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Colorado River Basin Study Webinar — SRAR continued, Study Limitation,Next Steps (5 of 5)


Slide 61: (Vulnerable Conditions)
Ken Nowak: At this point we switch back to our vulnerable conditions analysis. As a quick review, vulnerable conditions is an alternate analysis of vulnerability. Essentially we’re trying to identify the conditions associated with the vulnerability and examples being drought magnitude, reservoir conditions, demands, etc. Now, this is the same exact figure that we used earlier as an example for this type of analysis. It’s the Lee Ferry deficit vulnerable conditions scatter plot. And the top pane is the baseline results – which is what we saw earlier. You’ll recall 11.2 million acre-foot eight year dry period mean and 38.2 million acre-foot long-term average define that space. Now as we introduce some portfolios – you’ll see Portfolio A and B there – we’ve significantly reduced the number of red marks on the figure – meaning we’ve reduced a high number of vulnerabilities which would have been reflected in those bar charts we just looked at. Now we can take this a step further and say we can redefine our conditions based on the new vulnerability scatter plot under the portfolios. Now why is this important? Well, the key here is we can quantify what we’ve gained in terms of the portfolios implementation. I would venture to say that you could easily shift that vertical line on the x-axis about a million acre-feet to the left to redefine the vulnerable space for Portfolio A – meaning you’ve gained a million acre-feet per year resilience against that eight-year drought we’ve been talking about. Now that’s important but it goes beyond because depending on how you’ve quantified your scenarios if you’ve quantified too many and I’ll call them easy fixes meaning they’re sitting just in the vulnerable space a small portfolio investment might actually bring a lot of those traces from the red to the grey or from vulnerable to unvulnerable. The problem there is that you may be overstating the effectiveness of that portfolio because you’re simply counting the number of traces that moved from vulnerable to not vulnerable space. However you may have only shifted that space by a small amount. Conversely, if you have a lot of what I’ll call hard fixes – traces that are very vulnerable and hard to really move from the vulnerable space from the red to the grey – it’s going to be very difficult even with a large portfolio investment to see a high number of traces shift. And so you wouldn’t be very happy if you’d invested a large portfolio but only saw a few traces come out of the vulnerable space into the non-vulnerable. However, if you knew that you’d actually added a million or two million acre-feet of annual resiliency, that might make those results seem different in that light. And so in addition to offering this complementary information to simply counting the number of traces in and out of vulnerable conditions, we can actually start to think about are the traces I’ve quantified missing some spaces in the distribution, are there too many hard fixes, are there too many easy fixes that are maybe skewing my results a little bit. So what we’d like to do here is go back to our Tableau workbook and just look at a few results. Ken Nowak: So what we’re looking at here is the same type of figure we just saw in PowerPoint but now we’re looking at the Lake Mead falling below 1000 water delivery indicator metric. And you can see we’ve got different definitions in terms of what is vulnerable, in terms of that eight-year dry period and the long-term flow. But ultimately the concept is the same. And as we implement portfolios, we see fewer and fewer red marks and we see more potential to shift the vertical and horizontal definitions of this yellow vulnerable space both left and down. We can also introduce or filter using the Tableau workbooks so as to remove certain scenarios and see how the results change. So, if you’re particularly interested in these results here or perhaps some of these red circles that are vulnerable but didn’t fall within our vulnerable space, you can start to see what scenarios are they associated with and just to see are your conditions more effective for certain supply demand combinations and perhaps less effective for others. Slide 62:
Ken Nowak:So last we want to just talk a little bit about how is each portfolio accomplishing the results that we’ve just seen. What we’re showing here is two different vulnerabilities. The left column I that upper basin Lee Ferry deficit indicator metric and the right column is the lower basin Lake Mead below 1000 indicator metric and associated vulnerability. The rows across are different supply scenarios and the colors represent different portfolios. On the y-axis you have percent of years vulnerable and on the x-axis is total annual cost in 2060 and that’s in billions of dollars. I’ll just note that the costs are in fact in 2012 dollars even though this is out in 2060. And obviously there’s a number of assumptions going into these different portfolio costs and option costing and we’re more interested in using it as a relative comparison as opposed to focusing on it as a pinpoint precision number. The kinds of things we’re looking to explore in this analysis are how much are you reducing vulnerability relative to what we believe the cost might be, what type of options are you using to get there and I’ll just focus on this not an approach to identify a best portfolio but an exploration of the strategies and their associated tradeoffs. To talk a little bit about this figure that we see here, baseline reliability is shown in the dotted line for each of the results. And under the first two Observed Resampled and Paleo Conditioned supply scenarios we see very low vulnerability and that the portfolios have almost no differences amongst them. This is generally perceived to be the fact that they’re all pulling from a common set of for lack of a better term low hanging fruit to achieve those same results in bringing the risk or the percent of years vulnerable down to effectively zero. Now, as we get to the Paleo Conditioned we start to see that the baseline had more elevated levels of vulnerable years and we start to see a little bit of separation from our portfolios. However, we’re really not seeing a lot of difference. Finally, when we get to our GCM scenario, we start to see some differences amongst these portfolios. And what this means is that the low fruit is gone and we’re starting to see some differences amongst the strategies on how to meet our most challenging scenarios. And so we’re going to use the Tableau workbooks again to explore a little bit more as to how these different portfolios are going about accomplishing that effectiveness. Ken Nowak: So what we have here is effectively the same exact figure. However we’ve grouped our supply scenarios in a different manner. On the top row we’ve got all water supply scenarios. And what we see is that because the baseline had six or 19 percent of traces vulnerable we’re just not seeing a lot of separation amongst the portfolios when we’re averaging results across all those different scenarios. However, as we move into the middle row – which is supply scenarios with low stream flow conditions effectively below the 50th percentile – we do start to see some separation. And then when we get to the lowest stream flow conditions – meaning this bottom row – which I believe is about the 20th percentile and below in terms of their stream flow – we really start to see separation here. And so a few examples that we can look at are under the upper basin vulnerability the Lee Ferry deficit we see that Portfolio D has the lowest cost. However, it’s only bringing vulnerability down from about 30 percent of years to maybe 15. Now the two portfolios that brought it the lowest were C and A. And A might be a little bit lower than C, but the cost is substantially different. And so this is something that we may want to explore some more and understand how come Portfolio C is coming in at about 5 billion whereas Portfolio A is around seven and they’re achieving effectively the same vulnerability reduction. There’s probably a tradeoff there, but this is the type of first cut that allows us to identify things for future exploration. Similarly, if we look at the lower basin Mead below 1000 vulnerability we see that the baseline result was 71 percent of years vulnerable and that we were able to actually bring that down to around 25 percent with Portfolio D – which is again our portfolio with the fewest number of options. It’s that common space in the Venn diagram and probably what’s happening here is it’s just running out of options. And so it’s somewhat capped at its cost because of the number of options and yield at hand. However, some of our other portfolios with more options and related higher costs can bring that vulnerability down even further. And again we see a similar sort of situation where Portfolio B and Portfolio A are effectively bringing our percent of years down to the same level but at different costs. And this again is where we’d want to be able to explore and understand how are these two portfolios achieving that reduction and why is the cost different. This is a bit of challenging diagram to look at but it helps us to start to answer those questions of how are these portfolios going about achieving the reduction in risk that we’re seeing. All the columns represent Portfolios A through D. And on the y-axis you have a variety of options that we considered in our portfolios. The vertical black line you see in each individual box or cell represents the earliest possible time that that option was available. And so if we scroll down here, you can see that there’s a time axis on the bottom of each one of these columns and that the color is indicative of how many traces or the percent of traces that have that option implemented through time. And so when you see red and red indicates 100 percent or close to all traces, you know that that’s being used a lot. And when you see red right up against that vertical black line, like is the case here for this energy water use efficiency option, you know, that under all the traces in Portfolio A we’re really relying on that heavily and implementing that option as soon as it’s available. While if we just move over here to Portfolio B, we see that it’s never being implemented as soon as it’s available and then only in low amounts as we move forward to even in 2060 it’s a relatively low number of traces under Portfolio B, about 18 percent traces are using this option. So this is where we can start to go into some more of the detail of how are these different portfolios going about achieving the risk reductions that you see. And in some cases you don’t even see any color – meaning that that option was not part of a given portfolio. So Tamarisk watershed management apparently did not make the criteria for Portfolio B and Portfolio D for whatever reason – whatever those criteria that were established filtered it out — and so it’s not being used at all. Whereas Portfolio A and C by 2060 are actually seeing as high as maybe 70% of traces using it. And so that’s again where you’d want to go back and explore and understand what are the tradeoffs, maybe it’s less reliable and that’s why it didn’t make it in or maybe there’s something else going on and really get a good feel for why are these results showing the things that they are. Slide 63: (Summary, Study limitations and next steps)
Ken Nowak: Okay. So at this point we’re going to go back to the PowerPoint and Carly is going to take us through summary, study limitations and next steps. Carly Jerla: So I’m going to wrap up here with these three items over the next ten minutes or so and then we’ll open it up to questions. Slide 64:
Carly Jerla: So this is quite a difficult study to summarize in a few bullets or so but these are really broad kind of take home message to think about looking at all of the results of the study. So, the first finding is that across the board through all of this analysis and through all of the different resource metrics that we considered we’ve demonstrated that the system is vulnerable if we do nothing. So the results of that baseline analysis clearly showed that there are some vulnerabilities across all of those resource metrics. However, with the implementation of the portfolios that we explored we see that doing something will greatly reduce that vulnerability and through the analysis of the vulnerable conditions that Ken described we are able to make ourself more resilient to those adverse conditions, so those lower, long-term means and lower drought spells or more severe drought spells. We’re able to weather those better. However, we’re not eliminating vulnerability. So we’re always left with some level of vulnerability even if we’re implementing the portfolio that has the most options available and is very inclusive in terms of the options that it will select. And this is really due to the fact that we’re dealing with a system where our allocations and our use and demand exceed what the supply is that the system is bringing. And so we’re always going to have some type of vulnerability to weather and manage through. If we look at what all of the portfolios have in common, in the near term what’s being implemented throughout the portfolios are options such as municipal and agricultural conservation, a variety of water transfers from agricultural to municipal uses and reuse. We’re seeing these are cost-effective ways to reduce the vulnerability. However, as we look down the road in the longer term, in that 2040 to 2060 period, we’re really starting to see some more tradeoffs emerge in terms of what an acceptable level of risk is that these options are able to mitigate against, what is the expense of that mitigation – both to the resources and other implications. Slide 65:
Carly Jerla: As with all studies there are limitation associated with these studies. Just a couple that I want to mention here, the detail and depth to which the analyses were performed was limited by the availability of the data, the models, the methods and the capability of the existing models to be able to use that data and simulate future conditions. So some of the limitation that exist from this fact are the ability to asses future impacts to the basin resources. Many of the resources to fully understand how they’re performing require analyses beyond the time step or the spatial detail that we were looking at, in addition to other factors beyond flow. And our methods were limited in the ability to do some of these analyses. Another limitation was with respect to the options characterization process. I mentioned earlier on that a team was put together to do this characterization. It was very much at an appraisal level at best. In some areas it was less than that. In many cases the team disagreed with respect to some of the characterization. For example thought the ratings for various criteria should be higher or lower in certain cases. And I think in the end there was agreement reached that there needs to be additional analyses for many of these criteria to move forward and understand these options better. Another area that was limited was the consideration of options. Due to the time and resources available in the study, the quantitative analysis was really focused on a select set of options and this by no means should be considered the full gamut of options that should be considered in moving forward to deal with some of the supply imbalances that are projected in this study. Another limitation is with respect to the geographic scope of the study. The lower basin tributary, so namely the Virgin River, Bill Williams River, Little Colorado and the Gila River were handled differently than the other tributaries in the upper basin. These are not natural flows. These are gaged flows. And in the case of the Gila River, this is not included in the model that we used. And so this is an area that we’re going to move forward in to better understand the use on these tributaries and in some cases develop natural flows and include those into our model. Slide 66:
Carly Jerla: So where do we go from here? In the study report, so that 100-page document that summarizes all of those technical reports, there’s a section that describes next steps or more specifically the areas where next steps should be taken. Those ten areas are listed here. And that section of the study report discusses various methods and directions that we should move forward in for all of these areas. And it summarizes that direction by saying that we want to move forward in a collaborative approach – the same approach that was demonstrated throughout the study.
And so we are gearing up to move forward in each one of these areas in different ways. Slide 67:
Carly Jerla: But, before we do that and really what today the purpose of today was, was we wanted to conduct a series of educational outreach sessions to help folks really better understand the type of information that’s included in the study and what some of that information can be interpreted as. So we did two of these outreach sessions last week – face-to-face sessions – one in Salt Lake City and one in Phoenix – and today concludes the series of outreach sessions. Beyond that we’re going to work together to reduce uncertainties related to the areas that we found to be very promising and included in all of those portfolios in the near term, so things such as water conservation and reuse. And we’re also going to work to further our understanding of water banking augmentation-type options and weather modification concepts. We will also embark on a study of tribal water issues to better understand these. This is an area that the study didn’t go into much detail in, but working with the native tribes and communities throughout the river basin in the study we understood was an area that they want to understand better the impacts of imbalances on tribal water issues. We will always continue to advance the science and modeling tools used in the study to be able to address some of those limitations that I just previously listed. And in moving forward in all of this and really speaking to the comprehensiveness and the broad resources that the study considered we want to consider strategies that provide a wide range of benefits to all water users. Carly Jerla: And so with that this concludes our presentation for the educational outreach session. I want to thank you for your attention and we’ll be happy to answer any questions.

Glenn Chapman

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