Fig. 12-CO, p. 315

Fig. 12-1a, p. 317

Fig. 12-1a, p. 317

Post-Glacial Sea Level Rise0 0

75 20

150

60

40

22580

300100

Sea

lev

el c

han

ge

(ft)

fr

om

pre

sen

t d

ay

375 120

450 140

18 16 14 12 10 8 6 4 2 0

Thousands of years ago

Sea

lev

el c

han

ge

(m)

fro

m p

rese

nt

day

20

Fig. 12-1b, p. 317

Fig. 12-1b, p. 317

Sea Level Projections

30 80

7025

60

20

15

1030

20 Sea

lev

el r

ise

(cm

)

40

50

Sea

lev

el r

ise

(in

ch)

5 10

−5 −10

0Observations

0

1950 1975 2000 2025 2050 2075 2100

Fig. 12-2a, p. 318

Fig. 12-2b, p. 318

Fig. 12-3, p. 319

Fig. 12-4a, p. 319

Fig. 12-4a, p. 319

Blowhole

HeadlandSea cliffs Sea stack

Sea caveExposed beach

Sea arch

Wave-cut platform

Sediments

Fig. 12-4b, p. 319

Fig. 12-4c, p. 319

Fig. 12-4c, p. 319

Wave-cut platform

Original land surface

Sea cliff

Notch eroded by waves

Fig. 12-4d, p. 319

Fig. 12-5, p. 320

Fig. 12-5, p. 320

Wave crests

Wave energy converging on headlands

Wave energy diverging

Sediment movementQuiet beach

Quiet beach

Fig. 12-6, p. 321

Fig. 12-7, p. 321

Fig. 12-8, p. 322

Fig. 12-9, p. 322

Fig. 12-10, p. 322

Fig. 12-11, p. 323

Fig. 12-12, p. 323

Table 12-1, p. 324

Fig. 12-13, p. 324

Fig. 12-13, p. 324

Shallow-water wave

A

To shoreB

Fig. 12-14, p. 325

Fig. 12-14, p. 325

Back-shore Fore-

shore Nearshore (through breakers)

Dunes

Berms Beach scarp

Offshore

Berm crest

Longshore trough

Longshore bars

High tide

Low tide (dotted line)

Fig. 12-15a, p. 325

Fig. 12-15b, p. 325

Fig. 12-16a, p. 326

Fig. 12-16a, p. 326

Upper limit of wave actionSurf

zone

Longshore current

Path followed by sand grains

Direction of wave approach

Fig. 12-16b, p. 326

Fig. 12-17, p. 327

Fig. 12-18a, p. 328

Fig. 12-18a, p. 328

Coastal cellCliff

erosion River input Major river forming

a delta

Longshore transport Rocky

point

River inputSubmarine

canyon

Sediment entering longshore transport system

Sediment movement down continental shelf and slope

Sediment transport to ocean basin within a submarine canyon

Fig. 12-18b, p. 328

Fig. 12-18b, p. 328

Santa Monica

NMalibu

RedondoLos Angeles

Long Beach

Palos Verdes

HuntingtonNewport

Santa Cruz Island

Submarine canyon OceansideLongshore drift

Santa Catalina IslandRocky headlands

0 50 San Clemente Island

Laguna

km

Fig. 12-18c (1), p. 328

Fig. 12-18c (1), p. 328

W–

Cliff

C+Surf

zone

V+O+

Beach

V–

O–

Fig. 12-18c (2), p. 328

Fig. 12-19, p. 329

Fig. 12-19, p. 329

Longshore current

Sand spitBay mouth bar Barrier

islandBay

Inlet Sea island

Lagoon Bay Tombolo

Beach

Fig. 12-20, p. 329

Fig. 12-21, p. 329

Fig. 12-22, p. 330

Fig. 12-22, p. 330

Isle of Wight Bay

Fenwick Island

N

Ocean City

Ocean City InletMARYLAND

Upper Sinepuxent Neck Atlantic Ocean

Position of shoreline

19801849Assateague

Island

Sin

epux

ent B

ay

km0 1 2

0 .62 1.24mi

Box 12-1a, p. 331

Box 12-1b, p. 331

Fig. 12-23a, p. 332

Fig. 12-23b, p. 332

Fig. 12-23c, p. 332

Fig. 12-24a, p. 333

Fig. 12-24b, p. 333

Fig. 12-25, p. 334

Fig. 12-26, p. 334

Fig. 12-26, p. 334

0 10

km

Massachusetts

Elizabeth Islands

Recessional moraine Atlantic

OceanTerminal moraines

Martha's Vineyard

Moraine Present land

Nantucket

Cape Cod

Fig. 12-27, p. 334

Fig. 12-28a-c, p. 335

Fig. 12-28a-c, p. 335

Fringing reef Barrier reef Atoll

a b c

Fig. 12-28d, p. 335

Fig. 12-29, p. 336

Fig. 12-30, p. 337

Fig. 12-30, p. 337

a Drowned river mouth b fjord

c Bar-built d Tectonic

Mainland

Lagoon

Barrier islands

Ocean

Fig. 12-31, p. 338

Fig. 12-31, p. 338

River

Seawater

a Salt wedge

Fig. 12-31, p. 338

River

Seawater

b Well-mixed

Fig. 12-31, p. 338

River

Seawater

c Partially mixed

Fig. 12-31, p. 338

River

Seawater

d Fjord

Fig. 12-32, p. 338

Fig. 12-32, p. 338

Lat

itu

de

38.0 24.00

0.00

Longitude–76.0

Fig. 12-33, p. 339

Fig. 12-34, p. 340

Fig. 12-35a, p. 341

Fig. 12-35b, p. 341

Fig. 12-36, p. 342

Fig. 12-36, p. 342

(a) Groin Groins are structures that extend from the beach into the water. They help counter erosion by trapping sand from the current. Groins accumulate sand on their updrift side, but erosion is worse on the downdrift side, which is deprived of sand.

Current

(b) Seawall Seawalls protect property temporarily, but they also increase beach erosion by deflecting wave energy onto the sand in front of and beside them. High waves can wash over seawalls and destroy them and property.

(c) Importing sand Importing sand to a beach is considered the best response to erosion. The new sand often is dredged from offshore, can cost tens of millions of dollars, and can disturb aquatic biodiversity. Because it is often finer than beach sand, dredged sand erodes more quickly.

Fig. 12-36, p. 342

(a) Groin Groins are structures that extend from the beach into the water. They help counter erosion by trapping sand from the current. Groins accumulate sand on their updrift side, but erosion is worse on the downdrift side, which is deprived of sand.

Current

(b) Seawall Seawalls protect property temporarily, but they also increase beach erosion by deflecting wave energy onto the sand in front of and beside them. High waves can wash over seawalls and destroy them and property.

(c) Importing sand Importing sand to a beach is considered the best response to erosion. The new sand often is dredged from offshore, can cost tens of millions of dollars, and can disturb aquatic biodiversity. Because it is often finer than beach sand, dredged sand erodes more quickly.

Stepped Art

Fig. 12-37, p. 342

Fig. 12-38, p. 343

Fig. 12-38, p. 343

Alaska region Great Lakes region

28

66North Pacific region

1310 1391

14 North Atlantic region

5 7 1390California region

8180

3 9

Hawai’i regionPuerto Rico and the Virgin Islands (included in South Atlantic – Gulf region)

Percent stableTexas Gulf region

182

Percent noncritical erosion Lower

Mississippi region

Percent critical erosion

86 80

South Atlantic – Gulf region

6

74

88

72

104