 Well, welcome everybody to today's Hydrotera webinar. That's great to see so many of you here today. Really appreciate your presence. Today we've got a absolute specialist in climate change and really hydrology. So today's topic is about how climate change is affecting flood planning and design and certainly a very timely presentation. So our presenter today is Dr Conrad Wasco and I've got some information about him shortly. All right, there's a picture of Conrad and you can see him live as well. He's from the University of Melbourne. Before we get into Conrad's details. We love your questions and it's a big part of these webinars. So in order for you to ask a question, we ask that you type it in the Q&A section, which is at the top of your screen. And at the end of this, I will read out the questions and we will do our best to answer those questions for you. Why does Hydrotera do these webinars? We're pretty passionate about sharing knowledge and certainly this is a topic where we should be sharing knowledge as broadly as possible because there's some real challenges that need to be solved. We like to facilitate education. We feel that we provide a sort of supplementary to perhaps some of the university style education that were applied on the ground. And we like to be adopting a sort of leadership position in industry, helping industry to face up to some of the challenges of the time. The webinar today. Part one, we're just about through. I'm just about to introduce Conrad. Part two is broken into two parts. Conrad's section about how climate change is affecting flood planning and design. And then topic two, I'm going to just raise awareness of some of the really good monitoring networks we have in Australia that a lot of Conrad's research is dependent upon. Finally, part three, which is an ever growing part of our webinars is the Q&A section where we do our best to answer your queries. So a bit about our speaker today. Firstly, thanks very much Conrad for joining us. Really appreciate it. Conrad is an ARC Decra fellow at the University of Melbourne. Conrad has over 10 years of experience in both consulting and research. Conrad's been pretty successful in this area. He has won numerous awards, including good Lord Conrad. What's that abbreviation? Let's just go with that. Early career research, excellent award. The Victorian Fellowship and the Lawrence G Straub Award for best PhD thesis globally in water engineering. He has contributed to the current national guidelines on flood estimation. And his current research focuses on understanding the effects of climate change on hydrology and specifically extreme events. So without further ado, I will hand over to Conrad. And I feel very lucky to have you here at this particular time when we're dealing with so many floods Conrad. Thank you. Yeah, so I think just a few things I wanted to say probably upfront. One is that this seminar might raise more questions than answers. But I hope that it sort of forms, I guess, a bit of a backbone of understanding where the science is at. I worked as an engineer for four years at the Water Research Laboratory in New South Wales. If you're familiar, it's opposite the Manly Hydraulics Laboratory, MHL. I'm the government organised department there. So I am passionate about translating research into guidance. I'm not going to say that I'm the best at it. And you'll see in the slides that it is a challenging space. This presentation also presented to Engineers Australia a few weeks ago. So just so you know, there's a lot of information that will overlap with that presentation. Thanks, Richard. So just to start off, I guess we want to talk about guidance. And so where is our current guidance? So if you go to AR&R and you look at the chapter on climate change guidance, then the stipulation there is for every degree of temperature increase, we factor our IFDs by 5%. And so if we go to the next slide and hopefully if you click forward one, you'll see that this is really what we're saying is, well, if we have our flood magnitude or rainfall on the y-axis and the rarity of the event on the x-axis, well, we've got our flood frequency curve, let's say, and we apply 5% change and everything else stays constant. You can probably expect a future flood frequency curve to increase by that 5% per degree Celsius. But why is it tapering? Well, there isn't any guidance to factor the PMPs, so which is the problem maximum precipitation that really, really extreme on the right-hand side. So we've got a little bit of a discontinuity there, but this is where our current guidance is at. So I've got this slide. There's a lot of information on this. And I've adapted this from the AR&R guidance. And there's a really important point here to make. So the top panel is, again, a flood frequency curve. I think we're familiar with this type of curve as the event becomes more rare and the flood magnitude goes up. And so we have our design flood estimate. But there's multiple methods that engineers, practitioners use for design. If we have data, we might use flood frequency analysis. Some practitioners will use continuous simulation. I think it's probably more common in the UK from my experience. But really, you know, if we're designing a dam infrastructure, we need estimates of the PMP, but usually we're using IFD curves. And we're putting that through some sort of rainfall runoff model. And then it goes into our, say, you know, two-flow micro-hydraulic model. So really most of practice is in the IFD modeling space. So if we click forward, the research space or the state of the science really is in that blue section. If you read the literature, there is a lot being done on non-stationary flood frequency analysis. I mean, what does that mean? It just means that we're trying to make our flood frequency curves change with time and with climate change. But also climate science tends to look at the 99th percentile. Not of an, you know, when we say 99th percentile, we usually have an annual maximum series. So that would be something like a 1% event. But often climate science is looking at the 99th percentile of all daily events. So we're doing something that occurs once every couple of years. So the blue part is where the science really is at. And the red part is probably, you know, where most design is focused. And so, you know, we can say that, you know, part of the problem, right? Like there is a disconnect there between the science and engineering practice. And it is something that I'm really impassioned about trying to fill. And I'm going to try and put in context the science, but in the engineering context in the next slides. So in terms of event, like, so overseas they call it IFD analysis. But here I guess we call it event-based analysis. So we know that we need to put in IFDs. And so the science is saying that, well, our storm intensities are going to increase. We also need to factor. We put in temporal patterns. So these temporal patterns, it looks like they're becoming more picky around Australia, more towards convective events. And that has an impact on the spatial pattern as well. If you're using space-time patterns in your design, sea level rise is increasing. So that increases the tar water. You're doing hydraulic modelling. There is evidence now that anti-seed and precipitation events, so mean rainfalls are decreasing. We're having drier soils. We're having more possibly than airspace in our reservoirs before it actually rains and floods. Now I'm not saying that you have to take all this into account when you design. That's not the point. But it's just to say there is a lot of uncertainty. And we need to figure out what are the important bits that we're going to, I guess, consider in terms of climate change. So the next slide. Thank you, Richard. And you can move forward just perfect. Thank you. So I think I put this slide in because I really wanted to convey that, and this is something that I think we're all already familiar with in terms of, or we have a good feel for as engineers, but in terms of, you know, what is our flood risk and what's happening with climate change? The top, these are just binomial probabilities, right? Like, so if you have a 1% event, you know, you're tossing the coin every year, but it's got a 100 chance of landing on a flood. But what isn't conveyed, I think, to the public, is that, okay, you know, in a given year, maybe there's a 1% chance. But if you look over the lifetime of your structure, 100 years, then there's a 63% chance of one or more floods that are that size or larger. Or what's highlighted there is a 26% chance of two or more floods. So, you know, we're actually betting our infrastructure on failing, you know, with a quite substantial risk when we design to this 100 flood. There is evidence, and it's a very rough rule of thumb, that the 100 year flood might become the one in 30 flood with climate change. And so then we're talking about, you know, if you look at that right-hand column, you're going to say something like, well, the, you know, you've sort of got an 80, a 24% chance of seeing five or more of those floods, right? Or a 43% chance of seeing four or more of those floods. So actually the chances of seeing quite rare events is increased substantially with climate change. And it's just something we need to factor in. And if we go to the next slide, you know, I think even with the questions that have come in this morning, I'd like to think it's fair to say, and the conferences that I've been through, you know, people have assets that they're worried about how to design for and how to protect with climate change. And currently the guidance isn't necessarily factoring in all the possible changes. And so what has happened is these corporations have funded Rory, Ashish, myself and the people, and we've used, so the University of South Wales and the University of Melbourne, and we've used that to fund PhD students and post-docs to do research to try and investigate how exactly climate change will affect their dam assets. Now, I won't be presenting much of the research from that particular work, but I really want to acknowledge their funding. That's one thing. But it's also a really good example of how, you know, I think this is a topic that people are concerned about and want to see more guidance around how we design for climate change. So the first thing is that we're faced, unfortunately, with this problem which is called, in science, deep uncertainty. On the x-axis I've got the time, the year, on the y-axis is the persisting dew point, which is actually the dew point temperature that is used in problem-maximal precipitation estimates. The different colours are the different scenarios that are modelled in climate change, in climate change models. And the point is that the four curves there are diverging, right? So we don't really know what path we're on. And so we're in a position where we design based on a stationary assumption that the climate won't change, but we don't even know how the climate is going to change. So there's a very good argument for our guidance and our infrastructure to be continually updated. We don't actually know what trajectory we're going to go on. Next slide. Thank you. Thanks, Richard. So the first sort of avenue of, I think, evidence that I want to say that we have for climate change, and this is very much now summarising where the science is at, is a thermodynamic relationship. And it's as simple as, you know, if you've got increased greenhouse gases, you've got more warming as the temperature gets warmer, the moisture, the atmosphere can hold more moisture. I sometimes think of it as just like a boiling kettle, right? You have more water molecules in the vapour phase than the water phase. Increasing temperatures mean increasing evaporation. So we've got increasing moisture content in the atmosphere. And there's a very strong physical relationship there. It's approximated to 7% per degree Celsius. So we know that with increasing temperatures, that atmosphere can store more moisture. And if it rains, then we'll get larger or greater extreme rainfalls. Next slide. So if, you know, if we know that there's this relationship, then we can actually use historical data. So this is data that the Bureau of Meteorology collects that we use. And this is a paper done by our PhD students. So we can actually look at these precipitation, temperature relationships in our historical data. So if we go to the next slide, look, there's a lot going on here. And I'll give the take-home message in words. But the top left panel is all the Pluvio sites, so all the subdaily rainfall sites that we found we could use for our research. And the next slide, the next four panels, sorry, the next three panels here, the colors correspond to the climate zones in that first top left panel. And what we have on the y-axis is that relationship with temperature that we're observing in our extreme rainfalls. 99th percentile. So not terribly extreme, right? We're still talking things that occur quite frequently, but 99th percentile relationship with temperature. And on the x-axis is the duration of the event. And the point here is that, looking at our observational records at the association of rainfall with temperature, we see for short duration rainfalls. So let's say hourly on average, there is a 7 to 10 percent increase in the rainfall per degree increase in temperature. So our historical records are pointing to probably sounding like a broken record, increases in extreme rainfalls with increasing temperature. But it's interesting to note that you can see, particularly in the warm temperate area, so the bottom right hand panel, that's where we have most of our data on the coastal regions around southeast Australia, there's a decline with increasing duration. And that's important to note. So longer duration rainfalls are less likely to increase to the next slide. And I really want to say that there's other bits of evidence, right? And again, we're just looking at historical data here. And this is some work. So I've met this academic, she's in the UK, Ms. Selma, perfect. And what she did was she took an Australian historical data again from the Bureau of Neurology and split it in half. So she's gone from 1966 to 2013, split it in half at 1990 and then looked at the difference between those two slices. And what she found was if she divided that by the temperature increase that has happened over that time historically, the magnitude of extreme daily rainfalls increased around 7%. Our rainfall increases are much higher up to about two times the rate of 7%. So we have this evidence that even historically, if we just look at trends, we're seeing increases in our extreme rainfalls. Next slide. And the last sort of bit of evidence that I really want to probably talk about is, you know, a lot of people use climate models. I don't, I focus on historical data, but this is data that we use to assess how climate is changing. And this is work done out of the University of New South Wales. But again, even if we run our climate models out into the future, as I was showing with those projection curves in one of the earlier slides, and we divide that increase in rainfall out to the future, out to 2100 by the temperature increase. Again, we're looking at about 6% increases in our daily extreme rainfalls. What was interesting in this study was they looked at more extreme rainfalls and found an even greater increase. So I can summarize three points here in words, which is extreme rainfalls increase with increasing temperature, shorter duration rainfalls are more likely to increase, but also the more extreme the rainfall, the more likely it is to increase. So next slide. And finally, thank you. So what's happening at the far, far, far end, well with the PMPs, well the problem makes in precipitation really depends on how much moisture you can store in the atmosphere. And this picture, this blue colour, it's just a correlation between the precipitable water, this is from observations and dew point temperature globally. So this is actually using data that's measured by satellites now. But again, really strong correlation. So the point is, if you've got increasing dew point temperatures, which is what we're using to design our PMPs, and they're increasing, then we have more moisture in the atmosphere. And so PMPs will increase as well. So if we go to the next slide, we're moving from a situation which looks like this to if we think forward, it probably looks like this, the extreme rainfalls are increasing regardless of the rarity. So moving forward, thank you. Now to put things in sort of greater context, well, you know, I've really talked about rainfall through this whole time. And probably what we're interested in is flooding. So to start talking about flooding, we need to start talking about runoff. And this is using actually, there's a lot of details that are missing here. And it's actually probably really important to point out that this modeling work is based on a model called Aura-L. And this is actually run by the Bureau of Meteorology. It's a water balance model that's run across Australia. Now the rainfall is on the left-hand panel, is observed gridded rainfall. And this is from 1960 to current. If you haven't seen this before, it's worth noting that in the tropics extreme rainfall, sorry, in the tropics, rainfalls are increasing on average across Australia. But in the southern parts of Australia, particularly on the coast, our mean rainfalls are declining. So what that actually means is that we're having drier soils when it rains. So our antecedent conditions, I guess, are less. Our soils are drier. Our losses are larger when it rains. So that's the middle panel. And we've got less runoff. We've actually got less water in our river systems before a large rainfall event occurs. So next slide. So we've got soil moisture declining. The other thing worth noting, and this was using a global data set, but storm durations are also decreasing. So we're looking at possibly a shift to shorter and peakier storms, which is what this slide is. The red color is just the trend in the storm duration and it's getting shorter, again, looking just using historical data. And this is some work actually out of the Bureau of Meteorology that I've pinched for this presentation. The lead author is Acacia Peppler. And what she did was she actually looked at storm types. So she went a step further than what I did in the previous work, which is just looking at storm durations in general. But she split the left and the right panel are the different seasons. And so, again, she has plotted the changes in our total rainfall. So you can see in the winter months, which is when we get most of our rainfall in southern parts of Australia, you can see we're trending to dry conditions. But the point here is that she's taken these four regions. So it's southwest-west Australia, around Earth, southeast Australia, that blue one, the green one, the eastern seaboard, and Tasmania. And if we click to the next slide, there is a whole lot of information here. And again, I just have to summarize it in words. But C stands for cyclone, F stands for front, T stands for thunderstorm. So what Acacia has done and her team, they managed to classify the weather events and look at the historical trends in those four regions and what they actually found was the amount of rainfall, which is on the y-axis, the amount of rainfall that you get on average, it's changing based on the frequency of these and magnitude of these events. So we're actually getting, so if the bars are above zero, what we're seeing is, and they're usually the red ones, we're seeing more rainfall coming from thunderstorm-related events and less rainfall coming from front-related events. So again, all this evidence is pointing to the fact that we're getting probably bigger gaps between our events, we're getting drier soils when the event actually comes, it's shorter and it's peakier. So what's the impact on Reynolds? So that's really where we're going with this. So that's the next slide. So what we have here is on the y-axis I've got, well, these are, again, historical trends and I've used data that Richard will present at the end to come up with this plot. I've averaged across Australia, really trying to extrapolate out to, as far as I could take the record. So I've gotten up to one in 40-year events. But on average, extreme rainfalls are increasing across Australia and the more rare they are, the more they're increasing. But streamflows are not. So this is the final sort of implication for flooding and the reason is if we click forward, it's because we've got these declines in soil moisture. So what's sort of happening is, for your frequent flooding, I'm talking like one in two, one in five, the increase in extreme rainfalls is not large enough to offset the fact that we have drier soils, shorter storm durations and our floods are not actually increasing, but it's for those really rare events. I mean, you can appreciate, very much what we're seeing now, right? But if you get a lot of rainfall, everything gets saturated. When it rains, everything turns into runoff. And so indeed for, you know, events one above, you know, you're one in 40, moving forwards to one in 100, then well, indeed increases in extreme rainfalls cross onto increases in flooding. And again, this is just using historical data. So on the next slide, really what I'm trying to say is that rather than this, if we click forward, this is probably sort of what we're looking at in terms of our future flood frequency curves. You know, extreme events are going up, PMPs are probably going up, and those PMPs going up will lead to greater, probably maximum flooding, EMS. But you're more, Rory likes to use, garden variety, flooding, you know, you're more frequent events. They're quite likely to be decreasing with climate change, because we've had at least in Australia experience, particularly in the southern parts, large decreases in rainfalls and the soils are dry before it rains. So where I want to go to now is, there's only a handful of slides left, but I want to say, I hope that that has sort of given you a flavour for the science, and hopefully in a relatable way. And what we found was, again, I am passionate about translating science into practice, and it's not easy to do. So one of the things that we did, I was reading the literature a few years ago, and I really couldn't find anything in the scientific literature that really reviewed the flood guidance from around the world, from really a practitioner's perspective. So teaming up with a few people from around the world, and we looked at what we could find in terms of flood guidance from around the world. And I really just want to present these as examples, just so that we're all sort of on the same page of, well, what's happening around the world in terms of design flood guidance. So the first example I have is from, I think it's from New Zealand. It'll be the next slide. And I'm sorry, I want to say, I'm very happy a lot of research is behind paywalls, just email me, right? I'm very happy to always share things if you're interested. So the first example is New Zealand, and what they've done is they've used those climate models without going into too much detail, but converted those climate models into some sort of scaling factors for their IFDs. And here you can see the different colours of different event durations, and you've got on the y-axis that percentage change that they're applying, and on the x-axis, how red the event is. And so this is really nice, because you can see they're sort of increasing and tapering off. So the more red the event, the greater the increase, but you can also see that blue one. So for hourly rainfalls, they're saying, look, we're probably going to factor this by 12%. But for the long duration rainfalls, looking about 5% to 7%. So on the next slide, the UK has gone down a different line, but actually I think the second iteration of their climate change factors, again, just factoring IFD curves, again, using climate models, I'm not trying to push for any particular way that people do things, but I'm just trying to present the literature. But they've done a little bit differently rather than doing temperature sensitivities. They've actually said, look, we've had a look at our climate models. We're going to give you gridded factors, so they're spatially varying. For the New Zealand, they don't take into account where you are. These vary with space. They call them uplift factors, and they've said, look, we're going to give factors for 2050, 2070, specific ARIs and specific durations. So the next slide. And the last example, this is actually for Canada, so my apologies, but they've actually got like a little web portal. Some academics did. And you can actually click, and you can come up with IFD curves, again, for any of those future scenario curves that I showed at the start. So they actually process all the climate data for you and come up with some IFD curves for whatever scenario you're interested in. And one more. Next slide. Look, and I wanted to present this, there are other alternatives. So the thing is that all I presented was, we're all looking at factoring IFDs, but what if you want to do continuous simulation? And this is again an example of where, you know, we needed a bespoke solution because there wasn't necessarily guidance around this. So working with Hark for Melbourne Water, we came up with these climate change factors that they can use into this sort of design networks. And this is because they're using continuous simulation. So we can't just factor the IFDs. We need to factor the entire rainfall time series. So what we came up with was, well, look, this is a bit obscure, this graph. I understand. So again, just in words, let's factor those extreme rainfalls up by a lot more than the less extreme rainfalls. And so what then happens is we can make our mean rainfalls decline, our extreme rainfalls go up and our storm patterns become peakier. So it's just a simple sort of, you know, a scaling factor that actually just depends on how rare the event is. And that worked for their continuous simulation. So moving forward, you know, what we came up with, and this is us as scientists, so very happy to be contradicted on this. But as part of that review paper, we came up with these three sort of overarching principles. You know, I think there is often reticence, maybe I didn't use that word properly, reluctance I guess to, you know, to adopt climate change in our work. And that's fair enough because there's a lot of uncertainty. But actually what I hope I communicated here is that there are multiple lines of evidence for climate change and they're all pointing in the same direction. So one thing that we really need to start doing as an academic community, to be honest, is communicating consensus. Okay, we all need to show that we're all on the same page. And that doesn't always happen quite often, you know. Yeah, in public forums, you know, people will argue and disagree with each other, but we really need to be communicating consensus. And I think that would help a lot. The guidance that we provide needs to be practical. So I think it's fair to say that, again, a lot of the academic literature, which I didn't put here, focuses on flood frequency analysis, which, you know, we often don't use in practice because we don't have data where we design. And again, that the science is moving so fast. I mean, this is an incredibly fast moving space. So, you know, I appreciate the AR&R guidelines were updated recently. And all of a sudden we're talking about updating the climate change guidance again. It is a fast moving space. And so, and updates are hard to do. So there needs to be a way of doing these things that makes them easily updateable. So having said that, next slide. Yeah, I was really fortunate to be contacted by Dr. Ramona Dalaposa from DQ. So the Department of Climate Change, Energy, Environment and Water, and I asked her to present me with a slide which I could incorporate into this presentation. And they are commencing an 18 month project to actually look at updating the chapter 6 of the AR&R, the flood guidance for the climate change. So if you have any questions or are interested in the updates, you should feel very comfortable contacting Dr. Ramona. It is really exciting to hear that, you know, there is movement forward in this space that, you know, and I want to say I think, you know, again, based on the questions, based on the conferences that I go to, it's like people are listening, you know, like I appreciate that we don't necessarily know how to just, we know that, you know, we want to protect our infrastructure assets and we need to do this in the best way possible. And, you know, and, yeah, there is work being done to move this space forward. So I think with that, my little mumbling there, I'm going to say thank you and really appreciate you having me to present to you. Thanks very much, Conrad. That was excellent. Just in case any of you have any doubts about the veracity of Conrad's data that supports his work, I would provide you with a little bit of background of what Australia is doing very well in terms of monitoring the important data around climate change so we can get this right. So this is our Australian Climate Change Site Network. I'm not sure how many of you have seen this before, but for me it was the first time as I put these slides together. But I guess the first take home message is there's quite a lot of sites, right? And talking to Conrad just before this webinar, he said that we're probably third best in the world behind the UK and the US in terms of monitoring networks. So we've got a right to be proud in the investment we've put into running that and big thank you to the Bureau of Meteorology for keeping that network going. So we should feel confident about when people tell us there is change happening that we have a really strong Australian context around that. So just looking at this network, this network picks up daily temperature, daily rainfall, monthly rainfall, monthly pan evaporation and monthly cloud amount. And if you want more details on that network, you can go to the Bureau of Meteorology's site and there's a wealth of information on not only the data, but how it's homogenised and that sort of thing to remove errors, et cetera. So really impressed with what we've got on the ground in Australia. Similar to that, I thought, you know, we've been hearing a lot about sea level in terms of climate change and our needs to adapt to that. But I thought, do you wonder how they keep an eye on that? And once again, the Bureau of Meteorology has a pretty big network around Australia of what they call these sea frame stations. So there's 14 of those plus a couple of extra supplementary stations that are run by a couple of ports. And that data is used to provide us with that level of accuracy, which is honestly extreme, looking at small changes in sea level. And it's not an easy task. And the levels of rise that they're trying to pick up are sort of around, you know, 0.4 millimetres per year. And if you imagine what's going on with sea and how often it's still enough to get that sort of accuracy, it's quite a challenge. And with those sort of tolerances, they also need to be very careful about ground movements themselves, right? So there's that aspect too. So they have this global navigation satellite system to provide them with sort of independent survey of the elevations of those sites. So really a big investment and impressive and being a bit of a monitoring obsessive myself. I had a little bit more of a look at these stations. And this is what they look like. So you can see particularly on this right-hand side where they've got these tubes that they mount their sensors in, that they've done a fair bit of work here to try and avoid some of the wave action complexities that come in. You'll see there's a bit of a sort of lateral structure there which is presumably to reduce this sort of suction effect that you get as a wave moves past which translates to your water level in the stilling well. But there's also a bunch of other things being used to measure level at the same time. So there's an acoustic sensor that's looking at the water level in the stilling well but you've got pressure sensors over here. They've also got a temperature sensor. They've got radar looking down as well. So really they've got three different methods. They're all going on at once to look at the levels. So I thought that was pretty impressive. So a large network, well large 16 sites around Australia. Pretty impressive investment there too. Once again the Bureau of Meteorology, I believe has some involvement in that. But if you want more details on that you can have a look at the Australian baseline sea level monitoring project. Lastly, I thought I'd have a look at the hydrological stations which is obviously probably the most pertinent data to what Conrad's been talking about today. We have a national network of 467 stations around Australia and those dots on that map show you where those stations are and they're providing us with plenty of stream flow data for this sort of research to be undertaken. And the Bureau of Meteorology has a role of making sure we pull all that data together. Various state agencies are involved in maintaining those gauging sites. So a really impressive spread of sites that we're monitoring there as well. And without those sites Conrad wouldn't be able to do the research he does. So I was honestly really impressed with the coverage we have. So without further ado, we're going to move to initially just a couple of takeaways, I guess my takeaways on this topic today. Obviously we've got changing metrological conditions that are becoming more and more clear and I really like the way Conrad sort of extrapolated backwards with historical data rather than just using sort of modelled projections. So that's pretty powerful. But that's only part of the picture. You know really in terms of what generates floods, it's obviously intensity but in the rainfall but it's also your catchment characteristics and you would have seen a few webinars that we've run in the past like with the Malone Institute where they're looking at restoring some of those barriers to rapid stream flow down, highly degraded streams and that sort of thing to retard some of the flows further up the catchment. So there's a lot of things that can be done and a lot of them relate to catchment characteristics. Next take home message is there are multiple lines of evidence for the impacts of climate change and really as Conrad said there's consensus around now. So really the debate needs to move off is it happening to what are we going to do about it? And I think that's what Conrad's really focusing on is how can we get this adopted? How can we get this being used? And that's obviously really important. There are many methods used by engineers to design and any climate change guidance needs to be able to be I guess integrated into those methods. Now for a long time now we've been doing various projections and I used to get involved sometimes with some planning approval processes and you'd have the sort of projections of what's going to happen with climate change and quite often it wasn't actually that listened to. We would still go ahead with the various developments. So we are going to have to start thinking and applying this stuff with more conviction now it seems to be real. As scientific understanding is improving rapidly guidance should also be updated rapidly. Certainly is an amazingly rapidly changing place and some of the work that's being done like that aura L projection of antecedent soil moisture across the whole of the country at a daily time step and that sort of thing is really impressive. You might remember Paul Fakima from the Bureau of Metrology presenting on that a couple of months ago in one of our webinars but that sort of information needs to be translated into design processes in my opinion. Australia has a impressive range of measurement networks and I've just shown you a sample of those and Metrology has a lot of responsibilities around those measurements so we're lucky to have the Bureau. Right onto the Q&A which is the favourite part of our webinars I believe. First and foremost fantastic to have so many early bird questions I believe Conrad now is the record holder for the number of early bird questions. So first question for Conrad. Is there any case studies or examples that you can share with us about financial impact on businesses or land holders in response to climate change? Yeah and so this is like short industries which is unfortunate and it's mainly because it's just not work that I have been involved with but I would be surprised if there wasn't consulting work that has looked at this but it's not through the contacts that I have. I don't know if Richard you have any insights that are greater than mine. No you can own this one Conrad. Next question. I'm interested in the effects on hydrology in rivers with regional areas and the interaction with stream regulation. Yeah so there is I want to point to colleagues that we have here at the University of Melbourne so I am in particular interested in extreme events flooding but there's a whole group here that look at trying to best essentially manage as best they can the regulation of the rivers in the Murray-Darling Basin and trying to move towards how best we can do that and there's a lot of interesting research out there because it actually turns out that natural regions actually respond very well often to or a lot of fish species and things like that. They need certain pulses of rainfall certain pulses of stream flow at certain times so there's actually a lot of interaction between these sort of let's say frequent flood events and how the ecosystem the health of the ecosystem so there's actually a lot of research in that space trying to how best we can actually regulate our rivers in terms of achieving both the outcomes for meeting irrigator needs but as well as managing the ecological health of the systems and indeed I want to say that the federal government acknowledges this there has been a centre for research just recently funded between multiple universities around Australia and government organisations and we're talking millions of dollars over the next 10 years to actually try and manage the health of the Murray-Darling Basin so that that CRC is called the One Basin so if you Google One Basin you'll find that they're just starting up and investigating that more and HydroTerror is one of the partners of the One Basin thanks for that plug yeah that is it's an amazing from a very personal point of view I think as far as CRC goes that is probably the most partners that have ever come together so just this recognition that that everyone's on board is just really impressive you should be very you should be congratulated on that just on the technical matters I was involved in a project several years ago looking at Western Australian catchments and just the potential effects of climate change on Western Australia's water supplies and one thing that is a concern is and you sort of had it in your early slides was you know what happens to runoff as we have reduced anti-seedant soil moisture content and a lot of the Western Australian streams in the area I was looking at you have a base flow contribution which is very saline and you have an interflow and a surface runoff flow that's fresh relatively fresh and those stream systems are really dependent on having that ratio of fresh water to the base flow contribution being at a point where the salinity doesn't get too high and with the projections of reduced runoff obviously that's a problem base flow contributions increasing relative to those more fresh water runoff sources so it's a complicated area that's for sure and some of the implications from climate change are going to be poorer water quality and that's one of the guidelines right better keep moving forward what considerations in engineering for psych social mental health on people from flooding I love this question because I would be surprised if there's any particular literature out there or that's Australia focused I've just been recently talking social scientist. And there is just, so are there any formal considerations? I doubt it. And, you know, should we be formally considering these things? Probably. I mean, I want to say it goes to sort of the nature-based solution question later. The sense of community is really important. People don't want to move from their floodplain. They don't want to move from their community. And these things are just so critical. And I'm just not really aware of any sort of research or considerations that are given to this. So I think it's just a really important thing that should be or needs to be considered in moving forward. And just this recognition that engineering is, I like building things, but engineering needs floodplain management as much about social science as it is about engineering. But I think the engineering gets more of a focus. And so I think that's fair to acknowledge. All right. Next question, Conrad. ARR 2019 versus ARR 2016. Best practice implementation versus good practice implementation. So I must confess, I don't know what this is exactly referring to. I'm wondering whether there was a change in the wording between the two. And it's maybe that's what the question is referring to, but I don't. I wouldn't know specifically what the difference is between those two ARR versions, I must confess. Is there an adoption within ARR 2019 of some of the stuff you're seeing in terms of climate change? Yeah. So I think that was one of the pleasing things that came out of Ancult. I want to say that there are agencies that are adopting the 5% climate change guidance and looking at the sensitivities of their design to that. And that's just fantastic to see. And I mean, I hope it's okay to say, I think, you know, my interpretation of the presentation was also like, we have a problem. And it increases the flood risks to our infrastructure. Okay. So now what do we do about it was the next question, and there wasn't necessarily an answer to that. But it was really promising and encouraging to see the implementation of the guidance because there has been research done and not everyone does. So it was encouraging to see what answer. Next question. Design flood factors to be considered for climate. I think you touched on that in your presentation. Yeah, I think that's right. I think we have a factoring for IFD curves in our flood guidance. And I guess, you know, I'm arguing for the fact that that should probably vary with severity and duration to be more consistent with the current science. So yeah. Okay. Adjustments of intensity, duration, frequency, IDF that were established based on old records. Yeah. I mean, I wanted to probably say a few things on this point. I mean, to calculate IFDs is no small task to QA all the data across Australia. A lot of it was hand QA. I mean, they were looking at extreme rainfall reliquids and then going back to the radar and trying to see whether the events were plausible. It was a mammoth undertaken by the Bureau of Meteorology. And so this notion to update IFDs regularly is not ideal world we would, but it is a massive undertaking. Yeah. So do the records incorporate some sort of non-stationary in them? Well, I mean, they're historical records, so quite possibly extreme rainfalls have increased. And again, the argument that I want to say is that that 5%, that was the best that we had a few years ago. Like when that was originally written, which was 2016, the original projects that were done for AR&R were done early 20, I mean, I was involved in some of them. So we're talking like 2010 around that time. So yeah, you know, it's been, it's been 10 to, you know, let's say 10 to 15 years. So the science has moved forward and that's, that's hopefully what was, I hope was conveyed in this presentation. Yeah. I think it was. What design events, this is a good question. What design events should we be using to design structures and systems? I can't put my finger on the government report now. But there was a government report that was put out after I think the Queensland floods and looking at reviewing design levels from around the world. We're not the only jurisdiction that uses 1,100. Others use rare ones. Other agencies around the world use more storyline black swan type design guidance, like what's our worst case scenario. All I'm going to say is 1,100 of your floods, not that rare. I'm just going to throw it out there. That's as far as I'm willing to go at this point in time, but it's not as rare as what I think, you know, we think it is. It'd be interesting to get the insurance industry's view on this. Like at the end of the day, it's their bottom pocket, right? Well, I mean, if, you know, if you're paying, you know, yeah, I think that's a really good point. I mean, how much are you willing to pay for insurance? And that sort of is a pretty good indicator of what risk we're willing to adopt. And yeah, I was surprised at the frequency of what a 1 in 100 can be, right? So it would be interesting to look at some of these flood events we've put around now and see how that plotted on there. It's a big challenge for our time, isn't it? But in the end, it's a bit like bushfires. The insurance in the end insurers will walk away from certain areas being good to know what their threshold is. So yes, I guess watch this space on that one. Next question, how to factor in climate change variability? For example, high rain, low rain periods into water balance and flood models? Yeah. I think I guess, you know, in terms of event based models, you know, we have factors for the IFDs. And I really wanted to say again, you know, I was thinking about, like, I managed to squeeze $40,000 out of the university to look at converting some of the research that we've been doing into the anti-seed and moisture conditions into some sort of loss parameters. Look, there isn't any formal guidance translating these things into guidance is difficult. But yeah, I wanted to say, like, it is sort of like a, you know, watch this space. I mean, in terms of water balance, like, it is, there's a really good argument. And apologies that this is sort of going on off a bit of a tangent. Like the thing is, if you've got a flood model, you've got a factor, you're rainfall up and, you know, you're losses down, right? Or up, sorry, you know, because it's drier. And the guidance is, you know, it's hard to translate the research into guidance, but it's getting there. This is where there's a really good argument for continuous simulation, because Australia has the most variable climate in the world. There's so many papers written about this. It is, you know, in the UK, it's just wet. And then it rains in parts, whereas we have these really long dry periods, really long wet periods, like what we're experiencing now. And the only way to sort of capture all that variability is to do continuous simulation. So, you know, stochastically simulate 100 years of data and run that through a water balance model. But it's hard to get long, long record lengths that are realistic. But really, that's the answer to the question is to use continuous simulation, but continuous simulation has its own issues and statistical assumptions as well. And it's not as robust as doing flood modeling. It's just, yeah, not a very, I feel like I'm just doing glue anyway. That's good. I mean, I guess I would add to that and just say, in terms of the water balance, I mean, obviously the Bureau of Meteorology is already doing that with their L calculations and climate change projections into that. And DPI New South Wales have done a probably a higher resolution mapping of that. I'm trying to remember the name of the model. I've lost it out of the side of my head, but it's pretty impressive too. So their resolution from DPI New South Wales is down to one kilometer versus or L, which I think is five. Yeah. So it's improving all the time. So if you wanted to look at how they factor it in, there's plenty of information, DPI New South Wales and how they've utilized projections to come up with that water balance going forward. Next question. I am studying nature-based solutions for flood management in my PhD, half a year in, and want to learn more about this area. Yeah. So I think I just want to go back here. If you're interested in that, what Richard mentioned, it's that URL. I think if you Google Australian Water Outlook, I think it will take you to that website. And yeah, I can't commend that work. So thanks for reminding me of that. Yeah. There's a PhD student here at the University of Melbourne who's around the same time in that I'm chairing, looking at nature-based solutions. It's a, all I can say on that is it is an emerging area. You have picked a very good research topic. I think there's a lot of interest in it. One of the hurdles in nature-based solutions is their adoption. I think they're really great at mitigating small floods and improving the health of waterways. And it's just a matter of getting a research out there that encourages people to adopt them and quantifying their benefits. So just a little bit more on that. So there's a few things. Perhaps if you just send me an email, I can connect you up with some people in this area. The Maloon Institute have doing extensive work in this area. And they have got some really large monitoring sites as well that we're involved in. It's called the Maloon Rehydration Initiative, but they have a wealth of ecological data as well as hydrological data. And also the work we're doing with DPI in New South Wales, a sort of whole of New South Wales study of where these sorts of things can be applied. Admittedly, that's more sort of around leaky wear structures, but some good people we could connect you with in that area. So I suggest give us an email and we'll hook you up with those people. Next question. The other thing about just getting back to that modeling that the Bureau has done, if you just wanted to have a look on our website at the webinar that Paul Fakima presented on, he provides background to that modeling. So it'd be worth you having a look at that. So just go to our website and you'll find a link to the webinars and that'll be in there as one of the recordings. Next question. Key questions for community engagement in establishing levels of service for drainage infrastructure. So again, there's quite a few students here and researchers who look at community engagement and I'm not going to do justice at all, but they and I'd be curious to hear other people's experience, but it turns out I'm not sure that my impression from their presentations, I'm probably not doing it justice, is that it's not really about necessarily always key questions. It's really about just taking people on the journey with you and what's been really interesting that they found is that actually the community are pretty smart. So you can actually really communicate what you're doing with them in detail. You don't have to worry about dumbing things down. They want information and yeah, and if you engage them early, generally the outcomes are really positive. So yeah, I don't know if you want to add anything to that Richard. Well, it's just interesting to see the progression over the last 30 years, you know, so I remember when the catchment management approach first came out and there was a lot of community engagement around that and a lot of farmers and the like participated in that and came up with some unique approaches for managing flooding and that sort of thing in those catchments. A model similar to that might need to be applied more to the urban environment. Now we're moving into this sort of more peaky sort of event and it's I guess it's coming to town, isn't it? Right? So similar approach. Yeah, you just made me realise I think one of the things that has come out that I've noticed from the literature I've been reading, I think there is a sense of and whether this helps with forming the questions is that there's sort of a the sense of fault has a false sense of security around infrastructure. So often when we see a levy or you know, I mean, I appreciate a levy might not necessarily be the type of infrastructure that you're referring to in this question. But when we think about a levy, we see it and we're like, oh yeah, we're safe. But you know, it's only safe for a certain size of event and usually that size isn't that large. So I think there's just a huge level of a false sense of security and we're not always communicating, I think, you know, how the actual risk, yeah. Which really comes back to that question, what design events should we be using to design structures and systems? It seems it should be a good debate around that at some stage. Better keep moving. We're well over time, but we've got nine questions in the Q&A and one more here. So if everyone's willing to hang on, or more importantly, if Conrad is, we will continue. I talk too much. So yeah, but now I'm happy to hang on. Thanks. Appreciate it. How would the climate change affect the rationale formula in computing for peak discharge? So two things I'll say. I think, so we've moved to this RFFP. I think from the, if you do the drop down in the AR&R data hub to calculate, yeah, rather than using the rational formula, but I appreciate that the rational formula is used in urban design. I think you just backdrop the intensities really. So yeah. Okay. Good answer. On to today's questions. I just highlight the importance of early bird questions. Giuseppe, one of our favourite attendees of these webinars. Giuseppe from Melbourne Zoo. According to the flu's risk and the time horizon years, is there any local regional toolkit or guideline that can be used to build infrastructure that most likely will face extreme events? Yeah. My understanding, and this is where, I haven't been a practicing engineer in a while. Flood's risk, sorry. But no, I mean, depending on the class of infrastructure, there's a different level of risk that you design to. It doesn't necessarily explicitly say how long your infrastructure is going to survive for, but depending on how critical your infrastructure is, then the level of risk that it's designed for is rarer and rarer. And I think there's local guidance to state guidance. Different jurisdictions have their own guidance around these things, if that's my understanding. Okay. Now, we have a chap. I'm not sure if I'm going to get the pronunciation right. Saeed Mir Aga Manawi from Afghanistan. And he's an assistant professor at the Engineering Faculty Pact here at uni. I am looking for a PhD position in water resource or environment. Is there any opportunity? Who should he get in touch with? Do you think he can? Well, I think, yeah, I want to say, I know this is, I don't want to be like directing you to a website, but the reality is that, yeah, if you keep on top of university websites, they continue to advertise PhD opportunities. I know that with the one basin, CRC, there will be advertisements coming out from the University of Melbourne, advertising for the HD students. So, you know, it really is about getting onto those mailing lists, so that, yeah, you can take, yeah, take those opportunities when they're advertised. There isn't any, the unfortunate thing is there's no usually specific time when these things are advertised. So it's just sort of about monitoring the relevant channels. Okay, so HopOnline is the answer there. Next question from Bizarre Jamali. Is any of climate change impact somehow accounted for in the ARR 2019 IFDs given it is using more recent data? I hope you can, oh, no, okay. My laptop is running through. Sorry, Conrad, you're breaking up a fair bit there. You might want to start again. Yeah, apologies. Okay, I think it's, we're back. Yeah, I mean, the answer is yes. If there's non-stationarity in there and you've, and you use more updated data, then it is in some way in there by default, but that, you know, the IFDs would be an average of the entire record. So if there's climate change that's happened very recently, it wouldn't be, yeah, it's weighted towards the entire record. So it's in there, but it's only an average of what's happened over the record length that they, that has been used. Okay, oops, I've scrolled past, sorry. Matt Taylor. My takeaway is that rare rain events are likely to get more extreme, but the type of rain event is likely to be short duration. Long duration rain events are reducing. So future risks are likely to be extreme microburst type storms question. My understanding is that those style events have increased run-off despite soil moisture as the pressure head required to drive deeper soil percolation is generally too high, not to mention the increased urbanization increasing in pervious areas in the first place. Are future flood risks primarily going to be flash floods basically? Yeah, so I think that's spot on. So there is definitely, yes, particularly because it's really important to note that most research that we do is using, say, the HWRS data that Richard, you presented, it's in rural areas, right? So, yeah, in urban areas, flood risk will increase. That's spot on. Everything there is absolutely spot on. And the only caveat that I would have is that, yeah, if you move to more localized short rainfalls, but in very large catchments, then well, by the time that reaches the river system, then that won't necessarily translate into an increase. But otherwise, yeah, that's spot on, yeah. Okay. So I had sent his email through. I'll forward that on. Anonymous attendee, agree that consideration of historical data is incredibly important and often not adequately considered. However, warming climate leading to atmospheric rivers and stalling weather systems are resulting in unprecedented flood events. Could Lismore have been anticipated? One in 10,000 plus question. Surely we have to at least plan for historical worst case plus more and transfer of similar setup to Lismore happening in other locations. Yeah, that's a really, really good question. The Bureau of Meteorology is actively doing research to look at how weather systems are changing. There is evidence that weather systems are changing in a way where they're exactly stalling. They're slower, so they dump more rainfall. Yeah, look, the second bit of that question goes to what are you designed for? Do you design for the Black Swan event or do you design based on some sort of probabilistic risk threshold? There's no real easy answers to those questions. You could answer a question for me, Conrad. Whose job is that to set that level? Yeah, I don't. That's a really good question. If anyone out there still on this knows that Q&A, it would seem that hooking yourself up with those people would fulfill your dreams of more applied science. Yeah, I was always on the impression that it was state government authorities that set flood planning levels, but I'm happy to show my ignorance if I'm wrong. I think it's really important we find that out. I might take that one unnoticed and see if we can work out who sets design thresholds when it's obviously sits in an Australian standard or something. Must be some civil engineers still hanging on the webinar. Last question, and thanks, everybody, for hanging around and particularly yourself, Conrad. How to measure flood resilience at the regional level after extreme flood events like West Germany 2021? Yeah. I think these things are all related, Conrad. If you set a threshold for what you design to, then that's probably a level of resilience. There is, again, there's good argument for, but we're getting better at disaster preparedness. Our emergency responses are quicker. We are definitely becoming more resilient to flooding in terms of this less loss of life, but yeah, I think you're right, Richard. A lot of these answers are in, well, what do we design for? All right. Well, that brings us to the end of today's webinar. I'd really like to thank yourself, Conrad, for a fantastic presentation and also thank you, everyone, for such a good set of questions there at the end. Many thanks for your time and also to Melbourne University. I really appreciate your contribution. I hope you enjoyed it, Conrad. Thank you. No, thanks so much for having me.