Wednesday, 24 June 2015

Christchurch Waterways

Fresh waterways include ponds, rivers, creeks and lakes. There are also some man made waterways such as the stormwater system and artificial drains. When it rains the rain soaks into the grass and then go into aquifers which are underwater rivers. Then it flows into our taps and then we use it as drinking water. If the water falls on roofs, it flows into the drains then goes to the stormwater system and out into the river.

Rivers connect with artificial drains because artificial drains could affect the water in the rivers by flowing into the rivers and putting oil spills and other bad things in the river and that would be bad.

Habitats and River Ecosystems

A habitat is a place where an animal lives. A habitat should provide shelter and food. Habitats should also provide oxygen so the animals can live and survive.

In a river ecosystem, different creatures rely on other creatures. Like the pukeko relies on the vegetation for food and shelter. If there was no vegetation then there will be no pukekos.

Some animals and fish are a bit fussy about their habitats. The eel eats the koura (freshwater crayfish) the blue duck also eats the koura also the shag eats the koura. So if the koura dies then it affects the other animals that eat the koura, so they will die along with the koura because they eat the koura. Some people ruin some habitats and they don't even know that they are doing it.

A healthy waterway

You can tell if your river is healthy by looking at the river. If your river is unhealthy then you would only find snails and worms (or no animals) because they live in polluted and healthy waterways. If you find stonefly, mayfly or caddis fly larvae living in your river then that means it is a healthy waterway.

You might also want to test your water temperature too. Water that is warmer than 20 degrees celsius doesn't carry the oxygen so that means that your water temperature is unhealthy. If it was healthy the water temperature would be 15 degrees or under.

Also check for algae. Algae is an underwater plant. If there is a thick layer of algae then that is bad for your waterway, but it is good to have a thin coating of algae.

You should also check if your waterway has shade, so the water will keep cool. If there are no bushes or trees around the waterway then it won't be healthy and the waterway will get hot.

Testing our waterways

Our class visited lots of different rivers in Christchurch. I visited Styx river, the lake at Styx Mill, Dudley creek and the stormwater drain behind Waimairi School.

When we were at those those rivers we assessed the ecosystem to see how healthy they were. We used a chart called “In-stream and Riparian Habitat Survey” to test the water and see if it was healthy or not. We walked around and looked at the rivers. After we looked at the rivers we put a mark of what we think the river looked liked.

After, we tested the water we went to see what bugs lived in the river. We fished them out with a sieve and put them into a little container. Then we got some plastic spoons to fish the bugs out whenever we saw one. Then we put the bugs into little sections in another container. Then we got the magnifying glass and looked at the bugs. After we looked closely at the bugs, we looked at a map that had all the bugs on it. So we worked out what bug it was.


The stormwater drain behind Waimairi school is not as healthy as it could be, and there could be ways to improve it. There are no trees or bushes to provide shade. There is only long grass and weeds which don't provide shade at all this is bad because the creatures that live in this stormwater drain won't have enough shelter.

Secondly, this drain has no stream flow at all. This is probably because there hasn't been enough rain to fill it up.

There is also heaps of sediment (mud) over the rocks.This is really bad because some creatures live under rocks so if the sediment is over the rocks it could ruin their habitat.

Another thing we noticed was that the bank of the drain is a bit unstable because you can see the sediment this is bad because all the sediment could go into the water.

Suggested changes

Although there are parts of the waterway ecosystem that are unhealthy, there are many changes we could make to improve its health:

  • Maybe plant some plants because there isn't any around the stormwater drain. You should plant some so you have shade around the waterways to keep shelter for the macroinvertebrates.

  • We could put something like a log in the stormwater drain to change the streamflow of the stormwater drain to create different habitats.

Why are these changes important?

These changes are important because we can go canoeing, swimming, diving without worrying about getting sick. It will also make our waterways look nicer, and lots of people will see them and be able to enjoy using them.



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