How do we know whether a stream is healthy or not? Stream monitoring and assessment is important to understanding the impacts of land use on waterways.
Stream monitoring and assessment is important to understanding the impacts of land use on waterways. Measuring the positive impacts of riparian planting is just as important as assessing a stream that is in poor health.
Gathering data is a key science capability and it helps to inform what actions we could take to improve water quality. Using consistent methodologies when gathering data gives a robust picture of a stream’s health over time.
Use this interactive along with the activity Monitoring stream health, which has step-by-step instructions and data recording sheets.
To use this interactive, move your mouse or finger over any of the labelled boxes and click to obtain more information.
Transcript
Identify impacts
As you travel around your local area, observe how the land is being used. As you travel to the stream you plan to monitor, note any industry or land use that may be impacting on the health of the stream. Observe upstream and downstream from your monitoring site.
Use the following resources to explore impacts on water quality
- Water quality – factors and issues
- Land use – impacts on waterways
- Dairy farming solutions
- Horticultural solutions
- Urban solutions for water quality
- Human impacts on the Waikato river
Select here to view the video transcript and copyright information.
Acknowledgement: The University of Waikato Te Whare Wānanga o Waikato and Waikato Regional Council
Visual habitat assessment
The habitat conditions at a monitoring site can influence stream life. A visual habitat assessment involves close observation of some of these conditions.
The SOSMART visual health check uses the following observations:
Smells – smell the water, note what you smell.
Obstructions – is there anything restricting water flow?
Stream bed – is there anything covering or smothering the stream?
Margin or bank – what do you see?
Appearance of the water – note what it looks like.
Rate of flow – note if it is fast or slow.
Top surface of the water – note your observations.
The visual habitat assessment also includes an observational drawing of the stream. Protocols recommend a habitat assessment length of about 50 m if the stream width is greater than 3 m or 20 m if the stream width is 1 m. This depends on access, safety and time.
The observational drawing identifies the photopoint, various sampling points, water flow riffles and runs, stream bed composition and direction of water flow.
In addition to observational drawings, take photos of the area so changes can be viewed over time.
These Rivers and Us resources are in a downloadable PDF format. Use them as a guide to the scientific methodology for habitat assessment. They also contain discussion and reflection questions.
- Freshwater Monitoring – Bug Food and Stick Races
- Freshwater Monitoring – Habitat Assessment
- Freshwater Monitoring – Stream Health Monitoring Data Recording Sheet
Select here to view the video transcript and copyright information.
Acknowledgement: The University of Waikato Te Whare Wānanga o Waikato and Waikato Regional Council
Conductivity
Conductivity measures how well water can conduct an electrical current. Streams tend to have a relatively constant range of conductivity. Significant changes in conductivity (due to an increase in salt content such as chloride, bicarbonate, sodium or calcium) could suggest that a discharge or some other source of pollution has entered the stream.
This Rivers and Us resource is in a downloadable PDF format. Use it as a guide to the scientific methodology for measuring pH. It also contains discussion questions.
Acknowledgement: NIWA
pH
pH is a measure of acidity or alkalinity. pH is short for ‘pondus hydrogenium’ and indicates the concentration of hydrogen in a solution.
Most natural waterways are in the pH range of 6.5–8. Some streams are naturally acidic (less than 7) or alkaline (greater than 7) depending on the surrounding substrate and bedrock composition. pH also changes over night and day. Biological factors such as photosynthesis and respiration alter the chemical composition of the water. Aquatic life cannot tolerate extreme pH (high or low).
This Rivers and Us resource is in a downloadable PDF format. Use it as a guide to the scientific methodology for measuring pH. It also contains discussion questions.
Select here to view the video transcript and copyright information.
Acknowledgement: The University of Waikato Te Whare Wānanga o Waikato and Waikato Regional Council
Temperature
Temperature affects many of the chemical and physical properties in streams. Macroinvertebrates will not survive in temperatures above 22°C, and higher temperatures also increase conductivity.
This Rivers and Us resource is in a downloadable PDF format. Use it as a guide to the scientific methodology for measuring water temperature. It also contains discussion and reflection questions.
Select here to view the video transcript and copyright information.
Acknowledgement: The University of Waikato Te Whare Wānanga o Waikato and Waikato Regional Council
Water velocity
How fast is the water flowing down the stream? This can vary depending on the amount of water in the stream at any one point in time. It can be affected by drought or heavy rainfall events. You should be able to assess a base ‘normal’.
This Rivers and Us resource is in a downloadable PDF format. Use it as a guide to the scientific methodology for measuring water velocity. It also contains discussion and reflection questions.
Select here to view the video transcript and copyright information.
Acknowledgement: The University of Waikato Te Whare Wānanga o Waikato and Waikato Regional Council
Water clarity
Water clarity is a measure of underwater visibility in rivers and streams. It indicates how much fine sediment, algae and other particles are in the water column.
Reduced clarity can be harmful to the animals living in or near the water. It also restricts sunlight from getting to the plants that need sunlight to photosynthesise.
Measure water clarity by using a clarity tube or periscope viewer.
These Rivers and Us resources are in a downloadable PDF format. Use them as a guide to the scientific methodology for measuring water quality. They also have discussion and reflection questions.
Select here to view the video transcript and copyright information.
Acknowledgement: The University of Waikato Te Whare Wānanga o Waikato and Waikato Regional Council
Macroinvertebrate sampling
Benthic macroinvertebrates are animals that live at the bottom of streams and lakes, are large enough to be seen with the naked eye (macro) and lack a backbone (invertebrate). In freshwater, they are the immature stages of many insects. You can also find crustaceans (such as kōura/crayfish and shrimps), snails, worms and leeches. Stream bugs are a key part of stream food webs, feeding on periphyton, macrophytes, dead wood or each other. They are also indicators of stream health.
Different methods of sampling macroinvertebrates in streams are:
- kick-net method for stony substrates
- stone method (rubbing stones and debris)
- running the net along the sides of the stream under vegetation for soft, sandy substrates.
These Rivers and Us resources are in a downloadable PDF format. Use them as a guide to the scientific methodology for bug sampling. The bug sampling PDF contains discussion and reflection questions.
- Freshwater Monitoring – Macroinvertebrate (Bug) Sampling
- Freshwater Monitoring – Macroinvertebrate Identification Sheet
Select here to view the video transcript and copyright information.
Acknowledgement: The University of Waikato Te Whare Wānanga o Waikato and Waikato Regional Council
What does our data show?
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.
Select here to view the video transcript and copyright information.
Acknowledgement: The University of Waikato Te Whare Wānanga o Waikato and Waikato Regional Council
What action can we take?
Once we have a picture of how healthy our stream is and what factors we want to improve and why, we can make plans to take action.
The interactive Inquiry and action learning process provides step-by-step guidance for planning and investigating a water quality issue with the intent to take action.
Examples of actions that can improve stream health include:
- riparian planting
- maintenance of riparian planting
- fencing the stream from stock
- pest control
- raising awareness of water quality within the community
- exploring what has been done before and visioning for the future
Select here to view the video transcript and copyright information.
Acknowledgement: The University of Waikato Te Whare Wānanga o Waikato and Waikato Regional Council
Acknowledgement
This interactive has been developed in partnership with the Waikato Regional Council as part of the Rivers and Us resource.
