Annual report 2006-2007 - Taranaki Regional Council

8.3.2 Chemical sampling
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The Taranaki Regional Council undertook sampling of the water quality
downstream of the discharge point and mixing zone (site 6, Figure 1) on one occasion
during the monitoring year in conjunction with the low flow survey.
The summer low flow survey of water quality in the Kahouri catchment is a shared
survey between several industries. In relation to Fletcher Concrete, site 6 (unnamed
tributary above the confluence with Kahouri Stream) was sampled and analysed for
conductivity, pH, turbidity, suspended solids, chromium (acid soluble) and zinc
(dissolved) (Table 2).
8.3.3 Biomonitoring surveys
One shared biological survey was performed in seven sites in the Kahouri Stream
catchment on 17 April 2007 to determine whether or not the discharges from the
various industries have had a detrimental effect upon the communities of the stream.
The location of these sites is shown in Figure 1. When assessing the effects of the
Fletcher Concrete discharge, site D (in the tributary of the Kahouri Stream, was used
to assess the effects of the discharge on the biological communities of the stream. Site
E (Flint Rd) in the Kahouri Stream may also provide some information downstream
of the confluence with this tributary.
8.4 Results
8.4.1 Water
8.4.1.1 Inspections
The routine annual inspection was performed on 14 December 2006. It was found
that all washwater was collected and directed to sumps for settling prior to
treatment. The sumps closest to the main building were cleaned out prior to
inspection. The truck wash is a contained system, in that the final pipe that leaves the
fenced off ponds is blocked, and the water evaporates. The solids that are removed
are allowed to dry, and are then stockpiled. A soakage field for a septic tank system
had recently been installed. The consent holder was advised that during rain, it may
be worthwhile keeping an eye on the runoff at the northern access gate, to ensure it
doesn’t contain excessive contaminants.
8.4.1.2 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 this survey are
presented in Table 4 (refer to Section 2.4.2.2). One chemical monitoring site is located
in the receiving waters downstream of the Fletcher Concrete discharge (site 6,
KHI000369), which also encompasses discharges from Egmont Tanneries and
Taranaki Galvanizers (Figure 1).