Figure 1 Configuration of the HWWTP (adapted from NIWA 2012) 5
Figure 2 Compliance of DO concentration (g/m3) with consent conditions in the
primary and secondary oxidation ponds 2015-2016 13
Figure 3 Faecal coliform numbers in the HWWTP effluent, 1992 to 2016 16
Figure 4 Daily discharge volumes (m3/day) from the HWWTP and daily rainfall
data (mm) from a Council rainfall station approximately 5 km east of the
site, 1 July 2015 to 30 June 2016. Inset: Rainfall and outflow data from
Summary of performance for consent 7520-1 24
Table 12 Evaluation of environmental performance over time 25
List of figures
Figure 1 Configuration of the HWWTP (adapted from NIWA, 2012) 4
Figure 2 Daily hours where DO is greater than 0 g/m3 in Pond 1 and 2 8
Figure 3 Daily discharge volumes (m3/day) from the HWWTP and daily rainfall data (mm) from a
Council rainfall station located approximately 5 km east of the site (2018-2019) 13
Figure 4 Location of intertidal survey
irrigation was high. Most irrigation had
commenced by the middle of December.
Over the five month summer irrigation period, Mount Taranaki recorded between 69% and
88% of normal rainfall which meant that rivers were running well below mean flows for the
entire period. The low stream flows necessitated close and frequent monitoring by the Council
to ensure ecological flows were maintained in those waterways being used to supply water for
irrigation. During the period under review compliance with
the frequency of sample collection earlier in the period. Sampling commenced in
early November 2010 with three of the sampling surveys performed prior to January
2011. The majority of the surveys were performed over the latter half of the summer
period. Bathing water samples were normally taken between the hours of 0900 and
1800 hours (NZDST) with none collected within a three day period following
significant river fresh conditions. [NB: regional differences in rainfall patterns have
caused
Prolonged and/or heavy rainfall will often result in high
levels of enterococci in the samples as these are washed down flooded streams and rivers from farmland.
This can be exacerbated by a low tide where a sea sample collected from a site near a stream mouth may
contain a high proportion of freshwater.
Water quality at Middleton Bay
Contact recreational bacteriological water quality at Middleton Bay was monitored by the Council on 22
separate occasions between early November 2023 and late
generally very good. It is noted that the protocol for sampling has changed in the last couple of
years so that samples are collected irrespective of weather or tide, unlike previously where samples were
collected around high tide in fine weather only. Prolonged and/or heavy rainfall will often result in high
levels of enterococci in the samples as these are washed down flooded streams and rivers from farmland.
This can be exacerbated by a low tide where a sea sample collected from a site near a
Council meeting agenda November 2019
for irrigation was high. Most irrigation had
commenced by the middle of December 2014.
Over the five month summer irrigation period, rainfall was between 62% and 106% of normal
which meant that rivers were running well below mean flows for the entire period. The low
stream flows necessitated close and frequent monitoring by the Council to ensure ecological
flows were maintained in those waterways being used to supply water for irrigation. During
the period under review compliance with
Report 2017-2020.
5.2 It was noted that Council would like to increase the number of monitoring bores,
especially within the eastern parts of Taranaki, to improve understanding of areas
where there is limited data and information.
5.3 Water allocation in the region is well within current allocation limits and monitoring
shows that groundwater levels are generally stable, with fluctuations the result of
seasonal rainfall and pumping effects. It was noted that we are already starting to see
consent requirement. The reduction of
stormwater infiltration entering the reticulation, remains an issue to be minimised, with
some overflow issues occurring during the monitoring period, due mainly to excessive
inflows at the inlet of the plant following a very intensive rainfall event in mid-June 2015.
Remedial work undertaken to improve the hydraulic capacity of the new outlet and outfall
design together with additional sealing of the second pond’s cells’ walls has been successful
in