California’s Sacramento-San Joaquin Delta is a productive agricultural area and a vital linchpin in the state’s complex water supply system. It’s also a highly unique ecosystem, which was a hotbed for endemic species, many of which are now under stress and some facing extinction.

As various agencies and other stakeholders work on ways to balance the economic and environmental demands on the Delta, a new report released today attempts to build a framework to help locally driven restoration efforts.

Put together by the San Francisco Estuary Institute-Aquatic Science Center (SFEI-ASC), A Delta Renewed: A Guide to Science-Based Ecological Restoration in the Sacramento-San Joaquin Delta is the last in a trilogy of reports that have been eight years in the making. The first report researched what the historical Delta looked like and how it functioned using primary sources from accounts of Native Americans, explorers and early Spanish settlers.

The second report, A Delta Transformed, compared the historical landscape and its functions to present day, where 98 percent of the marsh has been lost. And the third, just-published report, provides a roadmap for restoration.

The ecology of the Delta has changed dramatically in the last couple hundred years, but the idea, said Leticia Grenier, senior scientist and program director of SFEI-ASC’s Resilient Landscape Program, is not to return to the historical conditions. Instead the goal is to figure out which functions can and should be restored, and the best places to do that.

Water Deeply spoke to Grenier about the health of the Delta, why it’s so ecologically important and whether communities will embrace restoration.

Water Deeply: You’re not advocating for going back to historical conditions, so what is the best way to move forward with restoration given our understanding now of how the Delta used to function?

Leticia Grenier: We need to create some of the original functioning – it’s not about returning all the way to the historical conditions – there’s no way. It’s about strategically figuring out what are the processes you need to restore and figuring out the habitat you need to restore in the right configurations to get back what you want – a healthy food web, native wildlife, the ability for our native organisms to evolve over time as things change and the ability for habitats to be self-sustaining with climate change.

It’s about fitting some restoration into this highly managed landscape so we can have ecological functions. We’ll still have agriculture, we’ll still have critical water supply.

Water Deeply: What do you hope the report provides?

Grenier: Our report is not the answer to the Delta’s problems, it’s the framework. This is the idea coming from science of how we can get our ecological functions back, then you have to sit down with the local people and integrate that with their needs.

The report provides localized, real design visions. For instance, if you want to restore tidal marsh processes there are maps of the best areas to do that and blurbs of what to think about and what the value would be of different steps. It doesn’t say how big a marsh should be, but instead what you’d get ecologically if you built different sized marshes.

This is holistic, and set up for local communities to make their choices.

Water Deeply: How would you describe the health of the Delta?

Grenier: There are different views on the health of Delta. If you want to change from one ecosystem to an agro-ecosystem, we’re doing great. We’ve traded a really productive marsh for really productive agriculture.

There is another viewpoint that thinks it works, but not for species we want – instead it works for species like the Asian clam, nonnative fish and water weeds from all over the world.

From the point of view of supporting native wildlife, that’s when you get quotes that there are moments when it’s at the point of collapse – the food web has crashed in some ways, at least for native fish. You have to think about it by ecological functions. If you go by the ecological functions of our report, it’s highly altered and not functioning very well to support those species and that food web.

Water Deeply: What are the biggest impediments to restoration?

Grenier: I would say space – you have to find the land to do it. Time – the juggernaut of sea level rise, subsidence and levies. Money – we need better funding. And the social component – the people who live there deciding that’s what they want too.

Water Deeply: How much water should be in our rivers is a hot topic. What role do river flows play?

Grenier: There is hope that with flows just as they are there are things we can do that will make a difference, like in the Yolo Bypass. But whether or not in the long run we can get everything we want without changing the way we manage flows, that remains a big question.

I don’t see the science that says this ecosystem can be healthy with the way things are. There is more science that suggests we may need to rethink how we manage flows if we are to get all the function back.

Water Deeply: Has there been a change in thinking about floodplains and the value of them?

Grenier: Fish people have known for a long time we need floodplains back. But how do we convey it? Flooding sounds bad, we need to change our paradigm around it so we can see the value of it.

Flooding can move the sediment that is blocking up our dams so we don’t have enough space for water. It can feed the rivers that are desperate for sediment that they ecologically need. It can bring the sediment down to these marshes that need to be built up because of sea level rise and those marshes can protect our shorelines.

That’s good flooding. We need to reconnect the rivers to the floodplains – that idea is not really out there beyond scientific community.

We’re such an engineering species. How do we convey that working with nature instead of holding nature back can help us in the long run? We want to hold back the flooding. It’s an interesting cultural moment that we have dominated up to a point and now we need to go back.

Water Deeply: We hear a lot about a few fish species, but what’s the value of the Delta ecosystem as a whole?

Grenier: It is almost unique in the world as an inland freshwater delta with a vast complex wetland. That’s an amazing thing on our planet in terms of productivity, in terms of biodiversity.

That is a precious jewel to me in terms of what our planet has to offer us and other wildlife. It was incredibly productive. It is still. It is giving us water and agriculture. Why not have it give us water and agriculture and a beautiful place to recreate and a place for California’s native wildlife?

To me that’s more exciting than having these species invading from all around the world. If we let them invade everywhere, we’ll have the same species everywhere. You go to a city and you’ll see starlings, house sparrows and rock doves (pigeons). It’s a little boring to go to every city and see the same thing. I’d much rather go around the world and see things that are unique to that place and that’s a lot of what the Delta is to people.

People want it to be their place still – that’s why the local community is so invested and I think the native wildlife are part of that place. If it lived there I would want to have these beautiful natural areas to be in as well as have the economy and culture and the water supply.

Water Deeply: What do you hope the Delta looks like in 50 years?

Grenier: I hope we are able to restore some lands in a working landscape of agriculture and water supply. I hope we have figured out what to do with the subsided areas. If there is a way to sustain the farming, great – or if there’s a way to do something else with them. I think the worst thing that could happen is if we don’t plan and we don’t coordinate and we get a disaster or big storm or earthquake and a whole bunch of the Delta goes underwater or gets salty. No one wants to see that. One way or another we need to agree on a plan and work as a team on that plan.

Water Deeply: Did anything in your research surprise you?

Grenier: I was surprised by how much we get back for so little restoration – how much success. Not that it isn’t a lot of people work – years, relationships, money – but even a small piece of restoration compared to the overall Delta and its historical condition gives you so much value. That made me really hopeful. Our vision of what could be is this integrated landscape for people and wildlife I think really is possible, if people go for it.