal Sedimentation Yan Ding, Ph.D. Research Assistant Professor, National Center for Computational Hydroscience and Engineering (NCCHE), The University of Mississippi, Old Chemistry 335, University, MS 38677 Phone: 915-8969 Email: firstname.lastname@example.org
Objective • The lectures are to introduce morphodynamic processes driven by waves and currents in coasts, estuaries, and lakes. Emphasis is placed on understanding the features of sediment transport and morphological changes induced by combined waves and currents. Numerical modeling in morphodynamic process simulations will be briefly introduced.
Outline • Introduction of morphodynamic processes driven by waves and currents in coasts, estuaries, and lakes • Initiation of motion for combined waves and currents • Bed forms in waves and in combined waves and currents • Bed roughness in combined waves and currents • Sediment transport in waves • Sediment transport in combined waves and currents • Transport of cohesive materials in coasts and estuaries • Mathematical models of morphodynamic processes driven by waves and currents • Introduction of a process-integrated modeling system (CCHE2D-Coast) in application to coastal sedimentation problems
Course Mechanics • Grades – Grades will be based on the homework assignments and the lecture • Lecture notes: http://www.ncche.olemiss.edu/~ding/Teaching/Engr691_73_Fall_2010/
References • van Rijn, L.C., (1993). Principles of sediment transport in rivers, estuaries and coastal seas, Aqua Publications, ISBN: 90-800356-2-9. http://www.aquapublications.nl/page9.html PART I: EDITION 1993; 715 pagesPART II: SUPPLEMENT/UPDATE 2006; 500 pages • Dean, R. G., and Dalrymple, R. A. (2002). Coastal Processes with Engineering Applications, Cambridge Press. • Sorensen, R. M. (1993), Basic Wave Mechanics for Coastal and Ocean Engineering, Wiley-Interscience (ISBN 0471551651). • Coastal Engineering Manual (2002). Coastal Engineering Manual, Part II: Coastal Hydrodynamics, US Army Corps of Engineers, ERDC, Report Number: EM 1110-2-1100. (http://184.108.40.206/publications/eng-manuals/em1110-2-1100/PartII/PartII.htm ). • Mei, C.C. (1989). The Applied Dynamics of Ocean Surface Waves, World Scientific, Singapore. • Dean, R.G. and Dalrymple, R.A. (1992). Water Wave Mechanics for Engineering and Scientists, World Scientific, Singapore.
Beautiful Coasts Sunrise at Turtle Bay Resort Hotel, Honolulu, Hawaii, 04/14/2008 Turtle Bay Resort Hotel, Honolulu, Hawaii, 04/15/2008 Waves in Turtle Bay, Honolulu, Hawaii, 04/15/2008
Estuaries and Coastal Waters Barrier Island Breaching Coastal Inlet Mouth of Columbia River, WA A small estuary Ocean City Beach looking north, Maryland
Vulnerable Coasts Wave crashed against a boat that washed into Highway 90 in Gulfport, MS, AP Photo Storm Surge, Hurricane Katrina Water spilled over a collapsed levee in New Orleans on Tuesday (8/30/2005)
Erosion in the beach A beautiful beach before 13 years Embankment and groin for shore protection
Hurricane IsabelHatteras Island Breach,21 Sep 03 (Breached ~ 18 Sep 03 )
Vulnerable Coasts Structure Failure by Katrina US 90, Bilox, MS, Feb 26, 2006
Analysis of Climate Change http://www.tidesandcurrents.noaa.gov/sltrends.html Long-term Variations in Sea Level and Analysis of Trends: NWLON Station Analyses New Global Station Analyses Exceedance Probability Analyses and the 100-year Event :* Annual Exceedance Probability Curves 1%, 10%, 50%, 99% Exceedance Probability Levels 12 * In development 2008
Landscape Change: Predicted Landloss in Louisiana USGS Published Landloss Since 1932 and Projected For the Next 45 Years 1932 1956 1978 1988 2000 2050 NWRC
Spatial and Temporal Multi-Scales of Hydrodynamics and Morphology in Coasts and Estuaries • Small-Scale Processes(0.1mm-10m; 0.1s-1day) • Fluid and sediment motions in turbulent wave-current bottom boundary layer • Intermediate-Scale Processes(1-10km; 1s-1yr) • Wave breaking across surf zone, wave-induced nearshore current, lower frequency infragravity wave motions by storm surges, sediment transport alongshore and crossshore, fresh water and sediment from rivers during floods, and tidal motions • Large-Scale Processes(1-100km; months-decades) • Ocean circulations, sea-level rising, global scale weather change, long-term shoreline change, etc. • A challenging goal: • a realistic coupled waves-currents-morphologic-ecological evolution model See http://www.coastal.udel.edu/coastal/
Coupling of the small-, intermediate-, and large-scale process:turbulent boundary layerwave deformationNearshore circulationSediment movementShoreline changeBar and tough
Strait of Georgia River flow Shoaling Refraction Breaking Reflection Wave Transformation Wave breaking in a tidal front of the Fraser Estuary, BC, Canada (after Baschek) Wave breaking in Turtle Bay, HI, 4/14/08 Columbia River Entrance, WA/OR after Smith & Cialone (2000) Wave breaking in a tidal front of an inlet
Wave Transformation Shoaling Refraction Breaking Reflection Columbia River Entrance, WA/OR, 1966 Smith & Cialone (2000)
Deformation of Irregular Wave (1) • Deformation of wave • Refraction • Diffraction • Reflection • Wave Breaking • Bottom Friction • …… Incident Wave Nearshore wave processes Seminar for Course ENGR 691
Nearshore Current System (Schematically) One Cell Incident Wave Mass Transport Rip Current Longshore Currents generated by breaking wave Seminar for Course ENGR 691
Wave Parameters crest trough Figure. Definition of wave parameters
Wave Celerity (1) • Solution of nonlinear equation (Newton’s method) Dispersion relation: Newton’s method n = 1,2, …… • A good estimate of initial value of L (deep wave length)
Wave Breaking in beach Deep wave breaking
Near-bed Orbital Velocities Applying linear wave theory, the peak value of the orbital excursion (Aδ) and velocity (U δ) at the edge of the wave boundary layer can be expressed as
Current & Sediment Wave Breaking Line Longshore Sediment Transport in Coasts Ocean City Beach looking north, Maryland Downloaded from: http://images.usace.army.mil/main.html Observations on natural beaches as well as in laboratory wave basins have confirmed that the longshore current is largely confined to the surf zone. This longshore current drives the shoreward movement of longshore sediment transport.
Longshore and Cross-shore Sediment Transport in Local Scale(2D Morphological Change in River Mouth) Sediment alongshore ql=? Sediment cross-shore qc=? Deposition of littoral sand Movement of littoral sand River Mouth Erosion Protection (Artificial Headland) The total longshore sediment transport model is not useful for this case.
Jetty and Navigation Channel Portage Lake Harbor, Onekama, Michigan From Digital Virtual Library, U.S. Army Corps of Engineers
Detached Breakwater Physical model testing of detached breakwaters and beach morphology in CHL's Longshore Sediment Transport Facility (LSTF) http://cirp.wes.army.mil/cirp/gallery/gallery.html
Scour holes at Indian River Inlet, Delaware Aerial Photo Scour: view looking seaward http://cirp.wes.army.mil/cirp/gallery/gallery.html
Waves Longshore Current Tides River River Hydrodynamic and Morphodynamic Processes in River Mouths and Estuaries Flood Shoal Tidal Inlet Touchien River Estuary An estuary: a semi-enclosed coastal water body with a river inflow Yangtze River Estuary