Dr. Bruce Herbold, Estuarine Ecology consultant, now retired from USEPA, began by saying he would be focusing on the Sacramento River and its tributaries, and some about the Delta, and he would be focusing on some of the work he has been doing for the EPA. “EPA Headquarters is trying to develop some guidance on how to put flow into discussing water quality concerns for the protection of beneficial uses,” he said. “That all sounds boring, but I don’t find it boring. And I’m going to talk about conceptual models.”
He presented a slide with two pictures, noting it was two different visions of the rivers flowing through the Delta. “The lower right hand corner is an integral part of San Joaquin salmon and steelhead migratory corridor. We talk about flows through there. You know, they don’t do so well no matter what we do as they do up in the upper left corner. So talking about flows independent of geomorphology, especially I think in this system is stupid.”
“The picture that keeps coming to mind as I was getting ready for today’s talk is of driving a car,” he said. “To drive the car using only the steering wheel is comparable to trying to protect beneficial uses only talking about flows. But to drive the car without touching the steering wheel and only touching the brakes and gas and looking at things is just as stupid. You don’t get there if you don’t know where you’re going, if you don’t watch where you’re going, and if you can’t speed up and slow down. All of those are essential and I would really push that some kind of integrated resources use and integrated regulatory situation is what we desperately need.”
“I have been a big fan of this picture of the interaction of a stationary habitat with water flowing over it and biological conditions all generating something that we call the environment where the fish live, and I will always come down to where the fish live, that’s the beneficial use to my mind, that’s what we’re trying to protect. And it requires that you look at all three of those things.”
In estuaries, rivers and tides move the dynamic habitat across the stationary habitat and that generates where you get fish, he said. Through Dr. Herbold’s work with colleagues at EPA Headquarters on flows in the context of water quality, they’ve developed a conceptual model.
“I think conceptual models need to be both comprehensive so that you can see how your bit fits in and which parts are relevant to you, and more importantly they need to be comprehensible,” he said. “I find that a lot of people who start writing conceptual models end up with spaghetti and meatball diagrams which nobody has any use for whatsoever and do not convey any real understanding of the system. A conceptual model to my mind is to capture your ideas of how the system works, so that people can say, but you’re wrong on this point, and so you can start identifying where you need to improve your understanding and what things are important on your local, particular area.”
Natural flow comes from two scales: On the right, the climate, the atmospheric rivers, orographics, topography, and this is where climate change comes in. “There’s nothing natural about the process that we get of water entering the basin from the atmosphere,” said Dr. Herbold. “We have actually altered that, and we’ve altered it faster than evolution has changed the responses of those organisms that respond to those hydrographic elements. There’s nothing natural in there. We’ve changed the direction of atmospheric rivers, we’ve changed the climate, all of that changes all of that, but still when that pours in across our local area and we look at what those soils are like and what the environment is like, we do come up something we call a natural hydrological regime, which is a useful starting point, even though it is artificial, or at least some part of it is artificial.”
That interacts with our environment, he said, presenting a graphic that depicts how that causes the interaction with the floodplain and the interactions with the surrounding landscape. “Because as these flows inundate various portions of that, you have sediment picked up and transported, you have all kinds of nutrients being brought in or not, and you provide them seasonality across years. In California, that seasonality is extremely diverse from year to year; sometimes we don’t get any of those flows, but you have some level at which you get some floodplain activation or inundation of riparian areas or whatever.”
Dr. Herbold emphasized that it’s a cumulative effect. “It’s useful in looking at that one piece, but as you move downstream, the stuff downstream is accumulating all the impacts of what came from upstream. We tend to think of the place that we work in isolation and it is dead obvious that we work in a river system that extends up into the Sierra Nevada, but we tend not to think about it.”
“So as we think about interannual variation and season variation and that temporal variation, we also need to keep in mind what has happened in the particular area where were working and upstream of that,” he said. “Then you can start looking at the interactions of those catchment areas with the local areas, and you start getting at habitats and population impacts. Without both of those, you are talking pure nonsense about habitats and populations.”
“Then we take that natural hydrologic regime, we run it through managed forests, we run it through dams, we move water into the system, we move water out of the system, we pave a lot of the system and we change land use patterns,” Dr. Herbold said. “We reinforce levees that are there or we build new ones or we channelize them and we start mucking about with groundwater, and all of those things take that natural hydrologic regime and alter the flow magnitude, the timing, the duration, the frequency and the rate of change of all those flow patterns. And it is those flow patterns that drive a lot of the habitat that we’re trying to protect or trying to produce to support the needs of the native fish, or whatever we care about.”
“As we do all that, that disconnect from the floodplain becomes very strong, and all those nutrients, all those sediments and everything else change as a result of these other impacts, and so that disconnect becomes strong and that amplifies through each of those cumulative stages,” he continued. “I feel this is really obvious, in conversation I think it really needs to be pointed out, and that’s where I find a conceptual model useful.”
So what then? “This is based on an EPA construct called the Environmental Limits of Hydrological Alteration or ELOHA,” he said. “I think it is a useful construct. This isn’t all out of my own little head. So as we change those flow magnitudes from what the natural hydrological regime might be, two main things happen: We change water quality, and that may be a change of oxygen, it may be a change of salinity, it changes nutrients, and we change that physical habitat, and those then start becoming what the habitats are on the population and fish.”
“Finally we can start saying the changes in water quality and the changes in physical habitat then can start producing impacts on the population that we care about in four ways: Either you screw up the reproductive success, you change their food availability either in qualitative or quantitative ways, you shift the competitive or predation angle from what it had been before, or you change physiological processes so that they need more food or they are more sensitive to other stressors.”
“The whole process then, and this is where I fear it’s inadequate is if your goal is to protect the biological response or to produce something which the general populations wants in that river, to stop at any one of those points or to look at only one of them. Every river in California anyway, is going to be different, and they all interconnect.”
Dr. Herbold then gave four examples.
Example 1: Stony Creek, west side of the Sacramento Valley
He presented a picture of Stony Creek, which is on the west side of the Sacramento Valley. Like many streams on the west side, it has a huge river plain and almost no water in it. Water comes in in huge rainstorms and washes through for a short period of time; there are flash floods in the wet years that maintain the braided channel, but through most of the year, there are only isolated sections with water.
“The native fish in there thrived,” Dr. Herbold said. “That disconnect from other water bodies allowed them to forego a lot of predation and competition that they might otherwise have seen. Those little groundwater basins kept the water cool enough for them to live there, and they still do fairly well.”
Downstream on Stony Creek is the Black Butte Lake reservoir which captures the high wintertime flows, stores them, and delivers them to agriculture down on the valley floor. “Agriculture then returns some of that water into this river, and Stony Creek then becomes a more perennial stream, nutrient rich and warmer throughout, the refugia go away, native fish can swim up that perennial stream and do well. Algal blooms really nicely because of the nutrients and warm temperatures, so we get an entirely different kind of stream downstream of that reservoir.”
Looking at the conceptual model, what do we have to worry about? “We might want to try to moderate how we operate that dam because maybe we want occasional times in that river when it’s dry,” he said. “That would go along ways towards reducing invasive species, invasive algal blooms, but we can’t do that without also looking at the land use around there because they return the water, so agriculture is going to keep putting that water in unless we address that, but it’s fairly simple and straightforward. If we want to protect those fish from the competition and predation issues, then we have to take care of the nutrients, temperature, and the nature of that physical environment and that goes back to land use and dams, and it probably comes back to climate change.”
“This is where I think a conceptual model is useful. You start with something that’s comprehensive, you look at your local problem, and you identify out of that comprehensive list, what you need to deal with that, and by that process, you’ve identified what your problems are and you are fairly confident that you haven’t overlooked something. It’s a good thing.”
Example 2: Cantara Loop on the upper Sacramento River
“The river is pretty well entirely restored, and it wasn’t restored by a whole lot of work. Because that river lies above Shasta, water flows down through those 43 miles and transports everything into Shasta Reservoir and then delivers it down south. … And that river restored itself. If you want to talk about resilience, here’s a great bit of resilience. The worst toxic spill in America’s history, and 20 years later, people are out there fishing.”
So what happened? “We had a little forest management, but we didn’t have anything going on there. We had the natural hydrologic regime and that didn’t get altered much. We still had the springs coming off of Shasta. About the only thing we did was inject toxics. It really had a biological response; it killed everything, but by that one major impact in a natural system or at least as natural as anything is in this system, it responded with great resilience and I think it is a model of what we can hope for as being resilient.”
Example 3: Iron Mountain Mine
Downstream of Shasta lie the spawning grounds for endangered winter-run chinook salmon. The area has been urbanized somewhat with the cities of Redding and others. There are forest practices going on, and the worst Superfund site in America. “Iron Mountain Mine is home to the lowest pH of any water body occurring in the wild,” said Dr. Herbold. “Negative 3. … The people analyzing this had to come up with a whole different way of calculating pH to deal with the number of hydrogen items that they were finding there.”
“It has spilled into the Sacramento River about 43 times. Fortunately, most of those times occurred before 1976, so winter run salmon were blocked from their cold water access by Shasta Dam, but Shasta Dam was operated mostly for flood control and was filled most of the time. We had a whole series of 30 years of wet years. We didn’t have a dry or critical year from the time Shasta was built until 1976. So the winter-run salmon enjoyed the fruits of that cold water even though it was getting stopped in our largest reservoir first, and even though it wasn’t getting the sediment that it would have gotten if the dam wasn’t there. They were still doing well. Actually well. And fortunately, all that was happening during the time we had spills from Iron Mountain Mine.”
“Then 1976-77 came along, we drained Shasta Reservoir, we cooked all the winter run chinook salmon eggs and we then ended up with an endangered fish that got down to as few as 193 adult fish coming up to spawn in 1991, but they were resilient. We had good flows coming down here, Iron Mountain Mine spilled, but they kept coming back and the flows were sufficient to keep moving that toxic soup downstream. It killed everything in the river, it didn’t do good things for the water supply for Redding, and because of sediment there, it still can be found there in the sediments but it got buried because we were getting enough sediment washing in from the nearby land. So it had short sharp shocks, but the system was fairly resilient, too.”
“Fortunately, Superfund came along and we started doing a lot to control that,” Dr. Herbold said. “At the same time as we got our first dry and critical years. One can imagine worst situations. If those 193 fish had been coming up at a time when Iron Mountain Mine was in one of its spills, there wouldn’t be any winter run salmon now.”
He acknowledged it’s a little bit more complicated than the first two examples. “We have all of these things changing the natural hydrologic regime to some altered hydrologic regime changing various aspects of water quality and aquatic habitat, and not surprisingly then, we have a less resilient system,” he said. “Some of these knobs we can turn more quickly; some of these knobs are more important. Those two things are different, and so the knobs that are important that we can turn now are the only ones we have available, but not to lose sight of knobs that could turn in the future if we got our act together and worked on it to allow a more integrated regulatory approach then what we have right now.”
Example 4: Climate change
Dr. Herbold said he was working on the update of the Bayland Habitat Goals, which was first developed in the late 1990s and didn’t consider climate change; there’s now a major effort underway to update the guidance in the document to factor in climate change.
“There’s a big focus on climate change effects as a linear trend through time and how that will change things over decadal pictures or averages over decades,” he said. “On the other side, from wildlife biology, I expect the actual fish populations to be driven by events. They are driven by droughts and floods. They are driven by the timing, frequency and duration of droughts and floods. Those have direct effects on reproductive success, on survival of these.”
“It’s that that I find is getting insufficient attention, but by trying to get together a comprehensive and comprehensible conceptual model, we can look at the models for long-term change and we need to look at the instances and frequency and duration between the populations getting hit by extreme events. And not lose sight of the fact that a lot of these are migratory species that are going to be driven by characteristics elsewhere. All of this to try to answer this question: How much water do fish need? And I love this picture of an Afghani fish monger answering that question for himself.”
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