Coastal Environments

Explanation

A coastline or a seashore is the area where land meets the sea or ocean. A precise line that can be called a coastline cannot be determined due to the Coastline paradox.

The term “coastal zone” is a region where interaction of the sea and land processes occurs. Both the terms coast and coastal are often used to describe a geographic location or region; for example, New Zealand’s West Coast, or the East and West Coasts of the United States.

A pelagic coast refers to a coast which fronts the open ocean, as opposed to a more sheltered coast in a gulf or bay. A shore, on the other hand, can refer to parts of the land which adjoin any large body of water, including oceans (sea shore) and lakes (lake shore). Similarly, the somewhat related term “bank” refers to the land alongside or sloping down to a river (riverbank) or to a body of water smaller than a lake. “Bank” is also used in some parts of the world to refer to an artificial ridge of earth intended to retain the water of a river or pond; in other places this may be called a levee.

While many scientific experts might agree on a common definition of the term “coast”, the delineation of the extents of a coast differ according to jurisdiction, with many scientific and government authorities in various countries differing for economic and social policy reasons. According to the UN atlas, 44% of people live within 150 kilometres (93 miles) of the sea.

Formation

Tides often determine the range over which sediment is deposited or eroded. Areas with high tidal ranges allow waves to reach farther up the shore, and areas with lower tidal ranges produce deposition at a smaller elevation interval. The tidal range is influenced by the size and shape of the coastline. Tides do not typically cause erosion by themselves; however, tidal bores can erode as the waves surge up river estuaries from the ocean.

Waves erode coastline as they break on shore releasing their energy; the larger the wave the more energy it releases and the more sediment it moves. Coastlines with longer shores have more room for the waves to disperse their energy, while coasts with cliffs and short shore faces give little room for the wave energy to be dispersed. In these areas the wave energy breaking against the cliffs is higher, and air and water are compressed into cracks in the rock, forcing the rock apart, breaking it down. Sediment deposited by waves comes from eroded cliff faces and is moved along the coastline by the waves. This forms an abrasion or cliffs.

Sediment deposited by rivers is the dominant influence on the amount of sediment located on a coastline. Today riverine deposition at the coast is often blocked by dams and other human regulatory devices, which remove the sediment from the stream by causing it to be deposited inland.

Like the oceans that shape them, coasts are a dynamic environment with constant change. The Earth’s natural processes, particularly sea level rises, waves and various weather phenomena, have resulted in the erosion, accretion and reshaping of coasts as well as flooding and creation of continental shelves and drowned river valleys (rias).

The Topics and Sub-topics for Coastal Environments are as follows:

Marine Processes

Constructive Waves

Destructive Waves

Processes of Erosion

Long Shore Drift (LSD)

Land Processes

Sub Aerial Processes

Costal Landforms

Erosional Features

Cliffs

  • Wave-cut Platform
  • Wave-cut Notch
  • Mass Movement
  • Cliff Retreated
  • Cliff Foot
  • Cliff Face

Headlands

  • Crevices/nocks
  • Caves
  • Arches
  • Stacks
  • Stumps

Depositional Features

Beaches

Sand

Gravel/Pebbles

Shingle

Cobblestones

Spits

Sand Bars/Sand Banks/Shoal

Tombolo/Mound

Lagoons

Coastal Ecosystems

Coral Reefs

Distribution

  • Temperature
  • Light
  • Water Depth
  • Salinity
  • Wave Action
  • Exposure To Air
  • Sediment

Value

  • Fisheries
  • Tourism
  • Coastal Protection
  • Source of Medical Advances
  • Intrinsic Value

Threats

  • Destructive Fishing Practices
  • Over Fishing
  • Tourism
  • Destruction of Mangroves

Types of Coral Reef

  • Fringing Reefs
  • Barrier Reefs
  • Atolls
  • Patch Reefs

Great Barrier Reef – Case Study

Mangroves

Distribution

  • Temperatures
  • Salinity
  • Exposure to Air

Value

  • Contain Natural Resources
  • Foraging and Living Place for Wildlife
  • Reducing Water Pollution
  • Protecting the Coastline
  • Flood Prevention
  • Ornamental Value

Threats

  • Clearing
  • Over Harvesting
  • River Changes
  • Overfishing
  • Destruction of Coral Reefs
  • Pollution
  • Climate Change

Bangladesh, Sundarbans – Case Study

Sand Dunes

How sand dunes are formed

  • Crest
  • Horn
  • Slip-face
  • Back-slope

Types of Sand Dune

  • Embryo Dunes
  • Fore Dunes
  • Main Dunes
  • Fixed Dunes
  • Dune Slack
  • Dune Heath
  • Climax

Values

  • Coastal Protection
  • Habitat

Threats

  • Humans

Salt Marshes

Formation

Stages of Salt Marshes

  • Estuary
  • Mudflats
  • Lower Marches
  • Upper Marches

Distribution

Threats

  • Sea Level Rise
  • Sea Defences
  • Dredging
  • Coastal Squeeze
  • Erosion
  • Disturbance by People
  • Land claim for farming or building
  • Pollution from Land or Sea
  • Grazing
  • Colonisation by Cordgrass

Example (Possible Case Study) – Chichester Harbour

Coastal Management

Threats to the Coast

  • Erosion
  • Flooding
  • Storm Surges

Management of Threats

Hard-engineering Management

  • Groyne
  • Sea Wall
  • Revetment
  • Gabion
  • Rip-Rap

Overall Disadvantages of Hard-engineering

  • Expense
  • Rising Sea Levels
  • Aesthetics

Soft-engineering Management

Beach Management

  • This replaces beach or cliff material that has been removed by erosion or longshore drift.
  • The main advantage is that beaches are a natural defence against erosion and coastal flooding. Beaches also attract tourists and have ornamental value.
  • It is a relatively inexpensive option but requires constant maintenance to replace the beach material as it is washed away.

Overall Coast Management

  • Do Nothing
  • Hold the Line
  • Managed Retreat

Coastal Conflicts

The Coastal System

The Conflict Between Development and Conservation

Conflicts Between Coastal Users

  • Local Residents
  • Employers
  • Farmer
  • Fishermen
  • Port Authorities
  • Transport Companies
  • Tourists
  • Developers

Benidorm – Case Study

Southampton Waters – Case Study

Holderness Coast – Case Study

Flamborough

Location

Geology

Coastal Features

Hornsea

Location

Geology

Coastal Features

Mappleton

Location

Geology

Coastal Features

Spurn Point

Location

Geology

Coastal Features

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