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Ever Wondered? Series 2 Episode 7

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In Episode 7 of Ever Wondered? Series 2, Dr John Watt finds out more about water in New Zealand and how computer modelling is used to understand water distribution. He then learns about some new developments in irrigation systems.

Understanding water in New Zealand

Water is the very life force that powers the planet. Kiwis can sometimes take this commodity for granted and assume that there's plenty to go round, but how do we really know that we have enough? John takes a trip to Canterbury, our biggest consumer of water, to meet NIWA scientist Roddy Henderson who gives him the low down on just how New Zealand is placed for water.

Next up, John heads to a Canterbury dairy farm to meet local farmer Craige Mackenzie to find out about the importance of irrigation. Craig explains to John why he's got NIWA's gadgets on his land helping to answer some of the important questions when it comes to water.

To demonstrate the importance of understanding water on a farm, John makes a simple model. John makes clever use of some top soil, rocks, a packet of powdered drink and a watering can to demonstrate the effects of over- and underwatering, which affect both the farmer and environment.

Computer modelling aids decision-making

Computer modelling plays a major role in better understanding just how we are placed when it comes to droughts and floods. John visits Dr Daniel Collins, NIWA, who was asked to find out how bad flooding might get if forests were cleared for dairy farming in the Waikato Basin. Daniel explains how he goes about building a computer model and the predictions he's able to make. To help our understanding, John heads outside to demonstrate how Daniel is able to calculate the amount of water that has fallen in a catchment area.
So how will climate change affect New Zealand's water supply? John visits another NIWA scientist, Dr Anthony Clark. Anthony explains the interplay between the global climate system and New Zealand's very own climate system. Checking out Anthony's computer model, we get an idea what the future might hold for rainfall over the North and South Islands over the next 80 years.

Irrigation system innovation

Two innovative engineers on top of the water issue are Stu Bradbury and George Ricketts. These guys initially developed a DIY farm-mapping kit using GPS called Wheresmycows. They then went on to developing state-of-the-art intelligent irrigation systems that promise and deliver far better irrigation and savings on water. Stu and George give John a crash course in how the system works and get him on a quad bike to make an electromagnetic map of the field using an electromagnetic sensor and real-time kinematic GPS. John then heads to a farm to meet farmer Johnny Fraser who installed the first prototype of Stu and George's irrigation systems in 2008.

John wraps up the episode by emphasising the vital role scientists play in helping to better understand our valuable water resource and in finding ways of managing the challenges coming our way.

Useful link

More about Wheresmycows farm mapping developed by Stu Bradbury and George Ricketts.

Activity idea

In conjunction with this episode of Ever Wondered?, your students may enjoy these activities.

In this activity, students build a model like John does in part 1 of this episode. The model is called an aquifer. It can be used to look at point sources of pollution (such as fertilisers or pesticides) and non-point sources (such as spills or landfills).

In this activity, students explore and make predictions about some factors that affect soil run-off and ground stability, including gravity, erosion and deforestation.

In this activity, students investigate the issues surrounding water in their local area and relate this knowledge to water issues in other countries.

Context links

For more information on water management and the water cycle, visit these Science Learning Hub contexts.

Enviro-imprints: Since humans first arrived in New Zealand, we have had a significant impact on the environment. This context examines how we have left our mark on our land, our air and our water.

H2O on the Go: This context examines how understanding the water cycle - the continuous movement of water through the Earth's upper crust, surface and atmosphere - is crucial for understanding our valuable commodity, water. Meet scientists David Hamilton, Louis Schipper, Dave Campbell and Keith Hunter who each study one aspect of the hydrological cycle. In their studies, they need to consider the Earth as a whole, dynamic and interacting system.

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