Statement of rebuttal evidence of Tim Fisher (water) for the New Zealand Transport Agency
Dated: 18 March 2014
Paula Brosnahan (pbrosnahan@furthernorth.co.nz) Luke Hinchey (lhinchey@furthernorth.co.nz) Before a Board of Inquiry
under:
the Resource Management Act 1991in the matter of:
notices of requirement for designation and resource consent applications by the New Zealand Transport Agency for the Ara Tūhono Pūhoi to Wellsford Road of NationalSignificance – Pūhoi to Warkworth Section
applicant:
New Zealand Transport AgencyRequiring Authority
TABLE OF CONTENTS
INTRODUCTION 1
RESPONSE TO SECTION 42A REPORT 2
RESPONSE TO EVIDENCE OF SUBMITTERS 2
Director-General of Conservation (DOC) 2
Dr Denise Civil (Civil Farm Partnership, The Puriri Springs Trust, Southway,
DIG Partnership) 4
CORRECTION TO OPERATIONAL WATER ASSESSMENT REPORT 6
CONCLUSIONS 6
ANNEXURE A – CORRECTION TO OPERATIONAL WATER
ASSESSMENT REPORT FIGURE 44 7
1
STATEMENT OF REBUTTAL EVIDENCE OF TIM FISHER FOR THE TRANSPORT AGENCY
INTRODUCTION
1 My full name is Timothy Simon Richmond Fisher
2 I have the qualifications and experiences set out at paragraphs 2-4 of my statement of evidence-in-chief (
EIC
) dated 23 January 2014.3 My rebuttal evidence is given in support of the New Zealand Transport Agency’s (
Transport Agency’s)
notices of requirement and applications for resource consent lodged with the Environmental Protection Authority for the construction, operation and maintenance of the Ara Tūhono Pūhoi to Wellsford Road of National Significance – Pūhoi to Warkworth Section (Project
).4 I repeat the confirmation given in my EIC regarding the Code of Conduct for Expert Witnesses contained in the Environment Court’s Consolidated Practice Note.
5 In this statement of rebuttal evidence, I respond to the relevant sections of the following:
5.1 Evidence of expert witnesses on behalf of Director-General of Conservation (106198):
(a) Mr Brian Handyside (Erosion and Sediment Control);
(b) Mr Robert Scott (Planning);
5.2 Evidence of Dr Denise Civil, on behalf of Civil Farm Partnership (103998), The Puriri Springs Trust (106003), Southway (106011), DIG Partnership (106016); and
5.3 Section 42A Planning Report – Stage 1 (
Section 42A Report
).6 I have also attended a facilitated meeting with the Lee Family Trust and attended witness conferencing since filing my EIC.
7 The fact that this rebuttal statement does not respond to every matter raised in the evidence of submitter witnesses or the Section 42A Report within my area of expertise should not be taken as acceptance of the matters raised. Rather, I rely on my earlier technical “Operational Water Assessment Report” (
OWAR
), my EIC and this rebuttal statement to set out my opinion on what I consider to be the key stormwater, streamworks and flooding matters for this hearing.RESPONSE TO SECTION 42A REPORT
8 Some issues that relate to Operational Water are raised in the Section 42A Report and these are considered in the rebuttal evidence of Ms Sinclair.
These issues and their engineering aspects are listed below:
8.1 The damming of water in relation to stormwater wetlands. For the indicative design, the stormwater wetlands are outside of
waterways. It is normal practise to build stormwater wetlands outside of streams (off-line) to avoid effects on streams.1 8.2 Diversion of water associated with filling of the floodplain. The
indicative design has bridge abutments in the floodplain. The residual effect of the Carran Road Flood Relief Bridge is to divert some floodwater to the main Mahurangi River left branch.2 8.3 That a statutory assessment against the National Environmental
Standard: Drinking Water (
NES
) is missing from the Transport Agency’s consent application. We have assessed3 the potential effects of the Project on Watercare’s potable water supply to Warkworth and the NES and the Drinking Water Standards.4 Watercare has been consulted, has considered the effects of the Project, and the Transport Agency has proposed designation and consent conditions to address Watercare’s concerns.RESPONSE TO EVIDENCE OF SUBMITTERS Director-General of Conservation (DOC)
9 I have reviewed the evidence of Mr Handyside and have been involved with expert conferencing on construction water.5 I have involved myself in the expert conferencing and I comment here briefly on construction water because Mr Handyside refers to the Transport Agency’s
Transmission Gully project (
TG
) in his evidence, and the TG consent conditions appear to be the basis for the additional resource consent conditions proposed by Mr Scott for DOC.10 I was involved in the TG hearing as a peer review witness on sediment matters. I can comment on these matters because I contributed to the development of the sediment assessment methodologies that are used in the Construction Water Assessment Report for this Project. I contributed to that process so that the learnings from the TG assessment and hearing
1 OWAR Section 7.4.1, bullet 4, (page 69).
2 OWAR Section 8.6(a)(iii), (page 139-146).
3 OWAR Section 8.4.1(a)(i), (pages 131 to 132).
4 Ministry of Health (2008) Drinking-water Standards for New Zealand 2005 (Revised 2008).
5 Construction Water Erosion and Sediment Control Conference Reports of 10 March 2014 and 12 March 2014.
3
were applied to the Project. Lessons from TG included the use of the GLEAMS model by NIWA in addition to the USLE method to ensure a more robust estimate of sediment yields.
11 It appears to me that DOC has taken the resource consent conditions for TG and applied these to the Project. For TG, the sediment experts, through conferencing, developed more specific conditions because a number of the experts considered there to be considerable uncertainty in the sediment yields. Conditions added for TG, such as those requiring a peer review panel, were included so additional oversight could be ensured and decision making to support the adaptive management could occur through construction. For TG, the sediment experts also considered the peer review panel to be beneficial because the Greater Wellington
Regional Council at the time had limited capability and capacity to manage a very large earthworks project with the adaptive management required.
12 I consider that the additional conditions proposed by DOC (and attached to Mr Scott’s evidence), that are over and above those agreed between the Transport Agency and Auckland Council, are not warranted on the basis that the Project is different to TG as follows:
12.1 The uncertainty in the sediment yields for the Project is less than it was for TG because the Project has used the GLEAMS model by NIWA in addition to the USLE for sediment yield estimates. The GLEAMS model was not used for TG, but was highlighted as a better model than the USLE by the Board peer reviewer and DOC experts during the TG hearing. Therefore, the GLEAMS model was included in our assessment methodology for the Project.
12.2 Mr Ridley in his rebuttal has sourced data on the measured sediment yields at three other Auckland earthworks projects and found these to be between 8 and 66% of the sediment yields predicted by the USLE method. This indicates to me that the USLE estimates are conservative for the Auckland region. I note that this is the opinion also of Mr Byrne.6
12.3 The other major difference is that Auckland Council has the capability and capacity to administer the resource consents for a project of this scale and with the adaptive management
requirements. I note that Mr Byrne (Auckland Council) considers the peer review panel to be unnecessary.7
6 Construction Water Erosion and Sediment Control Conference Report, 12 March 2014, paragraph 9.
7 Construction Water Erosion and Sediment Control Conference Report, 12 March 2014, paragraph 20.
Dr Denise Civil (Civil Farm Partnership, The Puriri Springs Trust, Southway, DIG Partnership)
13 Dr Civil raises the issue of flooding in the Carran Road sector8 of the Project and questions the appropriateness of the indicative alignment.9 14 I considered information from residents and from the Auckland Council
rapid flood hazard model in the design of the Project, and this information led to a change in the indicative alignment from that proposed for the previous scheme alignment.10
15 Dr Civil’s photos and observations11 of flooding support the flooding that is predicted by the Auckland Council rapid flood hazard model. This model was the basis for our design and assessments.12 I note that the Transport Agency proposed resource consent conditions require the flooding
outcomes of the Project to be within certain limits, such as not more than 0.1 m afflux upstream of the Carran Road Flood Relief Bridge, and for this adherence to limits to be demonstrated by a hydraulic computer model.13 16 Dr Civil identifies potential effects from the motorway from the
displacement of floodwaters and the increase in imperviousness,14 which I assessed in the OWAR.15
17 Dr Civil questions whether future development will cause the flooding to become more extreme in the Carran Road Sector.16 The “Future Urban”
zone within the Proposed Auckland Unitary Plan is downstream of the motorway at the north end of the Project area bounded by the indicative alignment, existing SH1 and Hudson Road. As this area is downstream of the motorway it does not affect the hydraulic sizing of structures. The effects of these future developments are not part of this Project and would be considered and mitigated at the time of that future
development.
18 Dr Civil challenges whether the flooding effects on the four affected dwellings at 151 and 152 Carran Road and 346 and 272 Woodcocks Road, are minor to moderate.17 I assessed these effects as moderate as the
8 Dr Civil evidence, paragraphs 68 and 69, (page 22).
9 A preliminary design alignment assessed by technical experts that may be refined on detailed design within the designation boundary.
10 OWAR, Section 7.10, (pages 92–94).
11 Dr Civil evidence, (paragraph 74, page 24).
12 OWAR Section 6.3, (page 54) and Section 8.6 (page 136-146).
13 Proposed consent Condition 68, as attached to the rebuttal evidence of Ms Sinclair.
14 Dr Civil evidence, paragraph 76, (page 24).
15 OWAR, Section 8.6 (page 136-146) and Section 8.2.1 (pages 99-110).
16 Dr Civil evidence, paragraph 77, (pages 24–25).
17 Dr Civil evidence, paragraph 78, (page 25).
5
dwellings would already flood under a 100 year ARI flood event, and there is only a slight increase in flooding depth as a result of the Project. 18 I stand by my assessment.
19 Dr Civil interprets the flood maps in the OWAR and Factual Report 10 to say that there is an increase in flood extent.19 My assessment is that the flood extents will change only very slightly as the increases in flood depths are less than 0.1 m.
20 Dr Civil has a concern that the increase in flood depth and related area will have an impact on stock management and grass recovery.20 It is my opinion that the change in flood extent is minor, so therefore will not significantly impact on grazing. Similarly, as the additional flood extent is minor and flood duration short (less than 24 hours), there will be no impact on grass recovery.
21 Dr Civil interprets from my OWAR that the flooding in the vicinity of Kaipara Flats Road will increase by up to 0.050 m.21 This interpretation of the flood maps is wrong. The flood differences between -0.050 m and +0.050 m were banded together by me as they are in the error range of the assessment. I therefore consider the effects in these areas are not discernible.22
22 For the reasons given above, Dr Civil interprets the flooding as worse for 111 Kaipara Flats Road, for sections of Kaipara Flats Road and for the intersection of SH1/Kaipara Flats Road/Goatley Road.23 The correct interpretation of the flood maps24 is that the flooding is unchanged in these areas. I note the model does not include bridges, such as the access bridge at 111 Kaipara Flats Road, with the exception of the Carran Road Flood Relief Bridge and the Woodcocks Road Viaduct.
23 Some of the confusion over these matters may be due to an error in the OWAR where the wrong Figure 44 was used. The correct Figure 44 is included in Annexure A refer paragraph 25 below.
24 Dr Civil considers that the Carran Road Flood Relief Bridge should be increased to totally span the 100 year ARI floodplain.25 I have previously
18 OWA, section 8.6, Table 30, (page 144). Refer also to revised Figure 44 (Annexure A).
19 Dr Civil evidence, paragraph 79, (pages 25-26).
20 Dr Civil evidence, paragraph 81, (page 26).
21 Dr Civil evidence, paragraph 80, (page 26).
22 The errors in the assessment arise from differencing of two models (with and without Project flood models) and is approximately -0.050 and +0.050. Any real effects less than ± 0.05 m are not discernible. Refer also to revised Figure 44 (Annexure A).
23 Dr Civil evidence, paragraph 82, (page 27).
24 OWAR Figure 18 (page 93) and Figure 44 (Annexure A).
25 Dr Civil evidence, paragraph 83, (page 27).
said that the proposed flood relief bridge is in my judgement the best practicable option, which balances bridge size and effects.26
CORRECTION TO OPERATIONAL WATER ASSESSMENT REPORT 25 I note a correction to the OWAR Figure 44 and have included the correct
Figure 44 in Annexure A. The correct figure has been made available to the Auckland Council and the National Trading Company during
consultation.
26 I note a correction to the OWAR, line 1, paragraph 2, page 141, where the peak flow at the Carran Road Flood Relief Bridge decreases by
approximately “10 m3/s”, not the “5 m3/s” in the text. Figure 45 is correct and the Water Assessment Factual Report 10 Flood Assessment Section 4.2 are correct. My flooding assessments remain unchanged as the change in flood depths used for the assessment are unchanged.
CONCLUSIONS
27 My rebuttal evidence covers stormwater, streamworks and potential flooding associated with the operation phase of the Project. My rebuttal also addresses the Section 42A Report and Dr Civil’s evidence. I confirm that my assessment and conclusion in the OWAR and in my evidence-in- chief remain unchanged. I have also commented that it is not warranted to apply TG conditions to this Project as has been proposed by Mr Handyside and Mr Scott for DOC.
_______________________
Tim Fisher 18 March 2014
26 Dr Fisher, EIC, paragraph 67, (page 18).
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ANNEXURE A – CORRECTION TO OPERATIONAL WATER ASSESSMENT REPORT FIGURE 44
Figure 44: Carran Road Sector water level difference for 100 year ARI
