wave mechanics assignment – example solution

Wave Mechanics Assignment – Example Solution

Cross Shore Morphology

”Dynamic personality" of the beach

Beach sediment is highly mobile - advantageous in that a beach can rapidly adjust its profile in response to a changing wave climate

Profile change can be considered a natural defensive adjustment which can change where wave breaking occurs and how energy can be dissipated across the surf zone.

By monitoring changes to the cross shore morphology (beach and nearshore topography), we can better understand beach behavior and how it changes in response to changing oceanic conditions.

“Emery Board” - Cartoon Man

Kenneth Orris (K. O.) Emery (1914-1998)

Straightforward, effective technique – has advantage of rapid surveying with minimal equipment:

1. Two flat boards connected by a rope of standard length

2. Sight across top of seaward board to level of horizon – record ‘a’ (see figure above), which is equal to ‘b’ = the negative “rise” over the “run” (rope length)

3. Repeat the procedure from dune to low water

“Emery Board” - Our class next week

Beach Profiling - Other Techniques

surfrover

CRABNumerous vehicles have been used within the surf zone and on the beach.

Basic premise - they can report "where" they are, in 3 dimensions, quite accurately

Correction is applied for the difference above the sea floor to obtain bathymetry.

Most common modern technique

High precision

Can be mounted on a backpack, a four-wheeler, a jetski, or a boat.

RTK - DGPS Beach Profiling

RTK - DGPS - UF Geo Dept.

Argus – “Remote Sensing” / Video Technique

Operating from Feb. 2003 to present

Argus Station

Oblique view of sand body migration

Panoramic view

Map view

East West

Panoramic View to Map View

Use the tide to contour the beach.

Large tidal range - 8+ meters.

Tide represents a horizontal plane of known elevation.

Intersection of tidal plane w/ beach surface gives a contour line.

Permits mapping of beach profiles.

Beach Profiling Technique

R_04_TideContouringMovie_June_14_2003.avi

Show HomerCam6_July6-10_2004.mov

Comparison of profile aquisition