Coastal Systems

Question 1

Coastal landforms evolve in response to…

Answer 1

Sea level history
geology
climate
waves & tides

Question 2

What are the 3 dominating factors of coasts?

Answer 2

Waves, Tides and Rivers

Question 3

What are the 3 main divisions of the coastal area?

Answer 3

Foreshore
Backshore
Offshore

Question 4

What is the foreshore?

Answer 4

Wet part of the coastline - not offshore

Question 5

What is the backshore?

Answer 5

Usually dry - only wet under storm conditions

Question 6

How is sediment carried in / through coastal areas?

Answer 6

-Orbital motion of water particles
-Breaking of waves
-Swash processes (rush of seawater on the beach after breaking of a wave)

Question 7

What are the 3 general phases of nearshore bar evolution?

Answer 7

Generation and initial growth of bar
Migration or consolidation of bar
merging or erosion of bar

Question 8

How has global sea level changed in modern times?

Answer 8

Risen 21-24cm since 1880s

Question 9

What are the 2 components of sea-level rise?

Answer 9

Main: Input of water from greenland ice sheets
Secondary: Thermal expansion as ocean warms

Question 10

Explain isostatic sea level changes?

Answer 10

Isostatic sea-level changes are local changes caused by subsidence or uplift of the
crust related either to changes in the amount of ice on the land, or to growth or
erosion of mountains.

Question 11

What does the nearshore zone represent?

Answer 11

Where waves start to ‘feel’ or morphologically influence the bottom of the littoral zone.

Question 12

What are the 3 types of nearshore currents

Answer 12

Longshore - dominant, often unidirectional current
Return Flow (undertow) - flow away from shore through gaps in intertidal bars.
Rip currents - short return (circulation cell)

Question 13

What are the 3 types of breaking waves?

Answer 13

Spilling - gradual breaking over distance - flat terrain.
Plunging - crest curls over nearly vertical wall of water
Surging - base advances at same time as top, usually on steep beaches.

Question 14

What is wave swash?

Answer 14

When water rushes up the beach. Limited by slope of beach

Maximum swash is the run-up level.

Question 15

Provide an example of coastline evolution on very small time scale

Answer 15

formation of coastal bars (constantly moving hour to hour)

Question 16

What deposition formation characterizes wave-dominated coastal landforms?

Answer 16

Spits - long narrow accumulation of sand with one end jointed to mainland and the other projecting out to sea or across an estuary

Question 17

What is a barrier island?

Answer 17

Spit that has detached from the coast. Depositional coastal landform

Question 18

What are 3 factors that influence the formation of barrier islands and spits?

Answer 18

Constant flow of sediment
Wave energy
Direction of wave motion

Question 19

Name some characterizing factors of estuaries

Answer 19

-Somewhat enclosed
-Mixing of salt and freshwater
-Tidal

Question 20

How do salt marshes and mangroves protect from coastal erosion?

Answer 20

-Trap sediment
-Act as buffer

Question 21

What is the main factor controlling costal cliff erosion?

Answer 21

Rock hardness

Question 22

What are the critical processes involved in coastal cliff evolution?

Answer 22

-Mass movement
-Weathering
-Rock-removal processes (marine processes)

Question 23

How is climate change affecting high latitude coastal zones (in the arctic)?

Answer 23

-Arctic is warming 4x faster than the global base rate
-glacial retreat
-increased meltwater discharge
-increased landform erosion
-glacial ice, sea ice, permafrost & beach ice

Question 24

Which processes contribute to the formation of beach ridges?

Answer 24

Wave swash

Question 25

What is a beach ridge berm? What does it indicate?

Answer 25

Active ridge parallel to shoreline formed by swash processes Indicates maximum sea-level run-up.

Question 26

How does a beach ridge plain form?

Answer 26

They are older sea berms. When a new berm forms and the beach ridge remains, then this will indicate the old sea level.

Question 27

What are the 2 ideas at the essence of integrated coastal zone management?

Answer 27

minimize disruption maximize benefits employ soft engineering (nature-based solutions)

Question 28

What are some examples of coastal geomorphological evolution at different chronological and spatial scales?

Answer 28

Smallest to largest: sand ripples & runnels at the cm/m scale sandbar m/100m beach km peninsula, coastal bar, spit etc entire coastline

Question 29

Provide some examples of small-scale and large-scale geomorph. evolution in river systems

Answer 29

Question 30

Provide some examples of small-scale and large-scale geomorph. evolution in glacial systems

Answer 30

Question 31

What are the 4 processes affecting Coastal Morphodynamics?

Answer 31

Sea level history Geology Climate Waves & Tides

Question 32

Explain the process of a wave as it moves from deep water to the shore (5 steps)

Answer 32

Shoaling Breaking Bores Breaking Swash

Question 33

The _____ is the maximum level the waves can reach on the beach

Answer 33

Run up level

Question 34

Wave _____ erodes and smooths coastlines

Answer 34

refraction

Question 35

explain the coastal classification triangle

Answer 35

Dominated by fluvial/wave/tide power/frequency/direction.

Question 36

Explain this picture

Answer 36

Spit formed by sediment deposit from fluvial forces when rounding the point from the stream. Reinforced by sediment deposit from ocean side and forced into triangular shape. Water slowing below transport velocity is caused by meeting of stream with ocean - opposing directions = slowing.

Question 37

Why do spits continuously curve inward?

Answer 37

Dependent on direction of longshore drift - recurved tip occurs by pushing sediment off the edge of the existing spit

Question 38

What is a common formation found in wave-dominated coastal landforms?

Answer 38

Barrier Islands

Question 39

What is a common formation found in tide-dominated coastal landforms?

Answer 39

Estuaries and wetlands/marshlands/mangroves

Question 40

Explain wtf going on here

Answer 40

Parallel lines on beach are beach riges - lowest one is the beach berm (formed by current swash processes). beach ridges are previous water levels/swash levels. 2 green lines are old fluvial streams worn down to the bedrock? green because of nutrient rich sediment?