Description

No matter where we live, water influences all of us. On the other hand, the actions of over 7 billion humans adds up to influence water.

According to the World Water Council, the average North American household uses over 300 litres of water a day. It’s easy to believe that water is an endless resource, especially if you live in coastal British Columbia, but that’s not the case.

This activity investigates the water cycle, which is the process water undergoes to get to our homes, as well as the importance of reducing water use to conserve it.

Background

How do we use water?

All living things need water to survive. Humans need between two and five litres of water every day to replace the water that we breathe, sweat or urinate. Although we can survive for about a month without food, we can only survive for five or six days without water. Our bodies are made of about 60 per cent water. We get a lot of water from the food we eat, but most of it comes from the liquids we drink.

Not only do we drink water, we use it for agriculture, transportation, energy production, sanitation, manufacturing and recreation. Because of its importance in so much of our life, understanding its cycle and how we impact the cycle brings us closer to appreciating water and conserving it for the benefit of future generations.

We use more water than we need. Water use statistics from Metro Vancouver show that the average resident uses about 325 litres of water each day—and much of it is wasted! All of this water comes from three separate reservoirs in the mountains. When we waste this water it is not only a waste of precious water, but also of energy and other resources because all our drinking water goes through lengthy treatment before and after we use it. As our city populations continue to increase and our reservoirs remain the same size, water conservation has become more of an important topic.

Where does our water come from?

In Canada, we’re often fortunate to have access to plenty of clean water, but the water supply isn’t limitless. Our sources of water are replenished by two methods: precipitation, and melting snow. Both of these vary seasonally, and year to year. We cannot use water at a faster rate than the water returns, or else we will be depleting our source of water.

Many places in the world are not as close to the source of their water, and although their water is replenished by the same two methods, their water may have travelled hundreds or thousands of miles before it reaches their homes. For example, much of the interior provinces of Canada use wells, rivers or lakes as their source of drinking water. This water has travelled from mountains, into creeks, down waterfalls, through rivers, and may even be used by other cities along the way, until it finally reaches them. This factor of distance creates a stronger need for more advanced filtering systems because the water will likely have picked up a lot of debris along its way.

What about the water cycle?

The water cycle, comprising of water that evaporates from rivers, lakes and oceans into clouds and falls again as rain, provides Vancouver with an average of 1.58 meters of rain a year. This amount of rainfall defines Vancouver as a rainforest climate. This is an abundant amount of rainfall compared to dry African countries, or even compared to other parts of the province, like the interior. While we get a lot of rain in Vancouver, it falls mostly in the winter. Throughout the winter, we collect this water in giant reservoirs and we rely on this collected amount to last through the hot, dry summers. Therefore, as our urban population increases, our demands on our reservoirs will also increase.

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Task

In this activity, students will work individually or in groups to make the most effective filtration system for clarifying dirty water. While, this activity does not filter the water to reach drinking standards, it does help students explore the first stage of water treatment— filtration.

Clean water for us to drink is not always easy to find without us having to treat it first. The water that comes out of our taps in British Columbia goes through two types of treatment. It goes through physical filtration and chemical disinfection and is sampled before it is declared safe to drink.

In a discussion post discuss what your thought process was to creating the create your filter. What challenges did you over come? Which techniques would you recommend to your colleagues? How can what you discovered in this process be applied to industry? You may post one discussion to represent you school, and then all participants may comment on their colleagues post to contribute to the national dialogue.

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Learning Objectives

• Describe the water cycle.
• Describe a watershed and how water flows through the environment.
• Describe methods and the importance of water conservation.
• Describe the process of water filtration before it gets to homes and taps.
• Explore the effects of water pollution.

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