CASE STUDY: Human Coastal Change (Unintentional): NZ Flashcards
1
Q
About
A
High quality sand along coastline. Perfect for construction industry.
Region rapidly growing. Coastal amenities booming (3.5 million foreign visitors)
2
Q
On average how much do people use?
A
On average people use over 200kg of sand per person per year (essentially non renewable)
3
Q
What sand mining used for?
A
Glass manufacture, beach replenishment, concrete manufacture, construction industry
4
Q
How much sand was extracted between 1994-2004?
A
165.000m^3/ year extracted
5
Q
Where is the sediment budget from
A
Most sand in sediment budget from offshore sources minimal from fluvial sources and is not replaced through inputs from rivers or offshore
6
Q
The impact of sand mining
A
- The depletion of the total sand supply on the sea bed beaches and sand dunes.
- As a result movements of sand between the major stores have diminished
7
Q
Future?
A
- Studies suggest that increased rates of erosion are likely in the future w/ declining natural protection from extreme storm events
- Long term coastal retreat by the end of the century is estimated at 35m.
8
Q
Impact on coastal landforms
A
- beaches starved of sediment, becoming wider and flatter, so less effective at absorbing waves
- this means higher energy waves erode beaches more, + dunes + spits become more vulnerable
- coastal retreat is already evident - partly due to sand extraction, but also due to climate change causing a rising sea level (positive feedback)
