Corte Madera Creek Flood Protection Project — Natural Solutions for a Rising Tide
A Sustainable Approach to Flood Protection in Marin County
Location: Corte Madera, Marin County
Partner: Ground Control
Division: Green Space & Landscape Services
When Marin County Engineering launched the Corte Madera Creek Flood Protection Project, the goal was clear: Reinforce a vulnerable creek embankment using natural materials and ecological construction techniques. Rising tides and increasingly severe storms had begun threatening nearby properties and ecosystems—demanding a solution that balanced engineering precision with environmental sensitivity.
A Collaborative Effort with Ground Control
Arborist Now partnered with Ground Control to deliver the log installation phase of this critical project. The design called for a series of Douglas fir logs positioned atop boulders along the creek bank, forming a natural barrier that would absorb water energy, stabilize the slope, and create new habitat for native wildlife.
While Ground Control handled the placement of boulders per the engineering specifications, Arborist Now took responsibility for procuring and installing the large Douglas Fir logs that would complete the structure.
Sourcing Native California Logs
Finding the right material proved to be one of the project’s biggest challenges. The contract required long, straight conifer logs sourced from native California species—no small task given the size, consistency, and environmental standards involved.
Arborist Now sourced the majority of the logs through Anvil, a leading forestry company in California, who provided access to a curated inventory of native Douglas fir. Every log used was part of a sustainable forestry program, ensuring that the project supported local ecosystems from forest to floodplain.
Working with the Tides
Unlike most construction projects, this one was ruled by the moon, the sun, and the tides. Corte Madera Creek is directly influenced by tidal cycles, which meant work windows were unpredictable and narrow—sometimes allowing only a few hours of safe access per day.
An additional challenge came from the need to securely fasten the logs onto the boulders beneath them. Because of the constant transition between high and low tides, any unsecured logs could easily float away or shift with the current. To address this, Arborist Now installed a water-resistant anchoring system designed for long-term durability in a tidal environment.
Log Anchoring System
Because the creek’s tide levels fluctuate dramatically, the logs are alternately submerged and exposed depending on the cycle. This meant each log had to be firmly anchored to the irregularly shaped boulders below, following strict specifications for size, orientation, and placement. It was a complex process, requiring both precision and adaptability to ensure water-resistant connections that could withstand constant changes in pressure and buoyancy.
To achieve this, each log was drilled using an auger to allow for the installation of 1” hot-dipped galvanized (HDG) threaded rods. The rods were then anchored to the underlying two-ton boulders using two different methods depending on site conditions:
- Direct Anchorage: Drilling directly into the boulder and inserting the rod with water-resistant epoxy to form a permanent bond.
- Linked Anchorage: When direct drilling was not feasible, the rod embedded in the boulder was connected to the log-mounted rod using HDG eye nuts and a screw pin shackle, forming a strong mechanical linkage.
Each log was then secured in place with a 3x3x3/8” HDG steel plate, similar to those used in seismic hold-down systems for buildings, and fastened with two 1” HDG nuts to ensure rigidity and resistance against fluctuating water pressure.
Racing the Storm
The timing couldn’t have been tighter. A major storm was forecast to hit the region just as the temporary bladder, which held back rising creek water, was set to be removed. Every hour mattered. The Arborist Now team worked extended shifts to complete the installation ahead of the storm, ensuring the structure was in place to protect the community and the natural corridor from surge impacts.
Behind the Work: The Team Perspective
Two of Arborist Now’s team members, Clint Stewart and Guillaume Pernet, played pivotal roles in bringing this project to life. Guillaume served as the field supervisor, managing on-site logistics and adapting technical solutions in real time. Both Guillaume and Clint brought their backgrounds as skilled carpenters to the job—an expertise that proved invaluable when aligning large, irregular logs with custom-drilled boulders under tidal pressure.
“During installation, one of the biggest challenges was the time available to complete the work, which shrank from eight days originally planned down to five before the temporary dam had to be evacuated due to a storm and heavy rain,” Guillaume explains. “We also ran into a few smaller issues such as on-site power for our tools being down, sourcing and collecting enough threaded rods for the extra logs, or finding the right auger bits to drill through 30-inch logs. Very interesting project overall, as this type of work is not common and requires adaptability and creativity. The crew was very invested and agreed to work overtime and weekends in order to get the work done. Thanks to Ground Control and Marin County for your trust—we’re ready for the next challenge anytime!”
Their dedication and craftsmanship exemplified the hands-on expertise that defines Arborist Now’s Green Space Division. Working under unpredictable tidal conditions, their adaptability and teamwork ensured the project’s success despite the extreme time pressure and field challenges.
Results: Engineering Meets Ecology
The completed structure now stands as a model for nature-based flood protection—combining engineered stability with ecological benefits. The logs not only stabilize the creek bank but also provide habitat and shelter for aquatic and riparian wildlife, helping to restore biodiversity along the waterway.
This project highlights Arborist Now’s ability to deliver complex, environmentally integrated construction under pressure—from sourcing sustainable materials to executing precise fieldwork in challenging natural conditions.
Acknowledgments
This successful project was made possible through the collaboration and coordination of:
- Ground Control – Partner in Construction and Site Coordination
- Marin County Engineering – Project Leadership
- Anvil Forestry – Native Log Supply
Protecting Landscapes Naturally
Arborist Now is proud to contribute to projects that protect both people and nature. Our Green Space & Landscape Services Division specializes in sustainable landscape construction, ecological restoration, and urban green space management throughout the Bay Area and Marin County.
Contact us to learn how our team can help design and build environmentally responsible solutions for your next green space or restoration project.