The permitting of tidal restoration projects is most often a costly and time-consuming process, causing substantial delays in implementation while endangered and threatened species remain at risk. Given the accelerating nature of sea level rise, restoration of tidal habitats that are resilient to climate change should be implemented on a large scale and soon to have any chance of contributing to the recovery of these species.
However, one of the snags in the permitting process has been the state’s policy of no net wetland loss. In this presentation from the 2018 Bay Delta Science Conference, Dr. Gerrit Platenkamp, Northern California Director of Biological Resources and Land Management with Environmental Science Associates, explains why the state’s policy of no loss of wetlands can cause permitting delays for projects that provide multiple benefits for species and humans, as well as adaptation to sea level rise.
He began by noting that when restoring tidal marshes, elevation is a critically important for tidal marsh species, as the physical factors and the habitat changes dramatically along the tidal marsh elevational gradient.
A paper by Zedler et al in 1999 looked at the ranges of elevations that plant species occupy within a relatively undisturbed marsh in Baja compared to a more disturbed marsh in an urban setting in San Diego. “What you see then is that most of the plant species seem to be occurring in the marsh plain,” he said. “You have plants that occur at a lower elevation like cord grass and pickleweed growing there, and those same species occurs at the San Diego marsh, but what is missing in San Diego is the whole complement of species at the higher elevation. Marshes in our urban settings are really not living to their full potential. They are being cutoff by development, and that really truncates the elevation range of the marsh.”
Sea level rise is accelerating, said Dr. Platenkamp. He acknowledged the huge range of estimates of how fast, but the process is pretty well understood and it is accelerating, so there is a real urgency to restore tidal marshes to stay ahead of that.
A paper in 2004 used the term ‘coastal squeeze’ to describe how marshes are being backed up into existing development. The paper was actually about England and agricultural development but it still applies here, he said. “So you have on the one hand development on the other hand sea level rise that is reducing the marsh in size, so what are we going to do about it?”
Dr. Platenkamp said they worked with the Delta Stewardship Council in preparing some science synthesis papers that describe some of the latest science in the various areas, including restoration and climate change as well as ecosystem stressors. “One of the things that was abundantly clear from that is that we have to really get serious about the issues of sea level rise and climate change in general and that we need to implement those into our projects.”
One possible solution is the concept of horizontal levee which is a levee that very gradually increases in elevation all the way up to the levee crown, and when sea level rises, the tidal marsh can just move up with elevation.
One example where this is being implemented is a project on Lower Walnut Creek which is located in Contra Costa County near the city of Martinez. The project proposes to restore and enhance tidal wetlands along the southern shore of Suisun Bay and from Suisun Bay upstream along Walnut Creek and its tributary Pacheco Creek, to provide sustainable flood protection, and to create opportunities for future public access through the Project area. The project will restore and enhance approximately 250 acres of tidal marsh, as well as adjacent lowland terrestrial grasslands, seasonal wetlands, and uplands, and is designed to be resilient to 2 feet of sea-level rise and adaptable to up to 5 feet of sea-level rise.
The Lower Walnut Creek project will incorporate a horizontal levee with a gradual 10:1 slope that would be designed to support the gradual, long‐term transition in response to sea level rise. The figure on the upper right shows how the project will perform with five feet of sea level rise, with the areas in green being wetlands that would be inundated. The project will result in some of the existing wetlands being filled in, and this is problematic for permitting because since 1993, it has been state law to avoid ongoing wetland losses—a so-called ‘no net loss policy. “We’re going to make it a lot better, but still there is going to be a loss of wetland acreage and since I work on permits, that’s what I have to deal with,” he said.
Another project, the Bay Point Restoration and Public Access Project, will restore 31 acres, much of which is diked former marshland that was historically used for sand dredging operations. The restoration site is contiguous with existing tidal wetlands to the north, east and west and thereby will increase the overall size of wetland habitat in the area once the project is completed, expected in 2019. The project will result in approximately 17 acres of tidal wetlands, 4 acres of seasonal wetlands, and 10 acres of transition and upland grasslands.
There is an existing trail around the site that the East Bay Regional Park District wants to retain, even after sea level rise, so the plan is to raise the trail quite a bit (upper, right). “There are wetlands here and it’s going to be filled when this is built so we need to somehow offset that or consider what the situation will be in the future after sea level rise,” Dr. Platenkamp said.
Lastly, the Tule Red Project in Solano County is a project being constructed by Westervelt Ecological Services to open more than 400 acres of wetlands to daily tides in the southern Suisun Marsh to benefit native fish species. Prior to being diked off to create freshwater habitat favored by game ducks in the early 1900’s, this property was estuarine tidal habitat, providing tidal inundation and seasonal fresh water inundation during wet winter periods. The project involves breaching a natural berm to allow for full daily tidal exchange through the interior of the project site and creation of a network of channels to convey water across the marsh plain.
The Tule Red Project is one of the larger tidal marsh restoration projects now being put into the ground. “The levee has to be heightened, it has to be raised because of potential for flooding because this is going to be open to tides,” said Mr. Platenkamp. “There are some areas that are really long gradients, shallow slopes that are being implemented as well as a variable slope system … In some of these areas there will be fill of existing wetlands, so the question is how do we deal with that to get a permit from the Army Corps of Engineers or the Regional Water Quality Control Board?”
“We have a problem: the coastal squeeze,” he said. “The solution is to use resilient designs. The problem with resilient designs is wetland fills, so what I would propose that we need to focus on science-based permitting. We want to have permit conditions that are using the best available science and we need to have permit conditions that focus on the future, not only on what’s happening right now. Obviously the permits are there to avoid impacts to the resources which of course we’re all in favor of. But we need to be looking at this as a bigger picture process, and these projects are all meant to be beneficial, so they are all meant to be helping the recovery of these species and these habitats.”
The other problem we run into with permitting is time delays, he said. “We worked with Westervelt for about a year and a half on getting the permits, so it was really fast. The other project that’s going to construction this year is the Dutch Slough Project, and I started to work on the permits for that one seven or eight years ago, so there’s a lot of things involved in the permitting and all of that that take a lot of time. Sea level rise is accelerating so we need to get these projects online as fast as we can. We have to deal with all these independent agencies that have very similar objectives, and still we have to go through this stuff over and over again and it’s really inefficient.”
Dr. Platenkamp said that there is good news on the horizon. “For Measure AA, there is the BRIT being started right now, which is the Bay Restoration Regulatory Integration Team where six different state and federal regulatory agencies come together and work together to actually permit projects,” he said. “I am expecting to really save a lot of time and really get these projects online much faster. And in fact, this would be a great idea for the Delta as well.”
Question: I see a lot of federal and state agency involvement, as an engineer I appreciate the whole elevation and how to work around it. How do you foresee working at the local level, at the zoning level, to address some of this restoration?
Dr. Platenkamp: “We need to focus on different areas where there are opportunities for restoration and so typically, this is why we end up in this situation where there are already wetlands, so duck clubs and diked baylands. They have values, and therefore when we affect those values with our construction, they need to be mitigated for. Hopefully our project will have higher functions and values than the ones that were there at this location, and in some cases, that has really helped us. For awhile, the Corps at the San Francisco District was really willing to consider that,and even though we had a little bit of net loss, they said ok, this is fine. In fact, we’ve been in discussions with the regional board also to consider that as well as well as just the future values of these areas, but we keep running into this situation where they say, no we cannot have any loss, like its cast in concrete. That wasn’t your question, but I think in general, it’s going to be difficult to go to areas that are not zoned as open space and restore those, so that’s not really my area, so I wouldn’t know what we do there. Typically we go to areas that are already used as open space.”
Comment from audience member: “I appreciate this as a tidal wetland restoration regulator. I would point out that I think, at least speaking for the water board, I think we’ve been pretty good at acknowledging the long-term transgression of estuarine habitats over adjacent uplands or ecotone levees or horizontal levees. One of the challenges with Tule Red, a component of it was the net loss and we considered that long-term transgression, but I think part of it was also the assumption that the CDFW lands on the rest of the island, that they would always be maintained as diked, seasonal managed wetlands, but over a 50 year time scale, I’m not sure that given all the unengineered infrastructure that’s out there, that’s that a valid assumption.”
(comment, continued) “I think it’s important when we’re talking about tidal wetland restoration designs, that we’re not just thinking about how wetlands will transgress over 50 years but what are reasonable assumptions for surrounding landscapes? Is it reasonable to build flood control levees in the middle of giant landscape complexes of diked managed wetlands? That management and that diking may not be feasible in 50 years with 3 feet, 4 feet of sea level rise, so I think that’s something for the designers in the room to consider. At the Water Board, we’re working on our policies with regard to no net loss and BCDC’s working on their policy, so I think this is something that the regulatory agencies are working on internally. We just have to make sure we update our policies in a thoughtful manner so that we can’t have the bad actors come in at the back end and take advantage of our policies.”
FOR MORE INFORMATION …
- Click here for more information on horizontal levees from the Bay Institute.
- Click here for more information on horizontal levees from the Naturally Resilient Communities project.
- Click here for information on the Oro Loma horizontal levee project.
- Click here for information on wetlands policies from Water Boards, Region 5.
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