Annual report 2006-2007 - Taranaki Regional Council

9.4.1.2 Receiving water monitoring
Water chemistry
The chemical water quality survey for the summer low-flow period was performed
on 18 April 2007 during fine weather. The results for all sites in the 2007 survey are
presented in Table 4 (refer to Section 2.4.2.2). The sampling sites relevant to the
Ballance Agri-Nutrients site are sites 1 and 3, which also encompass discharges from
the Taranaki Abattoirs site. The results for these sites are discussed fully in Section
2.4.2.2. There is the potential that the Ballance discharge contributed to the raised
levels of nutrients recorded in the Kahouri Stream. However, it is unlikely that this
contribution was significant, when compared to the Taranaki Abattoirs discharge,
when the nutrient concentrations and rate of discharge from the respective sites are
considered.
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Biological survey
A macroinvertebrate sample was collected from sites A and C (Figure 1) in the
Kahouri Stream on 17 April 2007. The sample was sorted and identified to provide
the number of taxa (richness), MCI and SQMCIS scores for each site.
The MCI is a measure of the overall sensitivity of the macroinvertebrate community
to the effects of organic pollution in stony streams. It is based on the
presence/absence of taxa with varying degrees of sensitivity to environmental
conditions. It may be used in soft-bottomed streams to detect trends over time. The
SQMCIS takes into account taxa abundance as well as sensitivity to pollution, and
may reveal more subtle changes in communities, particularly if non-organic impacts
are occurring. Significant differences in either MCI or SQMCIS between sites indicate
the degree of adverse effects (if any) of discharges being monitored.
These results are discussed in full in Section 2.4.2.2, with a full biological report given
in Appendix II. This summer survey of macroinvertebrate communities in the
Kahouri Stream indicated that the communities directly downstream of the tributary
that receives the Taranaki Abattoirs and Ballance Agri-Nutrients discharges were
significantly different than those upstream, where taxa richness and MCI score were
slightly healthier than median community conditions recorded previously at this
‘control’ site. There was a significant decrease in MCI and SQMCIS scores at the lower
site, which may have been due to additional instream nutrients supplied by the
tributary. This is likely to be due to the impacts from the abattoir, but this is unclear
without further monitoring. Therefore it is recommended that additional sites be
included in subsequent surveys to assess the impact of the abattoir discharge on this
unnamed tributary.
9.5 Register of incidents
The Taranaki Regional Council operates and maintains a register of all complaints or
reported and discovered excursions from acceptable limits and practices, including
non-compliance with consents, which may damage the environment. The register
(‘unauthorised incident register’) includes events where the company concerned has
itself notified the Council. The register contains details of any investigation and
corrective action taken.