CONFIDENTIAL
MAYORAL FLOOD TASKFORCE
BRIEFING PAPER 22 May 2014
Temporary Flood Defence Measures
Ministerial Briefing TEMPORARY FLOOD DEFENCE MEASURES 1
Purpose
This briefing has two objectives: •
To provide the Crown with an interim report on the immediate and short term flood reduction and mitigation measures outlined in the Temporary Flood Defence Measures: Technical Report Final Draft 1 ahead of the meeting of Earthquake Recovery Committee of the Whole on 5 June 2014.
•
To propose specific actions the Crown may wish to consider supporting the Council in delivering these short term solutions.
2
Summary of key short term proposals
The taskforce has identified several key areas where the government could work with the Council to address the immediate impact on households affected by flooding as a result of Canterbury Earthquake sequence. The Council also notes that the City faces medium to long term hazard mitigation choices that may include infrastructure, physical works, regulatory and planning controls, land purchase, and possible retreat. These latter processes are likely to require a continued joined up approach, building on the work of the Joint Steering Group on Flood Management. 2.1
Short term assistance for worst affected households •
Earthquake Support Co-ordinators Request that the Canterbury Earthquake Temporary Accommodation Service (CETAS) agree to extend its services to households impacted by earthquakerelated flooding.
•
Earthquake Temporary Village Request the Ministry of Building, Innovation and Employment to recommend changes to Cabinet, to the eligibility criteria for tenancy within the Earthquake Temporary Village(s) to accommodate people dislocated by the effects of flooding due to earthquake damage to their property.
•
Temporary Relocation / accommodation support Work with the Council and insurers to develop a financial assistance/relocation package to assist people who are required to leave their homes as a result of repeated inundation, which has made their homes uninhabitable, or where the health risks associated with continued occupation cannot be addressed in an acceptable timeframe.2
1
www.ccc.govt.nz/cityleisure/projectstoimprovechristchurch/landdrainage/taskforce.aspx Eligibility criteria to be developed based on property and social vulnerability matrix and applicability of individual property defence measures 2
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2.2
Resourcing and collaboration • Continued support for an open and transparent relationship and data sharing between CERA, EQC, and CCC to actively problem solve these householders impacted as a result of the recent flood events, where the impact of the earthquakes has been a contributing factor to their new circumstances. •
Ensure the SCIRT work programme is properly aligned and co-ordinated with the Land Drainage Recovery Programme (LDRP) and any short term flood protection measures being undertaken.
•
Provide CCC access to red zone dwellings for pilot house protection demonstration project.
•
Consider establishing a joint CCC/Crown short term flood defence fund in the order of $2m to provide a fund for rapid implementation of minor flood mitigation measures for properties subject to Increased Flooding Vulnerability (IFV) as a result of the Canterbury Earthquakes where immediate benefits can be realised. These measures could include house level or neighbourhood protections. Other interventions Appendix B, and Appendix C identify respectively the direction being adopted by the Council and the Summary of the Taskforce Recommendations. The latter provides a comprehensive list of possible interventions, while focussed on the short term, also begins to identify the medium and long term options available for Council. While largely operational and physical in nature, the longer term mitigation will require a stronger policy response notably through the District Plan. As noted above there is considerable opportunity for the Crown to support and assist Council through these processes, and the role of the Joint Steering Group on Flood Management is acknowledged. The outputs and ideas contained in Appendix C will both inform some of the immediate operational responses the Council will make, and provide options (amongst others) for the long term management responses.
2.3
Regulatory •
Seek the assistance of the Ministry of Business, Innovation and Employment to investigate ways in which the Building Act 2004 could be amended to require the floor level of a building to be raised where that property is subject to increased flooding vulnerability, as a result of earthquake damage to the land and or buildings.
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Briefing Contents Part A 1. Scope and dependencies 2. Earthquake contribution to flooding 3. Update on data and work programme
Part B Proposals Appendices A. Taskforce Stage One Rating Valuations ( confidential to stakeholder organisations) B. Temporary Flood Defence Measures: Technical Report Summary of Recommendations C. Summary of Temporary Accommodation Options analysis and costs D. Resolution of the Extraordinary Meeting of the Earthquake Recovery Committee of the Whole: 12 May 2014
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Part A Background The Land Drainage Recovery Programme (LDRP) was established by the Council in May 2012 to investigate earthquake effects on the city’s waterways and identify options for restoration of pre-earthquake flood hazard. These options are often large scale physical works which may take years to implement. The Flockton-Dudley area had been the subject of a significant amount of work due to the flooding in 2013, and two options were being considered to mitigate the risk of further flooding. A major storm hit Christchurch on 5 March 2014. The Minister for Canterbury Earthquake Recovery inspected the flood damage with the Mayor. They were jointly briefed the following day on possible engineering solutions for the Flockton/Dudley area. The Minister offered assistance including necessary regulatory interventions by way of a Private Bill. Government funding assistance was mentioned but not discussed in detail. The Dudley Creek Post earthquake remediation options were developed for the Council’s consideration on 27 March 2014. The resolution was that staff: •
commence an appropriate level of engagement with the community that will inform them of the benefits, risks and issues associated with the options;
•
work with key stakeholders, Canterbury Earthquake Recovery Authority, the Insurance Council, Ministry of Building, Innovation and Employment, the Earthquake Commission and Environment Canterbury on the options available to support the earliest delivery of the remediation works in the context of the wider flood risks for the city;
•
continue to finalise the cost estimates for each option, identify any funding issues and possible options to address these; and
•
continue to scope the remediation option for the remaining areas of the city that have heightened risk as a result of the earthquakes to ensure that council has a comprehensive understanding of the total scope of the programme.
Public engagement sessions on 2 and 3 April 2014 made it clear that there were major omissions from the work programme: •
What happens in the meantime? With two years required to implement either solution or a combination of both, there had to be an intermediate step otherwise people’s homes would continue to be at risk of flooding.
•
Some homeowners were having pressure put on them to settle with EQC/insurer, but they didn’t know whether they should proceed. What about floor levels?
•
Options for people had to be realistic that would definitely protect their houses. Or they needed to be able to get out (temporarily or permanently);
•
Unrealistic expectations were evident. Some people believe that they are entitled to a lot more from EQC for land damage than EQC is likely to pay and that they don’t need to apply this to mitigation (e.g. increasing floor levels).
•
People believe that the government can ‘red zone’ property, and that they can negotiate a compensation package of more than 2007 rating valuation.
Council staff were asked to undertake more work on these issues. Two weeks later (Easter weekend) there was more flooding. An urgent meeting of Council staff was called by the
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Mayor on Wednesday 23 April to emphasise the urgency to produce those intermediate solutions and to ensure that the other areas that were affected by flooding were being addressed as well. The establishment of the Taskforce was reported to the Council meeting on 24 April with a full public announcement of the Terms of Reference on 29 April (the day of yet another flood).
1.
Taskforce scope and dependencies
The Mayoral Flood Taskforce (the Taskforce) was formally announced on 29 April 2014. Its purpose was to investigate options for temporary flood protection of residential floor levels and to address the impacts of repeated flooding on affected households. The Taskforce builds on work already underway to improve the performance of the drainage system since the earthquakes. The first draft report was tabled at an Extraordinary Meeting of the Earthquake Recovery of the Whole on May 12.3 It set out a range of solutions, including “quick fixes” for each catchment area based on engineering assessments of the main causes and contributory factors leading to flooding in each of the targeted catchments.4 A number of these projects are already in train and others will be delivered within weeks rather than months. The 18 area-by-area assessments and mitigation/prevention/avoidance options for each were made public on the CCC website on 19 May. These assessments explain the history, extent and causes of flooding in each of the priority catchments.. In each of these catchments the report recommends the preferred mix of short term measures: in some instances short term localised engineering protection measures are favoured because they can be actioned quickly and benefit groups of homes; in other cases the Taskforce recommends property level measures, such as raising floor levels or wrapping. None of the short term solutions proposed for Flockton would obviate the need to consider more extensive permanent engineering measures for Dudley Creek.5 Staff recommendations on the Dudley Creek options will be made at the Earthquake Recovery of the Whole on 5 June 2014. This brief does not address the potential for permanent relocation or voluntary purchase offers. However it is possible that some temporary measures may become permanent once the cost benefit analysis of area wide mitigation solutions has been completed. The development of a policy framework and criteria for such an offer forms part of the Joint Steering Group on Flood Management’s work programme and will be reported on at a later date.
2.
The contribution of earthquake damage to flooding problem
The Taskforce’s mandate was to identify quick fixes and short term solutions for the worst affected households regardless of the primary cause or mix of contributory factors. The earthquake sequence in Canterbury has caused significant changes to the topography of the land in Christchurch. This has changed the flood vulnerability for a number of properties due to on-site changes in ground levels. Flood vulnerability has also changed due to the off-site changes to the piped network, streams/rivers and floodplains affecting the predicted flood levels. Some houses have also settled on their foundations due to the earthquake effects making them more vulnerable to flooding. Flood risks have also changed
3 4 5
See Appendix D. www.ccc.govt.nz/cityleisure/projectstoimprovechristchurch/landdrainage/taskforce.aspx Details of when released and web address
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on the Port Hills with increased land instability issues, particularly in periods of heavy rainfall.6 The increased levels of flood risk that can be fully attributed to the earthquakes have been caused by: • land settlement • foundation settlement • lateral spreading of land, particularly near waterways • liquefaction events that have changed the nature of the underlying ground conditions and reduced capacity in waterways • damage to the drainage infrastructure • increased risk of slope instability. The Technical report has identified that there are catchments where the primary cause of the flooding may not be directly related to the earthquake, namely: • a series of heavy rain events with land already saturated • scale of the March event and large amount of debris that entered the waterways • inadequate infrastructure in parts of the city and instances of inadequate maintenance • lack of timely repair to earthquake damage leading to lack of capacity in storm events. The Technical Report considered the Dudley/Flockton, Lower Avon, Lower & Upper Heathcote, Heathcote Valley, Little River, Lyttelton, Southshore and Sumner catchments and identified three levels of vulnerability: 1. two or more instances of flooding of dwelling floors since the earthquakes 2. two or more instances of flooding under the dwelling since the earthquakes 3. two or more instance of flooding restricting resident access to the dwelling since the earthquakes CERA’s request for more precise estimates and quantification of the expected costs and benefits of each of the recommended short term solutions impacted by different rainfall events forms part of the modelling work being undertaken by the second phase of the Taskforce to inform the Council’s decisions on June 5. This information will be shared with CERA as soon as it has been reviewed by the project governance group. Preliminary valuation information Council staff have estimated the rateable value (2007 & 2013) of the 53 properties believed to be most severely impacted by flooding in the last four heavy rainfall events.7 The Capital Value of the 53 properties currently confirmed as Level 1 was $19 million in 2007 and $21.3 million in 2013. These estimates will change as properties are ground-truthed and as information from residents in the catchments is collected and validated over the coming weeks. For example, if the final number of Level 1 properties were to rise to 85, the Capital Value would rise to approximately $34 million based on the 2013 valuation. 6
The degree to which the earthquake damage has worsened recent flooding across the city varies. The flooding in Little River is not considered to have been worsened due to the earthquakes. In Lyttelton the effects are secondary, where the greater debris volume since the earthquakes has resulted in blockages leading to flooding. In other areas such as the Upper and Lower Heathcote, and Heathcote Valley, the earthquake effect is limited to damage to pipe and stream networks. Dudley Creek (Flockton), Southshore and the Lower Avon all have flooding which has clearly been worsened by the earthquakes. This primarily relates to land damage making it harder for properties to drain, and also to damage to the drainage network. 7 Three properties were removed after being identified as businesses, one because it was an empty section.
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EQC EQC has identified up to 9,000 Christchurch properties that potentially meet the criteria for increased flooding vulnerability (IFV) “as a result of the earthquake series due to on-site subsidence.” It intends to ground truth this estimate through property by property inspections over the coming months.8 It is likely that the 53 properties identified as being most severely impacted will also be within the 9000 properties identified by EQC as being at increased flooding vulnerability. EQC is also seeking a declaratory judgment on legal questions about whether land damage cover by EQC includes financial loss caused by increased flooding vulnerability; and if that loss is covered, how to calculate the financial loss. The High Court is appointing a lawyer to be a "Friend of the Court" to argue for the interests of the people of Canterbury.9 EQC has also advised that repairs to 309 properties are currently on hold within the Canterbury Home Repair Programme because the property has been identified as potentially having increased flooding vulnerability land damage.10 However we are not aware that private insurers have adopted a similar approach. For these reasons the question of how risk and liability will finally be apportioned between homeowner, insurers (EQC and private) and the Council cannot be determined with any certainty until all data has been validated and cross matched and the declaratory judgment has been issued.
3.
Update on Taskforce Data and Work programme
Background Christchurch has experienced a period of high rainfall not felt since 1970s. Frequent large rainstorms have fallen across the city resulting in saturated ground, high river/stream flows and flooding of a number of habitable floor levels, properties and streets. In addition, the flood risk – in terms of both frequency and severity of flooding – has changed for a number of properties following the series of earthquakes. The Land Drainage Recovery Programme (LDRP) was established by the Council to investigate effects of the earthquakes on the city’s waterways and identify options for restoration of pre-earthquake flood risk. These options include large scale physical works which may take years to implement. The Mayoral Flood Taskforce (the Taskforce) was established on 1 May 2014 to investigate options for temporary flood protection of residential floor levels, and to address the impacts of repeated flooding on affected households, before decisions are made on the long term options being assessed through the LDRP.
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EQC has been working with Christchurch City Council to identify whether there are area-wide offsite flood mitigation works that could be undertaken to remove the flooding vulnerability or at least reduce it to pre-quake levels. Where these schemes can be identified, costed and completed in a timely manner then EQC has indicated it is open to contributing as a way of resolving some IFV claims. 9
Provisional legal advice to the Council is that there does not seem to be any operational or regulatory reason for the Council to join as a party to that High Court case. 10
EQC has advised these owners that they may either: • Have their property repaired through the CHRP programme ahead of the confirmation of their land damage, or • Receive a cash settlement and manage their own repairs, or • Remain on hold within the CHRP programme until such time as their land damage has been confirmed and they can make a more informed choice.
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Flood impact analysis categories Level One:
Two or more instances of flooding of dwelling floors since the earthquakes – 56 properties11
Level Two:
Two or more instances of flooding under dwellings since the earthquakes – 471 properties
Level Three: Two or more instances of flooding restricting residents access to dwellings since the earthquakes – 487 properties. Data collection, collation and validation During Phase 1 of the Taskforce, 56 properties were identified as falling within the parameters of Vulnerability Level 1. Following an internal review process this was reduced to 53 properties. Since the release of the Phase 1 Taskforce draft report, Council has received over 150 calls from people identifying their house as falling within the definition of Vulnerability Levels 1 to 3. Many of these calls may relate to houses already identified in the Phase 1 report. The second phase of the Taskforce will verify final numbers for the different vulnerability levels. It was always expected that the number of Vulnerability Level 1 houses would change, but it was not possible to quantify this until the findings were publicised. It is anticipated that the number of Vulnerability Level 1 houses will likely remain less than 85. Less certainty is available for Levels 2 and 3. Initial assessment of vulnerability As of Wednesday 21 May 2014, 45 of the 53 Level 1 properties identified in Phase 1 of the engineering review had been contacted in person by Council staff as part of the initial data validation process. Of these respondents:
19 were still living in flood-affected homes.
16 people/families have moved out of their house.
3 people did not provide an answer.
19 dependent children are living in nine of the habited homes.
2 respondents aged over 65 have already moved out of their property into temporary accommodation.
8 people with disabilities and health issues are still living in their respective houses.
5 people with disabilities or health needs have temporarily moved out of their home.
3 families are still living in their flood affected house and would like temporary relocation/financial support.
In addition to this more than 150 homeowners have contacted the Council directly. Provisional analysis shows:
40 callers have had water above floor levels at least once.
Many have reported health problems including children with respiratory conditions.
Many have reported financial hardship as a result of living in temporary accommodation.
These cases will cross-matched against the Level 2 and 3 Taskforce data and the information provided by the resident's groups as part of Phase two. 11
Revised to 53 as of 21 May 2014
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A Community Advisory group has been established to inform and assist the work of the Flood Taskforce. The group is made up of residents and Community Board members from affected areas and supported by the Community Advisor, Mayor's Office This group will assist the Taskforce with the collection of information about flood-damaged properties in their area, the identification of vulnerable residents and provide a network for communication between flood-affected residents and the Taskforce. Return Periods12 The primary purpose of storm water management is to reduce the frequency of flooding to a defined level of service. The storm water network is designed to contain: • 5 year average return interval storm for most of urban Christchurch • 20 year average return interval storm for hill waterways • 50 year average return interval storm for new Greenfield developments. There have been multiple storm events strike the city since the Canterbury earthquakes. Analysis of the rainfall during these storm events shows that rainfall depths of 75mm or more over 40 hours triggers flooding within the city, particularly within the Flockton Street area. There have been three of these rainfall events this year alone along with the previous events in August 2012 and June 2013, which also triggered flooding. It is difficult to place a single 'return period' on these storm events due to the uneven distribution of rainfall and the wide variance in flood responses within Christchurch catchments and the relatively short length of river flow records. However analysis of the records within the city show that the March storm was a major event for rainfall and flood flow. The Avon and Heathcote rivers reached their highest flows in 35 year and 24 year respective periods of detailed records. The other storm events that have triggered flooding have been at or below a 10 year rainfall event for the centre of Christchurch. Quick fixes and timeframe for interventions Physical works have commenced including dredging, stream widening, temporary pump stations, tree removal and housing tanking trials. The following timeline graphically illustrates the interventions that have occurred since the beginning of the Canterbury Earthquake series in September 2010.
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Return intervals of flows or flood levels in the river are location specific. Locations upper catchment respond to short high intensity events - and these may cause a minor effect in the lower river channel. Points in the channels in the lower catchment respond to the longer duration events - when all of the catchment is contributing to that location. These longer duration events are generally of a lower intensity and which cause very few flooding effects in the upper catchments. The flow at a particular location in the catchment also depends on the dampness in the catchment prior to the event and the status of natural or man-made storage in the catchment The river flow at any given location also integrates the variable rainfall distribution across the upstream catchment. Return intervals of specific rainfall intensities therefore have only an indirect effect on the return interval of the flow or level at a specific location. Rainfall is none-the-less often used as crude indictor of river flow return interval in the absence of better information.
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Part B: Proposals Regulatory Purpose-designed building consent The problem in relation to buildings that have increased flooding vulnerability is that insurers are only raising a buildings floor level where the buildings foundations are being fully replaced or the insurer is building a new dwelling for their client. Where earthquake damage to a foundation is being repaired there is no requirement to raise the floor level of the dwelling even if it is subject to increased flooding vulnerability. This is leading to dwellings being repaired and completed in areas of global settlement that now flood. The Building Act 2004 process described below (section 17 and section 112 additions and alterations to a building) prescribes the extent to which Council can require upgrades to existing buildings. Triggers for the requirement to undertake building work The Building Act 2004 requires a Council to issue a building consent for ‘building work’. There are basically two situations that the Building Act allows for: 1.
Building work to construct a new building - this is where the entire building is new building work and therefore the whole building will comply with the Building Code.
2.
Alterations to existing buildings – this is where parts of a building is changed through proposed building work, and the proposed building work is required to comply with the building code (not the whole building).
All repairs to earthquake damaged buildings fall in the alteration category, therefore the Council is restricted to what is required through section 112 of the Building Act. Section 112 of the Building Act only allows the Council to request an upgrade to the building in relation to means of escape from fire and access and facilities for people with disabilities. For housing the upgrade requirements means installing smoke detectors. The second part of section 112 requires the rest of the building to continue to comply to at least to the same extent as it did before the application for the building consent was made. This would be its damaged state after the earthquake. From this section of the Building Act a council is unable to require a building to be repaired or raised to an acceptable level to prevent flooding, unless of course the building is considered dangerous and a notice issued. Most residential dwellings needing repair will not be dangerous. It is worth noting that in some instances floor levels were actually lowered where the scope of work required the floor to be levelled without triggering a consent; this was beside the Heathcote River and may have contributed to floor levels being breached. (This is still being verified.) Issue 1.
In some examples the insurance industry have not undertaken an adequate damage assessment, therefore the scope of work to repair may be incorrect in some cases or the subject of increased flooding vulnerability has not been taken account of in the assessment (possibly due to extended timeframes).
2.
Misunderstanding about what an insurance contract actually requires, repairs versus a complete rebuild.
There are several areas within the Building Act 2004 that could be changed or altered in such a way as to require the floor level of a building to be raised where that property is subject to increased flooding vulnerability. There are limited options on how the legislation
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could be amended, either by OIC or powers in the CER Act; both would need Government approval. Assistance from the Ministry of Business, Innovation and Employment would be required. Recommendation •
Seek the assistance of the Ministry of Business, Innovation and Employment to investigate ways in which the Building Act 2004 could be amended to require the floor level of a building to be raised where that property is subject to increased flooding vulnerability.
Short term assistance for worst affected •
Earthquake Support Co-ordinators Request that the Canterbury Earthquake Temporary Accommodation Service (CETAS) agree to extend its services to households impacted by earthquake-related flooding.
•
Earthquake Temporary Village Request the Ministry of Building, Innovation and Employment to recommend changes to Cabinet, to the eligibility criteria for tenancy within the Earthquake Temporary Village(s) to accommodate people dislocated by the effects of flooding due to earthquake damage to their property.
•
Temporary Relocation / accommodation support Work with the Council and insurers to develop a financial assistance/relocation package to assist people who are required to leave their homes as a result of repeated inundation, which has made their homes uninhabitable, or where the health risks associated with continued occupation cannot be addressed in an acceptable timeframe.13
Resourcing and collaboration • Continued support for an open and transparent relationship and data sharing between CERA, EQC, and CCC to actively problem solve these householders impacted as a result of the recent flood events, where the impact of the earthquakes has been a contributing factor to their new circumstances. •
Ensure the SCIRT work programme is properly aligned and co-ordinated with the Land Drainage Recovery Programme (LDRP) and any short term flood protection measures being undertaken.
•
Provide CCC access to red zone dwellings for pilot house protection demonstration project.
•
Consider establishing a joint CCC/Crown short term flood defence fund in the order of $2m to provide a fund for rapid implementation of minor flood mitigation measures for properties subject to IFV as a result of the Canterbury Earthquakes where immediate benefits can be realised. These measures could include house level or neighbourhood protections.
•
Consider CERA CEO Roger Sutton joining the Taskforce Governance Group and seconding a member of the Flood Management Steering Group to work with the Taskforce to maximize efficiencies.
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Eligibility criteria to be developed based on property and social vulnerability matrix and applicability of individual property defence measures
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APPENDICES A. Taskforce Stage One Rating Valuations ( confidential to stakeholder organisations) B. Temporary Flood Defence Measures: Technical Report Summary of Recommendations C. Summary of Temporary Accommodation Options analysis and costs D. Resolution of the Extraordinary Meeting of the Earthquake Recovery Committee of the Whole: 12 May 2014
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Appendix A: Taskforce Stage One Rating Valuations (Confidential to stakeholder organisations)
During Phase 1 of the Taskforce, 56 properties were identified as being Vulnerability Level 1. Following an internal review process this was reduced to 53 properties (all of which were solely residential use, except for one property in Little River which is known to have dual use). The 2007 Capital Value of these 53 properties was $19 million, and in 2013 it was $21.3 million. Since the release of the Phase 1 Taskforce report in excess of 100 calls have been received identifying other houses that may have flooded to varying degrees. This unvalidated data may give rise to additional Vulnerability Level 1 houses. No allowance has been made in the above RV's for these properties. The estimates are based upon the best information which the taskforce currently holds but is likely to change as the initial findings are verified and further investigations are undertaken into the recent calls from the public.
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Information withheld under Section 7(2)(a) of the Local Government Official Information and Meetings Act 1987
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Appendix B
MAYORAL FLOOD TASKFORCE
Temporary Flood Defence Measures: Technical Report Summary of Recommendations 20 May 2014
Ci t y- Wi de Recom me ndati ons Location
Recommendation
City-wide
Emergency accommodation
City-wide
Communication
City-wide
Housing information hub
City-wide
Build community capacity
City-wide
Temporary accommodation
Description Establish an emergency accommodation scheme using the ‘We Find We Pay’ option if temporary engineering measures have not been implemented and the area floods again, or if temporary engineering measures do not work. This can be implemented in one to four months. Proactive Communication from the Council and other agencies to advise 1. what we are doing, 2. what we are going to do and 3. how to stay warm, dry and healthy. This communication needs to be ongoing, meaningful and regular. It needs to reach the right people using a variety of communication tools. Create a multi-agency hub that provides ‘one point of contact’ with information, advice and support. There could be one hub or many hubs depending on community need/desire; geography and resources (both people and financial). This recommendation can be implemented in one to four months; however, it requires the buy in from other agencies. Support community groups to mitigate the effects of households leaving an area in clusters and/or in streets. Vacant properties and uninhabited streets become unkempt making it vulnerable to crime and vandalism. It also reduces community pride and connectedness. Potential projects could be neighbourhood watch projects, growing neighbourhood support in the area, monitoring graffiti and vandalism and maintaining green spaces (mowing lawn, pruning hedges and trees etc). Offer temporary accommodation for property owners using the “We Find, We Pay” or the “They
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Earthquake Influence High
High
High
Location
Recommendation
City-wide
Temporary village
City-wide
Community engagement plan
City-wide
Wastewater overflow reduction
City-wide
Wastewater overflow impacts
Description Find, We Pay” options. We anticipate these options will be in place for up to three years while a permanent solution is implemented. This option can be implemented in four months and beyond. CCC to build a temporary village consist of 30 three bedroom houses on Council owned land (yet to be identified), then let to the affected property owners at a discounted market rent for a maximum period of 24 months. These are abridged versions of the Community Engagement Plan recommendations. 1. Community engagement exercises are led by Community Boards. 2. Community engagement exercises are tailored for each area. 3. Work priorities of Council staff across the Council are redirected to resource community engagement exercises across the city. 4. Community groups with similar reach, depth and levels of trust as the Flockton Resident's group are involved earlier in the process to improve the dissemination of information, the gathering of local knowledge and to understand the issues faced in affected communities. This in turn will assist in choosing community engagement tools and sampling methods. 5. Greater use of community networks to distribute key messages and information. 6. Designing a more flexible approach to obtaining the views of directly and significantly affected people versus the views of less affected and/or indirectly affected people. 7. Where appropriate, engagement tools, such as surveys, are posted on the CCC website. 8. Where appropriate greater use of Facebook and Twitter to improve the two way flow of communication between the Council and the community. Provide cross funding to wastewater operations team to install removable non-return valves at property level in flood prone areas and seal vented manhole covers. Design new temporary response procedures to respond to wastewater contamination of flood waters in flood-prone areas away from the main river corridors. Namely:
City-wide
Health effects FAQ
Earthquake Influence
High
Medium
Medium
posting contamination signs notifying affected parties of health risks organising or offering post-flooding clean-up.
Develop a Frequently Asked Questions and responses information leaflet with Canterbury District Heath Board (CDHB). Develop a single point of contact in Council is appointed to deal with and provide assistance and advice to residents in flood prone areas, advice to be specific to level of vulnerability.
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Medium
Location
Recommendation
City-wide
Post-flood clean up
City-wide
Public data access
City-wide
Rainfall warnings
City-wide
Response procedures
Description Until longer term solutions are in place, council should consider offering flooding clean-up / decontamination of properties facing large insurance excesses. There is an opportunity to provide a single point of access for all of this data. Access to live data feeds allows the public to informed and up-to-date, and may relieve anxiety over not knowing what is happening when away from home. It will also allow residents and the media to monitor rainfalls, flows and river levels to help them plan and make decisions around their properties. It is recommended that the various data sources are incorporated into ECan’s existing webpages for rainfall and flow data, though in the longer term, Council may prefer to develop its own webpage to host this data. It is recommended that a low level monitoring of the predicted weather for seven days in advance is done for the Christchurch area on a regular basis (such as every Monday, Wednesday and Friday). If there is a risk of a significant weather event (such as more than 50 mm expected within 48 hours) commencing within the next two days, then a higher level of weather monitoring and rainfall prediction is put in place until the risk is over. During this time regular updates should be provided two or three times a day, and there should be access to a qualified meteorologist to provide briefings and answer questions. Develop new interim response procedures to cover the next 2-5 years and the most vulnerable areas until long term solutions are implemented. These should ideally assign an individual who is responsible for each catchment area and who can then co-ordinate between wastewater, land drainage and road network operations. They would also work with Civil Defence. This avoids duplicating work by using a combined response. The new interim response procedures must incorporate any individual area interim response plans to ensure they are implemented. The response plan should list all notified parties (flooding and wastewater contamination) for contact and include a maintained list of preengaged people who are available to assist with emergency response work. The response plan could be formed through Civil Defence and the local community for those vulnerable residents in the event of a future significant flood event.
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Earthquake Influence Medium
Medium
Medium
High
Review Recommendations (likely to be included in final report) Recommendations from reviewers which may be included in the final report. Location City-wide
Recommendation Register of vulnerable residents
City-wide
Financial assistance
City-wide
Climate change effects
City-wide
Assess Level 3 vulnerability priority
Description A register of addresses and contact details for vulnerable residents could be held by Council and appropriate support (such as rescuers in four wheel drive vehicles or a programme of visits) mobilised through our civil defence office. There may also be other financial support options such as rates relief and covering that $10,000 insurance excess that has been noted. Or rates relief for uninhabitable properties. Determine whether recommended solutions are “no regrets” solutions – that is they will provide a positive cost:benefit regardless of the impacts of climate change. This is an important consideration for more significant projects and to be incorporated into stage two assessment work. Level three vulnerability (access cut-off by flooding) is very much more an issue for those with existing mobility problems or health issues where access is a priority. There also may be elderly residents who rely on support workers visiting to enable them to live at home.
Area-by- Area Recommendations (from main report body) These recommendations for local area schemes were included in the main body of the report. These generally excluded maintenance recommendations. Location
Recommendation
Description
Earthquake Influence High
Dudley Creek
Local area scheme
Pumpstation, street pumping, house tanking, capacity upgrades, backflow, house raising
Lower Heathcote Upper Heathcote Heathcote Valley
Local area scheme
Bunding, flap gates, pumping, house bunding
Medium
Local area scheme
Bunding, flap gates, temporary pumping
Medium
Local area scheme
Low
Little River
Local area scheme
Bridle Path Road – Cooks Lane: increased inletting Bridle Path Rd – Marsden Rd: increased inletting Martindales Rd: increased inletting, clear pipes Port Hills Rd – Bridle Path Waterway: increased inletting, debris screens, new pipes Truscotts Road: new pipes, flap gates Pawaho and Stedley Place: increase drain size, install flap gates Lower Cooptown / Church Road Area: improve secondary flow path, bunding, increased inlets, enlarge drains, clear obstructions Lower River Lower Township Area: improve secondary flow path, diversions, enlarge drains, clear obstructions Note that it is recommended that an integrated
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Low
Location
Recommendation
Lyttelton
Local area scheme
Sumner
Local area scheme
Description solution for highway flooding is pursued with the New Zealand Transport Agency (NZTA) who are also investigating flooding in the area. Environment Canterbury (ECan) have also completed studies in the area and because of this potential source of knowledge should be engaged in the development of solutions for Little River. Both of these fall outside of the scope of this report. Lyttleton options assessments did not just considered flood defence but also took into account public safety as a major concern. Therefore the costs reflect the greater issue of public safety rather than just reducing flooding damage. Two flood/slip risk reduction activities were considered. The first scheme is a list of recommended actions for the highest risk areas and the second scheme is a list of actions for the medium risk areas. Capacity upgrades, sediment removal and control, daylighting Sumner Stream, formalise secondary flow path
Earthquake Influence
Medium
Medium
Area-by- Area Recommendations (from Appendices) The recommendations included in this section are those that were not reported in the main body of the report. This is because they were either maintenance related, or were not directly affecting Level 1 or 2 properties. However, this list still contains actions that should be undertaken as a matter of course. Location
Recommendation
Lower Avon: river stopbanks
Maintenance
Lower Avon: Avondale area
Maintenance, temporary pumps
Description Ongoing monitoring and maintenance of the emergency stopbanks is required. They need to be regularly surveyed and topped up as identified by the survey. In particular, the Owles Terrace boat ramp is a gap in the network which requires filling. This could be temporarily sand bagged before an event or bunded at a gentle grade to allow use of the ramps by vehicles to be maintained. The existing flap gate at Pump Station 220 should be replaced. All flap gates long Avonside Drive and Hulverstone Drive should be checked, repaired or replaced as required. Temporary pumps could be installed during major events to keep ponded runoff from reaching low lying property. Suggested sites are, DN 375 outfall at Avondale bridge, DN 825 outfall at Orrick Street. Swales and stormwater ponding basins could also be installed to aggregate outfalls together.
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Earthquake Influence High
High
Location
Recommendation
Lower Avon: Brittans Drain area
Maintenance, sand bagging
Lower Avon: Knights Drain area
Local area scheme, maintenance
Dudley Creek
Maintenance, network re-routing
Lower Heathcote; riverside properties
Maintenance, pilot studies
Description Localised protection using sandbags could be considered for properties along Brittans Drain, although this is not a priority due to the lack of floor level flooding in the area. Immediate removal of a large tree blocking Brittans Drain would relieve the foundation level flooding experienced. Clearance of all constrictions in Brittans Drain is recommended immediately and on a regular basis. Street and sump clearing is also a common customer request and would mitigate nuisance localised flooding. Current maintenance activities may therefore need to increase in frequency. Undertake recommended maintenance activities: Regrading of Knights Drain invert
Repairs to the timber lined length of the drain
Removal of trees and vegetation within the waterway
Mairehau Drain – During site visits, the drain was observed to have some vegetation growth, so at a minimum this should be cleared. It is also not known what the design depth of the drain is, so it is suggested that the drain is dug to determine this and assess whether it should be further excavated. Lower Dudley Creek – A site walk over identified opportunities to enhance the capacity of the network through minor works and maintenance activities. Council has initiated this. Blocking Mairehau Drain intake from Dudley Creek - This could be blocked either through plugging or adding backflow control. Maintenance contracts may not yet be aligned with the increased numbers of outfalls found with recent survey work. Recommendations include the inspection and, regular maintenance of flapgates. Installation of more effective, less maintenance intensive inline check valves, particularly in low lying tidal areas such as Clarendon Tce and Richardson Tce. Pilot study recommendations
Pilot study dredging just upstream of Woolston cut stockpipe/drain then to waste.
Pilot study dredging just upstream of Woolston cut to fill Eco bags which could be used as a temporary stopbank. The
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Earthquake Influence Medium
Medium
High
Medium
Location
Recommendation
Description
Earthquake Influence
ecobags can then be landscaped at a later date to blend into the environment. It is recommended that a gap analysis is undertaken for assessing flood data over the past decade for trends in street and property flooding. It is recommend that a survey of and hydraulic modelling of the Heathcote River bed and banks is undertaken to quantify the reduction in hydraulic capacity as a result of the earthquakes. Lower Heathcote: Bells Creek catchment
Lower Heathcote: Tennyson area
Maintenance
Local area scheme, further studies
Undertake inspections and maintenance of sumps and pipework in the area.
Clear silt from drains to try and restore capacity.
Monitor area post maintenance during rainfall and mobilise sand bags and pumps if needed.
Local bunding of driveways to reduce flooding from streets
Increase the drainage in problem areas on Colombo Street to reduce flooding at the back of properties.
Install check valve in a new manhole to prevent backflow flooding from the brick barrel
Provide temporary pump installed in the manhole to pump over the bunding.
Medium
Medium
Prior to any permanent bunding, piping etc it is necessary to better understand highest risk of flow direction/volume and survey levels of land. Inappropriate placement of bunds may aggravate ponding depth by dwellings. Other options to consider include beheading street catchment with additional upstream sumps, raised downpipe wells on dwellings discharging to a separate piped system beyond bund ie reduce catchment to confined local surface drainage near dwellings. Investigations should be undertaken to pipe Tennysons Drain from Somerfield Street to the rear of Aylmer Street. Little River
Future studies
Low Recommendations for future studies
Drainage from Christchurch Akaroa Highway to river
It is recommended that an integrated solution for highway flooding is pursued
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Location
Recommendation
Description
Earthquake Influence
with the New Zealand Transport Agency (NZTA) who are also investigating flooding in the area.
Lyttelton: slips
Local area scheme
Environment Canterbury (ECan) have also completed studies in the area and should be engaged, as a potential source of knowledge, in the development of solutions for Little River
Stormwater defence measures
Street sumps should be regularly cleaned and where possible protected from blockage from gravel and floating debris
The stormwater drainage network on hillsides susceptible to slipping should be increased in capacity so that:
The primary flow is carried in a pipe
Rainfall runoff from the road should be directed to a stormwater pipe or channel
Private roof runoff should be checked in at-risk areas to make sure that downpipes discharge to the road or into the drainage network.
Medium
Where necessary there is provision for a lined or protected secondary flow path
Local area schemes
Lyttelton: stormwater drainage network
Local area scheme, maintenance
Educate and work with all occupiers in susceptible areas to identify and redirect sources of water,
Educate and work with all occupiers in susceptible areas to identify and seal ground cracks
As much as possible, locate and redirect under-runners into pipes
Locate and repair water supply leaks Low
Flood defence measures
Investigate removal of grates, enlargement or secondary intakes for all major pipe entries.
Monitor and clear important pipe entries during storms.
Risk reduction measures
Any new grates must be large, easily accessed, easily cleaned, low chance of
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Location
Recommendation
Description
Earthquake Influence
blocking before a response can occur.
Install trapping upstream of all 9 inlets for floating debris and rocks.
Maintenance measures
Education of maintenance contractor and an operating protocol for Lyttelton inlets.
In the longer term ensure vehicle access to all inlets. This will involve creating vehicle access across private property, on a hillside, to the Cressy St inlet
Sufficient crews in Lyttelton to monitor and clear 8 grates
Southshore
Pumping, maintenance
Emergency localised pumping solutions can be developed with the SCIRT Delivery Teams. These can be included within the Temporary Works program for the individual SCIRT Projects and managed through the ECI (Early Contractor Involvement)-SCIRT process. A maintenance contract is already in place between Christchurch City Council and City Care, a more robust process for repair, clearing and monitoring is required to ensure storm water outlets function properly. Local area solutions to investigate and address the stop bank issues in and around Ebbtide Street should be undertaken. There is a current risk of a breach should it fail. This is the one of two main links providing emergency access from South Shore to South New Brighton in the event of a Tsunami or other natural disaster and is therefore an important evacuation route. A full survey is required along the foreshore to highlight any potential ingress points in the high tide situation.
Medium
Sumner: Sumner Village
Local area scheme, maintenance
Upgrading sumps and pipes to increase drainage capacity at the low point on Wakefield Ave and reduce flooding of house on Wakefield Ave
Low
Removal of sediment from Sumner Stream/SMD and vegetation obstruction in Campbell Street culvert in conjunction with removal of private bridges to Red Zone properties crossing the Sumner Stream in Wakefield Street where feasible. Consultation with CERA is required regarding access bridges and proposed demolition timeframes to Red Zone properties on Wakefield Street.
Daylighting of piped section of Sumner Stream (approximately 38m)
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Location
Sumner: Moncks Bay
Recommendation
Maintenance, further studies
Description
Notification to CERA for sediment control of Red Zone properties and monitoring of slope stability including sediment control fences around properties and removal of sediment in downstream sumps, kerb and channels
Removal of sediment and debris from SFRP and SMD outfalls. Design review of Cave Rock, Burgess Street and SFRP outfalls in order to mitigate operational issues related to sand and marine deposits blocking these structures
Formalisation of the secondary flow path from DN1200 Cave Rock Drain outfall on Esplanade through to swale or ocean outfall
Removal of sediment and debris from SFRP
Develop and implement emergency response plan to ensure that key outfalls are able to operate effectively prior to a forecasted storm event. This requires comprehensive documentation of key outfalls and inlets
Maintenance measures
Removal of sediment and debris from stormwater pipes including the DN1200 and DN1350 on Main Road upstream of the Rifle Range Drain outfall and Beachville outfall where tidal inundation has caused silt deposits within these pipes
Maintenance of Rifle Range Drain weir. Reforming of open drain upstream of Rifle Range Drain weir to increase the cross sectional area and prevent high level flooding from the drain migrating down Bay View Road
Widening of the access point through the chain fence to allow vehicles/machines to enter into area to complete regular or emergency maintenance and cleaning of inlet structure Further studies:
Investigate impact of Variation 48 on existing low lying areas such as Cliff Street.
Investigate feasibility for increased retention upstream of Barnett Park.
Land purchase and formalizing secondary flow path from Rifle Range Drain
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Earthquake Influence
Low
Appendix C: Summary of Options Analysis for the Relocation of Flockton Basin Residents Possible Delivery Timeframe
Scope of Work
Option 1 – We Find We Pay
Option 2 – They Find We Pay
•
CCC to source and secure 30 suitable rental accommodations on a “similar replacement” basis, as practical as possible, to relocate affected property owners
•
CCC to guarantee the rent for the next 2 years or until a long term engineering solution is delivered to remedy the issue whichever is earlier
•
Affected property owners shall continue to be responsible for the ongoing mortgage repayments, if any and maintenance costs of their properties during the tenancy including Tenancy Bond payments
•
CCC to provide a lump sum of financial support to the affected property owners that is equivalent to a market rental of 3 bedroom house in Christchurch up to a residential tenancy of 24 months
•
Market rent shall be determined and based on MBIE’s latest publication of rental price on its official website
•
Affected property owners will be responsible of finding a suitable rental accommodation themselves
•
Affected property owners shall continue to be responsible for the ongoing mortgage repayments, if any and maintenance costs of their properties during the tenancy including Tenancy Bond payments
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•
•
Approximately 1-3 months but depends on availability of suitable rentals.
Approximately 1-3 months but depends on how quickly the property owners secure an alternative accommodation
High level Estimate of Costs •
Adopt a market rental rate of $480 per house per week for the first 12months and $500 (inflated at 5% p.a.) for the following 12 months
•
Total Project Cost - $1.8m
•
Adopt a market rental rate of $480 per house per week for the first 12months and $500 (inflated at 5% p.a.) for the following 12 months
•
Total Project Cost - $1.75m
Possible Delivery Timeframe
Scope of Work • Option 3 – Buy Back
•
CCC to purchase approximately 30 affected properties at a market value (or GV ) within a period of 2 years, 3 years at most with a first right to purchase back at a market value (or GV ) after a long term engineering solution is fully implemented in that locality.
CCC to build a temporary village consist of 30 three bedroom houses on Council owned land (yet to be identified), then let to the affected property owners at a discounted market rent for a maximum period of 24 months
Option 4 Temporary Village
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•
•
Approximately 1-6 months to complete negotiations in good faith with the property owners
Minimum 8-12 months to complete. This includes but not limited to procurement, design, consenting and construction.
High level Estimate of Costs •
Adopt an average market value of $385k per property based on recent sales in the area in the last 12 months
•
Total Project Cost - $12.5m
•
Adopt a typical build cost of $370k per unit
•
Typical build cost includes construction, consenting, professional fees, contingency, GST and development contribution.
•
Build Cost - $11.1m
•
Land Cost – unknown
•
Opportunity Cost at 7% $777k
•
Potential cost recovery/ rental income at $450 per unit per week - $1.4m
•
Management Cost at 8% p.a. of total rental income $112k
•
Holding Cost at 15% p.a. of total rental income - $210k
•
Total Project Cost excluding land component $10.9m
Appendix D Resolution of the Extraordinary Meeting of the Earthquake Recovery Committee of the Whole, 12 May 2014 It was resolved on the motion of the Mayor, seconded by Councillor Clearwater that the Council: 5.1
Receive the Mayoral Taskforce report and seek the support of the other two clients in the Horizontal Infrastructure rebuild (the Crown and NZTA) to retrospectively approve the bringing forward of expenditure of up to $600K to fund the Taskforce work to date from the stormwater temporary works programme of the infrastructure rebuild programme.
5.2
Note that the final draft of the temporary flood defence measures technical report (the technical report): 5.2.1 was completed on Friday 9th May 2014. 5.2.2 needs to be reviewed by senior Council engineers, policy and legal staff prior to being finalised. 5.2.3 agree to the release of the draft technical report without appendices and with financial and commercially sensitive information being removed 5.2.4 Delegate to the Mayor, Chair of the Environmental Committee and the Acting Chief Executive to approve the release of the final report.
5.3
Note the time constraints on the Taskforce and commend all those involved for producing such a comprehensive analysis on the specific causes of the flooding in each of the priority areas noting the commitment to find solutions for vulnerable property owners.
5.4
Requests the Acting Chief Executive establish a second phase Taskforce to: 5.4.1 confirm the level 1 properties are appropriately identified, including face-toface engagement to establish the most appropriate solutions and; 5.4.2 provide a recommended programme of actions and costs to implement urgent solutions in each catchment: (a) noting that this should include a temporary pumping solution in Flockton, the repair of flap gates in the Avon and Heathcote rivers, the dredging of the Heathcote river and the removal of debris and improved maintenance regime. (b) delegating to the Mayor, Chair of the Environmental Committee and the Acting Chief Executive to agree the programme and implementation timeframe by 31st May 2014. (c) noting, that some of this work may be authorised to commence immediately e.g. dredging, improved maintenance. 5.4.3 ensures that the SCIRT work programme is fully aligned with the Land Drainage Recovery Programme. 5.4.4 meets with the CCC/CERA Flood Steering Group to ensure that all workstreams are aligned with no doubling up or gaps. 5.4.5 Identify any areas that have been impacted by flooding on the proposed levels 1 to 3 vulnerability and report on those. 5.4.6 Urgently review criteria for assessing flood risk and land movement in Lyttelton to improve the analysis of vulnerability and strategic infrastructure. 5.4.7 Assess upstream developments for their contribution to flooding and whether mitigations requirements are being fully implemented.
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5.4.8
Talk to the Ministry of Education regarding a comprehensive response to flooding affecting schools.
5.5
Requests that Staff produce a programme of community information meetings in other priority areas by the 16th May 2014.
5.6
Reinforces its view that the use of the residential red zone is a major component of long term flood management and land drainage solutions for the City and requests that the Chief Planning Officer as a matter of urgency, prepare a master plan which identifies the parts of the residential red zone that are required for this purpose.
5.7
Request the Chief Planning Officer to ensure the alignment of the Land Drainage Recovery Programme with the Natural Environmental Recovery Programme.
5.8
Note that Section 16(3) of the Canterbury Earthquake Recovery Act of 2011 states that “A responsible entity may request that the Minister (for Canterbury Earthquake Recovery) direct it to develop a recovery plan and agree that the Mayor discusses with the Minister whether the Land Drainage Recovery Programme should become a statutory plan.
5.9
Request that the Mayor, the Chair of the Environmental Committee and the Acting Chief Executive meet with CERA, MBIE, the Earthquake Commission (EQC), and the Insurance Council to understand the progress they are making on land and repair strategies and their potential contribution to resolving these issues.
5.10
Request that a progress report comes to the Earthquake Recovery Committee of the Whole on the 5 June 2014 which is delegated the power to act on any recommendations
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