The Dutch Slough Tidal Marsh Restoration Project site, located in the Sacramento-San Joaquin Delta near Oakley, California. Photo by Florence Low / DWR

DELTA STEWARDSHIP COUNCIL: Delta Conservancy update: Analysis of juvenile salmonid habitat in the Delta

At the June meeting of the Delta Stewardship Council, Campbell Ingram, Executive Officer of the Delta Conservancy, updated the council members on the Conservancy’s activities.  Then, Bruce DiGennaro, program manager for the Collaborative Science and Adaptive Management Program and Principal Planner and Lead Facilitator with the Essex Partnership, gave a brief overview of a recent analysis of juvenile salmonid habitat in the Delta.

Campbell Ingram began by noting that the Delta Conservancy is a state agency established to do ecosystem restoration and economic development in the Delta.  The Conservancy is governed by an independent eleven-member board that includes five county supervisors.

Activities of the Delta Conservancy

Mr. Ingram began by noting that the Conservancy has two significant grant programs:

Prop 1 provided $15 million for ecosystem restoration projects.  There are currently 29 projects in the Delta, affecting over 5000 acres.  “I like to say that they are all unanimously supported by the local interests,” said Mr. Ingram.  “We’re charged with working very closely with the community to do restoration that works for the community as well as provides ecological function.”

The Conservancy has opened up the fifth and final solicitation for the remaining $3 million in Prop 1 funds for proposals, with concept proposals due at the end of August, full proposals due by mid-December, and final decisions in early 2022. For more information about the grant program and solicitation: http://deltaconservancy.ca.gov/proposition-1-resources/ 

Proposition 68 provided funding for economic development.   They are currently evaluating nine proposals for projects ranging from increasing recreation access to historic preservation.   

The Conservancy also works on Delta subsidence and related carbon emission issues, as well as invasive species issues.  They have a Lead Scientist heavily engaged with all the science activity at the Stewardship Council and throughout the Delta.

Study: Identifying suitable rearing habitat for chinook salmon in the Sacramento-San Joaquin Delta 

Mr. Ingram then turned it over to Dr. Bruce DiGennaro to discuss the habitat study for juvenile salmon, noting that in the upcoming Prop 1 grant solicitation, applicants with salmon habitat projects will be directed to this report to incorporate the findings and information in their projects, if possible.

Dr. Bruce DiGennaro began by noting that this project was a joint initiative with the Delta Science Program and the Delta Conservancy providing funding, in-kind services with a Science Advisory Group within the Collaborative Science and Adaptive Management Program) and project and management services from the San Francisco Estuary Institute.    

It’s a great example of cooperation. And I think it also shows in the quality of the product,” he said.

The study was focused on juvenile salmonid rearing habitat in the Delta with the goal to provide a resource for restoration planning.  Dr. DiGennaro noted that we don’t know much about juvenile salmon in the Delta because the size of a rearing fish at the fry stage is too small to be tagged and tracked.  However, some of the otolith studies done in recent years show that fry are rearing in the Delta, have historically reared in the Delta, and it’s an important component of a life history diversity that we need to be mindful of.

The study looked at the issue of juvenile salmon habitat in the Delta, considering what we know about the habitat in the Delta that might support rearing fry, where that habitat is, and what the characteristics of it are if we want to make more of it.  The intent of the study is to support future Prop 1 and other project submittals, so when people look at doing projects intended to benefit salmon, they can use the results as a resource to see where there might be good opportunities, as well as what other things need to be taken into consideration.  This will ultimately make our restoration investments more effective, he said.

Dr. DiGennaro then presented a map of the results, which serves as a bit of an executive summary for the study.  The areas shown in yellow are where they identified opportunities to build on good existing habitat;  those areas include the Cache Slough area, the area around the confluence of the Cosumnes and Mokelumne Rivers, and in the Western Delta. 

The areas shown in orange are areas where there may be opportunities to restore suitable habitat where current conditions aren’t very good, but it would be worth investing in.  Some of these areas could connect areas of good habitat, creating refuge along the way.  These areas include along the main stem of the Sacramento River and the San Joaquin River, Georgianna Slough, and the South Delta.

The areas shown in red, mainly in the central Delta, are areas where we just don’t know enough about the opportunities, so more study is needed.  The triangular exclamation points represent warning signs, showing where there could be entrainment or other issues that you would not want to attract rearing salmon fry to.

Dr. DiGennaro said the report goes into much more detail on the different areas and aspects of restoration to be considered.

The next steps include continued outreach to increase awareness of this resource and to make the mapping available online. 

There are some additional considerations that are challenging to map, such as the hydrodynamics and criteria around velocity, which is very dynamic and changing with the tides,” he said.  “And surprisingly, our knowledge of some of the shoreline conditions and substrates is limited. And so, there’s a potential opportunity to map and understand that better.  Also, continuing to understand some of the other stressors that would be important in terms of where you would invest restoration dollars, for example, predation and contaminants.”

I think this is a great resource and a great example of cooperation,” he said.  “We hope that it will improve the quality of the proposals that are submitted through Prop 1 or other funding sources.”

During the discussion period, Chair Susan Tatayon asked about the funding, the resources, and the collaborators for this effort.

Dr. DiGennaro said the funding was around $200,000 by his recollection, which doesn’t include in-kind resources.  “The Collective Science and Adaptive Management Program (or CSAMP) is a large, collaborative effort. It has kind of three legs of the stool: all of our state and federal agency partners that have some stewardship responsibility CDFW, Fish and Wildlife Service, NOAA Fisheries, the State Water Board, as well as DWR and the Bureau. So those are our six state and federal agencies, and they are actively engaged.  The second leg is the public water agencies, which includes a wide group of both north and south of Delta water users that rely on the water projects, as well as the Sacramento Settlement Contractors and in-Delta agencies, such as Contra Costa Water District.  The third leg is the NGOs, such as the Environmental Defense Fund, The Bay Institute, Defenders of Wildlife, and the Nature Conservancy.  The policy group, which is kind of our executive board for the program, is a 20 member board. So that gives you some idea, and then those board members represent others as well.”

On this initiative, a lot of them provided staff that had expertise in salmon biology, whether they were state or federal agency staff or they were public water agency staff or NGO staff.  We also brought in some academic researchers who had expertise. We looked to other places, particularly up in the Northwest, where they’ve done a lot on looking at estuarine systems and how those are used for rearing. So we tried to reach pretty widely there and had a number of consultants that have experience in those areas as well.”

Dr. DiGennaro closed by thanking the Council and the Conservancy for their support and involvement.  “We really couldn’t have done it if it wasn’t a joint effort,” he said.  “And I should recognize Leo Winternitz.  … This early on was an idea that he had that launched this vision. So as is so often the case, Leo’s had a lot of influence on what we did here.”

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