Attachment 7C - Flora and Fauna Survey Assessment_Noosa Landfill - Revision 3

                                                                                      Native Foresters



3.5.4 Changes in surface water / ground water quality

Water quality in the groundwater-dependent ecosystems to the north and east depend on
the quantity and quality of water discharged to it. This will include groundwater seepage as
well as surface flows.

Field investigations along the eastern edge of the landfill and stormwater discharge outlet
(SW5) are listed below. These investigations suggest the area currently impacted by
surface flows extends 150-200 metres east from the developed areas and that this has
occurred over the past 15-20 years of landfill operation. Refer to Figure 21 for the location
of the observed impacts related to surface flows.

        Field monitoring of surface water quality in late April 2019 suggests that surface
         waters have higher pH downstream of existing discharge points in the potential
         Impact Area (circa. pH 6-7), compared with the pH of surrounding natural areas
         further east of the landfill (circa pH 4.5-5.6) in the 100 metre buffer. Refer to
         Appendix F.
        The ponding of low pH water in the 100m buffer is likely to be associated with natural
         processes including surface expression of groundwater; humic acids from organic
         matter decomposition and/or acid sulfate soils (Figure 17).




           FIGURE 17: Ponded water in high value wet heath - low pH and tannin stained

        The drainage line that runs parallel to the landfill’s eastern boundary and the
         drainage lines that run perpendicular to the boundary from the constructed
         discharge outlets carry stormwater inputs from the landfill which may have a diluting
         effect on the naturally acidic soils of the closed heathland and Melaleuca wetland
         remnants, creating a plume of higher pH soil and water around them (Figure 18).


Noosa Landfill & Resource Recovery Centre – Fauna and Flora Assessment – Revision 3
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