Posted on February 26, 2024
The Laguna de Santa Rosa held an open house on Wednesday, February 21, to celebrate the release of the Laguna de Santa Rosa Restoration Plan. Funded by a grant from the California Department of Fish and Wildlife with matching funds from Sonoma Water, this document examines six potential restoration projects in the Laguna de Santa Rosa watershed.
Presented by Neil Lassettre of Sonoma Water and Scott Dusterhoff of the San Francisco Estuary Institute (SFEI), this plan was several years in the making.
“So six years ago, we were here with folks from the public, many of you here in this hall, saying ‘Well, we were going to do this restoration planning effort.’ And here we are six years later, unveiling this restoration plan to you all. So this is really an exciting time for us,” Dusterhoff said.
Dusterhoff explained the two major phases of the project this way: “The first component was developing an understanding of how the Laguna used to look and how it used to function and the habitats that it was supporting. So that’s developing an understanding of the historical ecology,” he said. “And then after we understand how the Laguna used to look and how it used to function, we can understand the landscape change—so the magnitude of change from what was to what is. So that was part number one. Part number two then was using that information to develop this long term restoration vision—this long term idea of all of the habitats we want to bring back in the Laguna. So then, we took that vision and we dove deep on a few areas, and we came up with this master restoration plan,” he said.
To be clear, the projects listed in this document are not currently funded. Rather, this document will be used by various agencies and organizations as the foundation for future restoration funding requests.
Lassettre put it this way: “So now what we have is a document that we can go out into the world and say, ‘Hey, EPA, this document says that these things are important.’ This is a case that we’re making to get funding. And I will say, that’s how it works—that’s what the funding agencies want to see. They want to see a document like this that took a community of people to pull together and agree upon, and they know that there’s a lot of support for such ideas. That’s how the funding that comes about, but we have to write the grants and we have to seek out those funding opportunities.”
Six potential restoration scenarios
The Laguna de Santa Rosa Restoration Plan outlines ambitious restoration projects for six regions in the laguna: Mark West Creek, Ballard Lake, Occidental to Guerneville, Lake Jonive, Highway 12 to the Santa Rosa Waste Water Treatment Plant (WWTP), and Bellevue-Wilfred.
This map identifies where each of the potential restoration projects are located. The colored areas represent the planned restoration types, described in the key.
Mark West: Several alternatives are described in this plan. Alternative A features a realignment of lower Mark West Creek to its historical course, expanded willow forested wetland and mixed riparian habitat, and increased in-channel storage and floodplain sediment deposition. Alternative B reroutes lower Mark West Creek to create a new confluence near River Road and expands mixed riparian forest habitat. Alternative C is similar to Alternative B but realigns the tributary to the south, creating more mixed riparian forest and willow forested wetland habitat. Alternative D reroutes lower Mark West Creek across the narrowest span of agricultural land currently separating the Laguna and the creek, creating forested wetland/mixed riparian habitat.
Ballard Lake: This restoration project concept restores a deep historical freshwater lake along the Laguna mainstem, while introducing a large upstream area of valley freshwater marsh and willow forested wetland.
Occidental-Guerneville: This restoration project concept between Occidental and Guerneville roads is the largest of the concepts and is associated with some of the largest changes to the landscape metrics and expected ecological benefits. It entails the rerouting of the Laguna mainstem to a more natural geometry, and the conversion of a large area of invasive Ludwigia and farmed wetland into restored freshwater marsh habitat.
Lake Jonive: Lake Jonive is the Laguna’s largest and only remaining historical perennial freshwater lake. The project attempts to return the lake to a more natural state through dredging it to historical depths, expanding the forested riparian habitat around the lake, and adding new wet meadow habitat.
HWY 12-WWTP: This restoration project concept involves expanding wet meadow habitat, dredging and deepening a historical perennial lake and expanding forested riparian habitat around the lake, and restoring valley freshwater marsh habitat around the Roseland Creek confluence and along the Laguna mainstem.
Bellevue-Wilfred: This project concept involves the expansion of wet meadow habitat around the Laguna mainstem, restoration of vernal pool habitat, dredging of a historical perennial lake just south of the Santa Rosa Wastewater Treatment Plant, expanding forested riparian habitat around the restored lake, and creation of freshwater marsh adjacent to the lake.
The goals, objectives and priorities of the restoration plan
Dusterhoff said the three management goals of the plan were to improve the overall ecosystem functioning of the Laguna, establish a landscape that is resilient to climate change, and enhance the environmental, agricultural and tribal benefits of the Laguna.
Regarding climate change, he said, “We don’t want to set up a landscape and restore habitats that are going to be gone in a few years once we have more large storms coming through or hotter summers. We know what’s coming our way.”
He also described three management objectives, which were more distinctly ecological. These include enlarging riparian and wetland habitat areas and improving their connectedness; establishing conditions for native plants to thrive; and improving water quality by improving drainage and removing fine sediment in certain parts of the laguna.
Based on these goals and objectives, the plan also contains detailed prioritization and sequencing criteria to determine which projects should be done first and in what order. Mark West Creek Option A won hands down here, which is why the group also developed a detailed project design—a so-called 65% plan—for that alternative. (You can see these plans here.) Restoring this section, which is already covered by a conservation easement and has the cooperation of the landowner, will almost certainly be the first one of these restoration concepts put into practice.
But what about Lake Jonive?
Lake Jonive played an important role in the early days of Sebastopol, but filling and sedimentation have rendered it a mere ghost of its former self. (Read this sad and fascinating history of our local lake.)
Here is a look at its historical habitat profile compared to its habitat profile today:
What would it take to restore Lake Jonive? These are the report’s suggestions:
A. Dredge lake to historical depths. Lake Jonive would maintain its current extent, but would be dredged to its historical depths (~7.5 m)[roughly 24 feet deep]. This would provide cold water habitat for resident and anadromous fish. Deepening the lake would also inhibit the growth of invasive Ludwigia, which currently covers large portions of the lake’s surface and diminishes water quality through annual decomposition.
B. Expand forested riparian buffer. This concept includes an expanded riparian buffer along the edge of the lake and to the south at the area known as Dei Island. Shading of the Laguna and the lake from mature trees would lower water temperatures and discourage growth of invasive Ludwigia. This habitat expansion would also serve as a valuable refuge and a corridor for movement of wildlife.
C. Expand wet meadow area. A substantial expansion of wet meadow (53 hectares) [131 acres] around the area of Lake Jonive would enhance nutrient assimilation from surrounding agricultural sources, as well as provide food and habitat for a variety of native species. Wet meadow can also trap sediment during flood events.
