Transcript: Dam safety webinar April 2024

Last updated: 2 May 2024

Transcript for webinar explaining the requirements of the dam safety regulations.



Suzannah Toulmin, Tim Farrant and Conor Topp-Annan.

Slide 1


Welcome to the Building (Dam safety ) Regulations 2022 webinar. The webinar will start soon.


  • Building Performance
  • Ministry of Buisiness, Innovation and Employment, Hīkina Whakatutuki
  • Te Kāwanatanga o Aotearoa, New Zealand Government.


Suzannah Toulmin: Ata marie everybody. Good morning. Thanks for joining us for this dam safety webinar this morning. My name is Suzannah Toulmin, and I'm the manager of Building Policy in Building System Performance at MBIE. And I wanted to welcome you all to this webinar this morning. And thank you for joining us. So before I get underway, I wanted to acknowledge that many of you may be in areas which have been suffering from substantial rainfall and weather events over the last 48 hours and in an ongoing basis. And just wanted to reassure you that if you have to duck away to take care of stock or, or any flooding issues around your property, that the recording of this webinar will be available on our website at a later date, and all of the information that we present today is also available on the website. Of course, I think this will be a really interesting and engaging webinar and I'm looking forward to listening in and joining us and learning as we go through the day. But if you need to duck off, then that is totally fine. The information will be available at a later date. So as I mentioned, we're here today to talk about the building dam safety regulations, which come into force on the 13th of May. I wanted to welcome Tim Farrant. He's one of our presenters here today. Tim do you want to say hello?

Tim Farrant: Thank you Suze, so my name is Tim Farrant. I'm the building engineering manager in Building System Performance and I am our resident dam engineer.

Suzannah Toulmin: Thanks Tim and to Conor Topp-Annan who will also be presenting today.

Conor Topp-Annan: Kia ora everyone, my name is Conor Topp-Annan and I work as a Senior Advisor within MBIE's Building System Performance branch, working on the implementation side of these regulations.

Suzannah Toulmin: Fantastic, thanks so much to you both, and we'll be hearing from them throughout this morning. So just wanted to give you a little bit of an overview of what the webinar will cover today. So we're gonna go over some of the key points or the things that you need to be aware of for the dam safety regulations. In particular, we'll also cover why is the government implementing dam safety regulations right now, how to comply, which dams are impacted and what are those really key timeframes that you need to be aware of.

Slide 2


Webinar overview:

  • Key points
  • Why is the Government implementing Dam Safety Regulations?
  • How to comply: which dams are impacted? Key steps and timeframes
  • Non-compliance
  • Q&A


Suzannah Toulmin: We'll point you to where you can find information and resources so that you can continue to find that information after the webinar today. We'll talk a bit about what happens if there is non compliance. And then we'll leave some time at the end for some questions and answers. So just a reminder that you can ask questions, if you think of questions throughout the day or throughout this hour long webinar, if you can put them into the Q&A function, please that will allow us to address those questions in a in a structured way at the end. So with that in mind, we'll move forward to talk about what we're going to cover here today.

Slide 3


Key points:

  • Dam safety regulations come into force on 13 May 2024
  • Impacted dams (recent change) = height of 4 or more metres and stores 20,000 or more cubic metres volume of water, or other fluid.
  • Submit a potential impact classification to your regional authority by 13 August 2024.
  • Visit for information and resources.


Suzannah Toulmin: So a couple of key points I already mentioned, the dam safety regulations come into force on the 13th of May 2024. And the impacted dams are those that have a height of four or more meters and store 20,000 or more cubic meters of volume of water or other fluid. Now that is a recent change. Some of you may be aware that the Minister for Building and Construction announced a change to the thresholds just a couple of weeks ago. And so we'll talk a little bit more on a future side about what that looks like. However, the key thing to take away is this threshold is the same as what it is for a building consent application. So it applies to dams of four or more meters in height and stores 20,000 or more cubic meters of volume of water or other fluid. So the other key thing that you need to be aware of is that if your dam reaches that threshold, then you'll need to submit a potential impact classification to your regional authority by the 13th of August 2024. So that's three months after the dam safety regulations come into force. So all of this information is available on our Building Performance website, which is So feel free to look and find those resources there for more information. Okay, so from here, I'm going to talk a little bit more about the change that Government has made to these dam safety regulations, if my keys are working properly.

Slide 4


Why is the Government implementing Dam Safety Regulations?


Suzannah Toulmin: So I guess the the key thing to note here is that across recent history or history in New Zealand, there have been several significant dam failures in Aotearoa's New Zealand's history.

Slide 5


  • Dam Safety Regulations have been made to protect people, property and the environment from the impacts of dam failure.
  • Several significant dam failures in Aotearoa/New Zealand history.
  • Since 1960 there have been 25 dam incidents, with at least 14 that could be considered serious.
  • Cost of typical dam failure estimated at ~$5.8 million (MWH, 2017)
  • Aotearoa/New Zealand lacks a scheme for assessing and monitoring the safety of dams.
  • Regulations will bring Aotearoa/New Zealands into line with most OECD countries.


Suzannah Toulmin: Since the 1960s specifically, there have been 25 dam incidents with at least 14 that could be considered serious. So some examples of those dam failures, some dams were compromised in the Kaikoura earthquake in 2016, which required some drainage of some structures in the Seddon District under emergency orders. In June 2023, a soil dam administered by the Waipa District Council on the edge of Hamilton burst sending 23,000 cubic meters of water through 20 homes in the suburb of Glenview in the city's south. I guess the key to note is the cost of a typical dam failure in New Zealand is estimated at $5.8 million or thereabouts. Until now New Zealand has lacked a scheme for assessing and monitoring the safety of dams in New Zealand. So these regulations bring New Zealand into line with most other OECD countries, which have a system, a nationally consistent system, for monitoring the safety of dams. So the decision was made, as I said, to lift that threshold to four meters a couple of weeks ago.

Slide 6


How to comply. Key steps and implementation timeframes.


Suzannah Toulmin: From here, I'm going to invite Conor to talk a little bit more about how you can comply with these regulations.

Conor Topp-Annan: Awesome thanks Suze. So yeah, I will take us through some key steps, I think you should work through to comply with these regulations, and also cover off the key timeframes. The images you're going to see in the following slides are from a poster we've got on our website. And it provides a bit of an overview of the key steps in a nice visual way.

Slide 7


Steps 1 and 2.

Dam Safety Regulations 2022. Implementation steps and timeframes

Regulations commence two years after the Regulations are made or after a new dam is commissioned.

Does the structure meet the definition of a dam as per the Building Act 2004?

Does the dam meet the definition of a classifiable dam as per the Building (Dam Safety) Regulations 2022?

If the answer is yes to both of these questions, here are the steps you need to follow.

Image: a settlement next to a river with mountains in the background.


Conor Topp-Annan: So as you can see here, this is one of the visuals.

Slide 8


Step 1 - Definition of a dam

An artificial barrier and its appurtenant structures, that:

  • is contructed to hold back water or other fluid under constant pressure so as to form a reservoir, and
  • Is used for the storage, control or diversion of water or other fluid.

This includes:

  • a flood control dam
  • a natural feature that has been significantly modified to function as a dam
  • a canal.

This does not include:

  • A stopbank designed to control floodwaters.


Conor Topp-Annan: So step one, is to figure out if the structure you have meets the Building Act's definition of a dam. So the Building Act defines a dam as an artificial barrier and its appurtenant structures that is constructed to hold back water or other fluid under constant pressure, so as to form a reservoir. And so for example, it could be used for the storage, control, or diversion of water or other fluid. So, structures include a flood control dam, a natural feature that's been significantly modified to function as a dam, so it's intended to function that way. And also a canal. Importantly, what doesn't this include, the Building Act states that it doesn't include a stop bank, which is designed to control floodwaters. So that's step one. So if your structure doesn't meet this definition, then it's not impacted by these regulations. So that's the key thing to know from the get go. And if it does, then you need to move on to step two.

Slide 9


Is your dam impacted by the regulations?

  • Height and volume threshold: a height of 4 or more metres and stores 20,000 or more cubic metres volume of water, or other fluid.
  • Dams impacted are called 'classifiable dams'.
  • The threshold is the same as for a building consent.

Image: a graph showing the height and volume at which dams must be classified.


Conor Topp-Annan: So step two, you know you have a dam that meets that definition, but the next thing is to figure out whether it's large enough to be impacted by these regulations. So a pretty key question, which I'm sure a few of us are here to learn about. So as soon as mentioned, if your dam has a height of four or more meters and stores 20,000 or more cubic meters volume of water or other fluid, then it is impacted by these regulations. Dams are impacted by the regulations are known as what's called a classifiable dam. So you might hear that term a little bit. And as Suze mentioned earlier, the threshold is the same for as a building consent. So this means, if your if your dam was built today, and needed a building consent, it would also need to comply with these regulations after it was built. These regulations focus on the post construction, safety of dams. Just to clarify, that's not to say that just because you don't have a building consent, say the dam was built pre 2004, that you don't need to comply with these regulations, it's more that we're just highlighting the height and volume thresholds because the building consent thresholds are quite well known within the industry.

Slide 10


Step 2 (continued): measuring height and volume.

Image: a cross section of a dam showing the crest, height and lowest elevation at outside limit.


Conor Topp-Annan: So we know what the height and volume thresholds are, but how do we actually measure this? And importantly, where do we measure from? How you measure the height of your dam is set and the Building Act. It does vary slightly depending on the type of dam, for example, if it's a dam across a stream versus not across a stream, and also for canals. But broadly, the height of a dam is the vertical distance from the crest of the dam, so the top to the lowest elevation at the outside limit of the dam. So that diagram there illustrates that. Importantly, a key question we get is, does it include water below ground level? No. So any water retained below the natural ground level, at the lowest downstream outside limit of the dam, is not measured. The rationale behind that is if the dam was to fail, then theoretically, that water wouldn't go anywhere.

Slide 11


Image: a cross section of a dam showing the crest/top of the dam, theorical maximum water level and lowest elevation at outside limit.


Conor Topp-Annan: I've included another illustration, I think it's easier than listening and there is some jargon there. This one shows the water level in blue and light blue, as well as the theoretical maximum water level, so that's illustrated in brown. The key thing here is that we're focusing on an overtopping failure for these regulations. And we're predicting breach flows based on that. So how much water would be released? Where would it go? What would that effect be? And that's why we're measuring from the crest of the dam. Acknowledge there's a little bit of jargon there, but we've developed a resource to help you measure the height and the volume of your dam.

Slide 12


Resource to help with height and volume measurement

  • Easiest way = use existing info like construction drawings or a building consent
  • No existing info?
    • Use this resource to determine the height and volume of your dam, or
    • Engage a surveyor or technical practitioner (eg engineer) for support.


Conor Topp-Annan:   The easiest way to do it is using existing information. If you have construction drawings, or a building consent, hoping that the information is there. So that's probably the first point of call. If you don't have that information on hand already, We've worked with Irrigation New Zealand and some engineers to develop a resource to help dam owners (a farmer focus) quickly and cheaply determine if your dam meets the height and volume thresholds. Alternatively, if you don't want to take on that work yourself, you can engage a surveyor or a technical practitioner, like an engineer, for support. Tim will talk a little bit more about where to find those people in further slides.

Suzannah Toulmin: Awesome, thank you so much for that Conor. Just a quick clarification question. So dams that were built before 2004, so didn't need a building consent. But if they have got that height above four meters and more than 20,000 cubic meters, are they classifiable dams?

Conor Topp-Annan: Yes, yeah. So if they meet the definition, and if they meet that height and volume threshold, then yes, they're, they're impacted, regardless of whether they have a building consent.

Suzannah Toulmin: Thank you for clarifying that. And I also just want to see this, what we're seeing on the screen now this resource for dam owners looks like it's a really useful document, where can people find that information.

Conor Topp-Annan: So that's on our website, someone will hopefully chuck a link in the chat function. But yeah, if you have a look on the resources page, you'll find that resource along with other ones to support you.

Slide 13


Change to which dams are impacted by the regulations. Approximately 1900 fewer smaller dams are impacted.

Why were the changes made:

  • The Government has listened and responded to feedback from farmers and irrigators.
  • The regulations need to be proportionate to the risks smaller dams pose.
  • Engineering resources need to focus on dams with greatest risk.
  • Dam owners need to be able to have the resources to meet their responsibilities.


Suzannah Toulmin: Brilliant, thank you so much, Conor. I wanted to take a little bit of time now just to talk about, I guess, why the classifiable dams threshold has changed recently. So the government received quite a lot of feedback, both since the change of government and prior around the number of dams and the resource available from recognized engineers to support the classification of dams. In so the government's listened to their feedback and decided to make a change to the size of the dams which are impacted by those regulations. And that has resulted in around 1900 fewer dams needing to comply with the regulation. So this leaves around 1100 from based on the limited information we have that are still in scope. So the changes are or where we've landed in terms of the thresholds, we wanted to make sure that the thresholds were proportionate to the risks that smaller dams pose, and also taking into account the cost of undertaking a potential impact classification, and making sure that those costs were proportional to the risks that we're trying to manage. In particular, we also want to make sure that the engineering resource that we need to use for this is focused on the dams with the greatest risk. And with that we're focusing on physical risk reduction from those dams. And that's because dam owners need to be able to have the resources available to meet the responsibilities and we know that there was some concern about the number of recognized engineers. So just a note, the regulations on the New Zealand legislation website, still currently include the old thresholds. That's because even though the government has decided to make the change in has announced the change, we're still working through the process of amending those regulations. The timing has to be confirmed, but the key takeaway is that as a dam owner, you should be looking at the new revised thresholds which are on our website, rather than the old ones in the regulations themselves. And we'll be actively communicating when those changes to regulations are made, and they'll also be notified through formal communications. So what I'm going to do now, I'm going to hand over to Tim Farrant, who's going to talk us through a little bit more of the next steps. So over to you Tim.

Tim Farrant: Thank you very much Suz. Cool, so I'm going to talk about steps three to seven, which is the next bit you need to do after you've identified if your dam is affected by the dam safety regulations.

Slide 14


Step 3. Up to three months after the Regulations commence, or after a new dam is commissioned, a Potential Impact Classification (PIC) must be submitted.

  • Determine the dam's PIC
  • Have the PIC certified by a Recognised Engineer
  • Submit the PIC to the Regional Authority for approval.

Image: Buildings next to a reservoir.


Tim Farrant: Potential impact classification. What is it? It's an assessment of the potential impact downstream of a theoretical dam failure on the community, historical and cultural places, critical and major infrastructure, and the natural environment. Is a site visit required? No. A site visit is not required under these regulations. However, that being said, a technical practitioner might ask you, the dam owner to provide some information, for example, site photographs or site measurements. As Conor presented earlier, we've got some resources available on our website to help you gather information on your dam to help a practitioner prepare a potential impact assessment. Why do PICs matter? Potential impact classifications are triaged is low, medium or high potential impact dams and that determines whether you need to complete a dam safety assurance program. A dam safety assurance program is required for medium and high PIC dams. However, it is not required under the regulations, the low impact dams. This the design of the regulations to prioritize the additional work on the medium and the high impact dams. Now, a note on who can do an assessment, the regulation provide for anyone to complete a potential impact classification assessment. However, it must be audited and certified by a recognized engineer for PIC. Once it's certified, it's the dam owners responsibility to submit it to the regional authority. Dam owners may choose to engage a recognized engineer or a firm to complete both the potential impact assessment and to get it certified. I'll now cover when it's due. So form one, that's the PIC form in the regulations is due to the regional authority by the 13th of August 2024, or three months after a dam is commissioned. So three months after the regulations commence or three months after its commissioned, and we're working with the regional authorities and they will provide the forms available on the website or if not, we've got copies on the building performance website as well. You can find them on Suz, did you want to ask me a question?

Suzannah Toulmin: Haha, I'm always keen to ask you a question Tim. So couple of things, how much will a potential impact classification cost?

Tim Farrant: Thanks Suz. It would depend on the scope of the engagement between the engineer and the client. That being said, we've published an impact assessment, and based on the information we had at the time, we estimate it in the order of three to seven thousand, depending on the scope of that engagement. We've, we've received some reports that there are some consultants providing a service within about that range, and some are a wee bit higher, depending on the dam and the scope of engagement that they have been asked to do.

Suzannah Toulmin: Cool thank you. I've got another question but I'm going to save it for the end of your section, I think. So I'll let you continue on and then I'll come back to you.

Tim Farrant: Awesome, thank you.

Slide 15


Step 3 – Potential Impact Classification

What is this?

  • Is an assessment of the potential impact your dam's failure could have on the community, historical or cultural places, critical or major infrastructure, and the natural environment.
  • A site/farm visit is not required. In many cases the assessment can be done remotely/online using existing info about the dam.

Why does it matter?

  • Outcome of assessment = dam will be classified as a low, medium, or high potential impact dam.
  • Low impact dams do not need a dam safety assurance programme
  • Medium and high impact dams do not need a dam safety assurance programme.

Who does it?

  • Regulations allow for anyone to complete the assessment.
  • It must be audited and certified by a Recognised Engineer.
  • Dam owners are responsible for submitting it to the regional authority.

When is it due?

  • Due to the regional authority by 13 August 2024, or 3 months after a dam is commissioned.

Need help?

  • Check out MBIE's Guide to Complying with the Dam Safety Regulations.
  • You can also seek support from a technical practitioner (farm consultant, engineer etc)


Tim Farrant: So the next part of step three is the potential impact classification assessment. I've covered a bit of this already so I'll just briefly cover this again. It's due to the regional authority by the 13th of August or three months after the dam is commissioned, but you can complete them now before the regulations come into effect, you just need to submit them from the 13th of May through to the 13th of August.

Slide 16


Role of a Recognised Engineer:

  • Recognised Engineers have an auditing and certification role.
  • A Recognised Engineer is not required to carry out the Potential Impact Classification assessment.
  • Engineering New Zealand is responsible for assessing and registering Recognised Engineers.

Image: a screenshot from the Engineering New Zealand website showing the register of Recognised Engineers.


Tim Farrant:  Now as I mentioned before, the role of the recognized engineer is to audit and certify the potential impact classification assessment. They're not required to carry out the potential impact classification assessment themselves. Although a firm may provide that service as both completing it and having an audit and certified. It is engineering New Zealand who's responsible for assessing and registering the recognized engineers.

Suzannah Toulmin: Okay, Tim, I think it's time for my other question here. Do you think there are enough engineers for this work?

Tim Farrant: The availability of technical resource was a key consideration by the government on revising the thresholds. So reducing the number of dams that require assessment will mean that this frees up resource to undertake more assessments, and also to get on with the dam safety assurance work, which is the end goal of these regulations. So you're freeing them up to help classifiable dam owners meet their obligations on time. It should be noted that recognize engineers will also have a team supporting them. So currently there's 18 recognized engineers registered with Engineering New Zealand and we understand that each one has about sort of five or 10 typically engineers working with them. So a firm may distribute the work across their employees.

Suzannah Toulmin: Thanks for that, Tim.

Slide 17


Step 4: Dam Safety Assurance Programme.

Image: Water flowing from a reservoir to a river. Information about the Dam Safety Assurance Programme taken from the 'One to two years' box of the Infographic.


Tim Farrant: I'll now move forward to the dam safety assurance programme, which is step four. As I mentioned before, this is required for dam owners who have medium or high potential impact dams. So, what is it and why is it needed? A dam safety assurance programme provides dam owners with a structured framework of plans and procedures that need to be carried out to ensure that dam is safely operated and maintained. It needs to be audited and certified by recognized engineer and then sent to your regional authority for filing. Just to note here, as I mentioned before, dams with a low potential impact classification assessment don't require a dam safety assurance programme to be completed under these regulations. Recognized engineers will audit and certify these.

Slide 18


Step 5: Prepare an annual dam compliance certificate.

Image: Workers standing next to a river with information from the 'One year' box of the Infographic.


Tim Farrant: Anyone can complete the DSAP but it's likely that you'll require some support from someone with experience in dam safety. It could be an engineer, but it doesn't have to be a recognized engineer or it might be a different engineer within that firm that prepares the assessment but has it signed off by a Recognised Engineer. Once it's certified, the dam owners are responsible for submitting it to the regional authority. Just recapping when it's due, medium PIC dams are due no later than two years after the Regional Authority approves the PIC assessment, and for a high PIC dam, the DSAP form must be submitted no later than 12 months after the Regional Authority approves the PIC. Our Guide to Complying with the Dam Safety Regulations provide more information on what a DSAP is and what it should contain. The next step is preparing an annual dam compliance certificate. This is a certificate which shows to the regional authority that the procedures and the DSAP have been complied with over the last 12 months, or any minor items of non compliance are noted. These are signed off, again, by recognized engineer but they reflect the work that has been completed by the dam owner over the course of the year. As before, they're not required for low potential impact classification dams, but they are required for medium and high PIC dams on the anniversary of the DSAP approval.

Slide 19


Step 6: Review the Potential Impact Classification.

Image: Information taken from the 'Within five years' box of the Infographic.


Tim Farrant: The next step is to review the potential impact classification. This applies to all dams, low, medium and high PIC dams that are classifiable dams need to have the PIC classification reviewed. This is repeating that step three. So, engaging technical practitioner or someone similar to review your PIC and then get it re-audited and re-certified, just to confirm whether there's been any changes since that potential classification was first done. So when is it needed? Dam owners must review the potential impact classification assessment within five years of the Regional Authority first approving it. After the first review, it must be done at intervals of no more than five years.

Slide 20


Step 7: Review the Dam Safety Assurance Programme.

Image: Information taken from the 'Within five years' box of the Infographic.


Tim Farrant:  Step seven, reviewing the dam safety assurance program. The dam safety assurance program must be reviewed to make sure it's all appropriate, and whether there's been updates or changes over the past several years, and these need to be reflected in their plans. When's it due? For medium PIC dams it must be reviewed on the 10 year anniversary of the dam safety assurance plan being approved, and at intervals of no more than seven years thereafter. For high PIC dams, they must be reviewed on the anniversary of five years of the Regional Authority approving it, and then after that first review, of not more than five years. Now I'm going to pass onto Conor who's going to talk more about some information and resources we have available to support us.

Slide 21


Information and resources to help you. Visit the Building Performance website:


Conor Topp-Annan: Awesome thank you, Tim. I just want to acknowledge there's quite a bit of information, we've just covered, steps one through through seven. But all of that is available on the website. Key thing is, it's not all needed straightaway. The sort of key bits to focus on right now our steps one to three. Do you have a dam, doesn't meet the thresholds, and then looking at that first step of a potential impact classification. I've provided a slide up here just around some of the resources and information we've got available on the website. Someone will chuck a link in the chat. I really recommend having a look at these. On the website, you'll find a resource to help you determine the height and volume of your dam, I talked a little bit about that earlier. You'll also find the three forms that you'll need to send, or potentially need to send, to the regional authority or your council. Also, the Council's website should have forms available as well. And if they don't, then they will do by the 13th of May. We've also included a short video that really sort of just summarizes, it's a bit of a promo thing. But yeah, check that out on the website, there's an online learning module, and then pretty key to this as a Guide to Complying with the Dam Safety Regulations. That's a guidance document that goes into a lot more depth. We've really tried to cover off from a video and eLearning module, all the way through to detailed guidance for people.

Slide 22


A screenshot taken from the dam safety webpage.

Managing dams to ensure they are safe | Building Performance


Conor Topp-Annan: I thought I'd just include this up as well, so this is what the website itself looks like. In addition to the resources I mentioned, the website itself has quite a lot of information that we've covered today.

Slide 23


Non-compliance with the regulations.

  • MBIE provides overall leadership of the building sector, is the central regulator, and is leading the overall implementation of the regulations.
  • Regional authorities adminiser and monitor the implementation /enforcement of the Building Act and the regulations.
  • MBIE is encouraging regional authorities to take educational approach to enforcement in the first instance.
  • Focus is to ensure dams are well maintained and kept safe.
  • Building Act does have fines and penalties for dam owners.


Conor Topp-Annan: And just the sort of last section we'll talk through is you know, what happens if a dam owner doesn't comply with the regulations? So just for a little bit of context. MBIE, who we work for provide the overall leadership for the building sector, as a central regulator, and is leading the overall implementation of these regulations. And then we've got regional authorities who we're working with really closely. And their role is to administer and monitor the implementation, slash enforcement of both the Building Act but also the regulations. At MBIE we're working closely with the regional authorities, and encouraging them to take an educational approach to enforcement in that first instance. The focus really is to ensure that dams are well maintained and keep safe. Sort of keeping that at the core. However, in saying that, the Building Act does have fines and penalties for dam owners who, for whatever reason aren't complying. For example, up to a $50,000 fine for an individual and up to $150,000 for a body corporate for not submitting either a potential impact classification, or a dam safety assurance plan. If you want more information about that, you can have a look at MBIE's guide to complying with the regulations. Section 10, specifically, so it's kind of down towards the bottom. Yeah, hand over to Suz...


Suzannah Toulmin: Thanks so much for that Conor. What I'm going to do now is just kind of reiterate, I guess what the key takeaways from today's webinar so far have been and then we'll jump into some of the Q&A section. So it's now my turn to battle with the slides.

Slide 24


Key takeaways

Dam safety regulations come into force on 13 May 2024.

Impacted dams (recent change) = height of 4 or more metres and stores 20,000 or more cubic metres volume of water, or other fluid.

Seven key steps:

  1. Determine if you have a dam
  2. Determine if your dam is impacted by the regulations
  3. Determine and send the Potential Impact Classification to your regional authority by 13 August 2024
  4. Prepare a Dam Safety Assurance Programme (only med and high impact dams)
  5. Prepare an annual compliance certificate (only med and high impact dams)
  6. Review the Potential Impact Classification
  7. Review the Dam Safety Assurance Programme (only med and high impact dams).

Visit MBIE's for information and resources.


Suzannah Toulmin: There we go. So, a couple of key takeaways. So, if you take just a couple of things away from the webinar today, let it be that the dam safety regulations come into force on the 13th of May 2024. That's just over a month away. And that the impacted dams, following the recent change, are those that have a height of four or more meters, and store 20,000 or more cubic meters volume of water or other fluid. The other key takeaway that I would take is that all of the information you need to understand what your obligations are, are available through our website, There are seven key steps in understanding how these would apply to you. The first one is to determine if you have a dam, based on the definition of a dam and the Building Act. The next thing to do is to determine if your dam is impacted by the regulations. And it's where the calculation of the height and the volume of water comes into play. And then determine in send the potential impact classification to your regional authority by the 13th of August 2024. Then, if you have a medium or high impact dam, to prepare a dam safety assurance programme, and then to prepare an annual compliance certificate for those as well. And then for all dams, you'll need to review the potential impact classification. And finally, review the dam safety assurance programme, for those that are medium in high impact dams on the regular basis. But the three key things today, is to determine if you have a dam, determine if your dam is impacted by the regulations, and determine and seen the potential impact classification to your regional authority by the date of 13th of August 2024. And just a reminder to visit for more information and resources. Okay, so what we're going to do now is I can see that we've had some questions coming in thick and fast so thank you so much for those I'm gonna get Conor and Tim to turn their videos back on, and David in the background, I might get you to turn off the presentation.

Questions and answers


Suzannah Toulmin, Tim Farrant and Conor Topp-Annan speaking.


Suzannah Toulmin: I'm going to start with a question of my own if I can. Conor, you kind of mentioned that it's MBIE that provides the information, but that it's the regional councils that need to follow the next steps. So how should Regional Council compliance officers prepare for these changes?

Conor Topp-Annan: Really good question. So we had some ones come through before so we'll try to cover those. I guess in the first instance, just become familiar with the regulations, but the website itself, it kind of it's a little more layman's terms you can have a look at that. I guess if the question is asking about dangerous dams and how they're managed, then your council should have a dangerous dams policy or be currently developing one. The who does what and which team they're in will vary a bit depending on each council. So whether it's within your sort of regulatory team or compliance, so I just suggest discussing that internally with them. If this question is come from a regional authority, get in touch with us here. And we've set up a bit of a network with regional authorities, so can definitely help out.

Suzannah Toulmin: Awesome thank you. Before I get into those questions, I've got another one for you, so some people may be aware that MBIE has been working on a PIC assessment tool. Can you give us a little bit of an update on where that's it?

Conor Topp-Annan: So we're working with Irrigation New Zealand, and some recognized engineers to develop. It's been split into two now, we've got a checklist for dam owners, as well as a PIC screening tool. So we're aiming to have that checklist ready before the regulations come into force, and then the screening tool soon thereafter. So the idea is the checklist, a dam owner can pick that up, have a look at you know, what information would be useful to contribute to a PIC, and work their way through gathering that information. So we're really trying to make it as easy as possible.

Suzannah Toulmin: Awesome. Thank you so much, Conor. So I think the first question from the chat is probably one for you as well. Is the volume calculated only using the water that sits above the ground or overflow? I think people are talking about the volume of the water, not just the height.

Conor Topp-Annan: I'd really recommend having a look the resource that we've linked in the chat, it does provide some lookup tables and calculations for circular dams, rectangular, canals as well as covered in there. But yes, and we're just focused on the water stored above ground level. I really recommend having a look at that resource, and sort of thinking about your dam in particular.

Suzannah Toulmin: Great thank you so much, Conor, I'm gonna let you off the hook for the next question and I'm gonna fire this one Tim's way. So, Thomas Fritz had a question. Risk is the combination of hazard times likeliness of the risk of occuring, how is excluding some of those dams that have no dam safety systems in place, and owners who have no idea about dam safety, and therefore there is a higher likeliness of the risk occurring, how is that making New Zealand safer?

Tim Farrant: Thanks Suz. Not an easy one to start with. Thomas look, I want to acknowledge your comments there on risk. So the focus here is very much on dams that have a greater consequence. When we are talking about risk, we are talking about larger dams that by definition, will have a larger predictive breach flow. And so they will have a larger impact, typically, downstream. So the prioritization the Minister has considered here is that focus on focusing on the largest dams that present the greatest consequential risk downstream. This is similar principle that's been applied in the building consent threshold, for example, it's been around for 20 years. So yeah, there's always there's an element of accepting some risk, and this change in the threshold does does accept more risk. But it's a similar approach to what has been done for building consenting for some time.

Suzannah Toulmin: Thanks, Tim. I'm also just curious what other tools are there for managing some of the, you know, some dangerous dams?

Tim Farrant: So this doesn't change Council's responsibility to have a dangerous dams policy, as Conor talked about, and to take action on dams, regardless of their size if they are identified as being dangerous dams.

Suzannah Toulmin: Cool. Thank you, really appreciate that. Conor, this next one I'm going to throw to you first but if you need me to step in to, I'm happy to do that. Andrew Balme asks, can you provide some insight on the range of feedback that we received on the targeted consultation on the change to the classifiabl damn threshold? So what did we hear from not just the owners of small dams, but from other stakeholders and owners?

Conor Topp-Annan: Really good question. The the consultation was targeted, in that it wasn't fully open. It was to those involved in the development of the regulations themselves. So I guess, based on, I mean the consultation provided options to amend the regulations based on that feedback. I got to say feedback was a little bit mixed as you'd expect from different audiences. The government sort of weighed up those options and decided that the new height and volume thresholds, from their perspective strikes the right balance between societal expectations for managing potential risks with the cost of compliance. We have to set the level somewhere and it's always about striking that balance.

Suzannah Toulmin: Thanks, Conor. I think the only thing I would add to that is that we did have a range of feedback, that said "don't make any changes", through to going further than the changes that we've made. So up to eight meters, for example, and much larger volumes of water. So, this was where government decided the right balance was struck. Joe Francis has a question. Section 133B of the Building Act, I love it when people quote the different sections of the Building Act to me. It states that subpart seven only applies to classifiable and referrable dams. So this is talking about the definition of referable dams. Do either of you want to have a go at answering how we treat referral dams at the moment. I guess the short is there isn't currently a definition, but through further policy, analysis and development, we may choose to develop a definition for a referable dam in the future. That's something that we are still working through with the Minister of Building and Construction, and one of the things may be working through is a review of how these regulations have gone once they've come into force, and we've been able to take that into account in terms of how we may progress that. Anything to add from the experts on the call? Great. So, Eli talks about I think you've kind of already answered this. So some smaller teams without engineering input could present a higher risk than a very large dam with appropriate engineering oversight. So have we taken into account a risk matrix or talked about consequences? And I think, Tim, you already refer to we do talk about consequence. But do you have anything further to add here?

Tim Farrant: I do want to acknowledge this point Eli's made and I see that Leah King has actually also asked a similar question further down about a dam that's less than four meters high and less than 20,000 cubic meters, that could also be a high PIC dam. So that's acknowledged that there are going to be some medium and high PIC dams that will be excluded by this higher threshold. And so there is a there's a cost reduction of not needing to undertake PIC for those 1900 dams. But there is an accepting of risk that some of those medium and high PIC dams will be excluded. It's not to say that we don't encourage owners to go and proactively manage their assets well. And so those medium and high PIC dams aren't required under the regulations to undertake activities. But they for various other reasons, including their own management of their asset, and meeting their Health and Safety at Work Act requirements might undertake potentially a similar amount of work. But they're not required to under this regulation.

Suzannah Toulmin: Thanks Tim, I think that's a really good answer. Conor, is this only new dams?

Conor Topp-Annan: No, it's existing dams as well.

Suzannah Toulmin: So in those, as we said before, also those that were built before 2004, and may not currently have a building consent. Awesome. And just to confirm, Jeremy, I think I can even take this one. If your dam is below four meters in height, then it's non classifiable and no PIC is required, that's correct. Yeah, that's right. So just catching up. Terry, I'm not sure, were you, maybe you'd like to put in another point here. Were you asking me some of the resources are? I'm not entirely sure where your comments from so if you can clarify that we can come back to your question. Tim, Steven McNally has got some really cool questions for you. So in parallel, some district and regional councils are currently reviewing the dangerous, flood prone, and earthquake prone dam policies. Does a PIC conducted under the dam safety regulations on its own, actually assess flood prone or earthquake prone status of a structure given a PIC only looks at uncontrolled discharge scenario and not the nature of the dam or spillway construction itself?

Tim Farrant: Thanks Suz. Yeah, that's quite a well considered question Stephen, so thank you. Many on the call will be aware here, but I'll repeat it, is that the potential impact classification only deals with the consequence downstream, it doesn't consider likelihood of that failure having occurred. So looking at flood and earthquake performance isn't something was done is part of it PIC assessment. It's something that may be identified, but not necessarily. And so it's really that dam safety assurance programme work that will identify when a dam is flood or earthquake prone. That being said, the regulations in the Act do require recognized engineer to refer a dam to the regional authority, if they identify in the course of their engagement, that a dam is flood or earthquake prone, but you may not identify that at the time of the PIC.

Suzannah Toulmin: Cool, okay thanks Tim. And just a follow up from Steven. And this may actually be, oh you said you want to answer it so you can take it. Can you clarify the need or not for re-certification of low PIC at the five year anniversary?

Tim Farrant: Yes, so the regulations call for all classifiable dams to be re-certified at that five year anniversary of the PIC. So that includes low PIC dams.

Suzannah Toulmin: Awesome, thank you. Alright, you can take a break now. I'll bring Conor back. So Bill Veale has a question for you, what is MBIE's recommended process to rescind dam classification certificates, form one, if they've already been signed by a recognized engineer for dams, for dams with heights less than four meters, particularly if they've been issued to a dam owner, and potentially already sent to a regional authority.

Conor Topp-Annan: Really good question Bill. So yes, some dam owners may be well on their way to meeting the regulations. And that, you know, with this threshold change, it might mean that the dam is no longer impacted. From MBIE's perspective, it's not wasted effort. I think, regardless of the size of the dam, you know, we encourage owners to understand the potential impacts if the dam was to fail, and have dam safety plans, for example, in place to safeguard around sort of surrounding sort of safeguard against that disproportional risk. The council's are aware of the threshold change. So if you've already submitted your dams PIC to the council, then I'd recommend just getting in touch with them. And just clarifying that the dam is no longer impacted by the regulations.

Suzannah Toulmin: Thanks, Conor. Firstly, can I say that it's really great to hear people have progressed their PIC, classifications, and done that work. And I think there's still a benefit from understanding what the PIC classification of your dam is. A reasonably technical question, I suspect the answer is in that resource you've shared Conor. But if the embankment crest height varies, so if it's not all at one level, where do you measure from? Is it from the highest crest level or their lowest crest level?

Conor Topp-Annan: Tim back me up on this, but I think it just would be the highest point?

Tim Farrant: I guess a dam when we talk about dam, could be one that is a reservoir formed by many dams, and so for example, if you had a reservoir that had a saddle dam plus a main dam, for example, you might have different, you may have different PIC classifications for each of those two dams. So that would be an example of where you have different height dams that form a reservoir. If you had one dam that had a very increased level, you could in theory, segregate out parts of it as different assessments. So yes, yeah, a reservoir can be formed by multiple dams, and could, in theory have multiple PIC systems.

Suzannah Toulmin: Thank you. Thomas has another question on if we're excluding some clear, high PIC structures, such as the Lake Taupo outlet structure, or various urban stormwater detention dams with the change in threshold, how can New Zealand be assured that the risks associated with those structures will be managed appropriately, given they are now not covered by Dam Safety Regulations? Tim, do you wanna have a go at that?

Tim Farrant: Yes. I'm just not 100% sure what the question was in that. But I guess what I would note is that there are some requirements existing and some resource consents for some of those smaller dams. I'm not familiar with the Taupo outlet structure, but it may have certain conditions, for example, on its use. I think it's a little bit more case by case Thomas, so I probably can't talk in detail on that.

Suzannah Toulmin: Thank you. I think there are also responsible business owner, health and safety obligations, etc. That may come into account there as well. So Tim, for you this one as well. Jon Rillstone has a question around the process of having your PIC certified by a recognized engineer. He's asking, is he right in saying that this audit process does not require an on site visit from the recognize engineer and can be done with a desktop review?

Tim Farrant: The clarification is the recognized engineer's role is specifically to audit and to certify the PIC assessment. It's not their role, as defined under the regulations, as is needing to complete the PIC assessment. So the potential impact classification could be done by the owner themselves, if they have the skills or another technical practitioner. Now whether a site visit is required is a little bit case by case for that technical practitioner, but in many cases, we expect that existing information would be able to be used, and possibly with some site measurements and photos, etc, from the owner. So it's really about the owners providing that information to a technical practitioner to complete the PIC assessment with enough detail, for confidence that the recognized engineer can sign off.

Suzannah Toulmin: Thank you, Tim. Conor one for you. What will the MBIE screening tool provide as an output?

Conor Topp-Annan: So it's still under development. But the idea is that using the checklist, a dam owner will gather information about the height, volume, but also about the downstream effects of the dam was to fail. So as their school downstream, for example. And then they would then use this triaging tool kind of, let's say a process map of sorts, to work their way through, to give them an indication about whether the dam would be a low, medium or high PIC. And sort of, if it's very clearly that it would be low, that's great, but if you need more information to determine the classification, then it would indicate that as well. But still under development at this stage.

Suzannah Toulmin: Thank you. And what do you mean in dam definitions about natural features that are modified to act as a dam?

Conor Topp-Annan: So for example, if you had a stream, or a river that you've dammed off, but you know, in terms of, you know, what's called a sorry, Tim back me up on this, like an earth dam for example. So sort of commonly seen on on farms, for example, so you've dammed off a stream to form a reservoir, and then using that for irrigation, for example. So that's pulling from the definition and the Building Act.

Suzannah Toulmin: Cool thank you. I'm going to answer a question from Mark Broughton right now who thought a different approach to completely ruling out dams of lower thresholds to allow those lower dams to be assessed at a later date, rather than by August 13. That was one of the options that we considered in some early advice, but that would have meant that we would have had to make changes to legislation, which takes years and we think they're having a dam safety program, consistent, nationally consistent dam safety regulations that come into force now, that allow us to start managing the physical risk from dams is important. So, we did take that into consideration, and the change to the height threshold was a one thing that we could do, and still have these come into force on the 13th of May. And we think that that is a good compromise. I'm going to now ask, or address Terry Hewitt's question or ask somebody else to address that. Can large teams be divided into cells, eg walls or partitions that are less than 20,000 liters? If we need to take some of these offline then we can.

Tim Farrant: I can answer that. I guess one example would be like a wastewater treatment plant where you have multiple smaller dams. And you might have potentially an intermediate dam between different parts of it. So if that for example, that the compartments in that wastewater treatment plant had less than 20,000 cubic meters, I assume you mean cubic meters, the then you would end up downgrading those to be below that low classification threshold. So you wouldn't be required to submit a PIC for those if the cells themselves are less than 20,000 cubic meters. Yeah, I'm just thinking of a treatment plant which had about seven or eight that were around that number.

Suzannah Toulmin: Thank you Tim, that's something I've learnt today. I think I'm gonna ask one more question from the list and then I'll wrap up because there's a few final messages I wanted to get across. So Shreesh has asked how does MBIE determine if an inadvertant dam will be part of the regulations? So if the primary purpose of the structure was not designed and built to be a dam? Conor, do you have a view?

Conor Topp-Annan: We've had this question from regional authorities a fair bit, so the position we've come to is really, if it hasn't been designed to function as a dam, then it's not covered by these regulations. So we really have to go back to the definition of a dam and the Building Act.

Suzannah Toulmin: So I think what we're saying is ultimately, the definition of a dam in the Building Act is kind of the primary thing that you can come back to, and if you make the test against that, and you meet that test, and that definition, then once you've gone through this threshold calculation, you'll know whether you are in scope or not. I am gonna give you one more Conor. So Paul Kirby has asked if dams are low risk under the new regulations, so no PIC required, but maybe dangerous of these expected to be covered by regional authority dangerous dam policy?

Conor Topp-Annan: That's a good question. So yeah, the regulations, well dangerous dams, the policies only apply to... sorry, the definition of a dangerous dam in the Building Act is that it has to be a medium or a high potential impact dam. And there are a couple of other things on there as well. But if you read through one of the policies from the regional authorities, there are sections in the Building Act around measures to avoid immediate danger. And that applies to all dams. So even if it was a low PIC dam, the policy could cover that even if it wasn't a classifiable dam, so impacted by these regulations, those sections apply to those dams.

Suzannah Toulmin: Perfect. Thank you, Conor. Um, so I did want to acknowledge that there are still a lot of questions in the chat. That's really exciting. Sometimes I do a webinar and there are no questions, so thank you so much for taking the time to share your questions today. And we'll undertake to get back to as many of those as we can. So I did just want to thank everybody now for joining us today. And listening into the webinar. It's great to see so many of you on the call. When you leave the webinar today, there will be, I think there's a survey today, and then be on the lookout as well for a survey for dam owners as a whole that we will send out soon, which is partially targeted at understanding how ready you are for those regulations to come into force. So, I want to thank Conor and Tim, for your contributions today. And thank you all for joining us and wish you all a very good day. Thank you so much for joining us, kia pai tō rā.

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