Boorowa
Indicator: Land Degradation
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What the results tell us for Boorowa
For the 2004-08 reporting period existing and future high salinity hazards were identified. Drought was experienced throughout the district for much of the period. Landuse in the district remained largely compatible with its capability class. Since the last reporting period, there has been no noteworthy data or information released on erosion, acidic or sulphate soils.
Sustainability of landuse
See also: Landuse
Landuse within the Boorowa Council area tended to be suitable for each land capability class (refer Figure 1 and Table 1). Approximately 20% of land in use is vulnerable to erosion because of current uses.
Some 54% of land within the district is classed as suitable for grazing, of which the majority of this land (93%) is used for this purpose. The remaining land is considered high risk of erosion if cleared, and is recommended to be maintained as vegetation (Department of Lands).
Some 14% of the district is under cropping, of which 66% of this land was not suitable for reasons of either climatic conditions or future soil degradation (CSIRO 2003). Around 20% of the district is used mixed farming, of which 30% of this area is unsuitable for cultivation.
Figure 1. Land capability within Boorowa Council area
Source: NSW Department of Lands 2008
| 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 | 1,709 | 10,758 | 14,785 | 3,107 | 4,890 | 726 | 375 | |
| Estimated grazing | 1,206 | 4,359 | 53,921 | 23,982 | 46,483 | 5,690 | 3,615 | |
| Mixed farming | 253 | 1,203 | 25,951 | 10,667 | 13,001 | 724 | 599 | |
| Other plantations | 0.1 | 15 | 01 | 55 | 8 | |||
| Quarries | 7 | 16 | ||||||
| Rural residential | 20 | 9 | ||||||
| Totals (hectares) | 3,167 | 16,326 | 94,672 | 37,756 | 67,471 | 7,158 | 4,589 | |
Types of land degradation
Erosion
Soil erosion data is restricted to surveys carried out between 1985 and 1992 (refer Figure 2 and Tables 2 and 3). The surveys revealed 1,120km of gully erosion and 430km streambank erosion (refer Table 2). Minor to severe sheet erosion was present throughout the district (refer Table 3).
Gully erosion was predominately classed as minor to moderate with gullies less than 3.0m deep (Table 2), most of which was caused soon after the original native vegetation was removed. Gully lengths have since stabilised however accelerated erosion continues as is revealed by the high sediment loads to streams relative to (Hughes and Prosser 2003). In New South Wales (NSW) the estimated overall accelerated erosion rate are 10–50 times the natural rates (Edwards and Zierholz 2001).
Figure 2. Degree of erosion
Source: NSW Department of Lands 2008
| Erosion type | Depth | Kilometres |
|---|---|---|
| Extreme gully erosion | greater than 6m deep | 9 |
| 3 to 6m deep | 57 | |
| 1.5 to 3m deep | 137 | |
| less than 1.5m deep | 14 | |
| extreme gully erosion total | 217 | |
| Severe gully erosion | greater than 6m deep | 9 |
| 3 to 6m deep | 41 | |
| 1.5 to 3m deep | 144 | |
| less than 1.5m deep | 137 | |
| severe gully erosion total | 331 | |
| Moderate gully erosion | 3 to 6m deep | 14 |
| 1.5 to 3m deep | 87 | |
| less than 1.5m deep | 272 | |
| moderate gully erosion total | 373 | |
| Minor gully erosion | 3 to 6m deep | 4 |
| 1.5 to 3m deep | 30 | |
| less than 1.5m deep | 169 | |
| minor gully erosion total | 203 | |
| Streambank erosion | greater than 6m deep | 5 |
| 3 to 6m deep | 33 | |
| 1.5 to 3m deep | 192 | |
| less than 1.5m deep | 196 | |
| Streambank erosion total | 426 |
| Major erosion type | Degree / type | Hectares |
|---|---|---|
| Mass movement | rock debris avalanche | 7 |
| slump | 4 | |
| soil debris avalanche | 97 | |
| Rill erosion | extreme rill erosion | 80 |
| severe rill erosion | 2,122 | |
| moderate rill erosion | 251 | |
| minor rill erosion | 53 | |
| Sheet erosion | extreme sheet erosion | 599 |
| severe sheet erosion | 19,385 | |
| moderate sheet erosion | 75,097 | |
| minor sheet erosion | 130,911 |
Salinity
Without management, salinity is anticipated to become a growing problem. Existing patchy salinity hazards have been recognised in the north of the district. By 2050 these hazards are expected to increase and further outbreaks to the south will occur (refer Figures 3 and 4) (AWR 2005).
Figure 3: Extent of salinity (2000)
Source: Australian National Resource Atlas 2001
Figure 4: Extent of salinity (2050) (approximate)
Source: Australian National Resource Atlas 2001
Acid soils
Soil acidity can have an impact through reducing crop yields, perennial pastures, ground water quality and inturn increase soil erosion and salinity (Upjohn et al., 2005). In rural Australia, soil acidity is usually associated with nutrient depletion or fertiliser use by agriculture.
In Boorowa Council area, soil classed as strongly acid covered approximately 93% of the district. Distribution was throughout the Council area. Most of the remaining land was identified as slightly acidic (DLWC 2002a&b).
Figure 5. Soil acidity in the Boorowa Council area
Source: NSW Department of Primary industries 2008
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 the Commonwealth Scientific and Industrial Research Organisation (CSIRO) (BoM, CSIRO 2008) the frequency and extent of exceptionally hot years and exceptionally dry years in NSW is 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;
- 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’ (refer Figure 6). This includes the Boorowa.
Figure 6. Drought declared areas
Source: NSW Department of Primary Industries 2008
Over the reporting period, the Boorowa Council area in the Young Rural Land Protection Board – Sections B & C, was rated as in full drought for most of the period (refer 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 14 month period starting in September 2006 to September 07 (NAMS 2008).
| Months | Seasonal Conditions |
|---|---|
| September 2004 | Drought |
| December 2004 | Drought |
| March 2005 | Drought, marginal |
| June 2005 | Drought |
| September 2005 | Drought |
| December 2005 | Satisfactory |
| March 2006 | Drought, marginal |
| June 2006 | Drought |
| September 2006 | Drought |
| December 2006 | Drought |
| March 2007 | Drought |
| June 2007 | Drought |
| September 2007 | Drought |
| December 2007 | Drought |
| March 2008 | Drought |
| June 2008 | Drought |
Figure 7. Pasture growth in the Boorowa Council area for the period 2004 to 2008
What is being done to improve land condition?
Boorowa Council area is located within the Murrumbidgee Catchment Management Authority (CMA). The Murrumbidgee CMA is responsible for planning natural resource and catchment management actions and projects in the Murrumbidgee Catchment. However, as Queanbeyan 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.
Boorowa 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 CMA.
About the data
For the current reporting period there has been a lack of new soil data due to the relatively long intervals between studies. Given the relevancy of the information in the 2000/04 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/
Boorowa Council Annual Report 2006/2007 http://www.boorowa.nsw.gov.au/files/2001/File/AnnualReport2006-2007.pdf
Bureau of Meteorology and CSIRO (2008) An Assessment of the Impact of Climate Change on the Nature and Frequency of Exceptional Climatic Event.
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, viewed 12 May 2006, 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 4 May 2006, 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 Primary Industries, NSW (2005) Soil Management Following Drought, Agnote DPI 355, Third Edition, Department of Primary Industries, viewed 18 April 2006, 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, viewed 8 May 2006, http://www.agric.nsw.gov.au/reader/drt-area?picQuant=100.
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, viewed 3 May 2006, http://palaeoworks.anu.edu.au/pubs/AustJSS03.pdf.
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, viewed 26 April 2006, http://www.clw.csiro.au/publications/technical2003/tr3-03.pdf.
National Agricultural Monitoring System (Namms) (2008), Simulated Pasture Growth for the Boorowa, 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, viewed 17 July 2006, http://www.agric.nsw.gov.au/reader/soil-acid/2991-soil-acidity-and-liming-.pdf
