Compiled Plans & Documents OPW18-0342 02

                                                              Retirement Living & Aged Care Facility
                                                                     Grasstree Court, Sunrise Beach

6.4         Effective Slope
Effective slope relates to the topography of vegetation beneath classified vegetation, as this
influences fire speed and rate of spread - namely, that the speed of fire doubles for every 10 degrees
incline. An on-site effective slope assessment has been conducted via detail survey, Council and
DNRM contour data and verified via site inspection.

The subject land is upslope from all areas of potential bushfire hazard which translates to a slight
upward run of fire on approach to the subject land. These slopes however are not steep but rather,
very gradual and unlikely to generate much increase in fire intensity and behaviour. The downslope
values below reflect those captured by both the original bushfire assessment report prepared by
Land Graphics in 2008 and the RPS peer review assessment conducted in 2016.




                                                      2.0 deg downslope
                                 1.1 deg downslope




                 4.0 deg downslope



                      3.6 deg downslope



                              3.7 deg downslope
                                                     4.0 deg downslope




Figure 13 - Effective slope assessment relating to the subject land (Source: Imagery derived from
DNRM, 2018 with slope values derived from Land Graphics, 2008 and RPS, 2016)

6.5         Aspect
Aspect can affect bushfire behaviour where slopes with northerly and/or westerly aspects
experience a higher level of solar access than those areas with a southern or eastern aspect. This
generally translates to drier fuels with lower moisture content and increased dead/drying/curing
material. Notwithstanding, in times of drought and below average rainfall, moisture levels in soil and
vegetation in more sheltered areas with southerly and easterly aspects can also decrease
substantially giving rise to significantly higher fuel abundance where the preceding fire regime has
been less frequent or intense. Thus, aspect is of only partial consequence in this respect and this is
reflected by the current SPP mapping methodology and information made publicly available by
QFES.

Insofar as slope aspect relevant to the subject area, the dominant aspect remains north to west for
Lot 6 and east to south for Lot 9 however given the narrow nature of the corridor and duplicated
north and south banks of the northern tributary adjoining Lot 6 and the gradual slope of land to the



Status: Final                                                                                March 2019
Project No.: 18-030                                                                             Page 29