hydrogeology. The risk assessment methodology was based on a matrix of likelihood and consequence adapted from Spies and Woodgate (2005). The groundwater trends and salinity risk assessments are reported for hydrozones that are regions of similar hydrogeological, climate, landscape and farming system attributes. The risk assessments are presented in Table 4.4. The salinity risk map is shown in Figure 4.1 and shows that the highest salinity risk occurs in: portions of the Northern and Central Agricultural Regions of the region, where groundwater levels have continued to rise, despite several decades of below average rainfall in the east of the Southern Agricultural Region, where rainfall has been above average for the past decade and watertables are already shallow. The significant proportion of bores with rising trends in and adjacent to areas of salinity hazard, indicates that, over most of the region, the impact of reduced rainfall on groundwater trends is still less than the impact of clearing. Climate variability therefore appears to be a moderating, rather than driving factor in the risk of dryland salinity in the south-west agricultural region. Appendix A Summary of groundwater trends by hydrozone Table A1 Summary of groundwater trends in each hydrozone in the 2001–07 analysis period (George et al. 2008) and the 2007–12 analysis period % of % of % of % of % of % of bores bores bores bores bores bores of of with with with with with with bores bores falling falling stable stable rising rising trend trend trend trend trend trend 2001–07 2007–12 2001–07 2007–12 2001–07 2007–12 Kalbarri not 11 not 45 not 18 not 36 31 32 90 3 6 6 3 91 Block East 1 25 not 0 100 16 not 84 Binnu Irwin 13 25 62 20 23 36 15 44 Terrace 40 53 75 45 18 25 8 30
hydrogeology. The risk assessment methodology was based on a matrix of likelihood and consequence adapted from Spies and Woodgate (2005). The groundwater trends and salinity risk assessments are reported for hydrozones that are regions of similar hydrogeological, climate, landscape and farming system attributes. The risk assessments are presented in Table 4.4. The salinity risk map is shown in Figure 4.1 and shows that the highest salinity risk occurs in: portions of the Northern and Central Agricultural Regions of the region, where groundwater levels have continued to rise, despite several decades of below average rainfall in the east of the Southern Agricultural Region, where rainfall has been above average for the past decade and watertables are already shallow. The significant proportion of bores with rising trends in and adjacent to areas of salinity hazard, indicates that, over most of the region, the impact of reduced rainfall on groundwater trends is still less than the impact of clearing. Climate variability therefore appears to be a moderating, rather than driving factor in the risk of dryland salinity in the south-west agricultural region. Appendix A Summary of groundwater trends by hydrozone Table A1 Summary of groundwater trends in each hydrozone in the 2001–07 analysis period (George et al. 2008) and the 2007–12 analysis period of bores of bores % of bores with falling trend 2001–07 % of bores with falling trend 2007–12 % of bores with stable trend 2001–07 % of bores with stable trend 2007–12 % of bores with rising trend 2001–07 % of bores with rising trend 2007–12 Kalbarri not 11 not 45 not 18 not 36 Block 31 32 90 3 6 6 3 91 East Binnu 1 25 not 0 100 16 not 84 Irwin Terrace 13 25 62 20 23 36 15 44 40 53 75 45 18 25 8 30
Groundwater%20trend%20analysis%20and%20salinity%20risk%20assessment%20for%20the%20south-west%20agricultural%20region%20of%20Western%20Australia%20-%20RMTR%20388%20%28Word%208.5MB%29.docx