There are several resource consents associated with the Wrights Road Storage Ponds:

These consents relate to activities authorised by the:

• The Regional Council (ECan): The consents relating to the damming and (mainly) construction related activities have formally been transferred to BHSL (noting that in the context of the Regional Council resource consents, the right to transfer such a resource consent is provided ‘as of right’ under the RMA).
• The District Council (WDC): The land use consent originally obtained from the District Council runs with the land and does not need to be transferred. This consent should be regarded as being held by BHSL as BHSL now owns the land.

Invitations to join the Community Liaison Group have been extended to members of the community who meet the criteria/stakeholder groups listed under the BHSL resource consents.

BHSL is proposing that stakeholder groups will determine their own individual representative(s) in accordance with the limits for representation of that stakeholder group. If this doesn’t work, then BHSL will work with the Councils (as the Regulatory Authorities) to determine the membership.

Most communication by BHSL will be via its website https://www.bhsl.co.nz/ and via the Community Liaison Group.

Residents are also welcome to contact BHSL by emailing admin@bhsl.co.nz

The Wrights Road Storage Ponds are two water storage ponds that when full will hold 8.2 million cubic metres of water. The stored water is diverted and taken from the Waimakariri River (under existing resource consents) and is stored in the two ponds during periods of high river flow or low irrigation scheme demand.

The stored water will be used by farmers for seasonal irrigation and to provide a more reliable supply of water for agriculture during times of either low river flows or sustained high river flows (during which Waimakariri Irrigation Limited is unable to take water).

The ponds are divided by a middle embankment with the level of Pond 1 being 3.7 metres higher than Pond 2 when full.

The design includes a fuse plug spillway to prevent overtopping of Pond 2’s embankment and a control system to manage the operation of the storage ponds.

The design is not unique, and the design includes previous experience gained from similar irrigation storage pond projects such as the:

• Rangitata South Irrigation storage ponds; and
• Carew ponds (Mayfield Hinds).

Yes, it is. Damwatch (a specialist engineering consultancy with expertise in dam engineering, dam safety and instrumentation) has been responsible for project design and review functions.

Damwatch is ISO 9000 certified (being an internationally recognised standard for management systems) and this has been the basis for the quality assurance standards adopted during design and through review.

Separate to Damwatch, an expert peer review panel of international dam engineering experts (Tony Pickford of Pickford Consulting Ltd, Trevor Matuschka of Engineering Geology Ltd, and Mike Sadlier of Geosynthetic Consultants Australia Pty Ltd), have undertaken an independent peer review of the design and dam systems. Feedback from the expert review panel has been incorporated into the design and management systems and confirms the safety of the Wrights Road Storage Ponds.

The design has also been the subject of significant further examination as a part of the resource consenting and building consenting process. The Councils (who had their own independent dam engineer engaged) and then the Environment Court were satisfied that the Wrights Road Storage Ponds were safe.

As set out below, the guidelines that have been relied on in determining the design and management systems are based on extensive national and international experience in relation to proven dam design and dam safety systems.

Rooney Earthmoving Limited (REL) has over 20 years of experience in constructing dams. Build projects that are similar in scale to the Wrights Road Storage Ponds include a series of seven dams for the Rangitata South Irrigation Scheme and a series of three dams for MHV Water known as the Carew Ponds. For further information about REL visit their website: https://www.rooneygroup.co.nz/our-projects

The site itself and underlying soils/gravels have all been surveyed as a part of the Damwatch design process.

Careful consideration has also been taken in relation to wider seismic parameters and design. There has been significant expert input from GNS Science (now part of Earth Sciences New Zealand).

The seismic modelling that informed the design has been based on the GNS National Seismic Hazard Model (which considers the likelihood and strength of an earthquake impacting the site) and included learnings from the Christchurch and Kaikoura earthquake events, as well as possible Alpine Fault earthquake events.

The design report (V6) discusses the expected performance of the ponds based on this work. Ground motion parameters provided by GNS were used to evaluate the pond’s stability under earthquake loading. The embankments have been designed to meet the performance requirements outlined in the New Zealand Dam Safety Guidelines (including both the 2015 and more recent 2024 versions). The “NZSOLD” guidelines are (as advised by https://nzsold.org.nz/dam-safety-guidelines-2024/):

The New Zealand Dam Safety Guidelines 2024 have been prepared by NZSOLD from the technical bulletins published by ICOLD and other internationally recognised references on dam engineering and outline appropriate practices that should be considered during the investigation, design, construction, commissioning, assessment, rehabilitation and operation of dams in New Zealand.

The reference to “ICOLD” within the above is a reference to the International Commission on Large Dams (https://www.icold-cigb.org/).

The ponds were designed and independently reviewed based on NZSOLD, 2015. This has subsequently been updated (NZSOLD 2024), and new dam safety regulations have also come into force for ongoing dam management, being the Building (Dam Safety) Regulations 2022.

Damwatch has confirmed that the storage ponds meet the requirements of NZSOLD 2024. The storage ponds will be managed in accordance with the 2022 regulations.

The ponds have been designed by Damwatch (as specialist dam engineers) and then peer reviewed using the appropriate New Zealand dam safety and earthquake engineering standards. They have been designed to withstand (i.e. not fail in) a 1 in 10,000-year seismic event. Matters such as high wind (including wave action) and flooding have been factored into the design and are not expected to compromise the embankments.

Hydrology and spillway design work has also been done so the ponds can safely pass extreme inflow events (noting that this is only likely to arise if there was an issue with the management of the take of water into the ponds given the absence of any natural catchment).

GNS (now part of Earth Sciences New Zealand) have carefully considered the seismic environment and have advised that the ponds are not built on or near a faultline.

Regardless, the design allows for very strong shaking at the site (including consideration of the risk of liquefaction and the need to ensure embankment stability under seismic loading).

A possible Alpine Fault rupture (based on the GNS National Seismic Hazard Model) has been accounted for in the design.

The storage pond is designed to withstand the strongest shaking predicted at the site.

There is no single or expressed “maximum magnitude”.

The ponds are engineered to stay stable during the strongest/most severe events modelled, including a magnitude 8+ Alpine Fault earthquake event.

Yes — snow, wind, storms, and heavy rain are all factored into the design and emergency planning.

Yes — the safety design already includes the possibility of new or unmapped faults like Starvation Hill. The dam designers have reconfirmed with BHSL that a possible Starvation Hill fault does not change the design assumptions.

The ponds are above ground because that’s the typical way to build irrigation storage ponds in Canterbury and the only method that is considered viable at the site.

The storage ponds have been engineered as earth embankment dams, which are designed to be stable, earthquakeresistant, and able to safely manage water levels

The engineers used by BHSL have the required experience and qualifications.

This has been extensively dealt with and approved through the Regional Council (as the regulator) as a part of the consenting process. BHSL will not providing individual details.

The resource consents impose various construction and pre-commissioning obligations (including certifications) on the consent holder (BHSL) and its consultant engineer. It is the consultant engineer that will have the core role in relation to initial reviews and certification (with the resource consents also providing for a quality assurance programme to ensure this work is reviewed).

The Regional Council (as the large dam authority) will have various roles in relation to reviewing the information that is required to be provided to it under BHSL’s resource consents and building consent. Completion will be approved by the Regional Council through the building consent process.

Once the ponds are built, they must be checked and re-certified regularly as a part of the required management regime under the Dam Safety Regulations.

The Storage Ponds will be monitored through a structured, multilayered damsafety system involving routine surveillance, real-time instrumentation, operational controls, and independent engineering reviews. This also includes, for example, a Time Domain Reflectometry (TDR) system in the pond embankment (as detailed in section 9.3 of the Technical Specification) that includes:

• a low-level alert (where a deformed cable indicates a small movement); and
• a high-level alert (where a sheared cable may be indicative

Monitoring is continuous, riskbased, and aligned with the NZSOLD damsafety regulations and guidelines, ensuring early detection of any anomalies and any longterm structural integrity issues.

The ponds are drawn down in winter to comply with the requirements of the resource consents to provide an additional buffer during the winter period.

Winter drawdown does not cause flooding in the Eyre River or the stockrace network because the discharge volumes are small relative to river baseflows, highly controlled, and released only when the receiving system has capacity.

Yes, water can be drawn down remotely. The ponds can be lowered safely and precisely, with various back-up systems and redundancy ensuring this can also occur during (for example) bad weather, any power outage or after an earthquake.

It’s a controlled, monitored, and regulated process, not an automated system that runs on its own.

The liner is manufactured with builtin UV stabilisers and is designed for longterm outdoor exposure.

Once the ponds are filled, the water itself protects the liner from sunlight. The upper edges are covered and anchored to prevent UV damage, and any exposed areas are inspected and maintained as part of our routine monitoring.

There is an ongoing requirement to monitor the liner and if required, additional protective layers can be added in highexposure zones and/or (as set out below) it can be replaced.

The dam embankment is designed for a lifespan of 100 years, but in practice it will be more than this, consistent with New Zealand dam safety standards.

The dam structures will be subject to regular review.

The liner has a shorter lifespan of around 25–40 years and will be replaced as part of normal surveillance and maintenance without affecting the dam structure.

Yes — the flood breach modelling already assumes that fastmoving water would carry things like branches, trees, and other debris.

The flow depths and speeds are calculated as a worstcase scenario that fully accounts for debris being in the water.

Under the BHSL resource consents, BHSL is required to hold public liability insurance that provides a sufficient sum insured (as determined through the process set out in the consent conditions) to cover:

• loss of or destruction or physical damage to any tangible property including resulting loss of use; and
• loss of use of any tangible property not otherwise physically lost or damaged or destroyed.

The quantum of insurance cover is determined by an insurance expert that is approved by the Councils.

BHSL’s insurance is brokered through Marsh. Currently, the cover includes cover for the construction period. This will be reviewed and a revised sum will be put in place prior to the storage ponds becoming operational (at which time the risk of dam breach will be factored into the insurance cover).

A copy of the certificate of cover and the basis of how it has been calculated will be provided on BHSL’s website.

BHSL’s insurance is brokered via an independent insurance broker (currently Marsh) and placed with New Zealandlicensed insurers who must meet strict Reserve Bank solvency and financialstrength requirements. This ensures that, in the unlikely event of a natural disaster or pond breach, the insurer has the financial capacity to cover damage to neighbouring property.

BHSL’s insurance will operate in conjunction with any policies held by landowners/occupiers.

BHSL does not need further information from individuals. The assessment methodology in relation to required insurance cover is done at a wider scale (considering matters such as rating valuations and dwelling numbers) and does not require additional information on individual properties.

Insurers already use (for example) national hazard data and council maps to assess flood risk. The advice that BHSL has received is that the presence of ponds will not impact on your insurance cover.

Although this has been alleged, BHSL is not aware of any actual evidence of this.

BHSL’s understanding is yes and as per the above, BHSL is not aware of any evidence that insurance cover will not be available due to the existence of water storage ponds.

You would make a claim with your own insurer in the normal way and settle your claim with your own insurer. Your own insurer may attempt to recover some or all the costs from BHSL/BHSL’s public liability insurance, but this is a matter for your insurer, and this would not impact on your ability to settle your own claim.

You will be fully protected (to the extent that you have your own insurance cover) and will not need to personally deal with BHSL’s insurer.

If you were uninsured, you would make a claim directly to BHSL, and if liability could be established, BHSL’s liability insurance would cover the damage and costs up to the extent of provided cover.

Although this has been alleged, BHSL is not aware of any actual evidence of this.

More generally, buyers, banks, and insurers rely on actual floodrisk data, and the advice BHSL has received is that a well engineered, consented pond does not change a property’s hazard rating or insurability.

This is a matter for the District Council and not BHSL.

Your LIM will only show damrelated information if the council has identified this as a specific hazard to your property. BHSL’s understanding is that a consented storage pond does not automatically mean this will be included on a LIM.

This would be a matter for you to determine with your insurer (and would depend on your own insurance cover arrangements).

The advice received by BHSL from its independent insurance broker (Marsh) is that major insurers have confirmed this only relates to limited instances of higher-risk natural floodrisk zones, not to properties near engineered storage ponds.

In a worst case natural disaster breach, the water would follow the natural downhill flow paths shown in the modelling, which conservatively maps the depth, speed, and direction of water movement to support emergency planning and community safety.

These maps are available as a part of the BHSL draft emergency evacuation plan (see pages 23 onwards) at https://www.bhsl.co.nz/wp-content/uploads/2020-06-15_DRAFT_Evacuation_Plan_v7.2-1-compressed.pdf.

Please note that these plans were prepared for the purposes of determining the potential impact categorisation of the storage ponds (as is now also required by 2022 regulations). BHSL understands that they are likely very conservative.

The maps will be updated as part of the Emergency Action Plan and the Evacuation Plan updates.

The inundation maps were created using high resolution LiDAR ground data, detailed engineering designs, hydrological modelling, and conservative dam safety assumptions to show the worst case flow path, depth, and extent of water in the unlikely event of a breach.

See Appendix 1 to the draft BHSL Emergency Evacuation Plan

It is emphasised that the modelling is conservative.

Water from a breach would drain away naturally and quickly (consistent with a natural flood event).

See the draft BHSL Emergency Evacuation Plan

Emergency evacuation is guided by the dam breach modelling.

The plan includes various procedures (and back-ups) for notifications and evacuation.

Civil Defence (with support from Emergency Services and Council) would manage an evacuation (not BHSL).

Yes — both the Emergency Action Plan and the Evacuation Plan will be updated prior to commissioning. Final versions will be shared with emergency services and the community.

Under the resource consents, the Emergency Evacuation Plan needs to be prepared in “consultation with the Civil Defence Emergency Management Group, the CLG and people who are resident in the area between the Eyre and Waimakariri Rivers as approved by the Compliance Manager CRC”.

Although not a formal approval process, BHSL anticipates the views of all the above interests would be included in the plan.

See section 4.1.3.5 of the draft Emergency Evacuation Plan available at: https://www.bhsl.co.nz/wp-content/uploads/2020-06-15_DRAFT_Evacuation_Plan_v7.2-1-compressed.pdf

The updated evacuation plan will include clearer guidance on safe animal evacuation (but overall evacuation will still ultimately be directed by Civil Defence and is not a matter for BHSL as consent holder).

The need to assist and account for vulnerable residents is already accounted for in the draft BHSL Emergency Evacuation Plan.

The individual household evacuation plans applying to such residents will need to account for their specific circumstances but could for example include specific warning processes and assisted evacuation by emergency services using safe, accessible routes identified in the dambreach modelling.

BHSL, the council, and Civil Defence will help each household who requests an individual household evacuation plan to prepare a personalised evacuation plan. This will occur once the updated emergency plans are finalised, using workshops, templates, and oneonone support for anyone who needs it.

See the draft BHSL Emergency Evacuation Plan.

The alert system uses multiple layers — Emergency Mobile Alerts, doorknocking, fixed sirens, and neighbourtoneighbour checks — so even if phones, helicopters, or loudhailers fail, it is intended that all people will receive a warning and know exactly where to go.

Evacuation is coordinated by Civil Defence through a multiagency system (i.e. not the small local police team). In practice, all organisations would work together using the dam break modelling as a basis for ensuring a well coordinated evacuation.

As set out in the draft BHSL Emergency Evacuation Plan, contingency plans or alternative routes will be factored in to evacuation planning. Once the Plan is completed it is expected that Civil Defence will develop further detail regarding this process.

The emergency plan assumes many residents will be away during the day, which may mean for example a need for alternative notifications and/or for emergency services to support anyone at home (you are not expected to return to the area during an event).

BHSL has extremely detailed procedures as a part of its Dam Safety Management System. These will be updated prior to commissioning.

In short, BHSL’s dam safety management system includes detection, early alerts, activation of the warning system and then support for evacuation and working with Civil Defence — with multiple layers of monitoring and backup systems to reduce risk at every step.

Yes — BHSL can release water through the pond gates if there is enough time and it reduces risk (emphasising that in an emergency the priority will remain warning people and evacuating safely).

The intention and expectation is that everyone should be able to evacuate safely with livestock/pets also being considered/protected through any evacuation process.

See question and answer #44 above.

BHSL (and its representatives) are not qualified to provide mental health advice.

A number of resources are available on the following Health New Zealand webpage: Where to get help for mental health