OCEN 201 Introduction to Ocean & Coastal Engineering Coastal Processes & Structures Jun Zhang

Coastal Processes Typical beach profile and coastal zone - Beaches dissipate wave energy and are constantly adjusting to the wave environment (shoaling, wave breaking, sand bar & surf zone, Fig. 4-1, pp80) Littoral Transport (sediment transport) - Long shore transport (parallel to the shoreline, long shore current) - Offshore-onshore transport (perpendicular to the shoreline)

Beach Profile Fig. 4-1, pp102

Consequences of Coastal Processes Beach erosion (Natural or Man-Made Causes) Table 4-1 pp104 (old E. pp81) Beach Protection & Nourishment - coastal structures

Coastal Erosion

Hwy 87 Texas Coast Infrastructure Property Environment Infrastructure Property Environment

Beach Nourishment

Economic value of Beaches

Coastal Processes Wind and Waves Sediment Transport

Coastal Structures Break waters: (rubble mound, sheet pile, stone asphalt, Dolos, concrete cassions, floating structures (coastal & offshore)) Jetties & Groins (normal to the shorelines) Sea walls Bulkheads, Revetments, G-tubes Sand Bypassing (continue the littoral process; passive and active) Ports, Harbors and Marinas

Shore Protection Projects- Breakwaters

Breakwater

Waterway Navigation Jetties

RUBBLE MOUND BREAK- WATER

VERTICAL BREAKWATER FIGURES :

Design Considerations

Shore Protection Projects- Groins

Shore Protection Projects- Revetments

Different Kinds of Dolos Concrete & Reinforced Concrete

Dolos

Various Sea Walls

Shore Protection Projects- Seawalls Construction of Galveston seawall ~ 1902

Ports and Harbors

New South Wales and Queensland, Australia Sand Bypass Facility

Jetties at the entrance of Tweed River Outlet of the sand pump

Laboratory Research Research Experience for Undergraduates (REU) Program Research Experience for Undergraduates (REU) Program

Haynes Coastal Engineering Laboratory

Wave Refraction*, Diffraction & Reflection Wave Refraction: The direction of waves may change when they enter from deep to shallow water or from shallow to deep water. Deep-1 Shallow-2 Shallow-1 Deep-2

Wave direction is normal to the wave crest line Examples of Wave refraction in the costal zone, see pp 117 Fig 4-21 (old Edition: pp 90 Fig. 4-12). Wave direction is normal to shore line. In other words, wave crest-line is parallel to the shore line.

Wave Refraction

Phenomena of wave shoaling (wave enters from deep water to shallow water) Wave refraction Wave length becomes shorter Wave group velocity is reduced Wave becomes steeper, which leads to wave breaking. Wave breaking leads to the generation of long-shore current. Definition of the surf zone: from the first breaker (due to water depth) to the shore line.

General Refraction Analysis

pp (old edition pp91-92)

Wave Diffraction: When wave energy is transferred laterally to wave direction, this phenomenon is known as wave diffraction. Wave diffraction occurs when waves passing by a surface piercing body. It may occur in deep or shallow water. An example in shallow water is wave diffraction behind a breaker water. See Fig at pp119 (old edition Fig at pp93). (internet examples)

Wave Reflection and Transmission: when the water depth suddenly changes, part of the incident wave energy is reflected in the direction opposite to the incident wave direction, part energy continues to propagate (transmit) in the incident wave direction.

Using Fig 4-23 at pp 120 (old edition Fig at pp 94), you may determine the reflection coefficient based upon the surf parameter.

Wave Runup Wave runup is important to the design of the height of coastal structure, such as seawalls and breakwaters.

Sediment Transport

Reading Assignment: Sediment Transport & Scour Littoral Transport (sediment transport in coastal or littoral zone) Coastal Structure (jetties, groins, breakwater, sand-bypass & G-tubes) Dredging

Reading Assignment: Sediment Transport & Scour Littoral Transport (sediment transport in coastal or littoral zone) Coastal Structure (jetties, groins, breakwater, sand-bypass & G-tubes) Dredging