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What is it?
We map changes in land use every five years to analyse trends and to understand the current and future risks to our water resources.
How is it conducted?
WaterNSW maps land use by collecting and interpreting high resolution aerial photography and satellite imagery.
Since 2000, four land use maps have been prepared (in 2000, 2002, 2007 and 2012).
Why do we conduct this research?
Land use mapping helps us to understand how our catchment areas are being used, and can be used to highlight areas where we may need to intervene to ensure water quality and quantity is maintained.
Land use and management practices can have a major impact on the quality and quantity of water resources in the drinking water catchment.
Currently, the top land uses across our 16,000 sq km catchment area are:
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- Livestock grazing - 37%
- Nature conservation lands (in national parks) - 26%
- Minimal use land (inc Crown lands and reserves) - 17%
- Other (inc intensive agriculture, horticulture and cropping, mining, public services, reservoirs) - 11%
- Plantation forestry - 6%
- Urban and rural residential - 3%
How our mapping is used?
We use land use information to:
- assess the potential risk of land use and management practices in our Pollution Source Assessment Tool (PSAT)
- plan and implement catchment intervention programs in the Healthy Catchments Strategy
- identify trends in land uses that may impact on water quality and quantity
- model WaterNSW's carbon footprint.
By conducting new research we are able to compare data and develop ways to more effectively use and manage land in the catchment.
We also use this data to assist local councils with their planning activities.
Councils are responsible for land use zoning in the catchment. To protect water quality, it is important to ensure zoning decisions are consistent with the physical capability of land.
What have we learned so far?
Since research began in 2000, we have learned quite a bit about the composition of land use in the catchment and how it has changed over the years (see table below):
|Land use type||Coverage||Increase in land area (2000- 2012)|
565,821 - 37%
18,387 ha (up 4%)
414,487 - 26%
81,334 (up 17%)
Minimal use land
261,842 - 17%
42,565 (down 14%)
Mining and quarries
2,985 - 0.19%
185 ha (up 17%) - quarries
180 ha (up 16%) - open mines
Horticulture and cropping
2,777 - 0.2%
79 ha (up 7%)
Plantation forestry (including softwood and private)
88,699 - 6%
1879ha (up 2%)
Rural and urban
51,084 - 3%
5,246 ha (up 11%) - rural
1,534 ha (up 19% - urban
What are the plans for the future?
Land use mapping has traditionally used imagery captured in a single point in time. However, land use changes with the seasons and from year to year depending on local climatic conditions.
Future land use mapping will aim to improve our knowledge of these changes, especially for cropping, by using imagery captured throughout the seasons and over a five year period.
We also plan to closely monitor the rural-urban corridor from Sydney to Canberra, which has shown significant growth over the past 12 years.