Theme 3: Human Impacts on Catchments

Topic: Impacts of Development

These days most catchments are not in their natural state. When we change the land use in a catchment we often change the way water flows, how much flows, how often and how clean the water is. This has major impacts for water quality and biodiversity and also the enjoyment of our waterways and catchment areas. Ultimately, what we do to our environment affects human health and wellbeing, as all life is interconnected, and we are all part of one large ecosystem.

How has development impacted on our catchments?

Altered water flows: In a natural catchment about 2% of rain runs off the catchment into local waterways - the remainder of the water soaks into the ground or is used by plants before it reaches the ground. However, in an urban catchment, full of hard surfaces, such as roads, footpaths and buildings, up to 95% of rainfall runs off the land into waterways. While stormwater flows have increased, since European settlement the extraction of water for agricultural, domestic and industrial use has left many of our rivers, streams and wetlands deprived of water. This has affected the health of aquatic plants and animals and resulted in a decline in water quality. Unregulated drainage to alleviate seasonal flooding of agricultural land has also had a negative impact on wetlands.

Pollution: Pollution is a significant threat to freshwater and coastal ecosystems, including the disposal of treated wastewater and urban stormwater into waterways, seepage from septic tank systems, faecal contamination from grazing animals, disposal of excess irrigation drainage and illegal waste dumping. These cause a number of problems including algal blooms, loss of biodiversity, poor water quality and erosion.

Loss of native vegetation and biodiversity: Invasion of weeds and the loss of native species in our catchments have also impacted on freshwater ecosystems. Poor water quality and declining river flows have contributed to biodiversity and species losses.

Student Activity Ideas

• Use the Water~Learning and Living poster (or other catchment photo of picture) to identify the different human impacts on catchments.
• Students to identify the different human impacts on local catchments. These may be at home, in industry and at school. Students may draw, write or make a model of these impacts.
• What are some of the positive actions being taken to protect catchments from human development and to restore local catchment areas? Some of the questions to consider include:
  • What might this area have once looked like?
  • Who might have once lived there?
  • Who is living there now?
  • In what ways has the area changed?
  • What might happen in the future and how can we influence that?
• As a class, discuss what is known about your catchment, the different land uses, and what effect these have on the health of the catchment, including downstream effects. Develop strategies for addressing these effects, including education, restoration works, lobbying, changed practices.

Enquiry Learning

• How has land management changed due to agriculture, human settlement, the introduction of exotic plants and animals, and water use management (among others) in Australia?
• How do these changes impact on water quality, water quantity and biodiversity?
• How have changes in land use compromised ecosystem services?
• What are the costs of providing services to replace those previously provided by ecosystems?
• What are the consequences of physical changes to the structure of watercourses, including habitat destruction, water quality decline, loss of amenity and recreational and aesthetic values?
• What are the consequences of changes to riparian vegetation? Look at things such as poor habitat for animals, plants and other living things, and reduced capacity of the natural environment to filter pollutants.
• How does the introduction of toxic materials, sediment, pollution and salinity result in human health problems, deteriorating natural ecosystems in freshwater, estuarine and ocean environments.
• How does the introduction of fish and other aquatic animals and plants outside their natural range add to the competitive strain on native species? How do exotic fish, and other animals and plants alter environments to decrease water quality?

Internet Resources

Type	Description	Resources Covering the Topic
Easy	About SA Water. Visit the education pages for information about water supply and its treatment in South Australia	SA Water www.sawater.com.au
	State of the Environment Report 2001. Overview of Australian Inland Waters issues.	Environment Australia www.ea.gov.au/soe/2001/inland/ introduction-2.html#activitiesinthecatchment
	Water Backgrounder, State of the Environment - NSW EPA Human land use and the water cycle. Diagram that summarises the issues.	NSW EPA www.epa.nsw.gov.au/soe/soe2000/ bw/bw_fig_2.htm
	Thorough overview of water pollution in the Murray-Darling. Looks at pollution contributions by different sectors of society.	Murray-Darling Basin Commission www.mdbc.gov.au/education/ encyclopedia/encyc.htm
	What is water quality? Colour cartoon poster to print. Includes sketches and brief descriptions of water quality.	US Geological Survey water.usgs.gov/outreach/poster5/ Poster5.html
	Human land use and the water cycle. Diagram that summarises the issues.	Water Backgrounder, State of the Environment - NSW EPA www.epa.nsw.gov.au/soe/soe2000/ bw/bw_fig_2.htm
	Sources of water pollution in the Mt Lofty Ranges. Concise summary of main issues. Includes informative facts, photos and tables. PDF download worth the wait.	SA Government EPA - The Mt Lofty Ranges Watershed Protection Office www.epa.sa.gov.au/ pub_water.html#mlr
	Overview of water quality and pollution.	Environment Australia www.ea.gov.au/water/publications/ index.html#quality
	Physical changes to the natural habitat across Australia. Includes maps.	Environment Australia - State of Environment Report 2001 www.ea.gov.au/soe/2001/land/ land02-2.html#condition
	Human settlement patterns across Australia. Covers a broad spectrum of issues, including the pressures human settlement puts on water resources.	Environment Australia - State of Environment Report 2001 www.ea.gov.au/soe/2001/settlements
	Impact of development on the water cycle.	WA Government Water and Rivers Commission www.wrc.wa.gov.au/public/waterfacts/ 7_water_cycle/impact.html
	Caring for our catchment worksheet. PDF download.	Onkaparinga Catchment Water Management Board www.onkaparinga.net/education/ downloads/folder_1/ 4a_care_quiz.pdf
	Impacts of development and alternatives. Fact sheet for teachers. PDF download.	Onkaparinga Catchment Water Management Board www.onkaparinga.net/education/ downloads/folder_3/ 2a_landscape_teacher.pdf
More Comprehensive	State of the Environment Report 2001. Extensive review of Australian Inland Waters issues.	Environment Australia www.ea.gov.au/water/index.html
	What is water pollution? Comprehensive summary the different types of water pollution.	VIC EPA www.epa.vic.gov.au/Water
	Water use. Comprehensive look at how we use Murray water.	Murray-Darling Basin Commission www.mdbc.gov.au/river_murray/ river_murray.htm
	Condition of Australia's freshwater resources. Overview of pressures on Australia's waterways.	Australian Bureau of Statistics www.abs.gov.au/ausstats/abs@.nsf/ 94713ad445ff1425ca25682000192af2/ 3f8d7e912784b4eaca256b35007ace03!OpenDocument
	What is groundwater? Covers the major issues with diagrams. Pollution, salinity, land degradation.	WA Government. Water and Rivers Commission www.wrc.wa.gov.au/public/waterfacts/ 8_groundwater/index.html
	Industrial pollution. Description of the types of pollutants from industry.	Info Please www.infoplease.com/ce6/sci/ A0851609.html

Activities

Band	Activity	Contact
Early and Middle Years	Do your activities affect the catchment? Student worksheet. PDF download.	Onkaparinga Catchment Water Management Board www.onkaparinga.net/education/ downloads/folder_3/ 2a_actions_student.pdf

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