Elkhorn Slough Tidal Wetland Project
Elkhorn Slough National Estuarine Research Reserve
Joint Science Panel and Strategic Planning Team
April 4, 2006
Meeting Date and Time: April 4, 2006 from 9:00 a.m. – 4:30 p.m.
Meeting Location: Elkhorn Slough National Estuarine Research Reserve
Prepared by: Jan Shriner and Barb Peichel
Attendees: Josh Adams, John Callaway, Ross Clark, John Day, Gage Dayton, Lesley Ewing, Sarah Fischer, Gage Dayton, Kim Hayes, Ken Johnson, Jessie Lacy, Bryan Largay, Steve Lonhart, Rebecca Martone, Joe Needoba, Julie Niceswanger, Jim Oakden, Julie Niceswanger, Barb Peichel, Peter Slattery, Emiko Shironaka, Jan Shriner, Mark Silberstein, Eric Van Dyke, Mike Vasey, Kerstin Wasson, Andrea Woolfolk
Purpose of Meeting: Expert review of interior marsh loss mechanisms and potential tidal habitat conservation and restoration alternatives and identification of research and monitoring projects that would help with decision-making for tidal wetland restoration planning and/or implementation efforts
Outcomes: Better understanding of tidal marsh dynamics and tidal habitat conservation and restoration efforts from an international perspective; Better understanding of interior marsh loss mechanisms; Prioritized list of research and monitoring projects to inform tidal wetland planning and/or restoration efforts
A. Presentation reviewing the outcomes of last Tidal Wetland Plan meetings (Barb Peichel, Elkhorn Slough Tidal Wetland Project Coordinator)
· In Jamaica Bay, New York, they have very similar patterns of marsh loss. This year they will be adding dredge sediments to raise the marsh elevations in a 70-acre site. In 2003, they held a workshop focused on research recommendations (a list of their research recommendations was handed out). This list included learning more about items such as the role of macroalgae, nutrients, subsidence, and sea level rise and marsh dieback.
· Please note pages 9-11 of the January 23rd meeting summary which includes a timeline of activities for the next few years. The Tidal Wetland Plan will be finished early next year. This year, the creation of large-scale designs and modeling of different restoration alternatives will begin and sediment elevation tables will be installed in some of the marsh areas.
· We applied for funding from the Environmental Protection Agency to hire folks to help us create a restoration plan for Parsons Slough/South Marsh. If funded, we would need to start some baseline monitoring soon.
· We will be holding a community forum about this project in Moss Landing.
B. Presentation: A wetland restoration perspective from Louisiana and the Mediterranean
(Dr. John Day, Distinguished Professor, Coastal Ecology Institute, Louisiana State University)
· Studied the Mississippi River drainage basin and other large delta systems in the world
· Similar to Elkhorn Slough, there are high fertilizer inputs, wetland loss, and hypoxia in the Mississippi Delta.
· In the Mississippi basin, we are trying to figure out how many wetlands would be needed and in what areas to reduce nutrient runoff.
· The Mississippi River took different courses during the past 1000 years and stopping the meandering has caused a new set of problems for marshes. This may be similar to the diversion of the Salinas River.
· To manage a system, you need to pay attention to large timescale patterns of flooding and meandering. Most of the marsh sediments historical were deposited during episodic events such as in 1927 (Katrina event allowed 10 cm of sediment to deposit in 2 days; otherwise the annual rate was 1 cm per year). Humans try to limit these episodic events.
· The delta also has subsidence issues because of oil and gas development.
· Caernarvon freshwater diversion project allows water from the Mississippi River to enter through gates to re-introduce river water to the marsh areas.
· Water control structures used on east coast for waterfowl management can limit sediment and water flux as well as the movement of organisms.
· Thibodaux wetland enhancement used created wetlands to clean treated sewage and surface runoff.
· There are types of Salicornia marshes: lush or broken. Marsh dieback is caused by sinking and multiple stress of flooding. More lush marshes have more freshwater input (leading to more sediment accretion and higher marsh elevations).
· Studied the wetland system in Venice Lagoon for 15 years. One river sometimes flows into the lagoon, but all of the other rivers have been diverted around the lagoon. Because of that active subsidence, increase in ESLR (eustatic sea level rise) and decreases in sediment inputs, the delta plain is at or near sea level which has caused marsh dieback. The long tidal channels end in salt pannes, similar to Elkhorn Slough. Wetland submergence margins along channels are well-defined but breaking up in the back of channels. An increasing tidal prism has this very set of characteristics. Venice lagoon has had increases in tidal prism, tidal creek widening and lengthening, and shoreline retreat averaging approximately 0.6-2.2 meters annually (very similar to Elkhorn Slough). Most marshes in Venice lagoon are not sustainable with sea level rise. There is a simple model that incorporates primary production, sediments, decomposition and wetland elevation that can be done for Elkhorn.
· Future sustainability: in the past 300 years we have been using a different model of how to use natural resources which is unsustainable compared with the one used in the previous 97,000 years. We will become more dependent on natural systems again and have to figure out how to maintain them in a sustainable manner to contribute to the human experience.
C. Discussion of interior marsh loss mechanisms and input on potential tidal habitat conservation and restoration alternatives/Lessons learned from tidal wetland restoration efforts nationwide including uncertainty/risk, appropriate scale, and threshold criteria
· The pattern of marsh loss caused by an increased tidal prism is classic. Going back to a more natural mouth is good, but a suite of things will need to be done. Are there areas were people have effectively reduced the tidal prism? I don’t know – modeling might help you answer that question if there aren’t examples.
· Is the increasing tidal prism leading to a greater tidal range? We expect so, but don’t know yet – we have funding to install tide stations. What is the subsidence due to? Could be groundwater overdraft or tectonic events. You have to get the marsh elevations back up.
· Not all water control structures are bad because you have to treat the source of the problem. You have to deal with the tidal prism.
· The prices of restoration and management seem like they are going to be high. How much should society spend? I’m not an economist but some work with energy analysis for natural systems has been done in a wetland in Louisiana. Restoration increased productivity by 20 times.
· What processes were incorporated in your model of marsh loss? It used a 2- and 3-D hydrodynamic model modified with variable timescales. It incorporated elevation, water transport, nutrients, sediments, and salinity (took about 20 years). The scale was a hectare or ¼ hectare.
· Can you elaborate on river reintroductions? The diversions are pulsed to simulate an episodic event. The flood flow over the marsh enhances sediment capture and nitrate uptake.
· How do we decide how much we need of different types of habitats such as mudflats and marshes? The mud will also disappear after the marsh loss and you will have an increased tidal prism. The increase in mudflat habitats is only transitional so you need to understand the trajectory to subtidal habitats.
· You mentioned some problems with water control structures – but is there another way to control the tidal prism of a modified system? If they are used in smaller areas, they seem to be only stop-gap measures. You need to address the fundamental problem as the source.
· What would you do out there in Elkhorn Slough? Address the watershed issues of pollution first. Find strategic places for wetlands. The agricultural community needs to be integral in this process. If you had $30 million you to fix Elkhorn Slough, what would you do? I’d use $5 million for doing a comprehensive study and modeling for 5 years to answer questions, get stakeholders involved, and spend $25 million actually doing projects.
· What is your sense of role of nutrients in marsh loss? In Venice Lagoon, I saw a bloom of macroalgae, but it decreased while I was there. What is the role of Ulva (macroalgae) – it seems that it is causing stress too? You need to know the stresses, nutrients, elevation, and sea level as these can all lead to stressed vegetation. What would be needed for a study about Ulva? Just use a piece of cloth to find out if it can kill an area of marsh or if the Ulva moves in afterwards. It seems that it has always been around, but there is more now that there are more low-lying mudflats.
· Right now, Elkhorn Slough isn’t even listed as nutrient impaired which doesn’t seem right. We need to provide evidence of effects to help with the Total Maximum Daily Load (TMDL) process. If nutrient pollution was the main driver behind marsh loss, we would see it dying behind tide gates and that is not happening.
· Would Spartina (cordgrass) have a buffering effect on higher marsh? Maybe. How about introducing Spartina (cordgrass) into the system? Then you might be dealing with an invasive species so fences might be better particularly if you will be pumping in sediments to a particular area.
· Like Venice Lagoon, subsidence and sea level rise plus degrading the sediment deposition and the elevation dynamics here are all part of the problem too.
· How about the decrease in sediment input? We don’t know how much mineral sediment input was lost and if marshes are not producing as much organic matter. Are marshes going to make it? They need sediment.
· How did the sediment fencing work for accretion? The sediments carried into marsh areas were trapped very well. The Dutch have used them for years for intertidal marshes. Can sediment fences work in a sediment deprived system too? It might if the fences help reduce fetch. We might not be that sediment-starved here – we just export it all. Fences can be just a foot high and students can be used to help put them in. We could improve the flow of Caneros Creek because right now sediment transport is reduced by levees and roads. Could we use models to demonstrate areas with lower velocities where there would be better sediment capturing zones? Yes.
· Any folks we should talk with about restoration projects? Bill Mitch, Mendelson, Florida everglades folks, and John Teal.
D. Review and discussion of research and monitoring projects
(Coordinator handed out a DRAFT list of projects)
· The draft list of projects was compiled from suggestions during Tidal Wetland Project meeting over the past few years and recommendations from consulting with experts. Participants will have to choose two overall subject priorities and ten project specific priorities. We will focus funding request efforts and staff time on the top priorities, but we recognize that the other projects are still important and could be done.
· Should I consider how much funding and effort each project might take in ranking them? Consider feasibility, but don’t let that limit you because different levels of funding would help us answer the same questions in a different way.
· It seems that a really robust hydrodynamic model would require some of these projects to be done so it could have input and calibration data which would answer a lot of questions as well. My understanding is that there that there is a minimum amount of input required for a model to start.
· In Louisiana, the process of model development and data collection actually ran in parallel so they could better inform each other. We found out that knowing the elevations was critical and so we had to go back to measure it more carefully.
· We need language in the project list that describes what type of model it would be – it would have to include wetland processes. We need to call it a numerical model that would include both physical and biological attributes (this language was added).
· If you have to choose between two projects of equal importance, you might want to rank the cheaper item higher because it might be more feasible.
· We need to make sure understanding the role of sea level rise is on the list of projects. It is.
· We need to track ecological community changes from biological perspective in a much more comprehensive way (this project was added). We should have a planned approach for monitoring that addresses those communities. We could start with simple abundance and distributions and then if there are particular needs such as understanding how decreasing mudflats effects birds, we could do a separate study for that. The Elkhorn Slough National Estuarine Research Reserve (ESNERR) staff is already committed to doing some studies such as tracking shorebirds and using GIS to track tidal habitat changes ((this language was added).
· The monitoring efforts should be discussed and designed along with each restoration plan. I assume that the planning framework for any future restoration project would include the costs, benefits, intended outcomes, and monitoring for expected and unexpected, and the strategy for a period of time to change the management strategy or not. Species or parameters should be in part driven by decisions. The real long-term costs of restoration will be monitoring because that requires a lot of people over a longer period of time. We should try to apply for monitoring funding along with the project funding.