From:
Richard Williams
To:
James Luty
Cc:
James Snowdon ; Rubie McLintock ; Paul Gardiner
Subject:
RE: BURST WASTEWATER RISING MAIN - SH1 Paremata
Date:
Thursday, 23 September 2021 5:05:13 pm
Attachments:
image002.png
Paramata Water Quality Monitoring - To GWRC.xlsx
Emergency Works - Paremata Wastewater Pipe - 17 July 2021 - Final to GWRC.pdf
Paremata Wastewater Riser Break - emergency works notification (s.330A(1)).msg
Tēnā koe James
Please find attached the Emergency Works Report in relation to the Paremata wastewater pipe
event on 17 July 2021.
Thanks again for your patience on receiving this report.
Please get in touch with us if we can clarify any of the attached information.
Ngā mihi
Richard Williams Senior Advisor (RMA, Consents and Environment)
Mobile 021 582 968
From: Richard Williams
Sent: 22 September 2021 5:01 PM
To: James Luty <[email address]>
Cc: James Snowdon <[email address]>; Rubie McLintock
<[email address]>; Paul Gardiner <[email address]>
Subject: RE: BURST WASTEWATER RISING MAIN - SH1 Paremata
Tēnā koe James
We have just received a comprehensive internal review and respectfully request until the end of
tomorrow to update the document.
Again, we apologise for the delay and will use this situation as a learning opportunity with our
teams.
Ngā mihi
Richard Williams Senior Advisor (RMA, Consents and Environment)
Mobile 021 582 968
From: James Luty <[email address]>
Sent: 17 September 2021 1:35 PM
To: Richard Williams <[email address]>
Cc: James Snowdon <[email address]>; Rubie McLintock
<[email address]>; Paul Gardiner <[email address]>
Subject: RE: BURST WASTEWATER RISING MAIN - SH1 Paremata
Thanks for the update Richard.
I look forward to receiving your document by 5pm on Wednesday 22 September 2021.
Ngā mihi,
makaurangi
James Luty [he/him]
Kaiāpiha Taiao | Senior Environmental Protection Officer
Greater Wellington | Te Pane Matua Taiao
M: 027 254 2230

From: Richard Williams <[email address]>
Sent: Friday, 17 September, 2021 1:28 PM
To: James Luty <[email address]>; Paul Gardiner
<[email address]>
Cc: James Snowdon <[email address]>; Rubie McLintock
<[email address]>
Subject: RE: BURST WASTEWATER RISING MAIN - SH1 Paremata
Tēnā koe James
Unfortunately we have been unable to finalise the emergency works document for your review.
Please accept our apologies for the delay.
We will endeavour to send it to you early next week.
Ngā mihi
Richard Williams Senior Advisor (RMA, Consents and Environment)
Mobile 021 582 968
From: James Luty <[email address]>
Sent: 09 September 2021 9:33 AM
To: Richard Williams <[email address]>; Paul Gardiner
<[email address]>
Cc: James Snowdon <[email address]>; Rubie McLintock
<[email address]>
Subject: RE: BURST WASTEWATER RISING MAIN - SH1 Paremata
Thanks Richard.
I look forward to hearing from you by next Friday.
Ngā mihi,
makaurangi
James Luty [he/him]
Kaiāpiha Taiao | Senior Environmental Protection Officer
Greater Wellington | Te Pane Matua Taiao
M: 027 254 2230
From: Richard Williams <[email address]>
Sent: Thursday, 9 September, 2021 9:31 AM
To: James Luty <[email address]>; Paul Gardiner
<[email address]>
Cc: James Snowdon <[email address]>; Rubie McLintock
<[email address]>
Subject: RE: BURST WASTEWATER RISING MAIN - SH1 Paremata
Tēnā koe James
Thanks for the follow up request.
I have prepared the draft notification summary, however, we were awaiting some information
from our operations team to complete the report.
I’ll finalise the report and provide for your review a.s.a.p.
Thanks again
Ngā mihi
Richard Williams Senior Advisor (RMA, Consents and Environment)

Mobile 021 582 968
From: James Luty <[email address]>
Sent: 09 September 2021 9:24 AM
To: Paul Gardiner <[email address]>
Cc: James Snowdon <[email address]>; Rubie McLintock
<[email address]>; Richard Williams <[email address]>
Subject: RE: BURST WASTEWATER RISING MAIN - SH1 Paremata
Hello Paul and Richard,
It has been six weeks since the first agreed deadline for the provision of this material. I accept
that the initial response to this event took priority and that Covid has been a difficult time.
However we need this material to progress our investigation. As you know, this matter is of
public interest.
I am now officially requesting this information. The new deadline for the provision of this
information is 17 September 2021. If we do not receive this information by this new deadline
then we will have to consider how best to engage over this.
Please feel free to email me if you have any concerns of questions.
Ngā mihi,
makaurangi
James Luty [he/him]
Kaiāpiha Taiao | Senior Environmental Protection Officer
Greater Wellington | Te Pane Matua Taiao
M: 027 254 2230
From: James Luty
Sent: Monday, 26 July, 2021 4:51 PM
To: [email address]
Cc: James Snowdon <[email address]>; Rubie McLintock
<[email address]>
Subject: BURST WASTEWATER RISING MAIN - SH1 Paremata
Hello Paul,
Thank you for your time on the phone just now. I have attached the email chain from the
incident. As far as I know, this is the extent of the information that GWRC has been provided to
date (please let me know if I have missed anything).
I understand that the discharge has ceased and that you are currently reviewing the response
and going through “lessons learnt” process to inform the next steps for WWL. You stated that
you are hoping to have some information relating to the incident available by the end of this
week and that you are happy to share this with GWRC. Thank you very much, I look forward to
receiving it.
If possible, it would be helpful if this information pack included the following:
A timeline outlining the incident, the cause, the response and the decision making which
informed the response
Any monitoring or sampling relating to the incident (include reports, sample data, photos
etc.)
Any assessment of the actual or potential effects
The steps taken to mitigate or remedy any actual or potential adverse effects on the
environment
As a guideline, the documentation we have received following the Jervois Quay stormwater

pipeline collapse has been excellent. If you have the time, I would suggest reaching out to GHD
and the contractor involved in these works as they have been excellent at providing us the data
to inform out investigations for this project.
I am happy to meet to discuss the information that you provide this week. In the event that
there are any gaps we can talk these through face to face.
I have cc’d in Rubie McLintock who will be assisting me with this investigation. Please keep her
and Mr Snowdon in cc if you can.
Let me know if you have any questions or concerns.
Ngā mihi,
makaurangi
James Luty [he/him]
Kaiāpiha Taiao | Senior Environmental Protection Officer
Greater Wellington | Te Pane Matua Taiao
M: 027 254 2230
100 Cuba Street, Te Aro
PO Box 11646, Wellington 6011
Follow us online: Facebook | Twitter | gw.govt.nz
ATTENTION: This correspondence is confidential and intended for the named recipient(s) only. If
you are not the named recipient and receive this correspondence in error, you must not copy,
distribute or take any action in reliance on it and you should delete it from your system and
notify the sender immediately. Unless otherwise stated, any views or opinions expressed are
solely those of the author, and do not represent those of the organisation.
ATTENTION: This correspondence is confidential and intended for the named recipient(s) only. If
you are not the named recipient and receive this correspondence in error, you must not copy,
distribute or take any action in reliance on it and you should delete it from your system and
notify the sender immediately. Unless otherwise stated, any views or opinions expressed are
solely those of the author, and do not represent those of the organisation.
ATTENTION: This correspondence is confidential and intended for the named recipient(s) only. If
you are not the named recipient and receive this correspondence in error, you must not copy,
distribute or take any action in reliance on it and you should delete it from your system and
notify the sender immediately. Unless otherwise stated, any views or opinions expressed are
solely those of the author, and do not represent those of the organisation.

Aotea pipe break/Paramata overf

18/07/2021 19/07/2021 20/07/2021 21/07/2021 22/07/2021 23/07/2021 24/07/2021 25/07/2021
Final
Final
Final
Final
Final
Final
Final
Final
Wi Neera Drive boat ramp
3100
770
180
2100
4500
220
65
76
Pauatahanui Inlet Paremata Bridge
1300
980
320
130
44
560
48
16
Pauatahanui Inlet Water Ski Club
1200
1100
530
60
96
690
20
8
Plimmerton South Beach
1500
1100
400
120
1100
450
36
56
Karehana Bay Cluny Road (control site)
610
940
160
20
110
190
12
4
Plimmerton Beach @ Bath St
450
92
58
Takapuwahia Stream Outlet @ Te Hiko St
140
190
230
Porirua Harbour at Rowing Club
630
24
12
Weather
Overcast
Overcast
Rain
Clear
Clear
Clear

flow Enteroccoci monitoring (cfu/100mL)
26/07/2021 27/07/2021 28/07/2021 29/07/2021 30/07/2021 31/07/2021 1/08/2021
2/08/2021 3/08/2021 4/08/2021 5/08/2021 6/08/2021
Final
Final
Final
Final
Final
Final
Final
Final
Final
Final
Final
Final
410
640
120
48
84
4
8
20
12
20
560
69
68
150
73
12
8
8
4
8
40
4
48
4
48
190
38
8
4
19
8
4
56
65
4
200
46
76
16
350
8
84
180
20
50
600
12
160
20
100
4
4
4
4
4
4
12
4
4
100
23
410
12
28
24
16
16
92
150
12
8
8
430
3400
110
38
40
220
12
12
3000
54
510
210
54
190
24
20
4
20
4
4
110
4
8
100
Rain
Rain
Clear
Clear
Clear
Clear
Partly cloudy
Clear
Rain
Overcast
Overcast
Overcast

Emergency Works
(RMA s330 and s330A)
1

RMA s330 and s330A Emergency Works Report
1.  Report Background

  This report provides information related to a ruptured pressure wastewater pipeline in
Porirua.
  The report describes the work completed in the context of s330 and s330A of the Resource
Management Act.
  The report is prepared for Greater Wellington Regional Council.
2.  Background information

  A 0.525m diameter trunk pipeline conveys wastewater from the communities of Paremata,
Camborne, Hongoeka, Plimmerton, Pukerua Bay and Whitby to be treated at the Porirua
Wastewater Treatment Plant.
  The Paremata pump stations (including Station Road Pump Station) collect the wastewater
from these communities and pump the wastewater through the pipeline. Accordingly the
wastewater is conveyed along the main trunk pipeline under pressure and also flows by
gravity in sections between the pump stations and Porirua Wastewater Treatment Plant.
  The Wellington Region was experiencing a high intensity rainfall event at the time (See
Attachment D)
  The pipeline unexpectantly ruptured around 8.00 a.m. on Saturday 17 July 2021.
3.  Site and Event Description

  The pressure wastewater pipeline connects the Paremata Pump Stations and Porirua Central
Pump Station. The pipeline is firstly located under Paremata Crescent, and Papakowhai Road,
and then transverses underneath State Highway 1 approximately 650m northeast of the
Whitford Brown Avenue (Aotea/Papakowhai) intersection. The pipe continues across and
then parallel to State Highway 1 until the Porirua City Centre Pump Station near the Porirua
railway station.
  The pipeline failed (ruptured) between the carriageways on State Highway 1, approximately
600m north of Whitford Brown interchange. (See Figures 1 and 2 in Attachment A)
  Wastewater from the break (rupture point) travelled southwest along the State Highway 1
median and entered a stormwater culvert approximately 400m from the pipe failure. The
wastewater then discharged to Te Awarua‐o‐Porirua Harbour (See Attachment B, Figure 3).
  The wastewater also flowed onto the two north bound State Highway 1 lanes.
  In order to avoid damage to property, avoid creating a traffic and health hazard, and to
facilitate the repair work of the ruptured pipeline in a safe manner, the Pumping Stations in
Paremata were turned off. These pump stations are directly ‘upstream’ of the rupture, and
intercepts all the wastewater from the surrounding communities that flows through the main
trunk pipeline towards the city centre. The wastewater then backed up within the
wastewater system and overflowed at Station Road and Paremata Crescent into the
stormwater system which then flowed into  Te Awarua‐o‐Porirua Harbour at Paremata (See
Attachment B, Figure 4).
2

  In addition, due to the capacity of the stormwater system, some wastewater ponded onto
Paremata School until additional mobile pumps could be deployed. These pumps transferred
the overflowing wastewater to the stormwater network, which then flowed into Te Awarua‐
o‐Porirua Harbour at Paremata (See Attachment C, Figure 7).
  To protect property and avoid creating a health hazard, the cross harbour pipeline between
Paremata and Whitireia Park Reserve was utilised to convey wastewater (See Attachment C,
Figure 8). This pressure pipeline had previously been inspected through creating small
openings at Onepoto and Whitireia Park Reserve, and unbeknown to Wellington Water, these
inspection points remained open when the pipeline began to convey wastewater under
pressure. These openings resulted in discharges of wastewater to Te Awarua‐o‐Porirua
Harbour at Onepoto and Whitireia Park Reserve.
Attachment A: Site Location Map
RMA s330 Emergency works and power to take preventative or remedial action
Clause
Assessment
(1)
Where—
(a) any public work for which any person has
The financial responsibility is borne by Porirua
financial responsibility; or
City Council (PCC) as the pipeline asset owner,
however Wellington Water manages the
network on behalf of PCC and therefore could
be considered an agent of PCC and this
subsection may be applied.
(b) any natural and physical resource or area for
Not applicable – Wellington Water is not a local
which a local authority or consent authority has
authority or consent authority.
jurisdiction under this Act; or
(c) any project or work or network utility
Not applicable – Wellington Water is not a
operation for which any network utility operator  requiring authority.
is approved as a requiring authority under
section 167; or
(ca) any service or system that any lifeline utility
As stated in section 330 (5) RMA, a lifeline utility
operates or provides—
is defined in section 4 of the Civil Defence
Emergency Management Act 2002. As stated in
Section 4, Interpretation, of the Civil Defence
Emergency Management Act 2002, a lifeline
utility is described in Part B of Schedule 1. Part B
(4) states “An entity that provides a waste water
or sewerage network or that disposes of sewage
or storm water”. Wellington Water operates the
wastewater network in Porirua. Wellington
Water is therefore considered a lifeline utility.
The emergency works relates to the operation of
3

the wastewater network which is a lifeline
utility, and therefore, it is considered that this
section applies.
is, in the opinion of the person, authority, network utility operator, or lifeline utility, affected by or
likely to be affected by—
(d) an adverse effect on the environment which
In a broad sense, the rupture of the wastewater
requires immediate preventive measures; or
pipeline created an adverse effect on the
environment which required the preventative
measures to repair the pipeline and avoid on‐
going wastewater discharge.
(e) an adverse effect on the environment which
In a broad sense, the rupture of the wastewater
requires immediate remedial measures; or
pipeline created an adverse effect on the
environment that required immediate remedial
measures to repair the pipeline and avoid on‐
going wastewater discharge.
(f) any sudden event causing or likely to cause
The wastewater network (lifeline utility service)
loss of life, injury, or serious damage to
was affected by a sudden event (the rupture of
property—
the wastewater pressure pipeline), that was
likely to cause injury (the illness of personnel
working towards repairing the pipe) and caused
or was likely to cause serious damage to
property (wastewater inundating Paremata
School and private property).
The provisions of sections 9, 12, 13, 14, and 15
In order to mitigate the effect and remove the
shall not apply to any activity undertaken by or
cause of potential injury to those personnel
on behalf of that person, authority, network
repairing the pipe and damage to the school and
utility operator, or lifeline utility to remove the
private property, Wellington Water as the
cause of, or mitigate any actual or likely adverse
lifeline utility operator undertook a number
effect of, the emergency
activities in order to enable repair and mitigate
the effects of the rupture.
For the purposes of section 330 these activities
include a number of discharges (without
resource consent) resulting from the repair work
(either directly or indirectly). In each case the
discharge is considered necessary to facilitate
repairs or an unavoidable consequence of
actions taken to remove the cause of, or
mitigate any actual or likely adverse effect of,
the emergency.
1. Wastewater (contaminant) discharge
approximately 8.00 am to 10.30 am on 17
4

July 2021 and approximately 4.00 pm to
5.00 pm on 22 July 2021 at Aotea (See
Attachment B, Figure 3). These discharges
are a result of the initial and subsequent
pipeline ruptures. These ruptures and
associated discharges are a result of an
unanticipated failure of the pipeline that
could not have reasonably been provided
against. Wellington Water acted
immediately to mitigate the effects of the
discharge by deploying vacuum (sucker)
trucks and making requests to the public to
minimise water use in order to reduce the
volume of wastewater being discharged.
Wellington Water also sought to minimise
the effect of the discharge by shutting pump
stations to move the discharge point closer
to open water to increase dispersion of
potential contaminants. Repairs were
completed and normal operation resumed
as soon as was reasonably practical.
2. Wastewater (contaminant) discharge
approximately 10.30 am on 17 July 2021 to
10.00 pm on 18 July 2021 at Paremata via
overflow through the stormwater system
(See Attachment B, Figure 4). Approximate
volume of discharge – 7,740m3. This
wastewater discharge is associated to the
decision to restrict wastewater flowing
through the pipeline by redirecting the
wastewater to the Paremata stormwater
network which overflowed and was in some
cases pumped into the Te Awarua‐o‐Porirua
Harbour at Paremata. The decision to stop
the pumps at Station Road and Paremata
Pumping Stations backed up the wastewater
network until it flowed into the stormwater
network. In addition, mobile pumps were
deployed to pump the overflowing
wastewater into the stormwater network.
This decision ensured that wastewater did
not pond on State Highway 1, Station Road
and Paremata School which would cause a
traffic and health hazard, property damage
and ensured the safety of our response
crews working to repair the pipeline at
Aotea. Vacuum sucker trucks were also
5

onsite to transport wastewater around the
site to Porirua City Centre Pump Stations. A
media notice was further issued that
requested the community limit their water
use.
3.  Wastewater (contaminant) discharge
approximately mid‐day on 20 July 2021 to
2.00 pm on 20 July 2021 at Whitireia Park
Reserve (See Attachment B, Figure 5). The
wastewater discharged from an inspection
opening within the pipeline that remained
open unbeknown to Wellington Water. The
decision to activate the cross harbour
pipeline was made to reduce the pressure
on the vulnerable pipe repair to reduce the
likelihood of further damage to the pipe
(property). The decision to utilise the cross
harbour pipe was determined to be prudent
decision based upon the information
Wellington Water held on the suitability of
the pipeline to convey wastewater.
4.  Accidental wastewater (contaminant)
discharge approximately 5.00 pm on 22 July
2021 to 8.00 am on 23 July 2021 at Onepoto
(See Attachment B, Figure 6). The
wastewater discharged from an inspection
opening within the pipeline that remained
open unbeknown to Wellington Water. The
decision to activate the cross harbour
pipeline was made to reduce the pressure
on the vulnerable pipe repair to reduce the
likelihood of further damage to the pipe
(property). The decision to utalise the cross
harbour pipe was determined to be prudent
decision based upon the information
Wellington Water held on the suitability of
the pipeline to convey wastewater.
5.  Wastewater (contaminant) discharge
approximately 8.00 am on 23 July 2021 to
7.00 pm on 23 July 2021 at Paremata (See
Attachment B, Figure 4). Approximate
volume of discharge – 1,302 m3. This
wastewater discharge is associated with the
decision to restrict wastewater flowing
through the pipeline by redirecting the
wastewater to the Paremata stormwater
network, which overflowed into the Te
6

Awarua‐o‐Porirua Harbour at Paremata. The
decision to stop the pumps at Station Road
and Paremata Pumping Stations backed up
the wastewater network until it flowed into
the stormwater network. In addition, mobile
pumps were deployed to pump the
overflowing wastewater into the
stormwater network. This decision ensured
that wastewater did not pond on State
Highway 1, Station Road and Paremata
School which would cause a traffic and
health hazard, property damage and
ensured the safety of our response crews
working to repair the pipeline at
Aotea.  Vacuum sucker trucks were also
onsite to transport wastewater around the
site to Porirua City Centre Pump Stations.
6.  Wastewater (contaminant) discharge
approximately 7.30 am on 25 July 2021 to
7.00 pm on 25 July 2021 at Paremata (See
Attachment B, Figure 4). Approximate
volume of discharge – 3,380m3.This
wastewater discharge is associated with the
decision to restrict wastewater flowing
through the pipeline by redirecting the
wastewater to the Paremata stormwater
network which overflowed into the Te
Awarua‐o‐Porirua Harbour at Paremata. The
decision to stop the pumps at Station Road
and Paremata Pumping Stations backed up
the wastewater network until it flowed into
the stormwater network. In addition, mobile
pumps were deployed to pump the
overflowing wastewater into the
stormwater network. This decision ensured
that wastewater did not pond on State
Highway 1, Station Road and Paremata
School which would cause a traffic and
health hazard, property damage and
ensured the safety of our response crews
working to repair the pipeline at
Aotea.  Vacuum sucker trucks were also
onsite to transport wastewater around the
site to Porirua City Centre Pump Stations.

7

RMA 330A Resource consents for emergency works
(1) Where an activity is undertaken under
Notification was given to the consent authority
section 330, the person (other than the
(GWRC) throughout the event and specifically
occupier), authority, network utility operator, or via email after the event (attached)
lifeline utility who or which undertook the
activity shall advise the appropriate consent
authority, within 7 days, that the activity has
been undertaken.
The unauthorised discharge of contaminants
(2) Where such an activity, but for section 330,
was wastewater diluted by stormwater. The
contravenes any of sections 9, 12, 13, 14, and 15 primary receiving environment of these
and the adverse effects of the activity continue,
discharges was Te Awarua o Porirua (Porirua
then the person (other than the occupier),
Harbour). The potential adverse effects on the
authority, network utility operator, or lifeline
environment resulting from these discharges
utility who or which undertook the activity shall
include; possible effects on public health as a
apply in writing to the appropriate consent
result of microbiological contamination,
authority for any necessary resource consents
ecological health of the harbour, and cultural
required in respect of the activity within 20
impact on the values of Mana Whenua. The
working days of the notification under
impact of those discharges were significant at
subsection (1)
the time of discharge, with gradual reduction of
effect within 48 hours (two tide cycles) of the
discharges ceasing, as a result of tidal flushing,
dilution with coastal water and UV exposure
(natural die‐off) (see water quality sampling
results (attached*)). Outside of this timeframe
Wellington Water would not expect any
additional public health risk or ecological effect
specifically arising from the discharges related to
the emergency event. Wellington Water
recognises that the cultural impact of these
discharges continued beyond the 48 hour time
line as evidenced by the placement of the rāhui
from 9am Saturday 24th July to 7am on
Saturday 7 August 2021. Following the lifting of
the rāhui it is considered that the adverse
cultural impact of the emergency discharges had
ceased.
No activity continuing.
(3) If the application is made within the time
stated in subsection (2), the activity may
continue until the application for a resource
8

consent and any appeals have been finally
determined
4.  Emergency Action

  Wellington Water Limited took immediate action to eliminate the risk of injury to people.
  Wellington Water attended the site on Saturday 17 July 2021 to access the failure.
  Wellington Water organised vacuum trucks to reduce the volume of wastewater on the
carriageway and entering the harbour.
  The Incident Response Team deployed a team to commence repairs including excavating the
pipe at 10.00 a.m.
  Traffic management was established on State Highway 1 to provide a safe worksite.
  The Wellington Water Emergency Management Team was activated at 10.30 a.m.
  A media announcement to the Porirua Community was issued at 11.30 a.m. It encouraged
communities to limit their water use and recommended avoiding swimming in Te Awarua‐o‐
Porirua Harbour.
  Wellington Water organised vacuum trucks to Paremata School and Station Road pump
station to reduce wastewater entering the pipeline and property.
  To repair the failed pipe adjacent to State Highway 1, the wastewater was diverted to the
cross harbour pipeline that directly connects Paremata to Onepoto. (Note: cross harbour
pipeline did not convey wastewater as drain valve in pipeline was inadvertently opened).
  The temporary repair of main trunk pipeline commenced Saturday night.
  The temporary repair was not successful as the pipe was too fragile to support the new
connector.
  Four sucker trucks were onsite throughout Saturday night to reduce wastewater pressure on
pipe.
  Excavation of main trunk pipeline commenced on Sunday (18 July 2021). To replace the pipe,
and for the safety of the repair crew, all wastewater conveyed through the pipe must be
intercepted. Wastewater was firstly diverted through the cross harbour pipeline (Note: cross
harbour pipeline did not convey wastewater as a drain valve in pipeline was inadvertently
open). Secondly, four pumps directed wastewater from the Station Road Pump Station to the
stormwater overflow in Paremata. Lastly, twelve sucker trucks on‐site continuously removed
wastewater from the site and transferred the wastewater to downstream pump stations.
  The new section of pipe was installed at 4.00pm.
  During installation, adjacent sections of pipe are shown to be corroded and reinstating the
pressure wastewater pipeline is not commenced as there is a high risk of joint failure.
  Further rainfall Sunday night, and the sucker trucks on‐site and gravity overflow were
overwhelmed. Temporary pumps at Station Road Pump Station in Paremata were turned on
to discharge to the stormwater network and harbour at Paremata. This avoided wastewater
ponding around Station Road and the school and enabled more mixing to occur in the
harbour.
  Pressure Pipe returned to service.
  The inspection on Monday (19 July 2021) morning showed that the main pipeline had visible
leaks beyond the repaired section. Stainless steel wrap on leaking area of pipe installed as a
temporary solution.
9

  On Tuesday (20 July 2021), wastewater diverted through cross harbour pipeline. On site
observation notes a leak in the pipe and wastewater entering Porirua Harbour. Commenced
dye testing to confirm location. Wastewater leak detected in Onepoto Road. Cross harbour
pipeline repaired and pressure tested with drinking water.
  On Thursday (22 July 2021) afternoon, the wastewater pipe on State Highway 1 ruptured
beyond the joints of the new section of pipe. Wastewater entered the harbour through the
culvert and some ponding on State Highway 1 carriageway. Sucker trucks on‐site and
wastewater directed to the cross harbour pipeline.
  Cross harbour pipeline observed to be leaking. Sucker trucks on‐site and pumps at Station
Road pumping wastewater to the stormwater overflow in Paremata to limit wastewater
ponding on State Highway 1.
  On Friday (23 July 2021) morning, 15 sucker trucks on‐site to enable repair of pipe. One break
repaired with clamps, however, unable to seal as the pipe is being crushed by the connector.
  On Friday night, a swale was excavated to contain the leaking wastewater and sucker trucks
on‐site overnight.
  On Saturday (24 July 2021) morning, additional pipe procured, and internal pressure patched
to be flown down from Auckland. Patches not picked up at Auckland Airport, and now
transported on truck and Wellington Water crew to meet in Taupo.
  On Sunday (25 July 2021) afternoon, pressure patches installed to enable connecting clamps
and new section of pipe. Wastewater pipeline pressurised and returned to function at near
full capacity.
5.  Monitoring

  Monitoring of the discharged water was sampled throughout the emergency event.
  The environmental monitoring is provided in an Excel Spreadsheet. It is noted that there were
widespread wet weather overflows of wastewater throughout Porirua during the 17 July
storm event and these would be captured in the environmental monitoring.
6.  Contact Details
Name: Steve Hutchison
Position: Chief Advisor ‐ Wastewater
Phone: 021 306 534
Email: [email address]

Name: Richard Williams
Position: Senior Advisor (RMA, Consents and Environment)
Phone: 021 582 968
Email: [email address]

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