PANEL DISCUSSION: The science of natural functional flows to the Delta

Some would argue that more storage in the system would actually benefit native species and our ability to provide environmental flows,” began moderator Chris Enright. It could be that would allow us to harvest wet year flows. So, additional storage allows us to do that. It allows us, perhaps, to have water for drier years. One thing we also know in this system is when wet years happen, good ecology happens. We generally have high abundances of all of our native species. The question is, do we maintain wet years as natural flow years or do we harvest those years and use those waters in other year times, perhaps dry year types?

Dr. Petts talked about a smart flow regime that would identify base flows and protect those, identify flood flows and protect those, and then, allow for some percentage of sort of natural flow pattern in the mid range. So, there are lots of perspectives. Harvest wet flows. Protect that diversity of hydrologic input. Protect those at a disturbance regime.

“So, the question to the panel, based on what you’ve heard and based on just common sense about smart flows, if we were to protect a portion of the hydrograph in its more natural state, what would we look to first? What water year types?”

DR. GEOFFREY PETTS:We’re told to think about the science, not about policy and management. I think in the ideal world, I would want to see a wet year immediately following a dry year because in all the examples that I know of, anytime we’ve had a really good drought, if we’ve had a wet year following simply five, simply six, simply six ended with a hum-dinger of wet year and recovery was fantastic. If we had two, three, four dry years together, that’s when we get a problem. In an ideal world … I have a coupling. I don’t mind having a dry year provided it’s followed by a wet year.

DR. BRUCE HERBOLD:In the 1987 to early ’90s drought, we emptied all the reservoirs in the first six years. So even though it was a wet year, on the seventh year, the fish saw nothing out of that. It became an eight year drought for the fish, where it had been a six year drought for everybody else. If we’re looking at co-equal goals or something, that’s an occasion in which the wet year is lost. On the other hand, usually when we have a wet year, we’re getting 60 million acre feet. We get something like natural flows for a good hunk of the year, like 2011.”

Moderator Chris Enright prompts, “The question is, do you want to harvest that flow? Should we store it?”

DR. BRUCE HERBOLD:The amount we can harvest is often a small portion of it. Especially with climate change bringing it as rain, it flows through the system much more rapidly than it used to then when more of it came as snow. Our ability to harvest has gone down, and it’s often a vast quantity of water and the fish do really well. By trying to protect those wet year conditions, accept in those isolated wet year cycles in the middle of a drought, that you really have a lot of storage that’s suddenly available because you’ve drained it all and killed all the fish below those dams. That seems like running to the going under side of the ship instead of trying to balance it out because what we have usually is a dry year comes along, and every other demand of water comes up, and so as dry year conditions get amplified by all the other uses that suddenly need more water also. To walk away from the environmental needs seems to me to be unnecessarily intensifying what would be a normal low flow condition by diverting more water to other purposes, so that you’re pushing up against the limits of those fish to tolerate the natural flows variability [by turning it] into unnatural flow variability.”

DR. GEOFF PETTS:Talking about the future and the climate change, one of interesting things, if the forecasts are right, the very fortunate position we are in is that we’re forecasting wetter winters and drier summers. Most of our rivers in southern and eastern England, which is the driest area, are dominated by groundwater fed rivers. The aquifer fills up in the winter and they maintain the flow through the summer. That will be a huge benefit for both the rivers and the environment and actually solve some of the problems that we possibly face. Back to looking at spatial variability, looking at the individual characteristics of the different river systems in many places in the UK, the wetter winters will be beneficial in increasing catchment storage – reservoir storage as well as groundwater storage. That will be enormously helpful to us.”

ROBIN GROSSINGER:The years I’d like to see are wet years being spread into flood plains and flood basins and really take advantage of that water in generate really big productive years for steelhead and for salmon. We still haven’t seen them, and we can carry through multiple years. It seems we don’t necessarily take advantage of those wet years because they’re not doing the ecological productivity and also the recharge that they could be doing if they had broad areas to work with.”

Moderator Chris Enright: “Can we turn this question a little bit … If we were to have an ecosystem with far more connectivity so that the flood flows could actually reach flood plains at lower levels, would your answer change?”

ROBIN GROSSINGER:They’d all work pretty well at that point, right? I don’t know. They are going to be in there. The question is do we have a system that can handle it? I think we want some dry years mixed in too to knock back the invasive species …

Moderator Chris Enright then reads a question from the audience. “There’s lots of discussion about processes, but less about framing ecological objectives, which would be served by improving flow regimes. Period.” So, the question is how would changes in a flow regime and development of ecological objectives work together? Which one should lead, especially in the context of climate change?”

DR. BRUCE HERBOLD:  “This was actually about my question to Les Grober at the break. You adopted a standard percentage, and then 15 years later you evaluate whether it’s adequate, and I have no idea how you would tell whether it was adequate from what I understand.”

LES GROBER:I think that’s part of the problem even now. Try to determine now with the information we have, which is why it’s always hard to develop certain flow prescriptions because we don’t have sufficient information to say it should be one thing versus another and to identify the causal effects of this or that. The water board’s proposal is for now is 35% recognizing that we don’t have this definitive information, but it’s not saying that “We don’t have it and we’re never going to know.” It’s saying, “Well, this is a starting point but for this to be successful, it needs to be combined with the studies, the information, that can help us assess how the system is responding to it.” Of course, I think it’s a great leap, and it’s a great challenge because you’re going to have to try to determine these things. At the same time, other things are changing, which is what is happened always in the past and always will happen in the future. I, frankly, don’t know exactly how that would happen, but I think they’re beginning to develop the science programs, develop the monitoring, and develop the studies to make the determinations that we can.”

Bruce Herbold directs a question to Les Grober: “If everything’s 30%, then your ability to distinguish the difference of how much more you need or how much less you need is really limited. Would you consider the possibility of an even numbered years making it 25 and in odd numbered years make it 45 and seeing if 25 or 45 is different in some measurable parameter of fish production or fish passage? Would that be within the board’s adaptive management approach? Do you have any thoughts on that?”

LES GROBER:I think within the construct of the proposed of 25 to 45% that could be a proposal certainly coming out of the COG [Coordinated Operations Group] is that “You know what? You need to conduct this experiment to do the 25% one year, 45% the next year. We’ve discussed this.” That would be overarching. You wouldn’t know beforehand what kind of year this was, so sometimes the 45 would be applied to a wet year, sometimes to a dry year, but it would just be assuring that you’re at least shifting the amount that is being provided, if you will, to the fishery use as opposed to the other uses of water. It’s an interesting hypothesis. I’ll answer it with a question back to you. How would you evaluate the results of such an experiment to make a determination for a species such as salmon?

DR. BRUCE HERBOLD: “I’d radio tag the little suckers and see how many of them made it out.”

LES GROBER:Just over for each year and just compare them as paired years basically?

DR. BRUCE HERBOLD:Sure.”

Moderator Chris Enright: “How do you make the linkage between the decision to have imposed 35% flow to radio tagging the little suckers and monitoring their response to something, not only to what we did as a management option but also they’re responding to the rest of the signals from the ecosystem? How do we discern if what we did had the effect that we think it did? We’re seeing effect because of what we did or for some other reason?”

DR. BRUCE HERBOLD:In 2009, it was the third year of a drought, and San Joaquin was flowing very low. Because it was flowing very low, the water was very clear. Because the water was very clear, predation impacts on our radio tagged fish were horribly high. None of them made it halfway through the Delta. We pretty reliably attributed that to predation because they stopped moving after they started moving back and forth in one place. Then, they’d get pooped out, and the radio tag kept staying in one spot. So, it looked like predation. It looked like predation that was greatly facilitated by low flows and high transparency. The next year was a wet year. Turbidity went way up. Predation went down. Some fish made it out. Not a lot, but more than before. I’ve got, in my head anyway, a conceptual model of turbidity and flow controlling fish passage and predation rates, and I think we can measure those things, and if I’m right or wrong, I think we can determine that. I stand ready to be corrected, but the technology we have now allows us to look at stretch specific loss rates and successful migration paths and rates. I think we can do that job.”

DR. GEOFFREY PETTS:I’d throw out a slightly different approach. I think as soon as you move away from the physical couple of models linking atmospheric dynamics with hydrology, and then you start to go down through looking at catchment change, looking at engineering works, looking at biochemical dynamics, looking at algal dynamics, looking at food webs, you’re getting farther and farther away from the primary physical data, then uncertainty grows enormously. If the world was just about looking at migratory fish, it would be great. But, we’re a nation of bird watchers. It’s about birds. … But, it’s not just about them. I think it’s a real problem here. For me, there’s much more certainty if we start off with what we can do, which is mobilizing the physical basis of the system and the hydrology itself. We can do that with a lot of certainty. Once you go down the faster road, then I think we get real uncertainty. For me, the answer’s quite simple. We start with the physical targets and then we piggy-back the ecological ones.”

Moderator Chris Enright then gave another question from the audience. “Dr. Petts noted that very dry periods are as important as very wet periods. Could the panel address whether there are any examples of therapeutic low flow events? … A lot of the discussion really is focused on the management of rivers creating life-line flows, minimum flows, peak flows, but I personally have never heard of a therapeutic dry period to try and change something. We have anecdotal examples where we think it might have been nice to dry something out, but I’ve never heard of it in active management.”

DR. GEOFFRETY PETTS:We need to remember, certainly, that when we’re talking about the river corridor, there are terrestrial species that depend on the river as well as aquatic species that depend on the floodplain. There’s been a lot of work, certainly, in the UK on looking at the dependency of terrestrial flood plain species, and other species who use the dry edge of the river, and indeed those who use the dry rivers to maintain their populations. Secondly, there’s good evidence in the UK of the number of important invertebrate species according to the conservation groups, species that depend on these intermittent streams and, you might want to come back in there. These intermittent streams have a pretty interesting, if not unique, fauna that represents an important part of the overall biota of our biogeographic regions. So, I think that there are, but it’s more from that side of the intermittent stream.”

DR. CLIFFORD DAHM:As you were asking that question, I was thinking about some of the work that I was introduced to when I spent time in the outback of Queensland. There’s a paper that’s basically titled “Boom and Bust and the Bits In Between”. It points out that the boom and the bust is when the water comes and when the water goes away, and then the bits in between are when they have these receding flows, but what happens, and they certainly have showed that it’s really important to the health of that system, is that ultimately the refugia become the water holes. As long as the dry periods do not exceed the time period necessary to completely evaporate those water holes, they then are quite effective at being the seed when the next boom comes. There is an explosion of productivity because what is then mobilizes all this material that needs to be decomposed and all these nutrients that goes into primary production. So, there’s an example of where that priming is very much on the dry side and then explodes when the wet side comes.”
The worry that they have there is that a lot of these water holes seem to persist for up to about 24 months, but they’re now starting to see droughts that last that long. So, they’re worried that the refugia will disappear. Then, there’s also the human abstraction of water in those same areas.”

Audience member clarifies: “Part of my question, just to clarify, has anyone actively put that in some kind of regulation or adaptive management event? I totally agree with all the speakers that there are these documented benefits, but I’ve never seen anyone mandate something like this.”

SARAH YARNELL:I’ve also never seen anyone mandate it. However, there’s been research that’s been done on the coast ranges looking at the influence of wet versus dry years on bullfrogs and foothill yellow legged frogs. The bullfrogs are the invasive species; they can tolerate the big pools and warm pools. Dry years, the flows are lower earlier. The bullfrogs creep up the system. Wet years, they’re pushed back down through the system. The way that they manage them in some of the parks is actually beneficial to help them get rid of the stock ponds where the bullfrogs are there, and then to dry out the streams and let the streams go to low flow. That kind of local level, the state park level, but there’s couple papers that have been published talking about this dynamic between the low flows helping the native species to persist and having to push back non-native.

Just off the top of my head the one other example is the floodplain … the idea of that once you can dry out the flood plain, the natives are gone. It’s the non-natives that are left. So, let the flood plain dry.”

ROBIN GROSSINGER:There is an example I was sort of personally involved in, which I’m not quite sure how it ended up playing out, but at one point NMFS had at least considered changing the recommendation. This was a stream that had been managed as perennial for a number of years, but we actually showed that it had been intermittent naturally, historically. Then, a number of the biologists in the agencies on this stream, started to consider “Well, maybe it’s actually not doing any good as a perennial stream, and in fact, the non-native fish are moving up the system as well as concerns about bullfrogs as well.” That was imported Delta water as it was, and maybe that was part of the reason that Central Valley hatchery salmon were coming up the stream, which was not in the Central Valley. So, wrong signals; bad timing. It was thought that it would be more therapeutic for the stream to actually reduce that perennial, imported, supplemental water and go back to more intermittent conditions.”

LES GROBER:Some years ago, I think it might still be in litigation, there was a water quality certification having to do with changes to flow on Piru Creek, which was receiving water from the State Water Project. It was receiving more perennial flows, and the water quality certification that was issued, the regulation if you will, was to restore it to more of the natural flow regime, which involved drying it up significantly, which had the effects on the recreational beneficial uses, swimming as well as fishing.”

DR. GEOFF PETTS:The issue for us in the UK … it must be 15 years ago now, when there was a presumption in the industry in – all areas – that artificially enhanced base flows during summer was a good thing. So, we had rivers with three, four, five, up to ten times the natural base flow – base water discharge, treated water discharges. There wasn’t a pollution problem. The assumption was that that was a good thing. So, year on year of higher flows was a good thing. That’s what’s been challenged.”

We have exactly the same question. Is there any evidence if we drop flow levels? We’re still working. Certainly, in Europe, there’s still that presumption that high base flows is a good thing for the ecology. … Certainly, the issue for us was, to go back to a very simplistic statement, that if you base your low flows as we tend to do on some very, very simple low flow statistic such as the historic 95th percentile flow, then we know that flows in summer always go below that because it’s on average for the year. If you look at the number of days that the flow should go below Q95, it’s a very large number. I think that if we can move towards mimicking the natural flow – allowing it to go down in June, July, August in the UK context, then there is a view that it should be beneficial. We won’t know unless we try it. That’s part of the problem.”

Moderator Chris Enright: “Let me just follow on with that … we heard from Les Grober earlier that the averaging period for the percentage of unimpaired flows is 14 days, and there’s going to be a Coordinated Operating Group that will adaptively manage those flows. You showed examples of what the hydrograph looks like when use shorter averaging periods. We tend not to lag so much, and we get much more variability in the signal. That comes at pretty high management costs and puts a lot of strain on our ability to collect the data, to actually do that management adaptively. On the other hand, the long averaging periods gives us those attenuation and lengths. The question to the panel is, in general, what kind of averaging period should we be considering for managing some percentage of the hydrograph?

LES GROBER:At least part of the rationale for the 14 day period is that that’s clearly something that’s achievable in terms of current technology measurements. I think with the increase in telemetry that’s available now, we can certainly do something much shorter time frame than that. If there’s money involved, in terms of hydropower operations, things like that – certainly we allow flood control, the sequence are being made on an hourly basis. Then … Part of this estimating of unpaired flow involves reservoir elevation operation; you start cutting pretty fine. The wind just comes up. What are you actually measuring? What’s the sweet spot in terms of operation?”

Once again, not to defer the hard questions, but you could tend to overthink this. Really, the impetus for the board is to put out something that provides a challenge and incentive to what can you do better than this 14 day? I think there’s potentially water savings and there’s potential great optimal protection of the use by converging on something less than that, but it’s a starting point.

We’re always thinking in terms of optimal. We tend to forget “Well, you know? There’s what we know. There’s what we don’t know. There’s what we don’t know we don’t know.” We’ve had the resiliency of the species and the history of the species is that we find if funny things happen, it’s like “Oh, we didn’t specifically operate to do this thing, and yet we see a success here.” We’ve had maybe early migration of the fry or the parr or something. Rather than putting all of our focus on the smelt. Very long answer. Don’t overthink it. Fourteen days is a good starting point, but what’s better?

DR. GEOFFREY PETTS:From my perspective, the shorter we can get it the better it can be in terms of making more water available for supply and for the environment. The longer the time period, then we tend to compromise both. So, if we can do it on a daily basis, actually brilliant. We’ve got one scheme in China where we’re running on a daily basis because it’s very simple. In Britain, we struggle, to be quite frank, to manage it on a three monthly basis. But, that’s more to do with the guys who are turning the wheels and pushing the buttons. If we can make it more automatic, with automatic gates that are triggered by daily stations, then there’s no reason why, theoretically mind you, we cannot move to a much more sensitive system. But, I think you’re absolutely right. It’s pragmatic.
Certainly, when I started out in the ’80s doing this stuff, they refused to think of anything other than an annual basis. I mean, the industry wouldn’t even think about it because there was a guy turning a big wheel mechanically. He was usually sick anyway.

Moderator Chris Enright: “There was a bit of a trade-off if we’re operating on a short time scale and trying to measure the results of what we’ve done. It makes it, then, very difficult. Now we’ve got a moving time series of operations that we are supposing have an effect and we have to show those effects through hypotheses and ultimately trying to prove those hypotheses. The advantage of having an annual flow, I suppose, is that it’s easy to then do an experiment that will last a year. At least in simple terms. Anybody want to respond to that?”

SARAH YARNELL:I think there’s different situations where different time frames might be appropriate. In the work that we’ve been doing in trying to figure out how to quantify a flow regime, a peak flow is very short naturally and particularly when you first start drawing down, they’re very steep. Things are changing very quickly. So, a daily basis is about the max you want to do. It really started losing the shape. Conversely, by the time you get down to the summer low flow, there’s actually enough variability just in dynamic fluctuations that you start to lose the signal if your time period’s too close.”

So, for example, if you wanted to define what’s the end of the recession. What is the low flow? We almost found that by averaging it on a weekly basis and taking a seven day moving average that we had a better luck. I guess my point is that there might be some times of year where it’s more appropriate to look at a little bit bigger window and sometimes a year it might be really helpful to look at a shorter window because it might be a scaling issue.”

DR. CLIFFORD DAHM:I’ll also add that there certainly are some very major differences in how they operate these decision making processes depending on where you are in the United States. They are topographically challenged in Florida, they don’t have lots of dams and reservoirs, and they do all of their decisions on a daily time step. So, how much they can extract is basically on the daily decision making process. Not going to work so well when you have high gradient major storage facilities like dams, so it also can be scaled to the system you’re working with.”

DR. GEOFF PETTS:I think the benefits of going to shorter time scales increase as you move away from a precise attempt to mimic the natural flow regime and move towards where we might say the first flood of the autumn has to be protected, but the second, third, and fourth can be used to increase reservoir storage. If you stopped it at certain times of the year, you need to have certain flows, then the ability to manage that on a short term basis, to make that tradeoff between water supply requirements and flood control requirements … For example, in the UK, we’re trying to move to a situation where we allow natural floods to flood the flood plain up to one in five year frequency. Big floods, you know? They’re the ones we still try to manage, but we still try to make sure that intermediate floods do, in fact, inundate the flood plain. You can do it much better on a short term time scale.”

If you’re simply trying to copy nature, but reduce the magnitude throughout the whole flow regime, you don’t need to do that on a one daily basis. It really depends on how flexible you are. Whether you’re really trying to mimic the whole flow regime or simply trying to insure that key functional flows linked into life cycle cues are actually preserved. If you can try that I think we need to do it in a more sophisticated manner.”

DR. BRUCE HERBOLD:If climate change represents a movement away from some of the value of those flows, then mimicking or amplifying impacts the changes in climate change is something we need to fight against. So, longer averaging times and shoving some of that water around, in a way that we think will do some good, whether we have models that we trust or not, is better than allowing those earlier floods because they’re now all rain and we’re not getting any snow, and it’s not coming at the time when the fish or the birds or the mice need it is more useful application of water flow.”

Moderator Chris Enright: “As Sarah pointed out earlier too, the ecosystem itself can tell us the time scale and the frequency with which that we need to make management changes. For example, on flood plains, flood plains need at least seven days to start to generate phytoplankton. Another seven days to start to generate secondary production. Now, that’s a scale right there where we would make a change that would inundate a flood plain for. We want it at least three weeks.”

LES GROBER:There’s quite a lot of thought that went into how prescriptive need one be and what should these periods be, but this is a compromise in terms of it’s more important to make some determination now that provides sufficient latitude to do all the things I’m hearing here, which is how do we adapt and make the best decisions in real time but provide sufficient regulatory back stop that if we do nothing, we’ll have something. Is it better than what we have? Even if it’s not at all times better than what we have, it provides, in total, something better than what we have, because we’re confident that once we know that initial budget we can fine tune it to do the experiments that are needed and also in real time make the decisions that are needed to optimize protection. We could spend, I would suggest, maybe too much time in terms of safely out the average period. We could spend a lot of time on that. If I do the math, the budget is the same if you go out the door, again, talking like the regulator with a fourteen day, a three day, it still provides a budget for us to do anything that we need to do.”

Moderator Chris Enright gives another question from the audience, this one addressed to Robin Grossinger. “From the historical documents you found, Robin, do you think the natural hydrograph for the Sacramento River could be determined pre-European?”

ROBIN GROSSINGER:I was talking to Mike McWilliams about that because also we’d like to, in theory, model that hydrograph through into the Delta and hydrodynamics and how the channel has mediated that. It’s interesting. Mike was more confident being able to the model in the complexity of the incredibly sinuous title channel network within the marsh than reconstructing the natural hydrograph with all the questions of wetlands and base flow and recharge and extended flooding. So, I really don’t know how hard that would be, and I guess it depends on what certainty level you’re looking for. I mean, often the answer is that it’s going to be so different from now that it maybe that the amount of errors still going to be minor compared to the dramatic changes, but I’m not sure that’s true. … That doesn’t sound easy.”

Chris Enright: It’s the Holy Grail to have to try to understand how the historical landscapes routed flows and how species responded. So, that’s obviously the first data point, so it’s valuable at least from that perspective. Very difficult to come up with magnitudes as Peter Vorster has pointed out, just small changes in the coefficients on native vegetation consumptive use can make an enormous difference in the overall run-off from the system, for example.”

LES GROBER:But to what purpose? Very interesting to know what could have been and come up with a rationale and come up with new numbers, but I’d say if we’re going to explore things like that, we should rather be looking at things that have bearing on other things we’re operating to or other goals that we’re trying to achieve. Things like a portion of it that would say in-Delta consumptive use and things like that. Those are more important metrics to help inform how we best manage the Delta system.”

ROBIN GROSSINGER:Thinking about how Bruce was talking about how these components of the water shed kind of add up, having a conceptual model, at least, about what would we like to see based on natural history and how we think it used to operate and how we think it could operate in terms of floodplains, extended floodplain, duration. Working our way up these rivers towards the top. That seems to be where it would be useful to be thinking about the sort of range of variation historically and today. I don’t think we have to model it all out, but it seems like that’s part of a thought exercise to figure out what that overall hydrologic system might want to look like.”

DR. CLIFFORD DAHM:I think a lot of the work that’s being done now that is attempting to try to give us a better picture of the extremes, the mega droughts and the mega floods. In the southwest, that’s 2000 years now of reconstructed tree rings that have basically identified three mega droughts that can kind of serve as the boundary of the worst we might expect. Again, seeing some level of stationarity, which we can probably argue is probably no longer in the system. And then certainly the recent paper by Detinger and Ingram used a lot of the flood deposits to get an idea of what some of the mega floods were and some of the reproduces. So, it works at the extremes; getting into nuances of the year to year variable is going to be very challenging …

Chris Enright, gave another question from the audience, “Please speculate about how fish populations managed to persist in the face of century-long droughts of the past.”

CLIFFORD DAHM: “I’ll suggest two types of refugia that were more prevalent earlier on and that is that we had groundwater, upwelling zones that are persistent in time that have recharges that are 50-100 year time steps, and certainly we can identify some of those that are still extant in some river systems. Then, that lateral connectivity, which we’ve largely eliminated, did produce some of the kinds of oxbow systems that the Australian study as their refuge that asked for three years.

Chris Enright: “One thing we know about the long droughts is that they weren’t droughts every single year for a long time. They were just more dry years than wet years, so there were wet years in there, even during the long droughts. So, one way the landscape would have provided for resilience of species, I think, too, is the groundwater connection. Anytime the Central Valley flooded, it happened in the winter time. That water was cold. It went into the ground. That refrigerates water anyway. It’s an enormous reservoir. The water table would have been higher than the streams during base flow periods for, I’m expecting, for possibly many years providing cold water. It had built into some geochemistry and geomorphic conditions that would have, even in hot, dry years would have provided cold water refugia, and then allowing a lateral gradient variablilities important as well.”

DR. BRUCE HERBOLD:… All of that California’s history to me is reflected in its fish fauna. It’s not a question of how do they survive; in the future with climate change, the fish that are going to do well are the ones that were here before because we’re going to amplify California’s variable climate. It will override our efforts to make it stable as we have for the last 100 years. That’s why I want some of our California fish to still be here so that we have some fish that are already adapted to the climate change future. We do. They do really well.”

I’m hearing people say that “Oh, well, climate change is going to wipe out salmon runs.” We are at the lower south end of our salmon, but they find cold water. To my mind, our job is not to walk away and say “Oh, well, the regional temperatures are going to go up.” It’s to look at the small scale levels and say “Where can we provide them refuge?” One of the other times I’ve been wrong is thinking that the Delta smelt could not live in the delta year around because the regional temperatures were too high for them, and they’re not cold. We’re sampling, and you get some habitat diversity, they find their refuge, and they are here year around in fresh water in the Delta, which is not what any of us thought 15 years ago. We learned things. Fish are also adaptable, and that the proper scale we can start doing things to protect those fish and they’re already well-adapted to deal with a lot of these stresses. I’m always looking for silver linings, and there are several in there.”

Chris Enright then asked: “Almost all of today’s talks focused on rivers, but the delta and the estuary are main object of current planning efforts. How do the concepts and issues you discussed translate to the estuary?”

LES GROBER:I think, once again, as an overarching theme, and it’s consistent with the science that’s been assembled going back to that 2010 report is that more flow of a more natural pattern is in general beneficial. Its things like variable salinity zones and things like that. It’s like this concept of variability is a good thing and it has some value. Again, how do you quantify that and how do you balance that against what we’re going to be most up-front against in the Delta is that you’ve got not just the competing uses as been characterized between ecosystem protection, fishery protection, and public interest uses such as Ag, hydropower. There you have “Well, how much water do you maintain for maintaining temperatures on the Sacramento side, and how do you balance that against flows that you need in terms of say, Delta outflow and variable Delta outflow?” In some ways that’s a false choice, a false question. … Short answer of then is, it’s a concept that the water board thinks has merit in terms of establishing flows for the rest of the Delta, but we’re very early in that process and we’ll be going through a lot of public process and a lot more science.”

Chris Enright: “California has a strong authority to regulate flows. The presentations today indicate that flood plain management and restoration are the key to ecosystem health. Who and how can we address the land use issue as the water board addresses the flow issue?”

LES GROBER:Not to take on too much for the water board, but if I haven’t made it clear already, the board is very aware that it’s about more than flow, which is why a part of that 11-page proposal for the flow objectives for the San Joaquin River, these that program of implementation were identified these other things. Habitat is important. Predator control is important. Hatchery practices. All those things are important, and they’re in some ways easy to describe and, even say, quantify what’s needed, but the difficulty is how do we ensure that some of those things happen whereas how is the responsibility to perform for those things to occur. We’re looking for suggestions as to how to make that happen. The board does not have direct authority over land use.

DR. CLIFFORD DAHM:When you start talking about land-use, it’s also about land change, and one of the things that’s starting to occur throughout the western United States is an increase in forest dieback and a dramatic increase in catastrophic forest fire. This is occurring throughout the western United States, and so we’re seeing land use changes that are human induced. We’re also seeing, I think, what’s being induced by climate change. I personally think that our waterways are as much if not more threatened by some of these major changes in the catchment. Think the stream and it’s valley, as they’re being affected by some of the things we’ve been talking about that go on within the channel.

I think we still need to think how these massive changes, human induced and now climate induced, are going to affect our waterways. I think the Southwest, because the predictions are all for warmer temperature and less precipitation, is likely to be the bell-weather of the future in this part. What do we do here in California? We have the biggest waterworks in the world to move the water from the north and from the east to the Central Valley and to the south. That south, everything indicates that there is going to be less water available to them and pressure to import is just going to get higher. Either that or conserve.”

FOR MORE INFORMATION …

Daily emailsSign up for daily email service and you’ll never miss a post!

Sign up for daily emails and get all the Notebook’s aggregated and original water news content delivered to your email box by 9AM. Breaking news alerts, too. Sign me up!

Print Friendly, PDF & Email
%d bloggers like this: