Coastal Landscape - 2B.4-2B.6

Question 1

When does coastal flooding occur

Answer 1

• when storms occur at spring tides, waves act on parts of the coastline that don’t usually experience them

Question 2

What are the characteristics of constructive waves and how do they influence beach morphology

Answer 2

• strong swash, weak backwash, deposition, calm conditions, long wavelength, short height
• create wide, flat beaches that are much shallower

Question 3

Describe the process of longshore drift

Answer 3

-direction of prevailing wind moves sediment up the beach wave via swash
-sediment moves back down beach due to gravity and backwash
-process repeated

Question 4

Describe the features of a storm beach
(berms, middle, offshore)

Answer 4

• a result from high energy deposition of coarse material
• Berms typically of shingle a result of wave deposition
• middle area mostly sand which is coarser where berms have been deposited
• offshore ridge formed by destructive wave erosion and subsequent deposition

Question 5

What is traction, saltation, suspension, solution

Answer 5

• traction - sediment rolls along, pushed by waves and currents
• saltation - sediment bounces along, due to force of water or wind
• suspension - sediment is carried in the water column
• solution - dissolved material is carried in the water as a solution

Question 6

What are depositional landforms and what do they depend on

Answer 6

• made from unconsolidated sediment and are dynamic land forms
• changes can result from major storms and spring tides
• depend on a continual supply of sediment and continuous deposition to balance erosion - equilibrium

Question 7

What is a sediment cell
- key concepts

Answer 7

• a stretch of coastline in which sediment is sourced, transported and deposited
• cell is usually closed to sediment from other cells
• cell is bounded by coastal features

Question 8

What is dynamic equilibrium

Answer 8

a state of balance between continuing processes

Question 9

How can a dam being built disrupt a sediment cell

Answer 9

• less sediment will be provided by the river therefore offshore bar and spit will shrink, becoming more prone to erosion

Question 10

How can dredging and offshore bar disrupt a sediment cell

Answer 10

• increased erosion of beach causing them to become depleted

Question 11

How can groynes being built disrupt a sediment cell

Answer 11

• reduced amounts of sediment will be provided to sand dunes and offshore bars. Spit will begin to erode due to limited supply of sediment