Annual report 2006-2007 - Taranaki Regional Council

Executive summary
The Kahouri Stream catchment, north of Stratford, is the location of several industries that
include an abattoir, a tannery, a zinc galvanising plant, a power station, an electricity
distribution substation, a concrete plant and more recently a fertiliser storage and
distribution site. The companies that run these industries hold a number of resource
consents to allow abstraction of water, discharge of stormwater and wastewater to the
stream and to land, discharge of emissions into the air, and placement of structures across
the stream. This report for the period July 2006-June 2007 describes the monitoring
programme implemented by the Taranaki Regional Council to assess the companies’
environmental performance during the period under review, and the results and effects of
the companies’ activities.
The companies hold a total of 20 resource consents, which include a total of 150 special
conditions setting out the requirements that the companies must satisfy.
The Council's monitoring programme included site inspections, the collection of water
samples for physicochemical analysis and a biological survey of receiving waters at seven
sites.
The biomonitoring survey in this monitoring period (April 2007) suggested that the
macroinvertebrate community at the site in the Kahouri Stream tributary into which
discharges from Taranaki Galvanisers, Egmont Tanneries and Fletcher Concrete flow was in
good condition. This community has not been recently detrimentally affected by activities in
the Stratford industrial area in the upper part of the tributary sub-catchment.
The April 2007 results suggest that generally the Kahouri Stream itself was in good
condition compared with past monitoring years, and that overall, any changes in
macroinvertebrate community composition with distance downstream were not indicative
of any significant decline in water quality. The abattoir tributary had a significant effect on
the macroinvertebrate fauna downstream of its confluence with the Kahouri Stream. Unlike
in the previous monitoring period, downstream of the tributary which receives the
discharge from Taranaki Abattoirs there was a significant decline in the MCI and SQMCIs
values, when compared to the upstream control site. This indicated that the elevated
nutrients and biological oxygen demand have affected the macroinvertebrate community
downstream of this discharge. This tributary also received the discharge from Ballance Agri-
Nutrients Limited, and therefore additional samples need to be taken within this tributary,
to isolate each site’s effect.
During the year under review the summer low flow survey indicated that the effects caused
by the discharge from Taranaki Abattoir Co (1992) Limited appear to be somewhat
assimilated at the monitoring site in the Kahouri Stream at Flint Road. It is still desirable that
the Company continues to make improvements to its wastewater treatment and disposal
system.
Leachate measured from the road drain adjacent to Taranaki Galvanisers during the year
under review contained dissolved zinc at a level near to the median of previous results for
this site. The dissolved zinc concentration in the tributary into which the drain flows, at its
confluence with the Kahouri Stream, was below the detection limit and was well below
recommended guideline levels for zinc concentrations in fresh water.