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Water Quality Monitoring
Each month your class will be collecting important information about the water quality of your local waterway. Your information along with water quality information collected by other schools will be included on the map in the 'View results' section of this site. By looking at the results you will be able to see how water quality changes throughout the catchment.
Collecting the water samples
Your class will visit your monitoring site each month to collect a water sample to test. If your monitoring site is too far from your school, a teacher or student could collect the water sample each month and bring it to class for testing. To ensure your sample is representative of the water body, it should be taken from about 20cm below the surface and "about the middle" of the waterway.
What are we testing for?
You will be using the equipment in your kit and doing some chemical tests to find out about the water quality of your local waterway.
Your class will be testing the water for Salinity (Electrical Conductivity), Dissolved Oxygen, Turbidity, Temperature, and recording rainfall each month. Students will also be encouraged to interpret their results to determine if the water quality in their part of the catchment is healthy or unhealthy.
How do we test?
All Catchment Capers schools have a method manual supplied with their kit. See on-line version below.
Catchment Capers Method Manual [PDF 136 KB]
Make sure that you have downloaded the 'Catchment Capers Water Test Results Sheet' before you start testing so you can record your findings.
Salinity
Salinity or electrical conductivity is the amount of salt present in the water. Salinity is measured using a conductivity meter in electrical conductivity units (EC).
Salinity can be a problem when present in high amounts. Plants and animals, like us, need a little bit of salt to help them grow. However when there is too much salt in the water, plants and animals have trouble surviving. Not many plants and animals can live in waterways that are too salty.
Some waterways are very salty because too many trees have been removed from the nearby land for farming and irrigation. When the trees are gone more water can get into the soil which causes the underground water (also known as groundwater) to rise. As this water moves to the surface it brings with it large amounts of salt that has been stored underground. This salt is then washed into our waterways with irrigation and rainfall runoff.
To see a diagram of salinity click here.
Dissolved Oxygen
Dissolved oxygen is the small amount of oxygen gas dissolved in the water. Dissolved oxygen is measured in mg/L.
Like humans, plants and animals that live in the water need oxygen to live. Lots of different types of plants and animals live in waterways that have high levels of oxygen. Waterways that have low levels of dissolved oxygen have less different types of plants and animals living in them.
Dissolved oxygen levels can change with temperature. So it is important to record what the temperature of the water is when testing for dissolved oxygen.
Turbidity
Turbidity is the cloudiness of the water. When the water is very cloudy or murky the amount of light that passes through the water is very low. Plants need light for survival as it helps them grow. This affects the animals which feed on and live in the water plants. Turbidity can be caused by soil particles, decaying plants and chemicals in the water, as well as bank erosion.
Turbidity is measured in Nephelometric Turbidity Units (NTU) using an instrument called a turbidity tube.
Clean rivers have a low turbidity of around 1 NTU and murky creeks are highly turbid at around 200 NTU.
Temperature
Temperature is measured in degrees Celsius (° C) using a thermometer. Temperature can speed up or slow down the rate of many chemical reactions that occur in the water. That is why it is important to record temperature when doing chemical testing.
Rainfall
Rainfall is measured in millimetres (mm) using a rain gauge. Once you have completed your water tests for the month use the rain gauge supplied to read and record the rainfall for the last 48 hours.