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à &HQWUDO4XHHQVODQG ,QIRUPDWLRQ 3DSHU &HQWUDO 4XHHQVODQG LQIRUPDWLRQ SDSHU WR VXSSRUW UHJLRQDO QDWXUDO UHVRXUFH PDQDJHPHQW SODQQLQJ 9ROXPH 0DFNHQ]LH &DWFKPHQW ÃÃÃÃÃÃ0HLHUVÃ5RDGÃ,QGRRURRSLOO\à ÃÃÃÃÃ3KRQHÃÃÃÃZZZFRDVWDOFUFRUJDX à © Cooperative Research Centre for Coastal Zone Estuary and Waterway Management 2003 Published by the Cooperative Research Centre for Coastal Zone Estuary and Waterway Management Indooroopilly Sciences Centre 80 Meiers Road Indooroopilly Qld 4068 Australia www.coastal.crc.org.au The text of this information may be copied and distributed for research and educational purposes with proper acknowledgement. While every care is taken to ensure the accuracy of this publication, the Cooperative Research Centre for Coastal Zone Estuary and Waterway Management disclaims all responsibility and all liability (including without limitation, liability in negligence) and costs which might incur as a result of the materials in this publication being innaccurate or incomplete in any way and for any reason. ISBN: 0 9578678 4 0 QNRM03151 à 9ROXPH &KDSWHU 0DFNHQ]LH&DWFKPHQW 12.1 Introduction 1 12.2 How to use this chapter 1 12.3 Land use and management 2 12.3.1 Critical assets 12.3.2 Condition and trend 12.3.3 Knowledge, data and information gaps 12.3.4 Targets 12.4 Terrestrial biodiversity 22 12.4.1 Critical assets 12.4.2 Condition and trend 12.4.3 Knowledge, data and information gaps 12.4.4 Targets 12.5 Inland aquatic ecosystem integrity 39 12.5.1 Critical assets 12.5.2 Condition and trend 12.5.3 Knowledge, data and information gaps 12.5.4 Targets 12.6 Estuarine and marine aquatic ecosystem integrity 47 12.7 Water quality 48 12.7.1 Turbidity/suspended particulate matter 12.7.2 Nutrients in aquatic systems 12.7.3 Nuisance algal blooms 12.7.4 Surface water salinity 12.7.5 Pesticides in aquatic systems 12.7.6 Metals in aquatic systems 12.7.7 Other human contaminants in aquatic systems 12.7.8 Knowledge, data and information gaps 12.7.9 Targets 12.8 Social and economic profile 56 12.8.1 Broadsound Local Governmant Area 12.8.2 Duaringa Local Government Area à &KDSWHUÃÃ0DFNHQ]LHÃ&DWFKPHQWà &KDSWHU 0DFNHQ]LH&DWFKPHQW ,QWURGXFWLRQ This chapter provides context to the information on the Mackenzie Catchment and its environs for the process of target setting. It assembles known information, research data, and local knowledge to inform catchment stakeholders. However, no information is ever complete, and there are gaps in our knowledge that occur at the catchment scale which also has impacts at the regional scale. Some of these deficiencies are listed, and it is expected that the process of catchment consultations to define targets will address some of these. The Mackenzie Catchment is characterised by a broad floodplain incised by a river channel which, in its natural state, has a low gradient and a number deep water holes. This highly productive system has been extensively developed and now less than 10% of the original vegetation of the flood plain remains. There are extensive areas used for irrigation and the introduction of buffel grass to areas cleared of brigalow supports a profitable grazing industry. The upper parts of the catchment are less developed and the remnant vegetation is well connected with high integrity. +RZWRXVHWKLVFKDSWHU The information brought together for the Mackenzie Catchment in this chapter is divided into five clusters. These clusters are: land use and management; terrestrial biodiversity; inland aquatic ecosystems; water quality and social and economic profile. Within each of these sections, information is supplied that addresses critical assets, condition and trend, information and knowledge gaps. Key points from these sections are provided in text boxes to help the reader to quickly gain an overview of the issues for the catchment. Finally, the section contains a listing of the recommended targets for resource condition and management actions for all clusters except for social and economic. Summary information of how the target was derived, indicators, monitoring and other details accompany the list of targets. Where possible, maps and diagrams have been developed to summarise the information and improve the effectiveness of communicating the key messages. All appendices and references referred to in the text are combined into Chapter 14 at the end of this Information Paper. It is important that the material contained in this chapter is read in conjunction with Chapter 5 so regional scale information can be integrated with the local catchment issues and information. This will ensure that the natural resource management plan developed meets the aspirations of all those who live and depend on the Central Queensland region. à &4Ã,QIRUPDWLRQÃ3DSHUà /DQGXVHDQGPDQDJHPHQW The land resources of the Mackenzie Catchment are shown as Land Resource Areas (LRAs) in Figure 12.1. The catchment has large areas of Ranges and Tablelands LRAs. The remainder of the catchment is dominated by Brigalow Plains and Alluvial Plains LRAs with significant areas of Eucalypt Duplex Uplands, Undulating Downs and Softwood Scrub Uplands LRAs Ã&ULWLFDOÃDVVHWVà The Mackenzie Catchment has Critical land assets for the Mackenzie Catchment: sufficient land diversity to support • Productive grazing and cropping lands • successful grazing, cropping, Coal mining makes a significant contributor to the economy irrigation and mining industries. • National parks and areas of conservation for Grazing land dominates the recreation catchment across all LRAs with • High proportion of farmers using conservation relatively small areas of dryland tillage systems cropping and irrigated land on Alluvial Plains and Brigalow Plains LRAs. There has been extensive development of coal mines between Blackwater and Middlemount. Most urban land is associated with the mines and the catchment is well serviced by roads and railways. Two National Parks occur in the south and there are small areas of State Forest. Coal mining provides coking coal for export and steaming coal for local power generation. The mining industry is a critical asset to the catchment, and provides significant inputs to the local economy through infrastructure, employment and support industries. Ã&RQGLWLRQÃDQGÃWUHQGà The Mackenzie Catchment experiences many conditions that are conducive to soil erosion. Three factors that contribute to soil erosion include the rainfall intensity, the erodibility of the soil, and the slope of the land surface. Representations of these three factors for the Mackenzie Catchment are given in Figure 12.2. An analysis of the long term rainfall is provided in Appendix A12.3. Rainfall energy is quite low across the catchment with some higher inputs in the east. Soil erodibility (K-factor) tends to be low/moderate but with an area of high erodibility on Brigalow Plains LRA in the north and large areas of moderate/high erodibility on Eucalypt Duplex Uplands and Alluvial Plains LRAs in sloping areas. The information in Figure 12.2 relates to the Processes that threaten land productivity: potential for soil erosion to occur when bare • Moderate-high intensity storms • ground coincides with high intensity storms. Moderate-high rates of hillslope erosion Rates of soil erosion are reduced when • Low amounts of surface cover management practices retain cover on the • Moderate-high salinity hazard areas surface and protect the bare soil from exposure to direct raindrop impact. Using information from remote sensing to determine surface cover levels, along with the factors shown in Figure 12.2, the Sednet model developed in the National Land and Water Resources Audit (Prosser et al. 2001) is able to estimate long term average annual erosion from hillslopes, gullies and streambanks at a catchment scale. à &KDSWHUÃÃ0DFNHQ]LHÃ&DWFKPHQWà The assessment of hillslope erosion and sediment movement within the Mackenzie Catchment is shown in Figure 12.3. Estimated hillslope erosion is high on grazing land areas of the eastern ranges and moderate or moderate/high on grazing land in the upper catchment areas to the west and on cropping land on Alluvial Plains LRA throughout the catchment. These areas should be priority management actions. Estimates of gully erosion are shown in Figure 12.4 and of streambank erosion in Figure 12.5. Although widespread within the catchment, the rates of erosion from gullies and streambanks is relatively lower than for hillslopes. The widespread occurrence of Brigalow Plains and Eucalypt clays uplands in the catchment indicates a high clay content of surface soils. These are prone to erosion and movement downstream causing higher turbidity and impacts on water quality of aquatic habitats. The Salinity Hazard map developed by the Department of Natural Resources and Mines provides an indication of the potential for salinity to occur within the Mackenzie Catchment (Fig. 12.6). The analysis considers groundwater flow systems, areas of recharge and areas of discharge within the catchment. The Salinity Hazard map shows high hazard in a large area on Brigalow Plains LRA in the centre of the catchment and on scattered areas usually on Eucalypt Duplex Upland LRA throughout the catchment. Most of the Brigalow Plains and associated Alluvial Plains LRAs have moderate-high hazard. Management actions in areas of high and moderate-high hazard are a priority. Generally, the Ranges, Tablelands and Undulating Downs LRAs have low or low-moderate salinity hazard. Ã.QRZOHGJHÃGDWDÃDQGÃLQIRUPDWLRQÃJDSVà The following are gaps in our understanding and knowledge for sustainable