christchurch waterways
There are many types of waterways in Christchurch. Some are made by nature such as rivers, melting snow, springs, tributaries, wildlife habitats, wetlands, estuaries and hill waterways. Some waterways are artificial like piped systems, surface runoffs, stormwater systems, artificial drains, retention basins and water races. Also there are things to do with water that aren't waterways like recreation and structures are two artificial ones and surface and groundwater soakage is one produced by nature.
Here are some I can connect: Wetlands are connected to retention basins because people take out the absorbent plants and build houses so we need retention basins to hold water that might overflow into drains when flooded. Drains connect to disease because chch is a flat lying area so it can't drain properly. So when the Maori population increased it caused epidemics of diseases. People are doing their best to make Christchurch flow better, for example turning boarded up drains into beautiful streams that hold lots of invertebrates! Why can't more people change boarded up drains into beautiful river habitats?
Aquifers connect to rivers because the rain falls from the sky and ends up in the aquifers and then they push up and end up in rivers. Some rivers are made by springs. Others are made by rain. Stormwater is also connected to rivers because some of the rainwater ends up in the stormwater system and flows straight to the rivers so I would think twice about throwing litter in a drain.
Ecosystems
The river ecosystem holds different creatures that rely on different habitats and food to survive. The Canterbury mudfish depends on sediment because if sediment was not there then the mudfish would have nowhere to burrow into in droughts. The Common Bully relies on mudfish because the mudfish is an umbrella species which means it protects other species. The Common Bully survives on mayfly larvae because mayfly larvae is a favourite food and if mayfly larvae and other larvae disappeared then it would only eat crustaceans. Mayfly larvae depend on the water temperature being ideally fiveteen degrees Celsius and below or otherwise the water has little oxygen and it will die.
The water temperature has a connection with sediment because if there is a lot of sediment in the river it makes the river look dark and dark colours absorb heat faster than light colours so the river becomes warmer. Sediment connects with vegetation because the plants on the edge filter the sediment and nutrients into the river. The paradise duck depends on vegetation because it eats the plants and builds shelters and lays eggs on them.
Waterway health
There are lots of different indicators to show whether a waterway has a healthy or unhealthy ecosystem. In an unhealthy stream we would only find snails and worms. In a healthy ecosystem we would find more sensitive species like dobsonfly, stonefly, mayfly larvae, also dragon flies and much more, another indicator is the water temperature.
If the temperature is below twelve degrees Celsius then the macro invertebrates will have enough oxygen to move and breathe comfortably, but when the temperature is higher than fifteen degrees Celsius then the macro invertebrates would use up more energy breathing and macro invertebrates can't move far so most die in hot water temperatures.
The algae should be a thin film so it gives just enough nutrients to feed the macro invertebrates but if the algae is a thick spongy stringy layer and it gives off too many nutrients, it uses a lot of oxygen so the macro invertebrates can't breathe and it is sometimes even toxic.
The riparian zone should be made of a mixture of small and tall trees so it holds the bank together and filters sediment and it should have nine or more meters of trees going out but if the riparian zone was just grass or nothing at all and. One to three meters then it would crumble and the water would look dirty. If the waterway was healthy then there would be no sediment and just pebbles and stones and the water would be clear, if it is unhealthy then it would be loaded with sediment and it gets in fishes gills and it looks polluted.
Testing our streams
Our class visited some local waterways such as streams, creeks, lakes and stormwater drains. We evaluated the health of the waterways by using an invertebrate survey, an in-stream and riparian habitat survey, a clarity tube, trays and an eye dropper. First we used the dropper to suck up the invertebrates then we put them into trays and then used the invertebrate survey to assess what species and how many specimens there were, next the
instructor filled a clarity tube with water from the stream and some people looked through and said it got blurry right near the end. After that we got into groups of three or more and we walked upstream filling in the in-stream and riparian habitat survey and at the end the score for the river for our group was a 'good' rating with a mark of 40 out of 56, when we got back the instructor had filled the clarity tube with water from the downstream end and this time it was a bit more murky and the same people tried it and couldn't even see 1/3 of the way to the other end!
Results
We visually tested Dudley creek in St James park and established that the ecosystem habitat was in 'good' quality but we found out that the stream flow was fair because it wasn't very wide and didn't have much water and it didn't have enough stones to provide rapids and riffles. But the erosion was good but needs improving because it has mostly grass down to the bank and about one fifth was flax and the rest was dirt but it seemed quite stable and there was quite a steep bank. The shade over the stream was very good, as most of the stream is shaded but where we tested and in some other was a little bit bare, and the sediment on the stream bed is fair and needs improving because there are little visible stones and most of the bottom is sediment so there wouldn't be much of a chance of finding invertebrates.
Validity
The validity of this test is affected by the fact that everyone has a differing opinion on what they see.
In addition people see different waterways in different perspectives and sees something different every time or wherever they look.
Suggested changes
I propose that we take the following actions:
- We tell people how important it is not to drop rubbish on the ground.
- Plant more trees to both create more shade and prevent erosion.
- Add more stones to create more rapids and riffles.
- Also add more rocks to help invertebrates hide from predators.
- Use native trees to plant because the native creatures are used to the environment.
We should do this because we want to sustain and protect the resources that come from the river for future generations. The Maori call this kaitiakitanga. We also want to sustain and protect the waterways for things like recreation, mahinga kai (food from nature) and make sure the waterways are a healthy environment.
