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Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
Sustainability: Water Pollution in New Zealand
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Sustainability: Water Pollution in New Zealand

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  • The blue represents sea and sky, the union flag our history as a British colony/dominion, and the stars (the Southern Cross) our place in the South Pacific.What else do you know about New Zealand?Source: commons.wikimedia.org
  • New Zealand is part of Australia. FALSE. We’re neighbours, not the same country. New Zealand has three main islands: North Island, South Island and Stewart Island. Image source: wikipedia.com
  • New Zealand has three official languages. TRUE. There are two spoken languages: Maori and English. The Maori name for New Zealand is Aotearoa. The third official language is New Zealand sign language.Image source: aotearoa.dk
  • 90% of New Zealanders live within 40 km (25 miles) of the coast. TRUE. NZ is an island nation, and the beach is an important part of recreational life for most of us. The beach in my hometown has black sand because of all the iron in it, and the area is very popular for surfing. This photo is taken in the centre of town in New Plymouth where I grew up. The shopping mall is right across the road.
  • New Zealanders are often called “Kiwis”, after the fruit. FALSE. The name kiwi comes from our national bird, which has an incredibly long beak, lays eggs that are about 20% of the mother’s bodyweight, and cannot fly! The kiwifruit is also named after the kiwi bird.
  • New Zealand as a land mass is roughly the same size as Colorado, and has a population of 4.5 million people—a little over half the population of NYC!Does anyone know what the capital is?Wellington is the capital, Auckland is our largest city, and our other major city is Christchurch in the South Island.I come from a town called New Plymouth, on the West Coast. The city is right between the sea and a mountain—my family like to spend time hiking on the mountain in the summer.Map image: Land Information New Zealand Crown copyright. Retrieved from mkiwi.com
  • New Zealand is known for having six times as many sheep as people!
  • We also have a lot of cows. This photo is from my region of Taranaki, that’s Mount Taranaki in the background that I mentioned earlier.
  • 6.6 million is a lot of cows.This is great news if you like milk in your coffee, or cheese on your pizza, because the cows produce nearly 700 million gallons of milk in a year…But it is bad news for water quality, because a lot of New Zealand’s rivers and streams flow through dairy pasture.Milk image: www.dairyreporter.comCattle image: www.niwa.co.nz
  • Before New Zealand was colonised, and people started farming, most of the landscape was covered in trees.In a system like this, the soil is held very securely by the roots of trees and plants in the undergrowth.When rain falls, the water drains into nearby waterways. Water that runs across the surface directly into the waterway is called surface runoff. Some water will drain into the ground, and move more slowly into the waterways. Because the plants and soil are so stable, both the surface runoff and the groundwater remain very clean.
  • Before New Zealand was colonised, and people started farming, most of the landscape was covered in trees.In a system like this, the soil is held very securely by the roots of trees and plants in the undergrowth.When rain falls, the water drains into nearby waterways. Water that runs across the surface directly into the waterway is called surface runoff. Some water will drain into the ground, and move more slowly into the waterways. Because the plants and soil are so stable, both the surface runoff and the groundwater remain very clean.
  • On the other hand, maybe now you have cleared the forest, planted your land in pasture, and put some cows on it. The soil here is not stabilised by tree roots, and the cattle dig up the soil with their hooves as they graze, and leave manure on the surface of the ground. When it rains on this system, the water picks up the soil and manure as it flows across the surface and through the ground, and carries them into the stream or river. The effects of this can be very fast, with surface runoff draining directly in the stream—but even if farming is stopped and the land is converted to a different use, such as forestry, the dirty groundwater can continue to carry pollutants into the waterway for years afterward.Cow clipart: silhouettesfree.com
  • Lots of different pollutants can enter waterways in this way, but there are three main classes that come off a typical dairy farm:The easiest type to see is particulate pollution: soil, sand and other large particles.It is more difficult to see the other problem pollutants: bacteria from cow manure, and chemicals like nitrogen and phosphorus that act as nutrients.
  • What sorts of problems do you think particle pollution causes?It makes clear water murky—making it unsuitable for drinking or swimming, and preventing sunlight from passing through the water, which is necessary for some forms of aquatic life.As it sinks, it can also form a layer of mud and silt on the riverbed, which also changes the lake or river system. This is a particular problem if it is depositing sediments into wetlands or other sensitive ecosystems.
  • What about bacteria? What problems do they cause?They cause disease in people and animals drinking, bathing in or eating shellfish gathered from the water systems. Commonly diahorrhea and vomiting…
  • What is a nutrient?Nutrients are chemicals that promote growth, like nitrogen and phosphorus. Do you remember where you would find nitrogen in a cell? Proteins, photosynthetic pigments (chlorophyll)…What about phosphorus? Cell membranes, DNA, ATP/energy transfer molecules…So they are pretty important—when there is no P or N present in the environment, cells can’t grow. Conversely, when they are present, cell growth is encouraged.Why could they be a problem in waterways?Farmers often add these chemicals to their fields to help make the grass grow, but in the water they also make algae grow much faster. Algae are single-celled organisms that photosynthesize like plants, they are freefloating in the water. So they respond noticeably to infuxes of nitrogen and phosphorus into the waterway.Algae, like plants, produce oxygen during photosynthesis, but this is released into the atmosphere. And oxygen from the water is used when they biodegrade. So where there is too much algae, often there is not enough dissolved oxygen left for fish and other species to survive. This is called deoxygenation.Also, some types of algae can be poisonous.Algae image: nhm.ac.uk
  • It is possible to drain a small quantity of particles, microbes and nutrients into a stream without affecting the quality. This is because the stream is able to process these things, by washing them away or processing them through the food chain. You may have one farm allowing pollutants to run off into the stream, and not notice any difference in the water quality.You may be able to add other farms, too, without affecting the water. However, once the inflow of pollutants reaches a certain point, the quality of the water will start to degrade. This point is called the assimilative capacity of the waterway.
  • The assimilative capacity of a water body depends on a whole host of factors, from the flow rate and volume of water to the shape of the riverbed and the types of species that live in it.To keep our waterways healthy, we need to keep pollution levels below the assimilative capacity.Remember that many streams and rivers are connected, and flow into one another. So we need to keep pollution below the assimilative capacity of the most sensitive part of the system…How can we reduce levels of water pollution? How do we reduce water pollution from the city?Will that work for farmland?What else could we try?Keep stock away from waterways (fences)Clean up water and effluent (settling ponds)Filter runoff??Break for activity.
  • Activity instructions.
  • Hopefully you all have seen that we can keep particles and dirt out of the water by passing incoming water through a thick filter of some sort.Obviously, I can’t go installing sponges around all the streams in New Zealand! What do you think we could use instead in an outdoor environment?Plants act like a sponge, soaking up excess nutrients, and trapping particles and microbes before they can enter waterways. Here you can see a well-established belt of plants on a farm in Taranaki.Native plants are particularly suitable for this task, and do a great job of filtering out pollutants if they are planted for several metres on the banks of streams. The practice is called riparian planting.Image source: news.ecocentre.co.nz (originally TRC)
  • As of last year, farmers in my home region of Taranaki had planted about 63% of the stream banks that were at high risk. The goal is to have all on-farm streams fenced to exclude stock, and suitable areas planted, by 2015.You can see in this picture that the native forest has been cleared from all the land outside the National Park. This cleared area—the Taranaki ring plain—is home to thousands of dairy farmers. You can see that rivers flow off the mountain in all directions, and nearly every farm has at least one stream flowing through it. So fencing and planting all of these waterways is a pretty big task!! But our clean water is worth the effort, and farmers are well on the way to meeting this goal, with the support of dairy companies, the regional council and plant nurseries.Image: www.withsparkles.com: Photo by Mollivan Jon
  • Takeaway points.
  • Transcript

    • 1. Do Now (Page 8) Global Guide: Samantha Hill Country: New Zealand Answer the Question: List 3 causes of Water Pollution.
    • 2. Water Pollution in New Zealand Samantha Hill Columbia University Sustainability Around the World
    • 3. Where in the world is New Zealand?
    • 4. True or False? New Zealand is part of Australia FALSE
    • 5. True or False? New Zealand has three ‘official’ languages TRUE
    • 6. True or False? 90 % of New Zealanders live within 25 miles of the coast TRUE
    • 7. True or False? New Zealanders are often called “Kiwis” after the fruit FALSE
    • 8. Auckland New Plymouth Wellington Christchurch
    • 9. 30 million sheep
    • 10. 6.6 million dairy cattle
    • 11. 6.6 million dairy cattle GOOD NEWS for the dairy industry….
    • 12. NH3 PO4 NO3 Particles Microbes Nutrients
    • 13. NH3 PO4 NO3 Particles Microbes • Murky water—sunlight can’t get through • Muddy layer on the stony riverbed Nutrients
    • 14. NH3 PO4 NO3 Particles Microbes Nutrients • Cause disease in animals • Cause disease in people—E. coli, Campylobacter….
    • 15. NH3 PO4 NO3 Particles Microbes • Chemicals that promote growth… Nutrients O2 • Cause algae to grow much faster More algae = less oxygen • Algae deoxygenate the water • Some algae are toxic
    • 16. Assimilative Capacity
    • 17. Assimilative Capacity The ability of a water body to process a substance without becoming degraded. • Keep pollution levels below assimilative capacity
    • 18. How do we reduce water pollution? Water pollution lab Task allocation Pour: Filter: Observe: Record: Treatment 1: Assign every group member to a task. Two people doing the same task is ok. What did you do for this cup? Observations: Try to be specific—how does the water in the cup compare to the water in the bottle? Color? Clarity? How fast does it flow? Treatment 2:
    • 19. Riparian Planting
    • 20. Riparian Planting Planting along the margins of a waterway (“riparian margins”) to reduce erosion and pollution.
    • 21. • Farming is a major source of water pollution • Particles, microbes and nutrients • Excess nutrients cause algal growth and deoxygenation • Pollution needs to be kept below the assimilative capacity of the waterway • Stock exclusion (fences) • Riparian planting • These practices are now mandatory for dairy farmers under the Sustainable Dairying: Water Accord (2012)
    • 22. Any questions?
    • 23. Kia ora!
    • 24. Closing Answer the two questions on Page 9

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