Making a decision about the health of a stream or waterway is like putting together a jigsaw puzzle. Looking at multiple sets of data will give a more robust picture of the health of the stream. Tracking the data over time will also give you a good indication of the success of any actions taken such as riparian planting. Using the same testing protocol will ensure your data is robust and can be used to make comparisons over time.
Pedagogical considerations regarding data collection:
- Processing your data – graphing data will allow you to see seasonal changes, trends and step changes.
- Understanding your data – all datasets will have an element of variability and it is important to gain a good baseline dataset so any variability that is of concern can be identified.
- What does your data tell you? Is the stream healthy? What does healthy mean? Swimmable for humans? Liveable for macroinvertebrates and fish? Able to support a biodiverse community?
- Decide on the important factors you are looking to improve and why. Use the data you collect to help inform what action you might take.
Consider inputting your data into a national citizen science database like the NZ Water Citizens website.
This Rivers And Us resource is in a downloadable PDF format. Use it to collate and record the data collected during the monitoring and assessment activity.
In the Waikato region, we follow national government guidelines. For example, for drinking water, there are Ministry of Health guidelines that stipulate the levels that are safe to drink. When it comes to swimming and recreation, there’s another set of guidelines by the Ministry for the Environment, and they determine how much bacteria is safe for people to swim in in our rivers and lakes and streams.
When it comes to water quality that protects our ecosystems and our aquatic life, there’s another set of guidelines, and they stipulate levels that are safe for things like nutrients and sediment and bacteria as well.
Recreational use water quality standards are all about keeping people safe, and that’s got to do with the amount of bacteria or toxic algae in the water. So that’s why the recreational water quality standards cover bacteria. The indicator bacteria we test for is called E. coli bacteria, and that occurs in the guts of warm-blooded animals, for example, humans, possums, ruminants like cows or sheep. So it’s not natural, it entered the waterway through our guts and our faeces.
We measure water clarity at the council to determine safety for swimming. For example, people don’t like swimming in water that’s full of sediment – they like to swim in nice clear water. So we measure it, and basically, if you can see less than 1.6 metres through the water, it’s not very clear and not very suitable for swimming. So we use that as part of our swimmability indicator, whereas our other water quality standards cover many other things.
So the Waikato Regional Council monitors a lot of different indicators of water quality – we monitor around 32 a month – but we look at seven different indicators to say whether the water is passable or not. And those indicators include temperature, turbidity, pH, the nutrients – total nitrogen, total phosphorus – ammonia and dissolved oxygen, because like humans, plants and animals need oxygen to breathe as well.
Dr Eloise Ryan
Waikato Regional Council
Footage of man fishing, Whaka Trout
This video has been developed in partnership with the Waikato Regional Council as part of the Rivers and Us resource.