investigation and design. No
construction occurred.
During the 2022/23 period expenditure on inflow and infiltration reduction consisted of:
• $457,127 spent on pipe renewals
• $17,774 spent on CCTV.
A wastewater network modelling project has recently been completed. This used rainfall and sewer flow
data to create a calibrated digital model of the entire Inglewood wastewater network. The calibrated model
will be used to assess network performance under different storm events of varying
downstream of ‘irrigation’ tributary INH000450
Inaha Stream, State Highway 45 INH000470
page
6
Figure 1 Wastewater irrigation areas, surface water monitoring and point source discharge locations in the Inaha Stream
and tributaries
Stormwater generated in the main yard, garage and raw material reception areas is diverted to a three-
stage stormwater treatment system (near B, Figure 1). The first flush of a rainfall event is discharged to Pond
1 and after that is
occur in heavy rainfall events. These flood flows spill overland but generally rejoin the main
channels before they enter the urban area. These overland flows will generally be caught by
the diversion channels which cut across the lay of land.
1.9 Climate
Because of its exposure to disturbed weather systems from the Tasman Sea, the Taranaki
region is often quite windy, but has few climate extremes. The most settled weather occurs
during summer and early autumn.
The mountain and
and detaching or detached mats accumulating on the river’s edge triggered the
‘Alert’ level at the same four sites (Waingongoro River at Ohawe, Kaupokonui River at the mouth, and
Waiwhakaiho River at the last riffle and at Merrilands Domain) on a total of 8 surveys. Levels of
cyanobacteria were higher than in the previous season; and lower than the preceding three seasons,
probably a reflection of the relative amounts of rainfall causing freshes that scour streambeds of
investigations, and interventions summary table 20
Table 10 Summary of performance for consent 5079-2 23
Table 11 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 …
caddisflies). The MCI index (widely used to monitor macroinvertebrates in
streams) is high (typically >100) in streams dominated by mayflies, stoneflies and caddisflies and low
(typically <80) in streams dominated by worms, snails and chironimids.
In Taranaki, nutrients are not such a problem because of fast flowing and relatively short rivers and
streams. High rainfall leads to frequent flushing events in rivers and streams that provide natural
scouring. Even in summer, most Taranaki rivers do
on aquatic life.
4.4.3 Climate
NIWA virtual Climate Station -38.975, 174.525 Thirty years of rainfall and evaporation data is
summarised in Table 1 below
Table 1: NIWA Virtual Climate Station 30-year data for a site near Uruti Site
Uruti Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Total
Rainfall 120.0 107.0 119.2 151.2 181.2 189.5 181.8 178.0 175.4 188.4 149.4 149.0 1890.
Evaporation 134.5 108.0 88.6 52.7 31.1 21.4 25.4 39.0 57.5 85.1 109.3 126.0 878.6
4.4.4
performance for consent 7470-1.1 16
List of figures
Figure 1 Location of TTR site production and monitoring bores 5
Figure 2 Daily abstraction volumes under consent 7470-1.1 (July 2014-June 2015) 10
Figure 3 Daily abstraction volumes under consent 7470-1.1 (2009-2015) 10
Figure 4 Maximum daily abstraction rate under consent 7470-1.1 (2014-2015) 11
Figure 5 Maximum daily abstraction rate under consent 7470-1.1 (2009-2015) 11
Figure 6 Observed groundwater levels and rainfall
Revised Assessment of Environmental Effects (AEE) - June 2020
2024 sample results, notably an increase of 40mS/m at ARW000999 (downstream location). This
increase is likely a result of the unusually low rainfall in the region, which has reduced the natural mixing
and dilution of stream water.
Figure 5 Potassium trend from April 2021 to March 2024.
Potassium levels also remained at a low level throughout the surface water monitoring, with the exception
of higher levels recorded at all sites in March 2024. As noted in previous reports, control site