DELTA PLAN INTERAGENCY IMPLEMENTATION COMMITTEE: Linking Best Available Science with Decision Making

Presentations on the State of Bay Delta Science 2016, San Francisco Estuary Institute’s A Delta Renewed

The second of two biannual meetings of the Delta Plan Interagency Implementation Committee was held in November of 2016.  The Delta Plan Interagency Implementation Committee (DPIIC) is comprised of eighteen heads of the state, federal, and local agencies that are responsible for implementation of the Delta Plan, and serves as a forum for these agencies to increase their coordination and integration in support of shared national, statewide, and local goals for the Delta.

At the meeting, Committee members heard presentations on two recently issued reports: the State of Bay Delta Science 2016 and A Delta Renewed.

STATE OF BAY DELTA SCIENCE 2016

Darcy Austin, Program Manager for the Delta Science Program in the Delta Stewardship Council and the lead for organizing the State of Bay Delta Science 2016 report, began the agenda item with a brief overview.

The State of Bay Delta Science is a synthesis of the current scientific information of the Bay and Delta, emphasizing progress made on key research questions and remaining knowledge gaps,” she said.  “It’s a key element of the Delta Science Strategy, and those elements include the Delta Science Plan which is a shared vision for Delta science, and the Science Action Agenda which is a compilation of prioritized science actions and a collaborative road map for science.”

Ms. Austin pointed out that the knowledge gaps that are identified in State of Bay Delta Science Report for 2016 will be used to help guide the Science Action Agenda for 2017, and the actions from the Science Action Agenda will be incorporated into the next iteration of the State of Bay Delta Science.

The State of Bay Delta Science 2016 builds on the first edition, which was published in 2008.  The chapter topics for the 2016 report were identified by senior scientists and managers to address the most relevant scientific issues in the Delta.  The individual chapters, three years in the making, have been published in the online journal, San Francisco Estuary and Watershed Sciences.  The chapters themselves are quite technical, so they have produced a summary for policy makers and decision makers.

Ms. Austin noted that the State of Bay Delta Science 2016 came together through the efforts of a dedicated team that included managing editors, a technical editor, and 50 authors, as well as the Delta Stewardship Council’s communication staff and legislative staff.

She then introduced Dr. Mike Healey, a former Delta Lead Scientist and professor emeritus at the University of British Columbia; he also served on the editorial board for the State of Bay Delta Science 2016, as well as the 2008 version of the report.

Dr. Michael Healey’s presentation focused on the summary document for the State of Bay Delta Science 2016 which is titled, Perspectives on Bay Delta Science and PolicyIt is an overview of the report and partially a synthesis, as well as an exploration of policy implications from the more technical papers included in the State of Bay Delta Science 2016.

Dr. Healey noted that the State of Bay Delta Science report issued in 2008 was written in a way they hoped would be readable and useful for decision makers, policy makers, and managers; however, in the 2016 updated version, the individual papers were written more for a technical audience and not really directed at policymakers or decision makers.  The editorial board felt that it would be important to have at least one paper from this series that was specifically aimed at decision makers and policy makers, and so the summary paper, Perspectives on Bay Delta Science and Policy, was produced for this purpose.

The editorial board for 2016 report was comprised of the same three people as the editorial board for the 2008 version, so there was continuity between the two reports.  The State of Bay Delta Science 2016 is divided into three main sections:  A section that looks at new science perspectives which is titled, ‘What have we learned since 2008?; the second section discusses the new scientific tools that have helped in advancing the science over the past 8 years; and the third section is policy perspectives.  “There is no forward looking section in that longer document, so these ideas are extracted from it,” said Dr. Healey.

What have we learned since 2008

Nutrients are important:  “What’s been happening in the Delta is that turbidity levels are going down, the Delta waters are getting more transparent, and as a result, more light is penetrating, and so plant growth is being stimulated,” explained Dr. Healey.  “Although the Delta has always had a pretty high load of nutrients, in the past, the impact of those nutrients was masked by the high turbidity loads in the Delta.  As turbidity has decreased, the nutrients are becoming more important as a driver of primary production at the bottom of the food web, and also potentially as influencing the growth of invasive species that we are concerned about, things like microsystis and Egeria. So nutrients are now taking on nutrients are now taking on a stronger role in our consideration and concerns about how the Delta food web operates.”

Delta waters contain a complex of cocktail of contaminants:  These contaminants enter the Delta waterways from agricultural runoff, from urban runoff, and some from industrial activities.  “The strategic plan for CalFed in 2000 said that this was a problem that had not received enough attention; the 2008 State of Bay Delta Science said it is still a problem, and we’re saying again, this is a problem that we really need to pay more attention to,” Dr. Healey said.  “Fortunately now we have some better tools to help us explore the implications of the contaminant load in the Delta for aquatic species and potentially for human health.  Also the Regional Monitoring Program for the Delta is now going to start gathering regular information on contaminant loading in the Delta, so overtime we’ll be in a much better place to understand this level of concern.”

The aquatic food webs no longer sustain native species:  “This was anticipated in 2008, but over the intervening years, it’s become much clearer that the changes in the aquatic food web as a result of species invasions and changing conditions in the Delta mean that native species are not well supported by that food web anymore, and this is certainly a contributor to the imperiled state of many of the native species in the Delta,” Dr. Healey said.  “It’s only one of several factors that are impacting our native species, but there does appear to have been a regime change in the food web in the Delta.  It appears we cannot reverse this regime change, so we’re going to have to live with the current situation in the Delta and any attempts to make things better for native species are going to have to take that current situation very much into account.”

Species declines are the result of multiple factors in the Delta:  “When I first came to work down here in the early 2000s, everybody thought it’s all about exports.  Other things have happened, but exports were the big deal,” said Dr. Healey.  “But with the pelagic organism decline and the analyses associated with that, it became clear that although water exports were a factor, that wasn’t the only factor that was affecting the well being of native species.  It’s only become ever more clear over time that species declines are the result of multiple stressors and it’s still not clear whether we can reduce the burden of those stressors enough on native species for them to sustain viable populations in the Delta.”

Future water management will be driven more by extreme events:  “Climate change is the big background here but there are other changing factors in the Delta that are impacting on water management and on ecosystem management,” said Dr. Healey.  “It’s becoming more clear that major events are more likely to drive management change then the gradual serial change in things like water temperature or water flow, so we think it’s time to begin planning for the way bigger floods and longer droughts are going to impact the way we manage water.  Then imagine it’s going to be a gradual pattern of change over time.”

The success of local restoration is going to be dependent on what happens in adjacent habitats:  “The Delta is a landscape that’s a mosaic of interacting ecosystems, and we won’t be able to understand the way in which we can achieve the goal of a healthy ecosystem without understanding the interplay among all of those ecosystems,” said Dr. Healey.  “This brings into play the field of landscape ecology, which has been widely talked about in the Delta, but so far is not well integrated into the planning and management process of the Delta.”

The situation for native species is pretty dire:  “Several of them are on the brink, particularly Delta smelt, and so we’re suggesting that it’s time to start thinking about other ways to address the conservation of these species other than conservation in place,” said Dr. Healey.  “All the effort goes on to habitat restoration in the Delta, trying to make the Delta a suitable home for this species, and that work has to continue, but in anticipation that that may not be sufficient, we think it’s time for the science community to begin thinking about alternatives to conservation in place, things like assisted relocation, cryopreservation, or establishing refuge populations.  For many of these species, we don’t know how to do that, and it would be nice to have some background of scientific understanding in case we have to bring those alternative mechanisms into play.

New tools for science

Dr. Healey said he couldn’t emphasize enough how important the development of scientific tools is to our advancing understanding of the science of the Delta.  The six tools listed on the slide are more fully elaborated on in the longer article.

The development of miniaturized tags for fish have helped us to understand much better where species like salmon move through the Delta and how they are impacted by hydrodynamics,” said Dr. Healey.  “New remote sensors provide continuous recording of water quality parameters.  Advances in two dimensional and three dimensional hydrodynamic modeling that have allowed us to understand much better the relationship between water flows and fish movements in the Delta.  Remote sensing tools can be used to assist us to understand the complex structure of the levees and how vulnerable they may be to things like sea level rise, flood, or earthquake.

There are new tools for downscaling global climate predictions to the local level so we can understand much better the kinds of weather and climate we’re going to be looking at in the future, particularly with regard to its impact for water supplies and things like longer term droughts,” he continued.  “New analytic tools for water quality provide a much more flexible set of tools for exploring the impact of water quality on aquatic species.  These have all given us a much stronger foundation for exploring a number of the issues that are particularly important for management of the Delta.”

Forward-thinking actions

Dr. Healey then discussed forward-thinking actions that he hoped decision makers and policy makers will consider in their future planning efforts:

There needs to be some longer term thinking:Looking many decades into the future was part of the Delta Vision exercise that went on, but it’s not clear to us that this long-range thinking has been well incorporated into the science communities working in the Delta,” Dr. Healey said.  “There is still a lot of focus on the immediate problems and the immediate policy issues, and not really doing enough in asking, if we do something, how is that going to play out 10, 15,20, 30 years into the future.  In order to do that, it means devoting some of your science resources to doing that kind of forward thinking.  I know how hard that is when there are so many immediate issues pressing on you … but if you’re going to deal with these things that are going to unfold into the future, I think it’s important that some of your science resources be put into that process.”

Widen career paths:  “One of the things that may help with longer-term thinking is to widening science career paths, particularly within the state agencies where there’s so much emphasis on the immediate and the here and now,” said Dr. Healey.  “When I was here, if you’re a scientist in a state agency, in order to move ahead, you have to go into administration, so it would be nice if there was a clear advancement path for science within the state agencies so that you could develop and nurture some senior scientists who have that freedom to think forward.”

Plan for variability and extremes:  “We think it’s going to be important to start planning for variability and extremes, rather than imaging that tomorrow is going to be much like yesterday,” Dr. Healey said.

Adapt to take advantage of the value of invasive species:We’re all focused on protecting native species and that’s really important in the context of biodiversity conservation, and living up to the expectations of the United Nations convention on biodiversity, but the fact of the matter is around the world now, almost every ecosystem is very heavily invaded, and a lot of those invaders are useful.  People like to fish for striped bass in the Delta; the largemouth bass fishery in the Delta is ranked very high among largemouth bass fishing areas in the U.S.  We think it’s time to start putting at least some of your thought into well, should we be managing any parts of the Delta to get maximum human benefit from some of these invasive species?

Explore alternatives to conservation in place:  “What’s Plan B if Delta smelt completely lose out in the Delta?  Do we just say, well, too bad we did our best, bye bye Delta smelt? or are there other alternatives for preserving that species, and is that the species you want to put your resources into?,” said Dr. Healey.  “There are all sorts of really complex scientific, policy, and socioeconomic questions around alternatives to conservation in place, and so if you really want to have those options in your toolbox, you have to start thinking about it and talking about it now, so that when the time comes, you’ve worked your way through some of those problems.”

For example, if you were going to relocate Delta smelt, where would you put them?  What would the people in the relocation place think about that, and how would it impact on the ecosystem to which you might move them?” Dr. Healey said.  “Those are only three big issues that have to be taken into consideration if you’re going to consider any kind of relocation alternative.  Same is true of other kinds of alternatives like assisted evolution; with new genetic techniques, we might be able to manipulate some of these species to be able adapt to some increase in temperature beyond their current acceptable range.  Is that something that we want to do?  We’re currently trying to do this with some coral species to see if we can make them better adapted to increasing water temperatures, and so on.  We go through a number of these possibilities in our longer paper.”

Invest in the development of models:  “We think it’s important to invest in the development of some of these integrated models you were talking about,” Dr. Healey said.  “We think it would be quite valuable to have forecasting models that are analogous to climate forecasting models that would let you explore the implications of some major management initiatives in the Delta.  How would those play out?  And would it result in the kind of Delta you actually want to have?  There’s a lot of modeling expertise here and there are the foundations of doing this sort of thing, but it does need to be put together if it’s going to be useful.”

Include Delta as an evolving place:  “We think it’s important to include some investigation of Delta as an evolving place in the science enterprise,” said Dr. Healey.  “The need for integrating social science into the science was one of the items highlighted at the science enterprise workshop, and this would be an example of that.  Just a personal comment, when I began my science career in the mid 1960s, integration of social sciences with the natural sciences was being touted as the next big thing.  So here we are, almost 50 years later, saying we should think about integrating social sciences with the natural sciences.  I spent a lot of my career trying to do this, and I know it’s not easy to do.  The fields speak different languages, they think differently about the problems, so it takes some effort, it may take a champion, but if you can make it work, then it is tremendously insightful, so I encourage you to pursue that.”

A DELTA RENEWED

Carl Wilcox began the agenda item with a brief introduction.  The report, A Delta Renewed, is part of an ongoing effort for 10 years since the first Ecosystem Restoration Program grant was awarded to San Francisco Estuary Institute to do the historical ecology of the Delta.

Understanding the history and the ecological history of any place is critically important to being able to figure out what you might do in restoring or reconciling that habitat, particularly in a place like the Delta, which is so dramatically changed from its historic condition,” said Mr. Wilcox.  “This is the culmination of this effort, and it’s really the tying together of what is the historical ecology provide to the species and habitats that we’re interested in, and how and where you might look to reposition those in restoring the Delta.  This also goes to the question of what is ecological restoration of the Delta look like, which I think is an issue that is critical as we go forward in looking at the future of the Delta.”

It’s the key in moving that forward, but also in recognition of the Delta as a place and how do you accommodate restoration of functionality and physical process within the web and context of the Delta as it is today, and the socioeconomic interests within the Delta in maintaining a sustainable Delta going forward,” added Mr. Wilcox.

Dr. Letitia Grenier, Program Director for the San Francisco Estuary Institute’s Resilient Landscapes Program, then provided an overview of the report, A Delta Renewed.  She began by noting that the report is not really ‘new’ science.  “It’s science synthesis and translation to operationalize a lot of new ideas coming out of the historical ecology report to actually do Delta restoration.  This is intended to be useful and usable, so hopefully you will be able to use it.”

She presented a slide with three maps of the Delta: the past, the present, and the potential future Delta.  The first map on the left is how the Delta used to function historically when it was being managed by Native Americans around 1800; the middle map is the Delta as it is today and it’s nearly 100% different, Dr. Grenier pointed out.  “Studying it as it is today doesn’t really help you understand how it used to work, and so that makes a really big challenge for how are you going to restore the functions that that historic landscape used to provide, such as sustaining native species? The key new and interesting aspect of this is the new knowledge that’s incorporated into this guidebook – this operationalized handbook for restoration.”

Dr. Grenier noted that there have been previous calls for these ideas in previous important plans that have been developed for the Delta.  “These ideas that we’re going to present here are big, they are long-term, and they may have felt like pie in the sky, but they’ve actually been called for, and it’s been acknowledged that we need this kind of large-scale landscape long-term thinking.”

To give a sense of what the historical Delta was like versus what it has become, Dr. Grenier presented two pictures: a view looking down the Sacramento River in the historical Delta, and the same view as it is today.  “It’s been changed from a very productive wetland to a very productive agricultural area,” she pointed out.

In developing the project, the researchers asked, ‘what are the functions that the Delta should provide that it’s not providing now?’  Those functions are shown in yellow on the diagram; five of them are functions to support native species, and the other three functions have to do with long-term adaptive resilience for the Delta.

We want our food web to be robust and to support native species,” said Dr. Grenier.  “We want our wildlife to be able to evolve over time because we know conditions are going to change; we don’t want to have a zoo here that we have to completely manage, we actually want the biology to function the way it should.  We want to maintain biodiversity, so not just those five groups of wildlife but we want to maintain that whole biodiversity that’s native to the Delta.”

Based on those functions, they then determined a set of metrics – things that could be measured on the landscape that would indicate whether or not those functions are being supported.  The metrics are things such as the extent of inundation, the size of marsh habitat patches, the distance to the nearest large marsh, the riparian patch size of woody riparian areas, and the ratio of marsh to open water.  The second report was about documenting and quantifying those metrics so that they could start to understand why the function was lost.

Dr. Grenier then presented a slide with two maps comparing the composition of the historical Delta to the modern Delta, noting that the colors have changed from teal blue to pink.  “That is showing change from tidal marsh and other kinds of freshwater emergent marsh to agriculture,” she said.  “Again, two highly productive uses of the land – one supporting native wildlife and the other supporting people, although wildlife can be supported in ag lands, and that’s something that we start talking about a lot in this report.”

However, it’s a lot more complexity to it than just that, Dr. Grenier said.  She presented a slide comparing flooding in the historical Delta to modern flooding, noting that the different colors of blue represent different types of flooding.

This is from the 1997 El Nino when the Yolo Bypass really flooded for a few days, so these are two really wet years that we’re looking at,” she said.  “What you can see is that big light blue in the middle represents tidal flooding, so that was marshes getting wet once or twice a day, very extensive tidal flooding.  The really dark purply blue at the top and the bottom was basin flooding, so it was a few feet deep and it lasted for a few months.  It generated really active and complex food webs; a lot of animals came down from the upland to eat.  It would attract huge amounts of predators, aquatic species – it was the refrigerator of California.”

The Sacramento River flooded at different times than the San Joaquin, so you can start to see that this is pretty complex,” continued Dr. Grenier.  “You have your daily flooding, you have your deep seasonal flooding, and then you have light blue right around the northwest edge of the Delta, which is somewhat parallel what the Yolo Bypass did in 1997.  This is intermittent flooding, it might last a week or a few days so it’s kind of a different habitat, a lot of wet meadows, and there again is another type of different flooding that connected several tributaries to the Delta.  So that was the mosaic of flooding that used to happen here, and it created a lot of productivity and it created a lot of options for places that animals could go.”

In the modern Delta, there’s a little bit of short-term flooding in the Yolo Bypass, as well as in the Cosumnes.  Even though it looks so little compared to the flooding that happened historically, it’s been very successful.  “Think of all the good things we’ve heard about what’s happening in those two areas where that kind of restoration work has been going on,” Dr. Grenier said.  “I find this to be a very extreme example of change, but also very hopeful that without a ton of land and without a ton of water, we can make a change, and this is one of our best examples.  This is an experiment where they looked at how big fish were that grew in the floodplain of the channel up in the Cosumnes versus the river channel, and you can see that the salmon did much better on the floodplain, so this gets at the food web properties or function that it provides.”

Dr. Grenier then presented a graphic showing the change in marsh from the historical Delta to the modern Delta, noting that it’s anout a 98% loss.  “I think this is something that wasn’t appreciated as much until our historical ecology report came out,” she said.  “The Delta was a big marsh.  That’s like a lot of other deltas.  When you lose 98% of something, it’s so not there that it’s hard to realize what it used to be like or to study it or to understand how it worked.”

With the change in the marsh, there was also a change in the channels.  Dr. Grenier presented a close-up of the channels in the San Joaquin River’s historical channel network, pointing out that they were very squiggly and capillary-like.  In the modern Delta, a lot of those little capillaries are gone.

What’s happened here is that those little tiny channels are gone and the large channels are actually really big – about 15 meters wide at the scale of the Delta,” she said.  “These smaller channels that used to bring water and energy and biota and sediment into the marshes are gone because the marshes are gone, and because of that, the system doesn’t function the way it used to.  It’s not getting the energy and the nutrients it needs to keep the wetland going and to help support the species that evolved to live here.

The other thing we’ve done is to add these yellow channel cuts,” she continued.  “In addition to getting rid of those little capillary channels, we’ve homogenized the big channels; we’ve made them straighter, we’ve made them more connected, and so the water moves through them more quickly.  We’ve taken something that used to be a complex system with a lot of different habitat types very close to each other and we’ve made basically these linear connected lakes that are all very similar to each other, so it’s not a surprise that it’s very hard for something that evolved in a marsh to have a challenge living in this big homogenous linear lake.  I think that’s a good insight to get from our work.”

Some of the ideas in A Delta Renewed came from the work SFEI did creating a Landscape Resilience Framework.  “This is an issue that people are starting to wonder about how in this time of climate change and other rapid change are we going to get the functions we want from our landscapes?,” said Dr. Grenier.  “There’s a huge body of academic research but it’s pretty esoteric out in the world of ecology.  So we tried to bring that all together with the real academics who wrote these papers and got them to try and make it operational with us.  We got them to make it real and applicable to a real landscape, and that’s what this framework is.  We applied it to our Delta work to make sure that we weren’t getting lost in the local challenges, but we were remaining open to that wider global literature and making sure we were using the best available science.”

The framework had seven principles which were incorporated into A Delta Renewed:

Setting:  “You have to take the right kinds of actions in the right kinds of places, and we’ve already seen that doesn’t happen on every restoration project, but this is a key idea that needs to come into very early thinking.

Process:  “What are the big physical processes that are needed to make this site resilient over time?  Are you going to have a tidal marsh without tidal action?  Probably not.  Are you going to have tidal marsh without some kind of sediment supply if sea level rise is happening? Probably not.”

Connectivity:  “Can your creatures get from one place to another? Are you connected enough? Are you over connected?  Your linear lakes are over connected.  Maybe you need to unconnect some of your habitats.”

Diversity and complexity:   “Moving away from the more homogenized landscape to the more heterogeneous, complicated landscape.”

Redundancy:  “This is a tough one for the Delta.  How are we going to have more than one migration route for salmon? That’s hard, but we know from the literature that’s really important, especially in the light of stochastic events …  we need to be prepared for these really big events and it’s something that we haven’t thought as much about as we have about the slow change.

Scale:  “We probably have to do things bigger and longer-term than we used to.  We’re not set up to fund it that way and we’re not set up to permit it that way, so how are we going to do that?

People:  “People are the most important part.  What do people want? What are the goals? That’s really more up to you than the scientists to figure out.  Then what can we do to accommodate those goals, how can we fit in ecology to social and economic needs?

Based on that, they developed a simple conceptual model for the historic Delta where there were intact physical processes, such as flows, flooding, and sediment supply, which acted on the landscape.  There were large swaths of natural habitats that were connected to each other, and out of that we got ecological functions, huge salmon runs, and large wildlife populations.

A lot of those physical processes have been interrupted; there isn’t the same flows, flooding, and sediment supply.  “We’ve really changed the landscape to different land uses; we have for the most part smaller, more isolated and different types of habitats, and we’re not getting the ecological functions we want.

So rather than just going right to the landscape and restoring some patches, what we need to do is to restore those processes that will create and sustain the patches, the habitats over time,” Dr. Grenier said.  “Without that, we’re not going to get resilience in the long-term.  Things are changing too much.  We don’t want to be managing every aspect of the environment; we want habitats to evolve.

We also have to address the landscape.  “We need to make larger, more connected habitat patches, and this is how we can get back ecological functions,” Dr. Grenier said.  “This doesn’t look like the historical situation.  This is a new situation where we still have ag, and water exports from the Delta, but we also get back more of the functions we want ecologically.

So with the report, A Delta Renewed, they put it all together to try to show how to get a certain function back.  “For example, this one is about supporting marsh wildlife, and we provide a map of the kinds of habitats that you would put back together in the kinds of places with the kinds of adjacency and relative size and other things,” she said.  “Here you can see all the parts, and you can see there’s a lot of different things going on.  There’s tidal marsh restoration, there’s also subsidence reversal, and there’s a lot of wildlife friendly ag, so it’s not just one habitat or another, it’s a systems approach.  It’s putting back together a system that works to provide a function.

It is intended to be the full Delta without saying where any one parcel could possibly be, she said.  “It gives you a sense of what should happen in the north, what should happen in the south, but then at the more localized scale of someone trying to implement a project, we say what are the strategies you would put together at a very local scale and how would they fit together?   We spend a lot of time explaining what the strategies are.  They are all processed based; they are all about returning processes rather than restoring static habitat types.”

There are several pages on the processes; Dr. Grenier presented slides giving details about reestablishing tidal processes.  “You have to think about full tidal flows, enough energy, and sediment supply – those are the kinds of processes that happen in the tidal zone,” she said.  “We provide a map that says, here’s the landscape scale considerations you should have.  For restoring tidal marsh, the right elevation is key; you don’t want to restore tidal marsh at the wrong elevation because it doesn’t work.  It has to be at the intertidal elevation.”

This slideshow requires JavaScript.

We know that sea level is rising so we can plan ahead, and we can look to elevations that are 3 feet higher or 6 feet higher than sea level is right now, and when you do that, you realize there’s a lot of opportunity,” she said.  “It’s not all on public land right now, but there’s a lot of land out there and we are seeing more opportunities on public land coming up, so this is intended to help people think about where’s an appropriate place to get started with this.”

They give even finer scale and targeted information to help people understand how big their marsh should be, how far from other marshes, what shape and size it should be, and how to reestablish physical processes.  The orange recommendations explain parameters for the physical processes, and the green recommendations explain parameters for the landscape.  “One example here is the guideline for reestablishing marsh patches, and the idea is that marshes should be as large as possible, they are very small right now.  What does that mean?  We as scientists can’t tell you how large you want your marshes, but we can tell you if you restore different size patches, what might you get back in terms of function.

For example, for a four hectare marsh, which is about what you have right now in terms of patch size, you might get a marsh bird showing up like a black rail or you might get a tri-colored blackbird nesting if you have just the right thing,” said Dr. Grenier.  “But if you get up to 100 hectares, then you’re reaching the maximum density of certain marsh birds species, so that’s showing that at the biological level, you’re getting a process going that’s working.”

But if you get to a 500 hectare patch size, which feels big right now compared to what we have, that’s when you get that dendritic network of capillary-like channels going in and out of your marsh,” she continued.  “That’s more of a self-sustaining functional marsh system that’s going to have the energy and sediment supply to eventually keep up with sea level rise where you won’t have to be constantly managing it or trying to bring it along with sea level.

It’s not the same as the historical Delta, as historical patch sizes were about 4500 hectares, she said.  “There is a real difference between getting back what we had before and getting the functions back that we want in a smaller footprint.  The largest marsh patch was 110,000 hectares, which is bigger than our cities.”

Dr. Grenier then concluded her presentation with pictures of the past, present, and possible future Delta.  “The Delta is a really different place now, and we think there is a way to make a future Delta what can reconcile the ecological functions we want with the economic and social needs that we have.

My request of this committee is to really use this,” Dr. Grenier said.  “It’s not intended to be a piece of science that sits on a shelf; it’s a guide to use and we actually have been able to secure some more funding to make it even shorter, more condensed version early next year, so as you guys are working on Eco Restore or McCormick Williamson tract or other new exciting opportunities on public lands, we hope that you can bring this in.

The video is a “flyover” of the Sacramento-San Joaquin Delta as it appeared in the early 1800’s, before conversion to agriculture and other uses. Based on a historical ecology study by the San Francisco Estuary Institute. the illustration shows the riparian forests along the Sacramento River grading into extensive tidal marshlands, heading north along the river towards Walnut Grove.

COMING TOMORROW …

Delta ecosystem restoration update with Carl Wilcox on the Delta Conservation Framework process underay, and David Okita and Kris Tjernell give an update on the progress of habitat restoration projects under the Eco Restore program.

FOR MORE INFORMATION …

Sign 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!

(Visited 231 times, 1 visits today)

Leave a Reply