1.1. How are coastal landscapes developed?
4b. Economic development unintentionally causes change within coastal landscape systems (Manga-
Pakiri Coastline, New Zealand)
What economic activity is taking place & why? Process:
Human management = Off-shore dredging off Holocene sand stores for use in Offshore dredging reduces flow of sediment from offshore
construction/glass making store to onshore beach store
Beach store is depleted - beach is less effective at absorbing
waves, flows of sediment between stores becomes
Unintended impact of coastal system?
diminished
LSD continues to transport material along the beach towards the spit - as beach Beaches are starved of sediment so are wider & flatter
sediment store decreases, rates of LSD decrease & the spit store receives less High energy waves erode beaches & landforms such as spits
sediment become vulnerable to erosion
Stores were depleted because it was a closed system & no longer a glacial period → Loss of vegetation cover makes beaches susceptible to wind
store is reduced 10 times more than natural stores. erosion
The depletion means that the beach becomes wider & flatter due to the dunes Shallower water in the harbour also threatened Manawhai’s
being eroded - less effective in absorbing waves → meaning the beach will be less waterfront community with flooding
resistant to marine erosion e.g. hydraulic action & abrasion AO2: In the future increased rates of coastal erosion are likely
Processes of erosion are more significant as beaches are flatter & resistance against with declining natural protection from extreme storm events
erosive forces is reduced Long term retreat by the end of the century is estimated at
35m
Width of the coastal zone susceptible to erosion varies from
How has this affected coastal landforms: 48 - 111m
Spit becomes narrower & flatter, decrease in the sediment store
Beaches are starved of sediment = less effective at absorbing waves
Consequence of this landform change:
Vulnerability to marine erosion increases, and eventually the spit was breached in
1978
Shallower water in the harbour also threatened Mangawhai’s waterfront
community with flooding
Sand removed from 6 – 10m depth = likely to be replaced by beach sand to restore
the equilibrium, since the slope here is the steepest
Deep storm waves will eventually move sand from deeper down (10 – 25m)
towards the beach, but this may take many decades - not immediate = long term
4b. Economic development unintentionally causes change within coastal landscape systems (Manga-
Pakiri Coastline, New Zealand)
What economic activity is taking place & why? Process:
Human management = Off-shore dredging off Holocene sand stores for use in Offshore dredging reduces flow of sediment from offshore
construction/glass making store to onshore beach store
Beach store is depleted - beach is less effective at absorbing
waves, flows of sediment between stores becomes
Unintended impact of coastal system?
diminished
LSD continues to transport material along the beach towards the spit - as beach Beaches are starved of sediment so are wider & flatter
sediment store decreases, rates of LSD decrease & the spit store receives less High energy waves erode beaches & landforms such as spits
sediment become vulnerable to erosion
Stores were depleted because it was a closed system & no longer a glacial period → Loss of vegetation cover makes beaches susceptible to wind
store is reduced 10 times more than natural stores. erosion
The depletion means that the beach becomes wider & flatter due to the dunes Shallower water in the harbour also threatened Manawhai’s
being eroded - less effective in absorbing waves → meaning the beach will be less waterfront community with flooding
resistant to marine erosion e.g. hydraulic action & abrasion AO2: In the future increased rates of coastal erosion are likely
Processes of erosion are more significant as beaches are flatter & resistance against with declining natural protection from extreme storm events
erosive forces is reduced Long term retreat by the end of the century is estimated at
35m
Width of the coastal zone susceptible to erosion varies from
How has this affected coastal landforms: 48 - 111m
Spit becomes narrower & flatter, decrease in the sediment store
Beaches are starved of sediment = less effective at absorbing waves
Consequence of this landform change:
Vulnerability to marine erosion increases, and eventually the spit was breached in
1978
Shallower water in the harbour also threatened Mangawhai’s waterfront
community with flooding
Sand removed from 6 – 10m depth = likely to be replaced by beach sand to restore
the equilibrium, since the slope here is the steepest
Deep storm waves will eventually move sand from deeper down (10 – 25m)
towards the beach, but this may take many decades - not immediate = long term
