Shoreline Processes Outline

August 29, 2003

1. Waves – wind blowing across the waters surface unobstructed forms waves.

a. Wavelength – distance between identical parts of the waves

b. Crest – highest portion of the wave with respect to the horizontal.

c. Trough – lowest point of the wave with respect to the horizontal.

d. Period – Time it takes identical parts of successive waves to pass a fixed reference point.

e. Wave Base – depth equal to ½ wavelength below which movement is not associated with surface waves. When a wave reaches this level it decreases in velocity and increases in height.

f. Refracted waves – waves bend towards the headlands as they reach the wave base.

2. Wave Erosion

a. Erosional landforms

i. Wave-cut notch

ii. Sea cliffs

iii. Wave-cut platforms

iv. Sea stacks

v. Caves

vi. Arches

vii. Buttresses

3. Sediment Transport

a. Backwash – water returning to the sea or lake. Flow is downslope under the influence of gravity. Sediment is transported in a zigzag fashion due to wash-backwash effects.

b. Longshore Drift – the net effect of backwash. Primary mechanism of sediment transport in shoreline environments.

c. Tidal currents – important in areas with high daily tidal ranges. (Bay of Fundi)

4. Tide vs. Wave dominated

a. Tidal – small and wide islands with numerous inlets

b. Wave – long and narrow islands with few inlets

5. Sediment Deposition

a. Landforms

i. Beaches – generally wide and gentle sloped in summer, narrow and steep sloped in winter.

A. Offshore Zone (seaward from low tide level)

B. Foreshore Zone (Area between low and high tide levels)

C. Backshore Zone (Landward from the maximum high tide level)

ii. Spits

iii. Lagoons

iv. Barrier Islands

v. Tombolos

6. Coast Types

a. Submergent

i. Drowned Estuaries

ii. Fjords

iii. Deltas

b. Emergent

i. Terraces