Bethlehem Shores Retirement Village Limited
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Under the Resource Management Act 1991 In the matter of an application for resource consents to undertake a proposed addition to the existing Bethlehem Shores Retirement Village (Stage 5) Between Bethlehem Shores Retirement Village Limited Applicant and Tauranga City Council Territorial Authority Statement of Evidence of Ognjan Kralj on behalf of Bethlehem Shores Retirement Village Limited dated 11 March 2021 BARRISTERS AND SOLICITORS COUNSEL FOR THE APPLICANT A J L BEATSON / T M CRAWFORD AUCKLAND LEVEL 22, VERO CENTRE, 48 SHORTLAND STREET PO BOX 1149, AUCKLAND 1140, DX CP20509, NEW ZEALAND TEL 64 9 916 8800 FAX 64 9 916 8801 EMAIL ANDREW.BEATSON@BELLGULLY.COM / TAYLA.CRAWFORD@BELLGULLY.COM
Qualifications and Experience
1. My name is Ognjan Kralj. I hold a Bachelor of Engineering from the
University of Zagreb-Croatia, and I am a Chartered Professional
Engineer.
2. I am the National Technical Director – Three Waters at Calibre
Consulting. I have thirty-five years of experience in the design and
construction of stormwater and wastewater drainage and water supply
projects, including international experience in Australia and Croatia. I
was the preferred Tauranga City Council consultant in delivering
Stormwater Recovery Projects from 2005-2010.
Project Involvement
3. Bethlehem Shores Retirement Village Limited has applied for resource
consents to construct Stage 5 of the Bethlehem Shores Retirement
Village (the Project). The Project involves the addition of 59 retirement
villas, a resident’s community centre and ancillary buildings to the
existing retirement village located at 123 Bethlehem Road.
4. I have been involved in Project design as a design lead since 2016,
including creating the following technical reports:
(a) Wastewater and Stormwater Feasibility Study (25 February
2016);
(b) Erosion and Sediment Control Plan (6 September 2016);
(c) Engineering Design Report for Land Use Consent (16 January
2017);
(d) Engineering Design Report-Stage 2 (includes Stage 3, Stage 4,
Stage 5 and Stage 6) for Building Consent (27 March 2017);
(e) Engineering Design Report Stage 6 for Land Use Consent (4
October 2018);
27390631_3 1
Statement of Evidence of Ognjan Kralj on behalf of Bethlehem Shores Retirement Village Limited dated 11 March
2021(f) Engineering Design Report Stage 5 for Land Use Consent and
Bay of Plenty Regional Council Resource Consent (20 November
2018);
(g) Erosion and Sediment Control Plan for Wetland Works (20
November 2018); Assessment of Environmental Effects for
Wetland and Coastal Structures (20 November 2018);
(h) Assessment of Environmental Effects for Wetland and Coastal
Structures (26 June 2019); and
(i) Stage 5 Services Design Report for Land Use Consent (4 August
2020).
5. I visited the site on several occasions in various stages of development
(preconstruction and during construction). Calibre Consulting also has
an office in Tauranga with personnel who actively monitor construction
on-site and report back to the Wellington office.
Code of Conduct
6. I have read the Code of Conduct for Expert Witnesses as contained in
the Environment Court Practice Note 2014, and I agree to comply with
it as if this hearing was before the Environment Court. My
qualifications as an expert are set out above. I confirm that the issues
addressed in this brief of evidence are within my area of expertise. I
have not omitted to consider material facts known to me that might alter
or detract from the opinions expressed.
Scope of Evidence
7. My evidence will address the following:
(a) Methodology and Limitations;
(b) Existing Environment;
(c) Assessment of Effects and Proposed Mitigation;
27390631_3 2
Statement of Evidence of Ognjan Kralj on behalf of Bethlehem Shores Retirement Village Limited dated 11 March
2021(d) Response to Submissions;
(e) Response to Officer’s Report;
(f) Recommendations for Conditions; and
(g) Conclusions.
Summary of Evidence
8. The key findings from my evidence are as follows:
(a) Flood level increase due to loss of floodplain is minor, assessed
at 10.4 mm higher than the current Tauranga City Council flood
level and deemed acceptable by Bay of Plenty Regional Council.
(b) The Project will mitigate the increase in stormwater discharge
from the development by rehabilitating wetland volume that acts
as detention volume. The additional detention volume will have a
positive effect considering it will result in the removal of
approximately 2,500 cubic metres of fill from the floodplain. The
existing railway drain conveys stormwater run-off from the
wetland to the Wairoa River. The water level increase in the
existing railway drain was assessed as being 51 mm for 10%
AEP and 67 mm for 1% AEP, including the high tide effect.
Water level increase in the existing railway drain will have only a
minor effect on downstream properties.
(c) Stormwater run-off quality from the existing development,
including sediment and suspended solids containment, is
mitigated by implementing a stormwater treatment device
(downstream defender) before discharging into the wetland.
(d) Erosion in the wetland is mitigated by employing an energy
dissipation outlet and rip-rap around the outlet structure that
minimises water energy and discharge velocities into the wetland.
27390631_3 3
Statement of Evidence of Ognjan Kralj on behalf of Bethlehem Shores Retirement Village Limited dated 11 March
2021Methodology and Limitations
9. Calculations for the relevant assessments for the Project were based
on the following documents:
(a) Tauranga City Council Infrastructure Development Code;
(b) Flooding extends from the Tauranga City Council GIS system;
(c) Tauranga City Council SMG-9 Detailed Stormwater Management
Practice Design;
(d) The National Environmental Standards for Freshwater;
(e) Terrane Railway Embankment Seepage Calculation;
(f) Laboratory stormwater quality testing from fully developed Stage
1; and
(g) Hynds information for stormwater treatment devices effectiveness
(downstream defender).
10. Assumptions were based on the following:
(a) Tauranga City Council Infrastructure Development Code;
(b) Tauranga City Council SMG-9 Detailed Stormwater Management
Practice Design;
(c) Tauranga City Council GIS flood extents for Wairoa River;
(d) New Zealand Building Code;
(e) NZ Standard 4404:2010 Land Development and Subdivision
Infrastructure; and
(f) The National Environmental Standards for Freshwater.
27390631_3 4
Statement of Evidence of Ognjan Kralj on behalf of Bethlehem Shores Retirement Village Limited dated 11 March
202111. Priority was given to the Tauranga City Council Infrastructure
Development Code and Tauranga City Council Detailed Stormwater
Management Practice Design as documents produced by the local
governing authority. Other documents were used as a reference if not
specified by the Tauranga City Council Infrastructure Development
Code.
12. The stormwater drainage design for Stage 5 has been developed as
per the New Zealand Building Code:
(a) Stormwater run-off for 10% AEP is to be conveyed by the pipeline
system; and
(b) Stormwater run-off for 2% AEP is to be conveyed by the overland
system (secondary flow paths).
Existing Environment
13. The proposed Stage 5 development area is 6.2 hectares and contains
59 villas, the River Lodge community centre and ancillary structures
located in the Rural Residential Zone and Rural Zone.
14. The following consents have already been obtained for Stage 5:
(a) Bay of Plenty Regional Council Earthworks, Remediate
Contaminated Land and Discharge to Land Consent RM16-0255-
AP (October 2016) for earthworks and the discharge of sediment
contaminated stormwater associated with earthworks for the
development. The consent approved earthworks and the
development area's infill for development. The flood zone's infill
effects analysis shows that the effect is minor due to the
reduction of the floodplain. The calculated increase in flood level
is 10.4 mm across the floodplain and was accepted by the
Regional Council as a minor effect.
27390631_3 5
Statement of Evidence of Ognjan Kralj on behalf of Bethlehem Shores Retirement Village Limited dated 11 March
2021(b) Tauranga City Council Earthworks Resource Consent RC25072
(October 2016) approved earthworks and the development area's
infill to establish a retirement village community. The ground infill
level and the proposed floor levels correspond with Tauranga City
Council requirements for dwellings/property flood protection.
(c) Tauranga City Council Building Consent BC171120 (December
2017) for Civil Works, Stormwater, Sanitary Sewer and Water
Supply. The consent approved the proposed civil infrastructure
(Stormwater, Sanitary Sewer, Water Supply and Roads) for Stage
5.
(d) Bay of Plenty Regional Council Earthworks, Wetland Restoration
and Discharge Resource Consent RM19-0710-AP (December
2019). The consent approved the proposed restoration of
wetland earthworks and stormwater discharge from development
into the wetland. Our engineering report addressed stormwater
discharge from the proposed Stage 5 development into the
wetland, stormwater treatment, and treatment devices that
comply with the National Environmental Standards for Freshwater
based on the proposed devices' performances. Our report also
addresses the loss of floodplain due to infill and assesses that
increase in flood level is 10.4 mm. The flood zone's infill effects
analysis shows that the effect is minor due to the reduction of the
floodplains. Stormwater discharge increase from the existing
development is assessed by analysing the increase in the flow of
the existing railway drain. Our analysis shows that increase of
water level in the existing railway drain is 67 mm in the 1% AEP
storm event, including high tide influence. The increase in the
water level of the existing railway drain is classified as minor.
(e) Tauranga City Council Land Use Resource Consent RC27452
(December 2019). The consent is to undertake earthworks,
including rehabilitation of a Special Ecological Area (wetland).
The existing wetland was filled during previous earthworks and
needed restoration to its previous condition. The Engineering
27390631_3 6
Statement of Evidence of Ognjan Kralj on behalf of Bethlehem Shores Retirement Village Limited dated 11 March
2021Report addresses erosion and sediment transport mitigation
during construction.
15. The effects associated with the stormwater discharge from the
proposed development have therefore already been addressed in these
granted consents through the following measures:
(a) Erosion and sediment transport control during construction
(RM19-0710-DC.01 Condition 5.1);
(b) Erosion and sediment transport control related to stormwater
discharge (RM19-0710-DC.01 Condition 5.3);
(c) Flood level increase due to loss of floodplain (RM16-0255-LC.01
Condition 9.1);
(d) Increase in stormwater discharge due to the development (RM19-
0710 DC.01 Condition 5.4); and
(e) Stormwater discharge quality (RM19-0710 DC.02 Condition 7).
Assessment of Effects and Proposed Mitigation
16. All effects have been considered and addressed under the previously
granted consents RM16-0255 and RM19-0710 as described in
paragraphs 17 to 23 below.
17. It is considered that construction effects would already be adequately
mitigated by the implementation of the Erosion and Sediment Transport
Mitigation Plan (RM16-0255-DC.01).
18. The additional stormwater discharge from the proposed development is
assessed by analysing the exiting railway drain capacity and increase
of water level in the existing drain. I addressed increase of stormwater
discharge from the proposed development in the assessment of effects
(RM19-0710 DC.01 Condition 5.4)
27390631_3 7
Statement of Evidence of Ognjan Kralj on behalf of Bethlehem Shores Retirement Village Limited dated 11 March
202119. The flood level increase due to loss of floodplain was assessed as
being 10.4 mm under the worst-case scenario. As a result of increased
stormwater discharge from the proposed development, it was assessed
that the water level in the existing railway drain would increase by 51
mm for 10% AEP and 67 mm for 1% AEP (RM16-0255-DC.01).
20. The stormwater discharge will be treated from the proposed
development via a stormwater treatment device (downstream defender)
to meet the National Environmental Standards for Freshwater (RM19-
0710-DC.02).
21. The wetland will be restored to its previous condition and will act as a
buffer (detention) for stormwater discharge from the proposed
development. This is because the wetland will minimise the impact of
high-intensity storms' on downstream properties (RM19-0710-LC.01).
22. The proposed energy dissipation outlet will minimise the energy and
velocity of discharge and will prevent erosion in the wetland (RM19-
0710-DC.02).
23. The stormwater treatment (downstream defender) will capture sediment
and suspended solids, ensuring that the quality of stormwater
discharge meets the National Environmental Standards for Freshwater
(RM19-0710-DC.02).
24. The effects of stormwater discharge from the proposed development
are therefore assessed as minor, including in relation to the impact on
downstream properties. This is because the downstream properties
are already in the existing floodplain, and the increase of floodplain
level by 10.4 mm is negligible (RM16-0255-DC.01, RM19-0710-DC.02
and RM19-0710-LC.01).
Response to Submissions
Te Runanga o Ngāti Kahu Incorporated and Wairoa Hapū Settlement Trust
25. Te Runanga o Ngāti Kahu Incorporated and Wairoa Hapū Settlement
Trust (Ngāti Kahu) have submitted that they have concerns about the
27390631_3 8
Statement of Evidence of Ognjan Kralj on behalf of Bethlehem Shores Retirement Village Limited dated 11 March
2021impact the development has had on the downstream flooding of hapū
lands and that the “rehabilitation” of the wetland to service Stage 5 will
further exacerbate the situation.
26. Ngāti Kahu states that they will become the receiving receptors of the
stormwater after it has been through the development’s wetland system
which will create tremendous pressure and responsibility on the hapū to
maintain the waterways.
27. Wetland rehabilitation will have a positive effect. The restoration of the
wetland increases the floodplain volume by approximately 2,500 cubic
meters (that was infilled during earthworks) and acts as a buffer
(detention) for high-intensity storms.
28. The wetland outlet is the existing railway drain that conveys stormwater
run-off to Wairoa River and ultimately to Tauranga Harbour. Our
assessment shows that the existing railway drain has sufficient capacity
to convey stormwater run-off from the proposed development. The
water level in the drain will increase by 51 mm for 10% AEP and 67 mm
for 1% AEP including high tide influence and this is considered to be a
negligible increase.
Response to Officer’s Report
29. The Officer’s Report accepts the previous engineering reports prepared
for the proposed Stage 5 development.
30. The Council Officer concludes at paragraph 8.26 that effects relating to
natural hazard risks, infrastructure services, and additional demand
capacity are considered to be acceptable.
Recommendations for Conditions
31. The Officer’s Report notes that a suite of draft consent conditions will
be circulated prior to the hearing. I will comment on the conditions
where required at the hearing.
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Statement of Evidence of Ognjan Kralj on behalf of Bethlehem Shores Retirement Village Limited dated 11 March
2021Conclusions
32. Based on the calculations for stormwater discharge from the Stage 5
proposed development, I am confident that effects relating to the quality
of discharged stormwater run-off, sediment and suspended solids
transport, erosion protection and attenuating peak discharge flows from
the proposed development will be adequately mitigated.
33. The increased quantities of discharged stormwater run-off are
consented and will have a minor effect on downstream properties
resulting in a 10.4 mm increase in flood level. Recipient water level
(railway drain) increases will be 67 mm in the 1% AEP storm event,
including high tide influence. This is considered to be minor.
Ognjan Kralj
11 March 2021
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Statement of Evidence of Ognjan Kralj on behalf of Bethlehem Shores Retirement Village Limited dated 11
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