exceedance rainfall event (AEP) event. The
maximum discharge rate from the pond during large rainfall events is 1,060 L/s as this is dictated by the size
of the outfall pipe (750 mm). However, there is also provision for the pond to overflow via a spillway
structure to a discharge swale (i.e. bypassing the 750 mm discharge pipe).
At the time of the application it was indicated that, as a result of stormwater inputs to the pond, the
discharge rate from the pond to the Mangorei Stream would be
Executive Audit and Risk Agenda February 2025
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
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
logging of
boreholes on site indicated a relatively shallow water table. Test bores were augured to 10m both around
the waste holding pit area and to the south-western site boundary, revealing alternating layers of sand and
clays. Bore construction also revealed localised peat layers within some augured cores (approximately 4–8m
below surface). Average annual rainfall for the site is 1,186mm (long term average to 2023 taken from the
nearby Pātea at Bore 3 monitoring station).
Origin Energy
year under review some unacceptable material was dumped at the Pātea Beach green waste
discharge site, but it was removed promptly by STDC. There was no leachate observed discharging from the
sand dune area or the stockpiled green waste during the period under review, or in previous years. These
factors, combined with the sandy substrate and low rainfall at the beach should be restricting the
production of leachate from the green waste. It is therefore considered that, so long as STDC continues
Remediation Hearing Ngāti Mutunga Legal Submission & Haehanga Report
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
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