We have a lot of waterways in Christchurch some of them are natural and some of them are human made.
Our groundwater system is connected to our waterways because the groundwater comes up to our wetlands and then it comes out of the ground and that's called a spring. Springs are what makes our wetlands and rivers. The surface water goes down the drain and into the stormwater system and then the water goes out into the rivers with the fish and water insects.
In an ecosystem different creatures like different habitats. Mayfly larvae is a macroinvertebrate. Mayfly larvae like cold water and shade. They like shade because it makes good hiding spots for them and it keeps the water cold. They like the cold water because it carries more oxygen. Mayfly and canterbury mudfish don't like the common bully because it's like a bully to them because it feeds on macro invertebrates and crustaceans. But mayfly and canterbury mudfish like brown trout and paradise duck because they eat bullies. Canterbury mudfish are umbrella species so if we look after them we're also looking after dragonflies, freshwater mussels and freshwater crayfish.
There are lots of different indicators to know if a river is healthy or not. If it's healthy it'll have things like mayfly and stonefly and for an unhealthy river you would find things like snails and worms. If the water in a river is 18 degrees Celsius and over then it doesn't carry much oxygen and the fish and water insects can't breathe properly but if the water is 15 degrees celsius and under then they can all breathe really good.
If there is long stringy algae it's hard for all the macroinvertebrates and fish to swim around in the water and takes the oxygen from the water and if there's short stubby algae they can go to different places easily.
If there are lots of trees on the sides of the rivers then it's good because the roots hold the dirt in the sides of the river. If there's not many trees then the dirt falls into the river and makes turbid water and the sediment goes into the fish's gills and gets stuck and then the fish can't breathe. The turbidity in the water tells you how clean the water is. If the water is clear then it's healthy water, and if the water is dirty then it's unhealthy water.
Testing our waterways
My class have visited some streams and creeks and lakes and rivers and stormwater drains. We assessed the water with a technical retrieval device A.K.A. T.R.D. A.K.A a sieve on a long wooden pole. We used a clarity tube, 2 different trays, a magnifying glass and an eye dropper. We used the clarity tube to see how clear the water was. We used the tray to put the water and the invertebrates in. We used the the magnifying glass to see what the insect was . And the last thing we used was an in-stream and riparian habitat survey. We used it so we knew what the insect was.
We tested the stormwater drain and found that it was in poor health. The shade over the stormwater drain is bad because there is no trees and the water will get to hot. The stormwater drain is about half covered in sediment because when the rain falls into the stormwater drain it goes under the ground and rises to make mud and sediment. Half of the stormwater drain is eroded because there is no trees and there is lots of mud on the bottom. There is no algae because there isn't much water in the stormwater drain.
Plant more trees
Put concrete at the bottom
Plant more plants
Put water in the stormwater drain to make a little bit of algae