Daily abstraction volumes under consent 7470-1.2 (July 2009-June 2018) 10
Figure 5 Maximum daily abstraction rate under consent 7470-1.2 (July 2009-June 2018) 10
Figure 6 Observed groundwater levels GND2102 and rainfall (July 2017-June 2018) 11
Figure 7 Observed groundwater levels GND2102 and abstraction (July 2017-June 2018) 12
Figure 8 Observed groundwater levels GND2103 and rainfall (July 2017-June 2018) 12
Figure 9 Observed groundwater levels GND2103 and abstraction (July
.................................................................................................................................................. 8
2.3 CLIMATE .................................................................................................................................................... 8
Table 2: Kaka Road Rainfall Events 2011-17 ............................................................................................. 10
Table 3: High Intensity rainfall data (NIWA) for site ................................................................................ 10
2.4 HYDROLOGY / HYDROGEOLOGY
wet weather from mid July to early
August 2008 resulted in further intermittent overflows of very dilute, treated wastewater to
the stream until mid August 2008. Similar intermittent overflows were recorded after very
wet weather late in the 2009-2010 period, over a four week period in September 2010 and
again, more briefly late in the 2010-2011 period. Seven intermittent overflows, each of one to
four days duration, occurred following heavy rainfall events in the 2011-2012 period. One
nitrogen concentration in the pond and the rainfall 30 days prior to the
sampling event. This was based on 7 ammoniacal nitrogen concentrations
measured between October 2017 and April 2019. The relationship has an
R2 value of 74%.
Using this relationship, the monthly rainfall from 2018 was used to
calculate monthly nitrogen concentrations in the pond. The concentration
was converted to a loading rate in kg/ha/month based on the volume
irrigated (calculated from 2018 irrigation hours and an
Agenda Consents Regulatory Committee 15 March 2022
“Therefore the calculations provided by RNZ
are extremely conservative, if not a completely unrealistic assessment of
page
10
the effects of nitrogen”. In the defence of using the 225 g/m3 concentration
I make the following points:
A) The amount a nitrogen applied to the irrigation fields is a
combination of the nitrogen concentration in the irrigation pond and
the volume of fluid irrigated. In summer there is less rainfall and
the evaporation from the pond
REMEDIATION NZ LTD Page 7
Document No: RU-P-650-0500-A
Revision No: V1.3
Date: 1 0-9-2018
Controller: C Kay
page
Leachate & Stormwater
Management Plan
f) Any conspicuous change in the colour visual clarity;
g) Any emissions of objectionable odour;
h) The rendering of fresh water unsuitable for consumption by farm animals; and
i) Any significant adverse effects on aquatic life.
3.4.3 Climate
NIWA virtual Climate Station -38.975, 174.525 Thirty years of rainfall and
climate, with abundant rainfall and high sunshine hours, makes the region lush, green
and fertile.
Rainfall
Annual rainfall varies throughout the region. Some coastal areas receive less than 1,400 mm annually, while
the summit of Mount Taranaki receives around 7,500 mm.
Heavy rainfall events do occur and there can be extremes. In 2012 heavy rain caused a number of slips on
the coastal road around Mount Taranaki, including a large slip at Oākura that covered the road, burying a
simulation model, developed by CSIRO,
Australia. The value of pasture ($/kg-DM) was estimated using local farm parameters
that were developed in consultation with Louise Hofmann, Taranaki FarmWise
consultant. The results of that work showed that the values of pasture in the area range
between $0.17 to $0.25/kg-DM, with an average value of $0.22/kg-DM.
Based on these values the irrigation marginal benefits were calculated for a range of
rainfall and soil combinations for three values of pasture:
monitoring year, with most
commencing irrigation in November or December and concluding in February. Rainfall recorded at the
Council’s monitoring locations over the summer irrigation period ranged between 55 % and 111% of
historical mean values. A particularly dry November and December lead to a drought being declared in
Taranaki during 23 December 2017. As a result, irrigation water demand was high during the 2017-2018
irrigation season, with a total water use across all exercised irrigation