Why did the National Park Service (NPS) do this restoration?
Drakes Estero is a federally designated wilderness area, a state marine conservation area (no fishing except recreational clamming), and inside of a national park. As one of only two marine wilderness areas in the NPS and one of the most pristine estuaries on the west coast, we had a unique opportunity to restore a native estuary, reduce invasive species, and increase eelgrass cover, thereby helping fulfill the NPS mission of preserving ecosystems for future generations.
What were the restoration plans?
Much like the highly successful Giacomini Wetland Restoration Project, now that the artificial structures (in this case wooden racks and debris) are removed, this is essentially a passive restoration project. We anticipate that eelgrass will repopulate the disturbed areas, and invasive species density should be lower with less artificial structures to adhere to. We will be monitoring eelgrass throughout the project and until normal eelgrass cover returns to the areas formally occupied by wooden racks and debris—likely 2–5 years following project completion.
What and how much was cleaned out of the Estero?
The two main types of debris removed from the estero were (a) 95 wooden, dock-like racks that weighed nearly 500 tons and totaled 5 miles in length, and (b) nearly 1300 tons of plastic, metal, and shell debris on the estero floor.
Did the restoration affect public access?
Public access to the estero was limited during the work week and Saturdays to ensure public safety. The estero was open for access on Sundays and holidays, as long as no work was underway. Unforeseen conditions necessitated closure of Drakes Estero and the Drakes Estero access road on some Sundays and holidays. Drakes Estero and the westernmost point of Limantour Spit are closed to public access annually from March 1-June 30 for harbor seal pupping season. Please always refer to our feed and the Alerts on our Current Conditions page for the most up-to-date information.
Why was there a partial closure of Drakes Estero?
Drakes Estero was closed on weekdays and some weekends to ensure public safety. Barges and mechanized equipment removed the debris from the estero and posed a danger to kayakers who might venture too close. This was especially the case as barges must navigate narrow channels, under often windy conditions. Drakes Estero is closed to recreational use annually from March 1-June 30 for harbor seal pupping season.
How long did this work take?
The restoration project took ten months, from August 2016 through May 2017.
Where was the debris taken?
The majority of the pressure treated wood and debris was sent to the Altamont landfill. Material not deemed hazardous (plastic, metal) was sent to the Novato Landfill. Routes were used that minimized inconvenience to neighboring communities/businesses.
Why did debris need to go to the Altamont disposal site (a Class 1 landfill)?
Most of the wood used to construct the oyster racks was pressure treated to withstand the saltwater environment. Recent testing showed that the wood still held toxic metals (arsenic, zinc, copper, and a creosote-like substance), therefore this debris must go to a hazardous waste facility.
How did the restoration affect the natural resources and wildlife?
The primary species of concern in the estero are harbor seals, water birds and eelgrass. Control of non-native species is also a concern. Several measures were taken to minimize impacts on these species and the ecosystem. Specifically, no work was conducted within a 1/4 mile of harbor seal haul outs during the harbor seal breeding season, the contractor used several best practices to minimize eelgrass disturbance removing racks and cleaning the estero floor, and all racks were carefully deconstructed to remove the invasive species clinging to racks and to minimize re-entry into the estero.
How much did the restoration project cost?
The project budget was $4,000,000 which includes removal of all 95 racks, most of the debris on the estero floor, and pre- and post-project environmental monitoring.
Why did the NPS paying for the restoration?
As part of the 2014 Settlement Agreement (1,307 KB PDF) between the NPS and the former commercial shellfish operation, the NPS agreed to assume responsibility for the cleanup.
Who did the work?
The NPS contracted the work with T.L. Peterson, who has extensive experience working on NPS projects. The subcontractor doing the in-estuary restoration work has unique experience conducting estuarine and wetland restoration in similar habitats.
How was the work done?
Excavators mounted on shallow water barges traveled to each rack and deconstructed them by cutting racks apart using tools that did not produce sawdust. The excavator then pulled out nearly 7000 wooden posts that were 5 feet into the mud. Excavators were also used to clean up bottom debris in areas where eelgrass was not growing.