Mangwhai pakiri

• 1/3 of new zealands total population is in Auckland so they use sand in Mangwhai Pakiri to help with beach recharge and for constructio
• Unintentional changes

  Mining of the sand depletes it moving between sediment cells

  The sand is not being replaced due to lack of river deposists

  Erosion increased from dredging forAuckland
• Increased coastal erosion and decreasing natural protection
• Long term retreat at 35m by 2100
• The beaches are becomming more flatter and wider which make them vulnerable to erosion from high energy waves
• 1978 a storm broke through a spit which then altered the tidal current and increased sediment into the harbour which increased flood risk
• tourism

  they reached a record number in 2015 so needed more sand for the beaches
• sediment budget

  closed system so the sediment is not being replaced
• restoring equilibrium

  they had to dredge the harbour following the storm which restored some equilibrium