Mangawhai Pakiri - Unintentional Human Activity

• Where is the Mangawhai-Pakiri coast located?

  It is located in New Zealand's North Island near Auckland.
• Why is the sand from the Mangawhai-Pakiri coast significant?

  It is high quality and suitable for the construction industry.
• How long has sand mining been occurring in the Mangawhai-Pakiri area?

  It has been happening for over 70 years.
• What are some economic uses of sand mentioned in the study?

  Sand is used in construction, concrete manufacturing, and glass manufacturing.
• Why is the sand from the near shore off Mangawhai-Pakiri considered high quality?

  It is excellent for construction due to its properties.
• What percentage of New Zealand's population lives in Auckland?

  Auckland has a third of the entire population of New Zealand.
• What is the significance of Auckland's economy in relation to sand extraction?

  Auckland has a growing economy that increases the demand for high-quality sand.
• What is the extraction rate of sand from Pakiri currently?

  The extraction rate is about 75,000 cubic meters per year.
• What impact does sand extraction have on the sediment budget?

  It can lead to a shrinking supply of sand in the coastal system.
• Why is the sand in this area considered non-renewable?

  There are no major rivers or sufficient waves to replenish the sand supply.
• What is the current state of the sediment system in the Mangawhai-Pakiri area?

  It is a closed sediment system with extraction rates five times the inputs.
• What are the consequences of reduced sand supply on coastal landscapes?

  It can lead to significant erosion and changes in landforms.
• What happened to the spit in 1978 due to reduced sand supply?

  A breach occurred due to high energy waves attacking the spit.
• How did the breach in the spit affect tidal currents in Mangawhai Harbour?

  It altered the tidal currents, pushing more sediment into the harbour.
• What is the impact of increased sediment in Mangawhai Harbour?

  It leads to a shallower harbour, increasing the risk of flooding.
• How does reduced sediment affect the beaches in the area?

  Beaches become flatter and less effective at absorbing high energy waves.
• What happens to the foredune ridges due to reduced sand supply?

  They are undercut by high energy waves, leading to slumping and steep scarps.