Palerang
Indicator: Land Degradation
Results for this indicator are also available for [an error occurred while processing this directive]
What the results tell us for Palerang
For the 2004-2008 reporting period, drought was experienced throughout the Council area. Landuse in the Council area remained largely compatible with its capability class. Since the last reporting period there has been no noteworthy data released on erosion, acidic or sulphate soils.
Sustainability of landuse
See also: Landuse
Land capability in the Palerang Council area is defined as agricultural areas suitable for both grazing and cultivation. State forests are also present within the Council area. (Figure 1).
Figure 1. Land capability within Palerang Council area (Source: DPI, 2008)
Source: Department of Lands 2008
The majority of land in Palerang Council area is under landuse types compatible with the land capability class (Table 1). The Council area has approximately 2% of the land area that has landuses not suited to land capabilities, therefore having the potential to cause erosion.
The Council area has 39% of land under grazing, which is the dominant land use in Palerang Council area, with 96% of this land within its capability. The remainder of the grazing lands is in areas of high erosion risk if cleared; the Department of Lands recommends that these areas remain timbered.
Palerang Council area has 0.2% of land classified under cropping, with 58% of this land not suitable for regular cultivation. Poor suitability for regular cultivation may be partially due to climatic variables as well as potential erosion. An impact of this may include low crop yields. Approximately 2% of the land in Palerang Council area is classified as private timber plantations, however only 6% is within land capability Class VII. In addition to this 2004 data, an additional 2000ha was purchased and largely planted over the last few years around Kindervale. (Holloway, 2008)
The lands classified under land capability class VII have a high erosion risk when cleared, and although much of the timber production forests within the state land in this classification, they are not necessarily suited to forestry operations; the Department of Lands recommends that these areas remain timbered.
Approximately 4% of the Council area has a land use classified as rural residential, only 2% of this land is not for this purpose.
| Landuse | Land Capability Class | |||||||
|---|---|---|---|---|---|---|---|---|
| Lands suitable for regular cultivation | Lands suitable for grazing—occasional cultivation | Lands suitable for grazing—no cultivation | Other lands | |||||
| I | II | III | IV | V | VI | VII | VIII | |
| Cropping | 86 | 58 | 20 | 40 | 0.2 | |||
| Estimated grazing | 7,749 | 6,482 | 91,559 | 27,282 | 60,781 | 5,883 | 1,436 | |
| Horticulture | 2 | 0.2 | 3 | 1 | 4 | |||
| Other plantations | 13 | 3,047 | 1,362 | 6,782 | 749 | 0.1 | ||
| Rural residential | 41 | 525 | 7,264 | 4,116 | 3,546 | 317 | ||
| Totals (hectares) | 7,878 | 7,020 | 101,930 | 32,780 | 71,154 | 6,950 | 1,436 | |
Source: 2004 Regional State of the Environment Report
Types of land degradation
Erosion
The data available on erosion extent in Palerang Council area is derived from surveys carried out between 1985 and 1992. These surveys indicated about 1,030 kilometres of gully erosion and approximately 380 kilometres of streambank erosion were present in the Council area at that time, as well as extensive areas of moderate to minor sheet erosion.
Approximately 37% of the gully erosion measured in Palerang Council area are classed as severe to extreme, and 10% of gullies were more than three metres deep (Table 2). Most erosion gullies in Australia would have formed soon after the native vegetation was removed, and although these gullies have since stabilised, they are continuing to contribute sediment loads to streams (Hughes and Prosser 2003). In New South Wales (NSW) overall, Edwards and Zierholz (2001) estimated that accelerated erosion rates were 10–50 times the natural rates.
Figure 2. Degree of erosion (Source: DPI 2008)
Source: Department of Lands 2008
It is expected that some erosion may have continued to occur within Palerang Council area during the current reporting period due to the ongoing drought, although there is also some remediation work being undertaken.
| Erosion type | Depth | Kilometres |
|---|---|---|
| Extreme gully erosion | 3 to 6m deep | 53 |
| 1.5 to 3m deep | 36 | |
| less than 1.5m deep | 52 | |
| Extreme gully erosion total | 141 | |
| Severe gully erosion | 3 to 6m deep | 30 |
| 1.5 to 3m deep | 97 | |
| less than 1.5m deep | 108 | |
| Severe gully erosion total | 235 | |
| Moderate gully erosion | 3 to 6m deep | 13 |
| 1.5 to 3m deep | 69 | |
| less than 1.5m deep | 231 | |
| Moderate gully erosion total | 313 | |
| Minor gully erosion | 3 to 6m deep | 5 |
| 1.5 to 3m deep | 50 | |
| less than 1.5m deep | 285 | |
| Minor gully erosion total | 340 | |
| Streambank erosion | greater than 6m deep | 3 |
| 3 to 6m deep | 8 | |
| 1.5 to 3m deep | 109 | |
| less than 1.5m deep | 256 | |
| Streambank erosion total | 376 |
Source: Department of Infrastructure, Planning and Natural Resources data from 1985 to 1992
| Major erosion type | Degree and type | Area (ha) |
|---|---|---|
| Mass movement | slump | 4 |
| soil debris avalanche | 6 | |
| Rill erosion | extreme rill erosion | 484 |
| severe rill erosion | 57 | |
| moderate rill erosion | 120 | |
| minor rill erosion | 14 | |
| Sheet erosion | extreme sheet erosion | 956 |
| severe sheet erosion | 3,328 | |
| moderate sheet erosion | 31,525 | |
| minor sheet erosion | 215,199 |
Source: Department of Infrastructure, Planning and Natural Resources data from 1985 to 1992
Salinity
Salinity is currently an issue in the west of Palerang Council area near Captains Flat. The salinity in this area is expected to increase in the future (Figures 3 and 4) (AWR 2005)
Figure 3. Extent of salinity (2000)
Source: Austrlia National Resource Atlas 2001
Figure 4. Estimated Extent of salinity (2050)
Source: National Resource Atlas 2001
Acid soils
Approximately 67% of surface soils within Palerang Council area were classed as strongly acid (pH 3.5–5.5) in 2002 (DLWC, 2002b). These soils occur throughout Palerang Council area, except in the areas along the Araluen Creek, Shoalhaven River and Taylors Creek. Although many soils in high rainfall areas are naturally acid, the level of acidity in agricultural areas may be partially due to application of nitrogenous fertilizers, removal of produce, and build up of soil organic matter (Upjohn et al. 2005). Also, approximately 48% of the Palerang Council area’s soils are classed at high to critical risk of soil acidification (DLWC, 2002a). This includes soils in agricultural areas such as the Araluen Creek and Shoalhaven River catchments that were classed as slightly acid but had a high to critical risk of soil acidification.
Figure 5.Acidity of Soils in Palerang Council area
Source: Department of Primary Industries 2008
Impacts of soil acidity can include reduced crop yields, poor establishment of or failure of perennial pastures, permanent degradation of soil if acidity leaches to deeper soils, increase in soil erosion and siltation and recharge of aquifers leading to dryland salinity (Upjohn et al., 2005).
Causes of land degradation
Land degradation can be caused directly by human activities, such as land clearing, over use of fertiliser and changing water tables. Indirect influences can include flooding of overgrazed or over cultivated land with little ground cover and erosion by wind and water. Drought breaking rain may also cause erosion and can make up about 90% of the total soil loss in an area in a 20–30 year cycle (DPI 2005).
Drought and vegetation condition
According to a recent study by the Bureau of Meteorology (BoM) and Commonwealth Scientific and Industrial Research Organisation (CSIRO) (BoM, CSIRO 2008) the frequency and extent of exceptionally hot years and exceptionally dry years in NSW are likely to increase in the future. The mean projections indicate that:
- by 2010-2040, exceptionally hot years are likely to affect about 60% of the region, and occur every 1.6 years on average;
- by 2010-2040, no change is likely in the frequency or areal extent of exceptionally low rainfall years; and
- by 2030, exceptionally low soil moisture years are likely to affect about 7% of the region and occur about once every 14 years on average.
As of September 2008, the Department of Primary Industry has classed 71.6% of NSW as ‘In drought’ including Palerang Council area.
Figure 6. Drought declared areas
Source: Department of Primary Industries 2008
Over the reporting period the Braidwood Rural Land Protection Board, the authority covering the Palerang Council area, suffered extended periods of drought (Table 4) (DPI 2008). This is further illustrated in Figure 7 where the continuing drought period resulted in a near 0% pasture growth for a 3 month period between December 2006 to February 2007 (NAMS 2008).
| Months | Seasonal Conditions |
|---|---|
| September 2004 | Drought |
| December 2004 | Drought |
| March 2005 | Drought |
| June 2005 | Drought |
| September 2005 | Drought |
| December 2005 | Marginal |
| March 2006 | Marginal |
| June 2006 | Drought |
| September 2006 | Drought |
| December 2006 | Drought |
| March 2007 | Drought |
| June 2007 | Drought |
| September 2007 | Drought |
| December 2007 | Marginal |
| March 2008 | Satisfactory |
| June 2008 | Drought |
Source: NSW Department of Primary Industries 2008
Figure 7. Pasture growth in the Palerang Council area for the period 2004 to 2008
What is being done to improve land condition?
Palerang Council area is located within the Murrumbidgee and Southern Rivers Catchment Management Authorities (CMA). These CMAs are responsible for planning natural resource and catchment management actions and projects in the Catchment. However, as Palerang Council is a key stakeholder in the majority of the management actions identified by the CMA, it also has a key role in natural resource and catchment management in the local community.
Palerang Council also supports a number of landcare groups to undertake on-ground works to help reduce many land issues such as erosion. Support is provided to these groups in conjunction with the Murrumbidgee and Southern Rivers CMAs.
An example of the landcare groups is Carwoola Landcare Group, who operate near Captains Flats. The group undertakes on-ground works, and works to raise and maintain the awareness of environmental issues in the local community.
The group is also concerned with water quality projects. A current project of the Carwoola Landcare Group is a pilot project to control willows on the Molonglo River. This project aims to assess the cost of control over a kilometre stretch of the river, killing and removing willows, revegetating as necessary, and monitoring the long term results. There is also currently viable remnant native vegetation that could re-establish if the willows are removed (Carwoola Landcare, 2008).
About the data
For the current reporting period there has been a lack of new soil data due to the relatively long intervals between soil studies. Given the relevance of the information in the supplementary report, some sections have been retained for this report. Where material has been used from the Supplementary Report, reference has been given to the report and original source.
References
Australian National Resource Atlas Mapmaker facility http://www.anra.gov.au/mapmaker/mapservlet?app=anra
Australian Water Resources (2000) National Land and Water Audit. www.nlwra.gov.au/
Australian Water Resources (2005) Land Salinity Maps. www.nlwra.gov.au/
AWR - see Australian Water Resources
BOM and CSIRO – see Bureau of Meteorology and Commonwealth Scientific and Industrial Research Organisation
Bureau of Meteorology and Commonwealth Scientific and Industrial Research Organisation (2008) An Assessment of the Impact of Climate Change on the Nature and Frequency of Exceptional Climatic Event.
Carwoola Landcare, (2008), Molongo Catchment Group, Carwoola Landcare viewed at http://www.molonglocatchment.com.au/carwoola_landcare.htm on 21 October 2008
Commonwealth of Australia (2005) National Action Plan for Salinity and Water Quality and Natural Heritage Trust Regional Programs Report 2003–04, Departments of the Environment and Heritage and Agriculture, Fisheries and Forestry, viewed 18 April 2005, http://www.nrm.gov.au/publications/regional-report/03-04/.
CRCCH—see Cooperative Research Centre for Catchment Hydrology
Department of Infrastructure, Planning and Natural Resources, NSW (2004a) 2003/04 Combined NSW Catchment Management Authorities Annual Report, Volume 1: CMA Activities and Achievements, Department of Infrastructure, Planning and Natural Resources, Sydney.
Department of Infrastructure, Planning and Natural Resources, NSW (2005) Meeting the Challenge: NSW Salinity Strategy Premier's Annual Report 2003–04. NSW Department of Infrastructure, Planning and Natural Resources, http://www.dlwc.nsw.gov.au/salinity/pdf/2003_2004_salinity_annual_report.pdf
Department of Land and Water Conservation (NSW) (1999) Groundwater Quality Protection Policy, Department of land and Water Conservation, Sydney, on line at http://www.dnr.nsw.gov.au/water/pdf/nsw_state_groundwater_quality_policy.pdf.
Department of Land and Water Conservation, NSW (2000) Taking on the Challenge: The NSW Salinity Strategy, Department of Infrastructure, Planning and Natural Resources, viewed http://www.dlwc.nsw.gov.au/salinity/government/govt-docs.htm.
Department of Land and Water Conservation, NSW (2002) Soil Acidification Hazard Mapping, produced for the 2003 NSW State of the Environment Report, Department of Land and Water Conservation, Parramatta.
Department of Lands NSW (2008) Soil Landscape Mapping Program – Soil and Landscape Qualities and Limitations http://www.naturalresources.nsw.gov.au/care/soil/ssu/quals4.htm
Department of Primary Industries, NSW (2005) Soil Management Following Drought, Agnote DPI 355, Third Edition, Department of Primary Industries, http://www.agric.nsw.gov.au/reader/pasture-crops-recovery/dpi355.htm.
Department of Primary Industries, NSW (2006) Drought maps—areas of NSW suffering drought conditions, Department of Primary Industries, http://www.agric.nsw.gov.au/reader/drt-area?picQuant=100.
Department of Primary Industries, NSW (2008) NSW Land Capability and Soil Erosion Maps and database, Department of Primary Industries.
Department of Primary Industries, NSW (2008) Drought maps and drought assistance eligibility status of RLPBs http://www.dpi.nsw.gov.au/agriculture/emergency/drought/situation/drought-maps
DIPNR—see Department of Infrastructure, Planning and Natural Resources, NSW
DLWC—see Department of Land and Water Conservation, NSW
DPI—see Department of Primary Industries, NSW
Edwards, K and Zierholz, C (2001) Soil Formation and Erosion Rates, in PEV Charman and BW Murphy (eds) Soils: Their Properties and Management, 2nd Edition, pp 39–58, Oxford University Press, Oxford, cited in Lu, H, Prosser, IP, Monn, CJ, Gallant, JC, Priestley, G and Stevenson, JG (2003) Predicting sheetwash and rill erosion over the Australian continent, Australian Journal of Soil Research Vol. 41, 1037–1062, http://palaeoworks.anu.edu.au/pubs/AustJSS03.pdf.
Holloway, S (2008) Personal Communication (Email) from Simon Holloway, Environmental Services Coordinator, Palerang Council on 13 November 2008.
Hughes, AO and Prosser, IP (2003) Gully and Riverbank Erosion Mapping for the Murray-Darling Basin, Technical Report 3/03, March 2003, CSIRO Land and Water, Canberra, http://www.clw.csiro.au/publications/technical2003/tr3-03.pdf.
National Agricultural Monitoring System (Namms) (2008), Simulated Pasture Growth for Queanbeyan, http://www.nams.gov.au/
Upjohn, B., Fenton, G. and Conyers, M. (2005) Soil Acidity and Liming Agfact AC.19 3rd Edition. NSW Department of Primary Industries, http://www.agric.nsw.gov.au/reader/soil-acid/2991-soil-acidity-and-liming-.pdf
