OCN 5401

Chapter 11

Coastal Ocean

Instructor: Dr. George A. Maul

gmaul@fit.edu / X 7453

Earth’s Estuaries

Estuary ClassificationsKnauss Nybakken Sumich Kennett

Salt Wedge Coastal Plain Coastal Plain Salt Wedge

Partially Mixed Tectonic Bar Built Partially Mixed

Well Mixed Fjord Delta Lagoon

Negative Delta

Estuaries and Inlets

Estuarine Issues

Mixing

Richardson Number

Ri < 0.25 internal shear waves develop

𝜒=𝑣𝑜𝑙𝑢𝑚𝑒𝑡𝑟𝑎𝑛𝑠𝑝𝑜𝑟𝑡=𝑚3

𝑠

Residence Time (t)

and

Sebastian Inlet

Coastal Ocean Observing System

Coasts and Beaches

A healthy coral reef

creates sand for healthy

beaches

Beach Terminology and Sand

D(mm) Wentworth Grade Phi

>256 Boulder -8

>64 Cobble -6

>4 Pebble -2

>1 Very course sand 0

>1/2 Course sand 1

>1/4 Medium sand 2

>1/8 Fine sand 3

Beach Sand Erosion and Accretion

h𝑤𝑇

>2⇒𝐸𝑟𝑜𝑠𝑖𝑜𝑛h𝑤𝑇

<2⇒ 𝐴𝑐𝑐𝑟𝑒𝑡𝑖𝑜𝑛

h=𝑤𝑎𝑣𝑒h h𝑒𝑖𝑔 𝑡 ,𝑤=𝑆𝑡𝑜𝑘𝑒𝑠 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 ,𝑇=𝑤𝑎𝑣𝑒𝑝𝑒𝑟𝑖𝑜𝑑

Short period wind waves(T<7 seconds)

Long period swell waves(T>9 seconds)

Classification of River Deltas

Brazos River Delta Ganges River Delta

Amazon Delta

6300 km3/year

~ 1/150 of Gulf Stream

The drainage basin of the Mississippi River encompasses a major portion of the central United States.

How much is this??

The Mississippi River has built a series of overlapping subdeltas as it continually dumps sediment into the Gulf of Mexico.

Satellite Imagery of the Classical Birdsfoot Delta at the mouth of the

Mississippi River

Mississippi River entering Gulf of Mexico - Note the color contrast.

(Picture from John Trefry)

Changes in sediment composition along the Nile River

Nile Delta Sediments

Denial is not a river in Egypt Photograph

False color Image

Semi-Enclosed Seas

Intra-Americas Sea

Intra-Americas Sea SSH http://www7320.nrlssc.navy.mil/GLBhycom1-12/navo/intramssh_nowcast_anim365d.gif

Lakes – The Aral Sea

Artificial Lakes

Lake Nasser

Coastal Ocean of the

Southeastern United States

OCN 5401

Questions?

Chapter 11