Christchurch City Council

Supplementary Agenda

 

 

Notice of Meeting:

An ordinary meeting of the Christchurch City Council will be held on:

 

Date:                                     Thursday 24 August 2017

Time:                                    10am

Venue:                                 Council Chambers, Civic Offices,
53 Hereford Street, Christchurch

 

 

Membership

Chairperson

Deputy Chairperson

Members

Mayor Lianne Dalziel

Deputy Mayor Andrew Turner

Councillor Vicki Buck

Councillor Jimmy Chen

Councillor Phil Clearwater

Councillor Pauline Cotter

Councillor Mike Davidson

Councillor David East

Councillor Anne Galloway

Councillor Jamie Gough

Councillor Yani Johanson

Councillor Aaron Keown

Councillor Glenn Livingstone

Councillor Raf Manji

Councillor Tim Scandrett

Councillor Deon Swiggs

Councillor Sara Templeton

 

 

22 August 2017

 

 

 

Principal Advisor

Dr Karleen Edwards

Chief Executive

Tel: 941 8554

 

Jo Daly

Council Secretary

941 8581

jo.daly@ccc.govt.nz

www.ccc.govt.nz

Note:  The reports contained within this agenda are for consideration and should not be construed as Council policy unless and until adopted.  If you require further information relating to any reports, please contact the person named on the report.
Watch Council meetings live on the web:
http://councillive.ccc.govt.nz/live-stream

 


Council

24 August 2017

 

 


Council

24 August 2017

 

TABLE OF CONTENTS

 

41.     Resolution to Include Supplementary Reports...................................................................... 4

3.2.1  Deputations by Appointment.................................................................................................. 5

STAFF REPORTS

42.     Southshore Floodplain Management Short Term Options................................................... 7

43.     Cost Share Agreement Discussion....................................................................................... 113

28.     Resolution to Exclude the Public......................................................................................... 126


Council

24 August 2017

 

 

41. Resolution to Include Supplementary Reports

1.       Background

1.1          Approval is sought to submit the following reports to the Council meeting on 24 August 2017:

3.2.1.     Deputations by Appointment

42.   Southshore Floodplain Management Short Term Options

43.   Cost Share Agreement Discussion

 44.  Cost Share Agreement Discussions

 45.  Communications Protocol

46.   Development Christchurch Ltd - Update

47.   Communtiy Facilitiy 

1.2          The reason, in terms of section 46A(7) of the Local Government Official Information and Meetings Act 1987, why the reports were not included on the main agenda is that they were not available at the time the agenda was prepared.

1.3          It is appropriate that the Council receive the reports at the current meeting.

2.       Recommendation

2.1          That the reports be received and considered at the Council meeting on 24 August 2017.

3.2.1.     Deputations by Appointment

42.   Southshore Floodplain Management Short Term Options

43.   Cost Share Agreement Discussion

 44.  Cost Share Agreement Discussions

 45.  Communications Protocol

46.   Development Christchurch Ltd - Update

47.   Communtiy Facilitiy 

 

 


Council

24 August 2017

 

 

3.2.1.          Deputations by Appointment

Reference:

17/892524

Contact:

Jo Daly

jo.daly@ccc.govt.nz

941 8581

 

 

Avon-Heathcote Estuary Ihutai Trust

Jo Hooker from the Avon-Heathcote Estuary Ihutai Trust will present a deputation to the Council on item 42:  Southshore Floodplain Management Short Term Options.

 


Council

24 August 2017

 

 

42.    Southshore Floodplain Management Short Term Options

Reference:

17/793802

Contact:

Keith Davison

Keith.davison@ccc.govt.nz

03 941 8999

 

 

1.   Purpose and Origin of Report

Purpose of Report

1.1       The purpose of this report is to inform the Council of the initial feasibility of the OCEL proposal and of potential short term measures to address tidal flooding and rainfall flooding in the area south of Bridge Street along the estuary side of the Brighton Spit.

Origin of Report

1.2       This report is being provided to fulfil Council resolution CAPL/2017/00022 passed on 20 June 2017, being to:

1.2.1   Direct the Chief Executive to report back to Council by 30 August 2017 with an initial evaluation of the feasibility of the OCEL Consultants Ltd's proposal for the Estuary Edge Protection at Southshore, and whether there are any other alternative options for short-term measures to address concerns raised by the community. The report back from the Chief Executive should include what statutory, planning or consenting mechanisms may be required to allow estuary edge protections (of any form) to be legally constructed; and should also include any assessment of the OCEL proposal undertaken by Regenerate Christchurch.

1.3       Council also resolved on 3 August 2017 (CNCL/2017/00176) following the flood event of 21 July 2017 to:

1.3.1   Seek urgent approval for resource consent to continue and complete to a robust standard the bund work created on Friday 21 July to Sunday 23 July 2017 and to extend this work as necessary to prevent seawater inundation along the estuary side of Southshore and the South Brighton Domain to the jetty.

1.4       This report will present options for short term measures that will address both rainfall flooding and seawater inundation (tidal flooding).  It will also present management options to address risks of erosion of any short term works constructed to manage flood risk.

2.   Significance

2.1       The options in this report are of medium significance in relation to the Christchurch City Council’s Significance and Engagement Policy.

2.1.1   The level of significance was determined by the impact that natural hazards could have on the local community and the potential implications for Council of decisions made in this area for other areas within the city also affected by the natural hazards.

2.1.2   Given the very limited time available the community engagement and consultation outlined in this report has been limited to discussions with other agencies, including Environment Canterbury, Regenerate Christchurch and Land Information New Zealand (LINZ).  The views of some members of the community have been expressed via correspondence from the local Southshore Residents Association and through the petition received by Council on 26 July 2017.


 

 

3.   Staff Recommendations 

That the Council:

1.         Receive the Southshore Floodplain Management Short Term Options Report with attachments.

2.         Approve Option 1 - a short term, temporary intervention to reduce flooding risks south of Bridge Street on the estuary side of Brighton Spit, and instruct staff to undertake the work identified in the report to progress this option into construction (noting the need to report back on implementation timeframes and any issues under resolution 4.).

Note: The Council is currently working on a long term Regeneration Strategy for Southshore and South New Brighton in collaboration with Regenerate Christchurch.

3.         That staff engage with Land Information New Zealand (LINZ) and Environment Canterbury to clarify roles and responsibilities in this coastal environment and funding options, noting that the timeframe of this report did not allow staff to fully explore these issues.

4.         Report back to Council at the earliest opportunity the outcomes of these discussions, the implementation timeframes for Option 1 and any issues that arise with pursuing Option 1.

 

 

4.   Key Points

4.1       This report supports the Council's Long Term Plan (2015 - 2025):

4.1.1   Activity: Flood Protection and Control Works

·     Level of Service: 14.1.5 Implement Land Drainage Recovery Programme works to reduce flooding

4.2       The Southshore Inundation Protection Levee Report (OCEL Consultants NZ Limited, December 2016) has been considered and the option presented in the report:

·   Is a typical hard engineered approach to management of tidal flooding

·   Would need further investigation before confirming feasibility

·   Would necessitate other engineering works, such as stormwater management and groundwater management systems, to effectively manage other sources of flooding

·   Would be likely to fail in a future earthquake if not set back from the estuary edge in the order of 50 m – 100 m (as far as Rocking Horse Road in places) or constructed with engineered foundations to reduce risk of failure (with consequential cost impacts)

·   Is useful for the development of options to inform floodplain management plans as part of the multi-hazard investigation

4.3       Approaches other than hard engineering may also be feasible, viable, more adaptable and provide a wider range of benefits.

4.4       Tidal flooding on 21 July 2017 overtopped the estuary edge and flowed through gaps in the existing landscape feature on residential red zoned land.  Emergency works were undertaken to fill low points to reduce the extent of flooding predicted on the following tide.

4.5       There are a range of concerns that have been raised by some members of the community through the Southshore Residents Association, correspondence received by Council staff and the petition to Council that was received on 27 July 2017 (CNCL/2017/00160) including:

·   Coastal flooding

·   Coastal erosion

·   Ecological impacts of emergency works

·   Estuary edge access

·   Maintenance of roads within the Residential Red Zone (RRZ)

4.6       There are a number of different statutory and non-statutory plans that are applicable in the area adjoining the Ihutai / Avon-Heathcote Estuary edge.  Options for physical works will need to consider the regulatory requirements set out within those plans.  Resource consents for the emergency works are needed and any future works would also need a consent.  Access to private land is required to undertake further works in some areas. 

4.7       The following short term options have been developed, to a preliminary stage, to address flooding (and consequential stormwater management), coastal erosion and ecological impacts of the emergency works:

·   Option 1 – Stabilise Emergency Works and Extend to Bridge Street

·   Option 2 – Stabilise Emergency Works (Do Minimum)

·   Option 3 – Stabilise Emergency Works and Extend to the Jetty

4.8       These options are short term and have a design life of 20 years. They would not address groundwater seepage or provide earthquake resilience.  A 20 year period will enable sufficient time for long term planning and adaptation planning to progress without unduly burdening later decision making with significant capital costs.  Any short term works may not be consistent with long term plans that will be developed over the coming years and by enacting the works Council could be tied to ongoing maintenance of the works and additional considerations before it could later remove such works.  Ongoing work on the multi-hazard analysis will inform floodplain management plans.  These plans may suggest alternative alignments or management options.

4.9       Further work is required to:

·   Evaluate the risks associated with enacting the works, for example, further geotechnical assessment is required to understand the risk posed by future earthquakes

·   Discuss with other agencies the potential for assisting with the works

·   Understand how any further defence works fit within Council climate change policies and other projects that will engage with the community around the adaptive management responses to coastal hazards and the effects of sea level rise.  This includes the Coastal Futures project and regeneration planning for South New Brighton and Southshore

·   Improve the costs associated with the works

·   Undertake floor level surveys and hydraulic modelling to better understand the benefits of the works

4.10    Further investigation is required to provide robust advice on any proposed works in this area.  The time required to develop this work will allow discussions with ECan on roles and responsibilities on coastal inundation and erosion.

 

5.   Context/Background

5.1       The Brighton Spit is formed by southward migration of sands within Pegasus Bay and has been in various states of deposition and erosion over time.  The spit has sand dunes on the seaward side that are elevated above sea level.  The western side of Brighton Spit is formed of estuarine deposits and is very low lying, particularly along parts of Rocking Horse Road.

5.2       Prior to the Canterbury Earthquake Sequence starting in 2010 (‘the earthquakes’) numerous private properties extended to the Ihutai / Avon-Heathcote Estuary (the ‘Estuary) edge.  These properties were subject to risk of coastal flooding and erosion.  The response of the individual property owners was to erect varying forms of coastal defences in an ad hoc manner.  Many of these defences were constructed on an unformed legal road, most of which is located within the coastal marine area. 

5.3       As a result of land damage from the earthquakes many of these properties were purchased by the Crown, commonly known as the residential red zone (RRZ).  The RRZ varies in width but is continuous along the spit to as far north as the Council-owned camp ground at Halsey Street, excluding two privately owned properties.  It has been reported that the clearance of these properties and the de-habitation of the land left many residents feeling exposed to coastal hazards.  The existing ad hoc defences are in varying states of dilapidation.

5.4       LINZ formed a low landscaping feature of topsoil as part of ongoing management of the RRZ.  This feature was discontinuous as it did not extend through privately owned land or Council roads.  As a result it was not effective at managing tidal flooding risks.  Figure 1 provides a map of the general area and the extent of options described later in this report.

Figure 1 Map of Project Area Southshore and South New Brighton (North to top)

5.5       Widespread tidal flooding occurred on 21 July 2017 due to overtopping of the Estuary edge as flow passed through the gaps in the landscaping feature and around existing coastal defences at Ebbtide Street.  This included (Figure 2):

·   Areas of Rocking Horse Road between Caspian Street and Tern Street

·   Estuary Road south of Halsey Street

·   Private properties, outbuildings and garages on these and adjoining roads

·   One permanent private residence and one temporary private residence were flooded above habitable floor level

·   Foundations of many properties with some very close to habitable floor level

 

Figure 2 Flooding of Rocking Horse Road (above) and Debris Showing Overtopping of the Estuary Edge at Penguin Street on 21 July 2017

5.6       Water levels of near to 11 m Christchurch District Datum (CDD) in height were recorded in the Estuary.  This level is the highest ever in the 20 years of record at Bridge Street and the 43 years of record at Ferrymead Bridge.  The water level resulted from a combination of king tides, long period offshore waves and a significant storm surge.

5.7       In response to the tidal flooding of 21 July 2017 emergency works were constructed that aimed to significantly reduce the extent of the flooding predicted to occur on the following tide (22 July 2017).  The following low points were filled along Southshore (Figure 3):

·   Council owned roads (heads of cul-de-sacs) at Penguin Street, Heron Street and Tern Street

·   Over privately owned land at 44A and 78 Rocking Horse Road

·   Through South New Brighton Park in the vicinity of the Estuary Road RRZ

 

Figure 3 Emergency Works Near to Penguin Street during Event of 22 July 2017

5.8       In conjunction with temporary pumping these emergency works significantly reduced flooding that might have otherwise occurred on 22 July 2017.  A higher astronomical tide level and wind set up across the Estuary was offset by lower storm surge on 22 July.  The resulting water levels were elevated almost as high as recorded on 21 July 2017.

5.9       Since the 21 July 2017 the works have been partially stabilised with additional compaction, levelling and widening (Figure 4).  Silt fences have been erected to help minimise environmental impact.  Some vegetation loss has occurred due to the works in areas of ecological significance through vehicle movements, placement of the bund and other construction activities.

 

 

Figure 4 Emergency Works in South New Brighton Park

5.10    The purpose of the emergency works was not to address erosion of the Estuary edge within South New Brighton Park (Figure 5).  Prior to the earthquakes attempts had been made to manage erosion of the Estuary edge using engineered coastal defences (reno mattresses).  These defences failed in some areas during the earthquakes through slumping or lateral spreading.  This lowered the top of the mattresses and exposed the bank in areas below high tide level to wave action.  Landward migration of the top of bank is now occurring with some tree loss and the formation of beaches behind the mattresses.  With time these beaches could stabilise and be colonised by plants.  The options described in this report include trial planting areas to assess if areas where beaches have formed (Figure 6) can be stabilised effectively. 

5.11    Ongoing monitoring (site observations and survey) to assess geomorphological changes is needed.

Figure 5 Estuary Edge Erosion within South New Brighton Park

Figure 6 Beach Formation within South New Brighton Park behind Reno Mattress around Park Bench

5.12    There is an area of slightly elevated bank to the north of the campground.  There is a longitudinal crack well back from the top of the bank (Figure 7) indicating instability of the land immediately adjacent to the estuary edge. 

Figure 7 Cracking in the high bank within South New Brighton Park

5.13    Other works are currently underway within South New Brighton Park, including reconstruction of the jetty and boardwalk areas with engineered erosion structures along the Estuary edge to reduce risk of erosion damaging or isolating the newly built Council assets.

Community Concerns

5.14    There are a range of concerns that have been raised by some members of the community prior to and after the recent flooding via the Southshore Residents Association, correspondence received by Council staff and a petition to Council that was received on 27 July 2017:

·   Coastal flooding

·   Coastal erosion

·   Ecological impacts of emergency works

·   Estuary edge access

·   Maintenance of roads within the RRZ

5.15    The wording of the petition was that:

The residents of Southshore write to express our anger and disappointment at the late and inadequate response from Council in relation to flood risk.

The flood events of this weekend highlight what we have been saying to the Council for six and a half years since the earthquake. The previous flood defences on Red Zoned property were demolished and the land scraped and lowered by Red Zone clearance and not reinstated. A new storm water system has been installed to half the community but this inadequate provision is a point of flooding as witnessed in the last few days. Water from the estuary comes up through the drains and floods the street during high tide. Once the high tide has receded the outlets do not allow water to drain out. The temporary bund had gaps in it which lo and behold caused us to flood.

This is a man-made and negligence issue and one that the Council have continued to ignore and deliberately obstruct. We have even offered a solution to try and help which has been met with yet more obstruction. Turning up with diggers after we have flooded is appalling. The time for action is now. As residents of Christchurch we urgently need the City Council to show some long overdue leadership on this issue and we seek urgent, effective remedial action rather than “bandaids”.

The council talk of resilient cities - yet the lack of action by the council is resulting in exactly the opposite and causing immense social upset, mental health issues and stress.

 

OCEL Initial Feasibility

5.16    OCEL Consultants NZ Ltd was approached by the Southshore Residents Association to prepare a report on a levee / berm to protect Southshore from tidal flooding over the Estuary edge.  OCEL proposed (OCEL 2016) a compacted, engineered fill embankment with erosion protection and a plastic sheet pile wall at its core to reduce fluctuations in groundwater level due to the tide (Figure 8).

 

 

Figure 8 Levee / Berm Proposed within OCEL Report (Replicated from Figure 2 OCEL 2016)

5.17    Aurecon New Zealand Limited were engaged by Council to consider the OCEL report (Attachment A – Southshore Inundation Protection Levee Report Evaluation).  Aurecon’s investigation found that OCEL’s proposed levee:

·   Is a hard engineered approach to manage tidal flooding

·   Would need further development and investigation before confirming feasibility

·   Would necessitate other engineering works, such as stormwater management and groundwater management systems, to effectively manage other sources of flooding

·   Would be likely to fail in a future earthquake if not set back from the estuary edge in the order of 50 m – 100 m (as far as Rocking Horse Road in places) or constructed with engineered foundations to reduce risk of failure (with consequential cost impacts)

5.18    The information presented in the OCEL report will be useful for Council in the development of options to inform floodplain management plans as part of the multi-hazard study.  The multi-hazard study will consider a range of potential intervention options, including engineered options (as presented to Council on 27 July 2017).  The OCEL proposal is an example of an engineered option that may be considered in the wider multi-hazard study.  The OCEL option will also inform longer term options for adaption for the effects of climate change and sea level rise to be considered as part of the South New Brighton and Southshore Regeneration Strategy, being developed by Regenerate Christchurch.    Other options and approaches may also be feasible, viable, more adaptable and provide a wider range of benefits.

5.19    Council resolved to continue with the multi-hazard study (CNCL/2017/00175) that will help inform decision on long term floodplain management options.  Any decision to progress with long term options without full consideration of the range of hazards present in this area could lead to maladaptive and perverse outcomes for the community, particularly if hard engineering interventions are pursued. 

5.20    Regenerate Christchurch has not independently evaluated the OCEL proposal.

 

Planning and Consenting Requirements to Enable Estuary Edge Protection Options

5.21    The area adjoining the Southshore estuary edge is within a complex planning environment.  This complexity recognises that the area has multiple values based around the natural and cultural environment, particularly in terms of its coastal location.  The relevant statutory documents that apply, include:

·   the Christchurch District Plan

·   Canterbury Regional Coastal Environment Plan

·   Canterbury Regional Policy Statement

·   the New Zealand Coastal Policy Statement

5.22    Depending on the exact location and type of works, these documents will influence the processes to enable any estuary edge works to be legally constructed.

5.23    The Regional Coastal Environment Plan will apply to any works within the coastal marine area (the area below mean high water springs tide).  This may apply given that the area of any potential works is located in close proximity of the estuary edge.  The Avon-Heathcote Estuary is recognised as an area of significant natural value under the plan.  Activities that are likely to require consent in the coastal marine area include any new structures, destruction, damage or disturbance of the foreshore and seabed, occupation of the coastal marine area and deposition of material.

5.24    On the landward side, the area is affected by a number of zones and overlays under the Christchurch District Plan, including:

·   Zones : Specific Purpose Flat Land Recovery, Open Space Coastal, Open Space Community Park and Residential Suburban;

·   Natural Hazard Overlays:  Liquefaction Management Area, Fixed Minimum Floor Level Overlay within Flood Management Area, High Flood Hazard Management Area;

·   Natural and Cultural Heritage Overlays:  Outstanding Natural Feature, Area of at least High Natural Character in the Coastal Environment, Natural Character in the Coastal Environment, Ngāi Tahu Sites of Cultural Significance (Ngā Tūranga Tupuna and Ngā Wai Coast), Coastal Environment.

5.25    Attachment B (Christchurch District Plan Analysis) an analysis of these zones and overlays.  Resource consent will be required for any works as a result of a number of overlays and the open space zones.  The application will require assessments in relation to ecological, cultural and landscape values and the risks from natural hazards.

5.26    The schematic diagram in Attachment B illustrates the relationship between the different planning environments, broadly showing the relevant plans, zones and overlays.

5.27    The New Zealand Coastal Policy Statement 2010 (NZCPS) will be a relevant consideration for any resource consent, as both the Regional Coastal Environment Plan and the Christchurch District Plan do not fully give effect to the NZCPS.  The Regional Coastal Environment Plan pre-dates the current NZCPS, while the coastal hazard provisions were removed from the replacement Christchurch District Plan process. 

5.28    Being a higher order statutory document, the NZCPS provides direction for the management of and responses to coastal hazards.  There are a number of objectives and policies that would be of particular relevance to any resource consent for estuary edge works.  Policies relating to coastal hazard risk (Policies 24 to 27) discourage hard protection structures and promote use of alternatives including natural defences.  While any strategies for reducing coastal hazard risks in areas of significant existing development promote taking a long-term risk reduction approach when considering options.

5.29    It is noted that, while it will not affect consenting requirements in the near future, there are projects underway to determine future adaptation pathways with coastal communities.  The Coastal Futures project will engage with the community around the adaptive management responses to coastal hazards and the impacts of climate change on coastal settlements and infrastructure across the district.  The South New Brighton and Southshore regeneration planning project, being undertaken with Regenerate Christchurch, will be the ‘pilot’ for the wider project

 

Alternative Short Term Measures and Other Options to Address Natural Hazards

5.30    Council’s resolution of 20 June 2017 (CAPL/2017/00022) requires an evaluation of alternatives for short-term measures to address community concerns.  There are three areas of concern that relate to natural hazards (or arise from addressing tidal flood risk): tidal flooding, rainfall flooding and erosion.

5.31    It is possible to consider these issues separately.  For example, works to reduce the risk of tidal flooding can be constructed away from the estuary edge so erosion of the Estuary edge can be treated separately, except in cases where the erosion puts at risk the tidal flooding measures.   Erosion reduction measures can be carried out independently of tidal and rainfall flooding works.  However, works to reduce tidal flooding will have an impact on rainfall flooding / stormwater management, primarily, blocking of overland flow paths.  These impacts will need to be managed in order to avoid adverse effects.  Also, any works to address rainfall flooding may not be completely effective if tidal flooding is not managed.

5.32    Measures to address these three issues are the topic of a report prepared for Council by CH2M Beca Ltd (Attachment C – Southshore Short Term Floodplain Management Options) (Beca 2017).

5.33    The options to address the tidal flooding concerns were in development when the flooding event of 21 July 2017 occurred.  The emergency works enacted as a result of this flooding are very similar in nature to the short term measures being considered. The subsequent Council resolution on 3 August 2017 (CNCL/2017/00176) provides approval to extend the emergency works to the jetty within South New Brighton Park and to complete the bund to a robust standard. 

5.34    The options presented in this report to address tidal flooding are based upon varying lengths of northward extension of the emergency works.  In all options some work would be required to stabilise and enhance the emergency works through landscape treatment of the exposed fill.  Covering the bunds with top soil and grass will reduce the risk of erosion of the bund and limit sediment laden runoff from discharging to the Estuary.  A walking track of a similar nature to the Te Ara Ōtākaro Avon Trail would be proposed in areas where pedestrian access is expected and where reasonable transitions can be made to other areas with walking tracks, for example, adjoining the Jellicoe Marsh but not necessarily in areas south of Ebbtide Street as the tracks would be discontinuous.  Tree removals would be required in the extension areas.  The number and location of trees affected would be established in subsequent design stages but is likely to include mature trees.

5.35    The design for any extension would be similar to the new lengths of stopbank being constructed alongside the Avon River as part of the Land Drainage Recovery Programme Avon River Temporary Stopbank Management Project.  The design is for an engineered fill bund with topsoil and grass cover on top of a shallow foundation that would be constructed to a height of no less than 11.2 m CDD (the water level recorded in the Estuary during the 21 July event was approximately 11m CDD).  As with the Avon stopbank project the design life would be approximately 20 years and would not provide groundwater control beneath the stopbank.  The bund would not be designed to resist ground movement, e.g. lateral spread.  It is expected that significant remedial works would be required following a seismic event.

5.36    Further investigations are required to understand the likely earthquake event that would initiate lateral spread or cause settlement of any extension works.  This would inform an assessment of the likelihood of this event occurring during the functional life of the works and the risks associated with failure of the works.  It is possible that remedial works could be enacted to repair any earthquake damage following a seismic event and prior to a significant storm event or that the design could provide some earthquake resilience.  These investigations are required to enable the provision of robust advice on the options as the cost of inclusion of earthquake resilience within the design could significantly increase costs of the works.  Earthquake resilient designs could include features such as geotextile wrapping of layers of fill within the embankment or lateral spread resistant foundations.

5.37    Providing infrastructure with a short term design life would allow the long term planning process to proceed and also provide time for funding for long term works to be considered.  A low capital expenditure reduces the risk of the capital cost associated with this decision prohibitively restricting any future options however further work is required to understand potential failure modes and the risks that these present to the communities benefited by the works, such as groundwater seepage or earthquake related land damage. 

5.38    Although these works will have a short term design life, there is a risk that expectations of permanent tidal flood defence will result from a decision to proceed with these works.  This may impact on future options and decisions to alter or introduce a new adaptation pathway that shifts away from solely engineering defence as would be delivered with the extension of the emergency works.  Council has powers under the Christchurch District Drainage Act 1951 in relation to the construction and maintenance of defences against water (and drainage infrastructure).  This legislation will impact on decisions and options around any new flood defences.  Environment Canterbury also has powers in relation to minimising and preventing damage within its district by floods and erosion, under the Soil Conservation and Rivers Control Act 1941, and the Council should discuss future measures with them.

5.39    Monitoring and management of coastal erosion is also required to reduce the risk of the tidal flooding works being eroded.  The nature and extent of management activities can vary with distance between the Estuary edge and the bund.

5.40    North of Ebbtide Street there is a large distance between the potential bund alignment and the Estuary edge.  Given that the intervening distance is part of the park a potential approach is to establish an Estuary edge monitoring and management programme to provide an effective and adaptive way of managing the erosion risk.  Existing reno mattresses could be retained and some tree loss would be expected with time.  Pilot planting areas would be required to confirm the viability of beach formation in the local environment.  The existing path would have to be relocated in short sections if the erosion progresses beyond the existing alignment.  The general principle would be for a natural estuary edge and this would result in some landward migration of the top of bank.  This approach is in accordance with the South New Brighton Reserves Management Plan and Development Plan that was consulted on and adopted by a hearings panel on 31 March 2014 and resolved by the Burwood-Coastal Community Board on 3 June 2014.

5.41    A slightly different approach to risk of erosive failure of the bund is possible south of Ebbtide Street.  Additional planting in areas where the berm between the bund and the Estuary edge is narrow is an alternative to more hard engineering.  Some additional erosion management works would be required at the ends of the cul-de-sacs where the bunds are very close to the Estuary edge.  This is likely to require a geotextile layer being placed beneath the existing rock armouring.

5.42    Erosion management works would be required to reduce the risk of the bund being eroded and in large areas a naturalised edge would be preferred.

5.43    The construction of a bund will interfere with overland flow paths between Rocking Horse Road and the Estuary that will activate in extreme rainfall events.  To remediate this impact and maintain the existing level of flood risk it would be preferred to excavate areas of the emergency bund and install structures with stop logs.  The stop logs can be removed if flood levels become elevated behind the bund.  Temporary pumping will need to be installed if there is rainfall at the same time as elevated Estuary water levels.  Construction of pump laydown areas and some new stormwater manholes will be undertaken to facilitate the temporary pumping activities.

5.44    Remedial works will be required in areas where enacting the emergency work caused significant vegetative loss, particularly in areas adjoining the Jellicoe Salt Marsh (on the southern end of the South New Brighton Park).

5.45    Two longer term options were also considered by Beca (CH2M Beca 2017): rebuild and realignment.  These options include significantly greater works with construction of a new bund along much of the study area either along a similar alignment or an alignment near to the back of the RRZ.  The additional costs for these options are large and they are not considered to be short term measures.  As with the OCEL proposal there is a risk of perverse or maladaptive outcomes with investment of this scale prior to completion of long term planning.  It is proposed to pass this information to Regenerate Christchurch so that they can consider these options within their South New Brighton and Southshore regeneration planning process.

5.46    Detailed hydraulic modelling and floor level surveys have not been undertaken to inform the assessment of options within this report.  Further work is required to give greater certainty on the benefits of the potential options.

 

Addressing Other Community Concerns

5.47    Other concerns raised by the community, including:

·   The condition of road related assets within some streets adjoining the RRZ

·   Maintenance of side roads

·   Ineffective vehicle barriers and prolonged surface water ponding on Ebbtide Street

·   Public access along the entire Southshore Estuary frontage.

5.48    Council resolved on 10 December 2015 (Item 14) to alter the status of some roads adjoining the RRZ to limit maintenance costs in areas where full service was no longer required.  Many streets were classified as ‘Out of Service – Decommissioned’.  As a result, this street is not being maintained at a full service level.  The state of Ebbtide Street and Tern Street, in particular, are a cause of concern for some residents.  Long term planning for the Southshore RRZ is underway and the future of these roads will be considered as part of that process.  Any repair of streets and footpaths in areas that service only RRZ could be wasted if the future use of the land is altered.  It is not recommended that repair of these assets be undertaken until the long term planning process is completed.

5.49    Minor repair of any damage caused during the enacting of the emergency works will be undertaken in the short term.

5.50    Issues related to maintenance of side roads have been forwarded to the Council operations team to consider.  Issues relating to vehicle access barriers have been identified to LINZ.

5.51    Public access along the Estuary frontage is currently restricted at two locations where privately owned land extends to the Estuary edge.  It may be possible to create public paths on the unformed legal road on which the Estuary edge currently sits.  The aim of these paths would be to permit pedestrian access past these points, however this would require works within the Coastal Marine Area, with subsequent consenting challenges.  Further concept design and investigative work, including discussions with LINZ, would be required prior to making a recommendation on this matter.  As with road maintenance in the RRZ any works of this type may be inconsistent with long term plans.

 

6.   Option 1 - Stabilise Emergency Works and Extend to Bridge Street

Option Description

6.1       This option would see the emergency bund span low points in the existing topography within South New Brighton Park (pink line in Figure 9) and stabilisation of the emergency works.  This would provide a reduction in risk of tidal flooding for properties within South New Brighton and Southshore.  Extending the bund would offer a uniform approach to tidal flood risk that would be consistent with upstream areas of the Ōtākaro / Avon River.  Construction of a bund with a design life of up to 20 years will allow time for long term planning processes to develop.  Future decisions on floodplain management could require moving or abandoning the bund if a differing adaptation pathway is found to be preferred.

Figure 9 Potential Extension of Emergency Bund in Parts of South New Brighton Park (North approximately to the left)

6.2       It is estimated that there are a large number of low lying homes and properties within South New Brighton and Southshore (Table 1).  Approximately 36 houses with floor levels estimated below 10.8 m RL are within the area benefited with this option.  This does not represent the total numbers of houses and properties at risk as it is unlikely that there would be sufficient volume of tidal inundation overtopping the estuary edge to fill to this level.  Debris marks from the 21 July 2017 event have been surveyed at levels between 10.62 m CDD and 10.87 m CDD.  The floor levels have been estimated based upon building age and have not been surveyed.  Floor level surveys and detailed hydraulic modelling would improve the assessment of benefits.

Table 1 Estimated Number of Benefited Houses and Properties

Level (m Christchurch District Datum)

Number at Risk

Estimated Houses with Floor Level at Risk

Estimated Properties at Risk (Land not Houses)*

10.8

36

343

11

161

633

* Based upon estimate average level of the land within a property.

6.3       This option also includes the monitoring and management of the Estuary edge erosion to varying degrees and the rainfall flooding approach as outlined above.  A summary of the option is presented in Table 2.

6.4       The total budget for this option has been estimated at approximately $2.0 million +/- 40%.  The confidence in the cost estimates will increase as the design develops.


 

Table 2 Option 1 Components

Item

Northern Area

Southern Area

Tidal Flooding

§ Build a new bund through park behind Campground connecting to high ground near jetty

§ Build a new bund behind Seafield Pl

§ Bund alignments as per South New Brighton Reserves Management Plan and Development Plan

§ Both bunds finishing similar to Avon temporary stopbanks (topsoil, grass with crusher dust top), minimum level RL11.2 m

§ Landscape works to existing bund in saltmarsh area

§ Landscape treatment existing only - topsoil, grass and crusher dust top in some areas

Bund Erosion

§ Monitor and maintain to protect bund

§ Keep existing reno mattresses

§ Remove trees as required

§ Move path in future if required

§ Pilot planting areas in existing beach formation areas

§ Monitor and maintain to protect bund

§ Geotextile and rock on bund at road ends

§ Additional planting in areas where berm between bank and bund is narrow

Rainfall Flooding

§ Stop logs to allow drain down

§ Construct new manholes where existing sumps/manholes aren’t suitable for temporary pumping

§ Formalise temporary pump locations

§ Stop logs to allow drain down

§ Formalise temporary pump locations

§ Swale in Residential Red Zone draining to road ends

 

Significance

6.5       The level of significance of this option is medium and is consistent with section 2 of this report.

6.6       Engagement with the community was undertaken to inform the South New Brighton Reserves Management Plan and Development Plan.  Feedback from the community prompted this report.  Consultation with the community might be required to inform resource consent applications for these works.

Impact on Mana Whenua

6.7       This option does involve a significant decision in relation to ancestral land or a body of water or other elements of intrinsic value, therefore this decision does specifically impact Ngāi Tahu, their culture and traditions.  Engagement with Ngāi Tahu would be required to inform resource consenting of the works.  The area is of high cultural significance.

Community Views and Preferences

6.8       A large proportion of the local community are specifically affected by this option as illustrated above in Table 1.  Some of the community’s views have been expressed through their local residents association, within the petition and other correspondence received by Council.  There are a range of views within the community on the various values of the area.

Alignment with Council Plans and Policies

6.9       This option is largely consistent with Council's Plans and Policies, and Community Outcomes, including the South New Brighton Reserves Management Plan.   This option may be inconsistent in part with some policies in the Christchurch District Plan.  These do not require amendment as the option would be assessed against the provisions of the plan through the resource consent process under the Resource Management Act. 

Financial Implications

6.10    Cost of Implementation – The construction cost for this option has been estimated at $1.6 million.  A budgetary provision of $2.0 million +/- 40% which provides for project contingency, design costs and project management / support costs.  Costs for contaminated land, access to and restoration of private land, groundwater seepage and ground improvement is not provided for within the budget.  Costs would be re-estimated at the completion of detailed design.

6.11    Approximately half the cost estimate is for the extension of the bund through South New Brighton Park.  The remaining costs are associated with stabilising and mitigating the adverse effects of the emergency works.  Landscaping and planting of the bund through Jellicoe Marsh, providing a walking trail, planting areas for erosion risk reduction, rock armouring at the road ends, construction of stop logs and stormwater manholes to facilitate stormwater pumping are the key components of these potential works that contribute to the cost estimate.  The costs of top soiling and grassing of the emergency works is only a small component of the cost estimate. 

6.12    There is cost risk associated with the findings of compaction testing of the emergency works.  Some lengths of the emergency works may require additional compaction to meet the required design life.

6.13    Maintenance / Ongoing Costs – Ongoing monitoring and management of the Estuary edge is required in this option.  This would require ongoing funding but will be dependent on the frequency and severity of storm events.  As such ongoing costs are reactive in nature and very difficult to quantify.

6.14    Funding source – Capital costs would be met from within the Land Drainage Recovery Programme.  This project is not currently specified as a line item within the Long Term Plan.  Some budgetary balancing will be required in order to fund the capital investment.  There is potential to utilise budget from the LDRP508 Lower Avon River Stopbanks Preliminary Design project, LDRP521 Avon Floodplain Management Implementation and LDRP524 EQ Waterway and Retic Repair to fund these works. 

6.15    The proposed expenditure on these projects would have otherwise delivered planning and design associated with the Avon River Floodplain Management project in advance of decisions on the Ōtākaro / Avon River Corridor RRZ.  There will be a period of time next financial year where this design work could be progressed in advance of the planned final decision on future use of the RRZ.  It is likely that construction of any Ōtākaro / Avon River permanent stopbanks will take many years and any delay in starting their construction will be immaterial in comparison to other programme risks.  Also the current works on the temporary stop banks will increase their longevity beyond a likely construction completion date.

6.16    A cost share agreement of some description with LINZ may be possible with regards to the works within crown-owned land.

6.17    Ongoing monitoring and maintenance costs will fall within existing operational budgets for park, roading and land drainage maintenance. 


 

Legal Implications

6.18    Resource consents will be required to enact the works from Council.  A determination on works within the Coastal Marine Area is being sought from Canterbury Regional Council (ECan).  Emergency works were enacted on private and crown owned land.  Access agreements will be sought from those parties.

6.19    Roles and responsibilities for coastal erosion and inundation management need clarification with ECan.  The governing acts include the Land Drainage Act 1908 (LDA), Christchurch District Drainage Act 1951 (CDDA), the Soil Conservation and Rivers Control Act 1941 and the Local Government Acts 1974 and2002.  These acts set out the responsibilities of the Council as a Drainage Board and ECan as a Catchment Board.  ECan has responsibility to “minimise and prevent damage within its district by floods and erosion” within Christchurch and to exercise a general supervision of Drainage Board (i.e. the Council) with respect to the powers conferred under the CDDA.  The Council’s powers under the CDDA (and LDA) can be exercised in relation to watercourses and drains, but also banks and defences against water.  Engagement with ECan is required as to how these various acts have been interpreted historically and presently, and how they could impact the options presented in this report, presently and in the future.

Risks and Mitigations   

6.20    There are a number of risks associated with enacting these works from both engineering and social standpoints.

6.21    Risk of flooding caused by system failure, overtopping during events that are larger than the design capacity, storm event erosion or operational deficiency (e.g. the stop logs are not removed) remains.  This will result in flooding of streets, properties and potentially some homes.

6.21.1 Treatment: Ongoing operational management of the network is fundamental to ongoing flood management.  Response plans are already in place and will need to be continued.

6.21.2 Residual risk rating: the rating of the risk is low given the nature of the potential system.

6.22    Failure of the works could occur during an earthquake or through a groundwater seepage induced geotechnical failure (i.e. a piping failure) as the design options discussed in this report do not mitigate these risks.  Regular inundation of the toe of the works will not occur within the design life of the short term works so failures resulting from groundwater seepage are low.

6.22.1 Treatment: Ongoing monitoring of seepage beneath the works and maintenance of the works following an earthquake.  Monitoring during extreme storm events will be a method to identify seepage paths beneath the works.  This could identify areas where remedial works are necessary.  Extension of the current stopbank inspection procedure would be an important tool to confirm any change in crest height over time or during an earthquake.  Remedial works could be undertaken to top up the works, if required.

6.22.2 Residual risk rating:  Given the infrequent required operation of the works it is likely that there will be sufficient time following an earthquake to enact remedial works, however, further investigative effort is required to understand the residual risk associated with this approach.

6.23    There is a risk that long term planning is not resolved (e.g. plans are not agreed or funding is not available) within the design life of the works or the outcomes of the plans diverge from the outcomes of this decision.

6.23.1 Treatment: Ongoing maintenance of the works will be required and a detailed risk assessment will be needed if the temporary works are to remain beyond 20 years.

6.23.2 Residual risk rating: the rating of the risk is low given the specified design life.

6.24    It is possible that exposure to other hazards will diminish the benefits achieved through these works.  For example, is it possible that groundwater levels could rise with sea levels and that properties will suffer from groundwater water inundation.

6.24.1 Treatment: Hazard assessments continue within the LDRP 97 Multi-Hazard project and long term decision making be progressed within the 20 year design life.

6.24.2 Residual risk rating: the rating of the risk is low given the specified design life.

Implementation

6.25    Implementation dependencies - There are no dependencies with starting the design and consenting work.  Resource consents would be required prior to starting physical works.

6.26    Implementation timeframe – Delivery of the project would be dependent on the determination of the resource consent level of notification.  It is expected that the project could be completed this financial year.

Option Summary - Advantages and Disadvantages

6.27    The advantages of this option include:

·   Able to be delivered in the short term

·   Is adaptive as it can easily be modified in the future

·   Consistency with the Council resolution of 3 August 2017 (CNCL/2017/00176)

·   Reduces the risk of tidal flooding in extreme events to up to an estimated 343 properties and 36 homes

·   Consistency with the South New Brighton Reserves Management Plan and Development Plan

·   Provides a consistent treatment of flooding risks to all properties on the spit

6.28    The disadvantages of this option include:

·   The budget has been estimated at approximately $2.0 million +/- 40%

·   Greater cost than the Stabilise Emergency Works (Do Minimum) Option

·   Reliant on ongoing maintenance and wet weather responses

·   Tree removals and vegetation clearance would be required

·   Risk of limiting future decisions on floodplain management or necessitating ongoing maintenance from Council beyond the original design life

 

7.   Option 2 - Stabilise Emergency Works (Do Minimum)

Option Description

7.1       This option includes only the stabilisation of the emergency works as they stand today.  This option does not extend the works to the north through South New Brighton Park.  Stabilisation of the bund with a design life of up to 20 years would allow time for long term planning processes to develop. 

7.2       It is estimated that there are a large number of low lying homes and properties within South New Brighton and Southshore (Table 3).  Approximately 17 houses with floor levels estimated below 10.8 m RL are within the area benefited by these works.  This is 19 houses fewer than Option 1.


 

Table 3 Estimated Number of Benefited Houses and Properties

Level (m Christchurch District Datum)

Number at Risk

Estimated Houses with Floor Level at Risk

Estimated Properties at Risk (Land not Houses)*

10.8

17

202

11

93

308

* Based upon estimate average level of the land within a property.

7.3       This option also includes the monitoring and management Estuary edge erosion to varying degrees and the rainfall flooding approach as outlined above.  A summary of the option is presented in Table 4.

7.4       The total budget for this option has been estimated at approximately $1.0 million +/- 40%.  The confidence in the cost estimates will increase as the design develops.

Table 4 Option 2 Components

Item

Northern Area

Southern Area

Tidal Flooding

§ Landscape works to existing bund in saltmarsh area

§ Landscape treatment existing only - topsoil, grass and crusher dust top in some areas

Bund Erosion

§ Monitor and maintain to protect bund

§ Monitor and maintain to protect bund

§ Geotextile and rock on bund at road ends

§ Additional planting in areas where berm between bank and bund is narrow

Rainfall Flooding

§ None

§ Stop logs to allow drain down

§ Formalise temporary pump locations

§ Swale in Residential Red Zone draining to road ends

 

Significance

7.5       The level of significance of this option is medium and is consistent with section 2 of this report.

7.6       This option would leave a section of the community exposed between the areas of tidal flooding works.  Consultation with the community might be required to inform resource consent applications for the potential works.

Impact on Mana Whenua

7.7       The Impacts on Mana Whenua associated with Option 1 apply to this option.

Community Views and Preferences

7.8       A large proportion of the local community are specifically affected by this option as illustrated above in Table 1.  Their views have been expressed through their local residents association and within the petition received by Council.  Reducing the extent to less than Option 1 may cause some concern amongst residents who are not offered the same level of service.

Alignment with Council Plans and Policies

7.9       The commentary associated with Option 1 applies to this options.

Financial Implications

7.10    Cost of Implementation – The construction cost for this option has been estimated at $0.8 million.  A budgetary provision of $1.0 million +/- 40% which provides for project contingency, design costs and project management / support costs.  Costs for contaminated land, access to and restoration of private land, groundwater seepage and ground improvement is not provided for within the budget.  Costs would be re-estimated at the completion of detailed design.

7.11    The costs are associated with stabilising and mitigating the adverse effects of the emergency works.  Landscaping and planting of the bund through Jellicoe Marsh, providing a walking trail, planting areas for erosion risk reduction, rock armouring at the road ends, construction of stop logs and stormwater manholes to facilitate stormwater pumping are the key components of these works that contribute to the cost estimate.  The costs of top soiling and grassing of the emergency works is only a small component of the cost estimate.

7.12    The other commentary on financial implications associated with Option 1 applies to this option.

Legal Implications

7.13    The legal implications associated with Option 1 apply to this option.

Risks and Mitigations   

7.14    The risks associated with Option 1 apply to this option.

Implementation

7.15    Implementation dependencies - There are no dependencies with starting the design and consenting work.  Resource consents would be required prior to starting physical works.

7.16    Implementation timeframe – Delivery of the project would be dependent on the determination of the resource consent level of notification.  It is expected that the project could be completed this financial year.  The construction period for this option would be less than Options 1 and 3.

Option Summary - Advantages and Disadvantages

7.17    The advantages of this option include:

·   Able to be delivered in the short term

·   Is adaptive as it can easily be modified in the future

·   Reduces the risk of tidal flooding in extreme events to up to an estimated 202 properties and 17 homes

·   Consistency with the South New Brighton Reserves Management Plan and Development Plan

·   This is the lowest cost option

7.18    The disadvantages of this option include:

·   Inconsistency with the Council resolution of 3 August (CNCL/2017/00176)

·   Does not provide a uniform approach to all properties within the study area

·   The budget has been estimated at approximately $1.0 million +/- 40%

·   Reliant on ongoing maintenance and wet weather responses

·   Tree removals and vegetation clearance would be required

 

8.   Option 3 - Stabilise Emergency Works and Extend to the Jetty

Option Description

8.1       This option includes stabilisation of the emergency works as they stand today and extending these works as far north as the Jetty within South New Brighton Park (pink line in Figure 10).  Stabilisation of the bund with a design life of up to 20 years will allow time for long term planning processes to develop. 

Figure 10 Potential Extension of Emergency Bund in Parts of South New Brighton Park (North approximately to the left)

8.2       It is estimated that there are a large number of low lying homes and properties within South New Brighton and Southshore (Table 5).  Approximately 21 houses with floor levels estimated below 10.8 m RL are within the area benefited by the potential works.  This is 15 houses fewer than Option 1 and 4 more than Option 2.

Table 5 Estimated Number of Benefited Houses and Properties

Level (m Christchurch District Datum)

Number at Risk

Estimated Houses with Floor Level at Risk

Estimated Properties at Risk (Land not Houses)*

10.8

21

252

11

109

437

* Based upon estimate average level of the land within a property.

8.3       This option also includes the monitoring and management Estuary edge erosion to varying degrees and the rainfall flooding approach as outlined above.  A summary of the option is presented in Table 6.

8.4       The total budget for this option has been estimated at approximately $1.4 million +/- 40%.  The confidence in the cost estimates will increase as the design develops.


 

Table 6 Option 2 Components

Item

Northern Area

Southern Area

Tidal Flooding

§ Build a new bund through park behind Campground connecting to high ground near jetty

§ Bund alignments as per South New Brighton Reserves Management Plan and Development Plan

§ Both bunds finishing similar to Avon temporary stopbanks (topsoil, grass with crusher dust top), minimum level RL11.2 m

§ Landscape works to existing bund in saltmarsh area

§ Landscape treatment existing only - topsoil, grass and crusher dust top in some areas

Bund Erosion

§ Monitor and maintain to protect bund

§ Keep existing reno mattresses

§ Remove trees as required

§ Move path in future if required

§ Pilot planting areas in existing beach formation areas

§ Monitor and maintain to protect bund

§ Geotextile and rock on bund at road ends

§ Additional planting in areas where berm between bank and bund is narrow

Rainfall Flooding

§ Stop logs to allow drain down

§ Construct new manholes where existing sumps/manholes aren’t suitable for temporary pumping

§ Formalise temporary pump locations

§ Stop logs to allow drain down

§ Formalise temporary pump locations

§ Swale in Residential Red Zone draining to road ends

 

Significance

8.5       The level of significance of this option is medium and is consistent with section 2 of this report.

8.6       This option would leave a section of the community exposed between areas of tidal flooding works.  Consultation with the community might be required to inform resource consent applications for these works.

Impact on Mana Whenua

8.7       The Impacts on Mana Whenua associated with Option 1 apply to this option.

Community Views and Preferences

8.8       A large proportion of the local community are specifically affected by this option as illustrated above in Table 1.  Their views have been expressed through their local residents association and within the petition received by Council.  Reducing the extent to less than Option 1 may cause some concern amongst residents who are not offered the same level of service.

Alignment with Council Plans and Policies

8.9       The commentary associated with Option 1 applies to this option.

Financial Implications

8.10    Cost of Implementation – The construction cost for this option has been estimated at $1.1 million.  A budgetary provision of $1.4 million +/- 40% which provides for project contingency, design costs and project management / support costs.  Costs for contaminated land, access to and restoration of private land, groundwater seepage and ground improvement is not provided for within the budget.  Costs will be re-estimated at the completion of detailed design.

8.11    The other commentary on financial implications associated with Option 1 applies to this option.

Legal Implications

8.12    The legal implications associated with Option 1 apply to this option.

Risks and Mitigations   

8.13    The risks associated with Option 1 apply to this option.

Implementation

8.14    Implementation dependencies - There are no dependencies with starting the design and consenting work.  Resource consents would be required prior to starting physical works.

8.15    Implementation timeframe – Delivery of the project would be dependent on the determination of the resource consent level of notification.  It is expected that the project could be completed this financial year.  The construction period for this option would be less than Options 1 and greater than Option 2.

Option Summary - Advantages and Disadvantages

8.16    The advantages of this option include:

·   Able to be delivered in the short term

·   Is adaptive as it can easily be modified in the future

·   Consistency with the Council resolution of 3 August (CNCL/2017/00176)

·   Reduces the risk of tidal flooding in extreme events to up to an estimated 252 properties and 21 homes

·   Consistency with the South New Brighton Reserves Management Plan and Development Plan

·   Lower costs than the Option 1

8.17    The disadvantages of this option include:

·   Does not provide a uniform approach to all properties within the study area

·   The budget has been estimated at approximately $1.4 million +/- 40%

·   Reliant on ongoing maintenance and wet weather responses

·   Tree removals and vegetation clearance would be required

·   Risk of limiting future decisions on floodplain management or necessitating ongoing maintenance from Council beyond the original design life

 

Attachments

No.

Title

Page

a

Southshore Inundation Protection Levee Report Evaluation

33

b

Christchurch District Plan Analysis

40

c

Southshore Short Term Floodplain Management Options

41

 

 

Confirmation of Statutory Compliance

Compliance with Statutory Decision-making Requirements (ss 76 - 81 Local Government Act 2002).

(a) This report contains:

(i)  sufficient information about all reasonably practicable options identified and assessed in terms of their advantages and disadvantages; and

(ii) adequate consideration of the views and preferences of affected and interested persons bearing in mind any proposed or previous community engagement.

(b) The information reflects the level of significance of the matters covered by the report, as determined in accordance with the Council's significance and engagement policy.

 

Signatories

Authors

Thomas Parsons - Surface Water Engineer

Debbie Hogan - Team Leader City Planning

Approved By

Keith Davison - Manager Land Drainage

John Mackie - Head of Three Waters and Waste

Richard Osborne - Head of Planning and Strategic Transport

Peter Langbein - Finance Business Partner

David Adamson - General Manager City Services

  


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24 August 2017

 

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Council

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43.    Cost Share Agreement Discussion

Reference:

17/877654

Contact:

Brendan Anstiss

Brendan.anstiss@ccc.govt.nz

941 8999

 

 

1.   Purpose and Origin of Report

Purpose of Report

1.1       The purpose of this report is to seek Council approval to updated arrangements between the Crown and the Christchurch City Council under the Cost Sharing Agreement (CSA).

Origin of Report

1.2       This report is staff generated following discussions between senior Council and Crown officials. 

2.   Significance

2.1       The decision(s) in this report are of medium significance in relation to the Christchurch City Council’s Significance and Engagement Policy.

2.1.1   The level of significance was determined by assessment of the impact of the primary decisions sought at the current juncture.  Many of the more substantive decisions have already been determined through the existing 2013 Cost Sharing Agreement (with the exception that additional land is proposed to transfer to the Council) and as such, all of the capital expenses are already budgeted for and have been consulted upon since at least the 2015 Long Term Plan (and all subsequent Annual Plans).   

2.1.2   However, it is acknowledged that with land ownership confirmation, operational costs will also begin to be incurred.  While some of these costs are already in operational budgets (and hence have already been consulted upon through successive Annual Plans), cost related to maintenance for the residential red zoned land is not.  This will need to be addressed through the 2018 LTP – which gives a further opportunity for community consultation. 

2.1.3   There is also a possibility that Regenerate Christchurch will at some point seek to develop a Regeneration Plan for future use of all or part of this land.  If this occurs then Regenerate Christchurch will thoroughly engage with the public and any affected parties in the subsequent development of any Regeneration Plan. 

2.1.4   Reflecting this level of significance (and the consultation that has occurred to date), no community engagement and consultation has explicitly occurred for the purposes of this paper.

2.1.5   In determining the level of significance, consideration has also been made to what reasonably practicable alternative options may be available to Council (beyond the staff recommendation).  It is not considered reasonable practicable that the Council not follow the general arrangements specified in the CSA (2013), and therefore – if Council does not accept the staff recommendations – the status quo will remain (i.e. the 2013 CSA still stands).  We will still have a legal arrangement between the Crown and Council on sharing costs, however, will need to resolve issues on a clause by clause, and schedule by schedule basis.  This is not recommended by staff, but is a legitimate option to Council if it chooses not to follow the staff recommendation.   


 

 

 

3.   Staff Recommendations 

That the Council:

1.         Notes that Council and Crown officials have discussed updated arrangements to the Cost Sharing Agreement which was originally signed in 2013, and have now proposed to Council a package that clarifies payments and ownership related to the Bus Interchange, central city public realm (Margaret Mahy Family Playground and Ōtākaro/Avon River Precinct), and residential red zoned land in the Port Hills, Brooklands, and Southshore. 

2.         Notes that the proposal is consistent with all capital expenditure forecast by the Council, but includes the transfer of additional assets, namely, all Port Hills red zoned land, plus Brooklands and Shoreshore Red Zoned land purchased by the Crown, and full Council ownership of the Bus Interchange.

3.         Notes that the Council has not previously budgeted for operating costs for the residential red zone assets and if this proposal is accepted this will need to be addressed. 

4.         Notes that the proposal would result in the Council ultimately owning the Bus Interchange, the Margaret Mahy Playground, the Ōtākaro/Avon River Precinct assets, and all of the residential red zoned land purchased by the Crown in the Port Hills, Brooklands, and Southshore – a total of 1,261 properties.

5.         Approves the proposed update to the Cost Sharing Agreement with the Council paying up to a total of $75m for ownership of the Bus Interchange (land and buildings $23m), residential red zoned land in the Port Hills (land only $39m), Brooklands (nil), Southshore (nil), Margaret Mahy Playground (assets only $6.6m – land already in Council ownership) and Ōtākaro/Avon River Precinct (assets only excluding the Earthquake Memorial Wall remaining in Crown ownership - $6.4m). 

a.         Approves pursuant to section 12 of the Local Government Act 2002 the purchase from the Crown of:

i.          The Bus Interchange land and buildings at the consideration referred to above, such land to be held for the purposes of a public bus interchange

ii.         All the Crown-owned residential red zone land in the Port Hills, Brooklands, and Southshore at the consideration referred to above, subject also to Resolution 9 below, such land to be held by the Council for the purpose of identifying future uses for the land.

iii.        The Margaret Mahy Playground and Ōtākaro/Avon River Precinct assets at the consideration referred to above.

b.         Approves the transfer to the Council of relevant contractual rights associated with the above land and buildings and assets (including warranties and guarantees relating to buildings and infrastructure).

c.         In order to implement these resolutions, delegates to the Property Consultancy Manager (in respect to land transfers) and the Head of Parks (in respect of assets) the authority to negotiate, enter into, implement and enforce such agreements with the Crown on such terms and conditions as he shall consider necessary or expedient to purchase the above land and assets and to transfer any contractual rights relating to such land and assets to the Council.

 

6.         Approves that any technical changes to give effect to the above resolution be agreed by the Mayor as required, including the timing of any transfer and exact quantum of payment, subject to the budgets and timing already determined through Council’s 2017 Annual Plan. 

7.         Approves that a project team will be established to undertaken the necessary due diligence work with DPMC and LINZ to successfully transfer the agreed assets; finalise the operating and maintenance arrangements and costs; and that the ongoing maintenance costs associated with the residential red zone land will be incorporated in the 2018 LTP. 

8.         Approves pursuant to section 12 of the Local Government Act 2002 the sale by the Council of any of the properties identified in Appendix A (attached to this report) at no less than market value (with a tolerance of up to 10% on the downside) as determined by a registered valuer appointed by the Council, and

a.         Delegates to the Property Consultancy Manager the authority to take such steps as he considers necessary or expedient to maximise value (where practical and possible), to prepare and market those properties for sale, and to dispose of them (including the power to negotiate, enter into, implement and enforce agreements for sale and purchase with third party purchasers), and

b.         Authorises the Property Consultancy Manager, for reasons of practicality, to depart from the Council’s policy of tendering all properties for sale so long as the process adopted is open, transparent and public.  The Council notes that there is no intention to amend the policy to accommodate this decision.

9.         Notes that the project team will report back to Council as necessary to recommend decision making around future options, including options such as public works, roading corridors, hazard mitigation, amalgamation with parks or open public spaces, or other community uses (including those desired by the relevant Papatipu Rūnanga).  The first report back is expected in approximately March 2018.  

 

 

4.   Key Points

 

4.1       As a result of the Canterbury earthquakes, Christchurch City suffered significant damage to land, buildings, infrastructure and civic assets.  The Crown and the Council entered into a Cost Sharing Agreement (CSA) in 2013. The purpose of the CSA was to agree the respective responsibilities and financial contributions of the Crown and the Council in relation to the repair and ownership of horizontal infrastructure, anchor projects, and red zone land.

 

4.2       Given the time that has elapsed since the original agreement was signed, and with the progress of many of the anchor projects and infrastructure repair, the parties have been in discussions on implementing the intent of the CSA.

 

4.3       These discussions have occurred at senior official’s level between the Council and the Crown. 

 

4.4       We are now at a point where officials have agreed to jointly submit to their respective decision makers (Council and Cabinet) a proposal.  The proposal must be agreed by both parties to become effective.  The proposal is a complete package and will need to be renegotiated if either the Crown or Council declines any individual aspect of the proposal.    

 

 

5.   Cost Sharing Agreement Refreshed Proposal

 

5.1       The focus of the CSA discussions has been on the ownership, cost, and transfer timing, for the central city Bus Interchange, central city public realm, and the Port Hills, Southshore (and a very small section of South New Brighton around Admirals Way / Evans Ave) and Brooklands residential red zone (refer Appendix B for maps of the residential red zone locations).

  

5.2       Other issues, such as the respective Crown and Council financial contribution to the Multi-Purpose Arena / Stadium (the Council has its $253m / 50% contribution on budget for 2022 onwards); ownership of the Avon / Otakaro residential red zone; and operation of the Convention Centre are out of scope for this proposal.  If necessary, officials will discuss any relevant issues on these matters in due course.  

 

5.3       Crown and Council officials therefore propose - as a package - the transfer of the following Crown assets and land to the Council, with respective payment by Council:

 

Asset/land to be transferred

Comment in comparison with 2013 CSA

The Bus Interchange (for $23m)

·     Consistent with planned financial contribution from the Council

·     Confirms CCC ownership of Bus Interchange

·     Timing of operational transfer to be determined

Port Hills red zone land (for $39m) – includes 597 properties in total (404 rockfall/rock roll properties and 190 cliff collapse properties, 3 other)

·     Consistent with planned financial capital contribution from the Council

·     Additional land to be transferred from the Crown to the Council, i.e. cliff collapse properties and rockfall properties not adjacent to Council reserve 

·     The Council will own all red zoned properties on the Port Hills

·     Timing of operational transfer to be determined

Brooklands red zone land (at no cost)

 

·     The 2013 CSA did not make any commitments on final ownership of Brooklands red zone land.

Southshore red zone land (at no cost) – includes in total with Brooklands 664 properties)

·     As above, the 2013 CSA did not make any commitments on final ownership of Southshore red zone land

Central City public realm (Margaret Mahy Family Playground plus Ōtākaro/Avon River Precinct for $13m)

·     Consistent with planned financial contribution from Council (at $6.6m and $6.4m respectively)

·     Confirms CCC ownership of these assets

·     Timing of operational transfer to be determined (for both land and assets)

5.4      The exact and final financial contribution may vary slightly from the above figures (but still within approved budget).  For example, the Port Hills red zone estimate of $39m includes forecast land insurance settlements from EQC to the Crown (not yet finalised).  Similarly, the final figure for the Bus Interchange is net of NZTA proceeds (already paid to the Crown) and net of the two super stops (at approximately $6m), hence the reduction from $29m (in the 2013 CSA) to $23m currently.   

5.5      Further technical implementation details, including the timing of any asset transfers, and timing and final amount of any payments, will be further considered by a project team of senior staff from the Council, DPMC and LINZ.  Subject to Council approval, officials will provide advice jointly to the Mayor and Minister to make any further technical decisions to give effect to this proposal.  The first joint report back is not expected until November 2017 (to give time for a Government to form and Ministerial portfolios to be allocated).

6.   Financial Implications

6.1      There are three separate components of the financial implications; (1) capital costs; (2) operating (maintenance) costs; and (3) temporary project operating costs.

6.2      Capital costs

6.2.1  The Council has on budget the full capital costs for this proposal ($75m).  This includes the Port Hills land payment (on balance sheet), Margaret Mahy Family Playground (on balance sheet), Ōtākaro/Avon River Precinct (budgeted 17/18), and the Bus Interchange (budgeted 18/19 [this timing reflects the Crown’s financial commitments / appropriations for the Bus Interchange – it was originally on Council budgets earlier]). 

6.2.2  The Council is expecting to pay approximately ½ of the total cost for the Port Hills residential red zone to the Crown prior to the end of the 2017 calendar year.  This will be subject to an appropriate invoice from the Crown.  This payment is budgeted for and staff will therefore process the invoice as appropriate. The timing of other capital payments to the Crown will occur within existing and approved Council budgets, generally commensurate with the transfer of assets (including any remaining payments for Port Hills residential red zone).

6.3      Operating (maintenance) costs

6.3.1  The Council has on budget operating costs for the Margaret Mahy Family Playground and the Ōtākaro/Avon River Precinct (combined, $950k). 

6.3.2  The Council has operating costs for the Bus Interchange of $307k (net, after revenue) commencing in 2019/20.  Due diligence will need to be undertaken to determine for Council the gross operating costs of this facility, the revenue opportunities, securing the NZTA subsidy (which is not available to the Crown), and the resulting net cost.  Council staff will advise if there is any need to seek an adjustment to the existing Bus Interchange operating budget. 

6.3.3  Operating budgets do not currently exist to cover Council maintenance costs for the residential red zone land.  The Crown currently pays for maintenance, security (esp where there are still clearances taking place), and rates (to Council).  This is approximately $1.2m p/a for the Port Hills, Brooklands and Southshore.  However, it is expected that the operational expenditure may be higher when the land transfers to Council as the public expects a higher level of service for some park lands compared to red zoned land. 


 

6.3.4  It is proposed that staff undertake a joint due diligence exercise to accurately determine the Council maintenance costs for any residential red zoned land to be transferred to Council.  This exercise will consider the Council direct maintenance costs, plus if there are any alternatives such as community maintenance, amalgamation with Council reserves already maintained by existing groups / Trusts, or transfer of some land if desired by relevant Papatipu Rūnanga.  The necessary budgets for this activity will then be factored into the 2018-28 LTP.

6.3.5  At this stage, no consideration or allowance has been made for any additional hazard remediation of residential red zone land (although Council decisions pertaining to Southshore are pending).  Council, the Crown, and private land owners have already completed some hazard removal and remediation – most significantly on the Port Hills.  There are some categories of land where remediation may technically be feasible, but at this stage it is proposed that this be considered as part of the due diligence to be undertaken and reported back to Council in due course. 

6.4      Project Operating costs         

6.4.1  It will be necessary to establish a dedicated team to manage the transfer of the assets as proposed, to complete all necessary legal formalities and conveyancing (for in excess of 1,000 individual titles), determine future maintenance costs, engage with neighbouring and interested private parties, and determine future use options.  It is estimated that this project will exist for at least 2 years, commencing immediately.    

6.4.2  Given that Council has not budgeted for this activity, it is proposed that proceeds from land sales be used to fund as necessary the project costs.  These are expected to occur in each of 2017/18 and 2018/19.  Funding the project costs in this manner will require an early transfer from the Crown of land that can be sold for development.  In total, it is estimated that up to 70 of the property titles (out of a total of 1,261 [about 5% of all properties]) can be developed in the near future (as the hazard has been mitigated, the building platform is outside the risk area, or a boundary change would segment the risk).  These properties are detailed in Appendix A.  No work has yet been undertaken on the expected market value of these properties – they are likely to range in value from nil (e.g. for properties where Council have already built a bund) to residential market value for some locations that can be immediately developed in areas such as Scarborough and Sumner.  The 2016 Land Value of these properties is approximately $1.6m.  A Council decision to dispose of suitable properties to enable the project funding is therefore included.  There is a low risk that sales revenue will not cover the project team costs.  If there is any indication of this risk emerging staff will report to Council with a proposed course of action.  

6.4.3  Any sales proceeds in excess of the amount needed to cover costs will be used to reduce Council’s rate funded borrowing requirements.    

6.4.4  An alternative will be to fund the project costs from rates via the LTP, commencing on 1 July 2018 at the earliest. This would significantly delay the project commencing and impose a cost on rate payers. 

7.   Legal Implications

7.1      Legal Services have inputted into the development of this paper.  There will be an ongoing need for legal input as there are a range of technically complicated issues related to transfer, disposal, and future use options for much of the land.


 

8.   Other Issues

8.1      Crown officials are considering the implications of the recent Quake Outcasts Court of Appeal judgment on private property owners in the residential red zone.

8.2      The Crown will retain all responsibility for resolving issues related to the Quake Outcasts decision, including any subsequent impacts on property owners within the residential red zone who have not sold to the Crown.

 

Attachments

No.

Title

Page

a

List of 70 Port Hills properties that may be sold

120

b

Maps - 3 areas

122

 

 

Confirmation of Statutory Compliance

Compliance with Statutory Decision-making Requirements (ss 76 - 81 Local Government Act 2002).

(a) This report contains:

(i)  sufficient information about all reasonably practicable options identified and assessed in terms of their advantages and disadvantages; and

(ii) adequate consideration of the views and preferences of affected and interested persons bearing in mind any proposed or previous community engagement.

(b) The information reflects the level of significance of the matters covered by the report, as determined in accordance with the Council's significance and engagement policy.

 

Signatories

Author

Brendan Anstiss - General Manager Strategy and Transformation

Approved By

Brendan Anstiss - General Manager Strategy and Transformation

  


Council

24 August 2017

 


 


Council

24 August 2017

 

PDF Creator


 

PDF Creator


Council

24 August 2017

 

PDF Creator 

 

  


Council

24 August 2017

 

 

28.  Resolution to Exclude the Public

Section 48, Local Government Official Information and Meetings Act 1987.

 

I move that the public be excluded from the following parts of the proceedings of this meeting, namely items listed overleaf.

 

Reason for passing this resolution: good reason to withhold exists under section 7.

Specific grounds under section 48(1) for the passing of this resolution: Section 48(1)(a)

 

Note

 

Section 48(4) of the Local Government Official Information and Meetings Act 1987 provides as follows:

 

“(4)     Every resolution to exclude the public shall be put at a time when the meeting is open to the public, and the text of that resolution (or copies thereof):

 

             (a)       Shall be available to any member of the public who is present; and

             (b)       Shall form part of the minutes of the local authority.”

 

This resolution is made in reliance on Section 48(1)(a) of the Local Government Official Information and Meetings Act 1987 and the particular interest or interests protected by Section 6 or Section 7 of that Act which would be prejudiced by the holding of the whole or relevant part of the proceedings of the meeting in public are as follows:


Council

24 August 2017

 

 

 

ITEM NO.

GENERAL SUBJECT OF EACH MATTER TO BE CONSIDERED

SECTION

SUBCLAUSE AND REASON UNDER THE ACT

PLAIN ENGLISH REASON

WHEN REPORTS CAN BE RELEASED

44

Cost Share Agreement Discussions

s7(2)(b)(ii)

Prejudice Commercial Position

Commercial sensitivity - Due to possibility of asset disposal and to not prejudice Council commercial position

When commercial decision is made

 45

Communications Protocol

s7(2)(i)

Conduct Negotiations

Commercial negotiations are continuing in respect of a transaction involving the Crown, the Council and two Council-related entities

Once all parties to the transaction agree, the Council's Chief Executive decides there is no further reason for withoholdng the information.

46

Development Christchurch Ltd - Update

s7(2)(b)(ii), s7(2)(f)(ii), s7(2)(h), s7(2)(i)

Prejudice Commercial Position, Protection from Improper Pressure or Harassment, Commercial Activities, Conduct Negotiations

Briefing includes commercial matters

At a time to be determined by General Manager Finance and Commercial when the information is no longer confidential

 47

Communtiy Facilitiy

s7(2)(b)(ii), s7(2)(i)

Prejudice Commercial Position, Conduct Negotiations

Negotiations with the Crown are ongoing.

25 August 2017

OR With the agreement of the Crown