Healthy or not? Year 7&8 Research Project

The Year 7 & 8's have been learning about how to analyse the health of a stream. Using a water testing kit we journeyed to Haruatai Park to investigate the health of a local stream. The students were asked to write an information report to demonstrate what we have learnt. These reports are examples by Charlie Dale-Low and Zoe Rogers demonstrating our research, investigation and results about healthy streams.

Report by: Charlie Dale-Low

80% of NZ rivers are poor quality. This is appalling. Farmers are getting lazy, polluting rivers with their cows and strip grazing. This process creates topsoil which eventually builds up in our rivers turning them to mucky brown trickles. What about the poor animals that live in that water? Fish, eels and critters. Otaki rivers are not so rural this should mean our streams and rivers don’t have problems with topsoil, therefore they should be a lot cleaner. ATN is about to find out…

The Mangapouri stream is fairly long and has extensive features; its 54km stream flows through forest, wetland, urban areas, farmland, lakes and coastal estuary. Although it has a history of erosion and flooding it looks like a beautiful place to take a dip. (some parts may be to shallow)

What makes a healthy stream?

According to GWRC “The temperature of the water affects the amount of oxygen dissolved in the water.” (colder water has more oxygen, whereas warm water has less) “Water at 0°C has twice the oxygen than water at 30°C. Most invertebrates living in the stream prefer temperatures of 10 to 15°C. the animals become stressed as temperatures increase and will eventually die if they are unable to move to a cooler stretch of stream.”The shading surrounding the stream plays a big part in the temperature. The more shading the more consistency to the stream's temperature, If the temperature is lower less algae will grow which makes the stream more healthy another thing to factor in is the Water clarity. According to GWRC “Water clarity is affected by the amount of sediment in the water. Too much sediment reduces the ability of light to penetrate the water to allow aquatic plants to grow.” This limits the food supply to the animals that eat it. Too much Sediment can also damage the gills of animals. “Too much sediment may cover the stream bed making it an unsuitable habitat for much aquatic life.” So in conclusion to have a healthy stream you need decent shading, cool water temperature and clear water clarity.

Once we knew what a healthy stream was we chose a local stream to gather facts about how healthy our stream was. So on monday 7th of september our class ATN walked down to the Mangapouri stream at haruatai park. We learnt that our water temperature was good, GWRC states that “Most invertebrates living in the stream prefer temperatures of 10 to 15°C” and our average temperature was 11.5°C, though the Mangapouri stream water clarity was 54cm which according to GWRC is ok (not excellent). The invertibery average was roughly the same, with many snails, some worms and mayflies which again is ok.

For the invertebrates, water temperature and water clarity the tests came out as ok

So in conclusion the Mangapouri stream is Ok but not in excellent health.

Report by: Zoe Rogers

Rivers are the lifeblood of our land. We use the water to drink, provide for our plants, wild animals rely on it, farmers use the water, our native forests need it to survive and we use it for our enjoyment. So why aren’t we taking care of our local rivers? 80% of our rivers are poor quality. They’re polluted by things like top soil, our local dairy farms and more. Our class is going to test the health of a local stream and if we all help we can save our rivers.

The Mangapouri stream has many different features. The stream is over 54 square kilometres long and it flows from the Tararura hills to the Tasman sea. You can find 14 to 22 species of freshwater fish in the stream. Areas round the Mangapouri stream occasionally flood. The stream water is believed to have poor quality due to things like livestock and pest plant species.

In order to have a healthy stream it needs to be well maintained. This includes the correct amount of shade. good temperature, little human impact, good water flow and clarity. Water temperature needs to be cool as it contains more oxygen that aquatic animals need. Humans need to be aware of the impact they have. Rubbish goes in bins not streams, not farming and cutting down trees around streams

On Monday 7th September our class, ATN took a trip down to Mangapouri Stream at Haruatai Park. During break one we got changed out of our uniforms and into different shoes then we started walking. We were put into groups to test things like waterflow, water clarity, water depth and aquatic animal life. The overall speed of the stream was 0.122. The overall water clarity was of 54.72cm distance and the temperature was 12 celsius. We found a range of worms and mayflies. We found some rubbish in the stream and the water flow had some pools/riffles and runs. All of this information together tells us the health of our stream is only fair.