Monitoring water quality

Focus

This activity provides opportunities for students to monitor the water quality in their local area, using a range of tests, and to draw conclusions about human impacts on the quality of water in their catchment area.

Science

Science and Society

5.3 Students analyse the relationship between social attitudes and decisions about the applications of science.

6.3 Students use scientific concepts to evaluate the costs and benefits of applications of science (including agricultural and industrial practices).

 

Materials

Teaching considerations

Approaches to sampling

Two approaches to sampling can be taken, depending on the accessibility of a suitable local waterway to the school.

1. Single site sampling

Students can sample from the same location at the same time every week for the duration of the module. Students could sample from a site once to gain an appreciation of the site and then analyse subsequent weekly samples in the laboratory. Sampling over a number of weeks aids students’ understanding of the significance of the tests. It is useful to link in a riparian vegetation assessment and a waterbug survey to gain a more complete picture of the ecology of the waterway (see developmental activity ‘Assessing waterways’).

2. Multi-site sampling and catchment crawls

Alternatively, students can sample three or four different sites along a waterway on a single day. The sites should be a couple of kilometres apart and have a variety of landforms and vegetation. For instance, a range of sites could be well shaded, in full sun or below a stormwater outlet. If access is difficult, samples could be collected and taken to the classroom for analysis. However, if students have not visited a site, they will be unable to visualise the associated landforms and vegetation. If a range of sites are chosen in lower, middle and upper parts of a catchment, this method of sampling is often referred to as a ‘catchment crawl’. At each stop students investigate similar characteristics or parameters so that a comparative overview can be taken of the catchment. This can be achieved by:

After the excursion, students draw conclusions about the relative health of the waterway at the various sites and the possible human impacts that may affect the waterway.

Other tests

Other parameters can be tested, depending on the availability of equipment, the skill level of the students and the risk assessments of the tests. These include dissolved oxygen, phosphates, nitrates and faecal coliforms.

Water monitoring kits

Some local councils and regional natural resource management bodies will lend water quality test kits to interested groups.

Working scientifically

Time: 30 minutes for information retrieval; 30 minutes for monitoring (or one-day excursion plus another 40 minute lesson for collation and interpretation of data, if you choose to do a catchment crawl)

Students reflect on the investigation they are about to conduct. Questions to support reflection might include:

Working in groups, students collect their water samples from the site/sites concerned. The group will also need to take notes describing the human impacts that are visible adjacent to the sampling site. Students analyse their sample and record the data in a table. If sampling is to occur over a number of weeks, groups could take turns to perform a particular test. Data from the whole class could then be collated.

Students complete the retrieval table in Resource Sheet 9 from the information cards, which give background information on each of the tests. Guided by the teacher, students discuss the significance of their test results and draw conclusions about the effect that human impacts may have on the water quality at their sites. Ideas from the introductory activity ‘Which catchment area do I live in?’ could also be linked at this time.

Individually, students write a short report tabulating their data, graphing their results and explaining their conclusions. The report should also offer suggestions for actions that could be taken to improve the quality of the water so that the natural resources of the area can be used without causing long-term environmental damage.

Where human impacts have occurred, students should say in the report whether there is evidence that the behaviour of people has now changed to address any of these impacts, or whether the cause of the impact still remains.

Students should also indicate whether they think social attitudes would support the solutions that they have proposed to improve water quality.

Gathering information about student learning

Sources of information could include:

(The ‘Monitoring water quality’ activity is adapted from Foster 1995, Waterwatch action by school communities)

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Last updated 2 August 2010

Catchment management