NCWR

About NCWR

Rainwater harvesting

In a nutshell

In this activity we learn how a rainwater harvesting system operates.

1 class hour

10-13 years old

In class

Our objectives

In this activity you will:

  • Find out about the operating parts and functions of a rainwater harvesting system.
  • Learn how we can use the collected rainwater.
  • Consider possible applications of such a system in your home or school.

Stop and wonder

DISCUSS IN GROUPS


  1. Until recent years in various Mediterranean islands, many houses had their own rainwater harvesting . Why so? Why did they stop using them?
  2. Today, in several cities around the world, even in those where water is abundant, many new buildings are equipped with rainwater harvesting systems. Why so? Where do you think this water can be used ?
  3. All around the world, infrastructures like sport fields and airports are equipped with rainwater collection systems. How do they use the collected water?

Play & learn

Find the pot to collect the rain!

If you wished to collect the rainwater, what equipment would you use? Here are some ideas given by students!

 rainwater-harvesting quiz-hotspot
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Water-readings

The parts of a rainwater harvesting system

A rainwater harvesting system includes the following basic parts:

  • catchment surface, on which the rain falls. This can be a roof, a terrace, etc.
  • A gutter or drainage pipe that is an open horizontal or closed vertical pipe through which the rainwater flows. A sieve (net) is placed at the opening of the gutter to retain any debris, leaves, pebbles etc.
  • control valve to control the flow of water from the gutter either to the tank or the yard.
  • A filter to further clean water from small sized solids, dust, etc.
  • A tank (cistern) to store the water. This can be made of cement, plastic or metal. It may stand freely on ground or be carved underground. In any case the users need to have access to it.
  • A pump and pipes to transfer the water.
  • An overflowing siphon that leads the excess water out of the tank  (and helps out the aeration of the system as well).

Play & learn

The parts of rainwater harvesting system

Based on what you read in the previous water readings, drag & drop the parts of the rainwater system to the right spot in the diagram.

 rainwater-harvesting quiz-hotspot
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  • 1 1 catchment surface
  • 2 2 gutter / drainage pipe
  • 3 3 filter
  • 4 4 pump
  • 5 5 tank
  • 6 6 overflow siphon
  • 7 7 control valve

Stop and wonder

DISCUSS IN GROUPS


  1. Even when the tank is underground, why do we need to have access to its opening?
  2. During which season we need to clean the filter?
  3. The control valve gives us the option to choose whether to direct the rainwater inside the tank or not. In which cases the rainwater is not wanted?

 

Play & Learn

How do you think we can use the collected rainwater? We can use it for ... (choose the right options)

Rainwater is appropriate for watering our garden, flowers and vegetables.

This way we can achieve an important water saving.

Rainwater can be drunk only after its disinfection, as it might contain microorganisms. Disinfection takes place using specific filters or chlorine or UV rays. In any case, before we drink it it is necessary to have it tested in a chemical lab.

Rainwater does not contain salts, thus, is proper for washings. Actually, certain washing machines have a "rain" operation mode. However, if we do not disinfect the water first, we should avoid using it in the washing machines..

Rainwater does not contain salts that is why women in the past, preferred it for washing their hair. Today, when installing a modern rainwater harvesting system we avoid bathing with it because we do not know if it contains microorganisms. It needs disinfection and lab test in order to use it for showering or drinking.

Rainwater can be used for such outdoor cleaning purposes

Activity

How much rainwater can you collect at school?

If your school has a water tank, you can easily calculate how much rainwater it collects approximately within a year. Even if there is no tank, you can still calculate how much rainwater could have been collected if you know:

  • The area of the catchment surface (in square meters, m2). With help of your teacher calculate it after measuring the building’s perimeter.
  • The annual average rainfall of your area (in millimeters per year, mm/ yr).  You can find this in the website of the Meteorological Agency.

Then, the amount of rainwater that can be collected in a year (in cubic meters, m3) is:

Area (m²) x Average annual precipitation (mm) x [runoff coefficient] *** = .... m3)

What is a run-off coefficient? During the rainwater system operation there are some losses e.g. due to evaporation or spills at the catchment surface.  So, we use a “run-off coefficient”, a number that expresses these losses and it depends on the material of the catchment surface. For instance, it is about 08-0.9 for metal; 0.75 to 0.9 for concrete surfaces; 0.8 – 0.85 for gravel; 0.5  for clay tiles, etc.

Water shares


Water meter

I liked this activity . . .

Way forward

Surfing around the internet

Watch here a short animation about the rainwater harvesting system that has been installed in a Primary School in Malta.

Dive in…

The water cycle if you want to  make rain through a model of the water cycle!

Rainwater Harvesting Systems in practice if you want to read more about a real installation of a rainwater harvesting system!

Go back to the homepage!

Acting for Climate

Water works through time

Water in the city

The water basins

Desalination

Greywater recycling in practice

Do you know about grey water?

Wastewater treatment

Rainwater Harvesting Systems in practice

Rainwater harvesting

Reduce-Reuse-Recycle

Climate change: Why should I care?

Water resources

The water cycle

Where do I begin?

Acting for Climate

What are the main sectors contributing to climate change? What are countries doing to address it? What can we do for climate collectively at school and at community level?

Continue!

Water works through time

Let's discover the story behind the old fountains, cisterns and aqueducts of our town!

Continue!

Water in the city

What is the "urban water cycle"? Which are the important aspects of water management within a city environment?

Continue!

The water basins

In this activity we learn what a water drainage basin is and why it is important for the experts to study it.

Continue!

Desalination

Let's find out how sea and brackish water can become a freshwater resource!

Continue!

Greywater recycling in practice

How a greywater system is installed? Let's find out!

Continue!

Do you know about grey water?

Let's find out what "greywater” is and how we can use it!

Continue!

Wastewater treatment

In this activity we learn about how wastewater is treated and what we can do with the treated water.

Continue!

Rainwater Harvesting Systems in practice

What are the various types of rainwater harvesting systems? Let's find out more about them!

Continue!

Rainwater harvesting

Can we collect rainwater? And how do we use it? Let's find out!

Continue!

Reduce-Reuse-Recycle

What is our water footprint and how can we reduce it?

Continue!

Climate change: Why should I care?

We discuss the greenhouse effect and the greenhouse gases, how climate change is linked to our lifestyles and ways we can cope with it on a personal level.

Continue!

Water resources

Lt's discover the water resources of our region.

Continue!

The water cycle

Let's travel within the water cycle!

Continue!

Where do I begin?

Let's see why it is important to know about water in our region.

Continue!