Bald Eagles Thrill Birdwatchers

by Parker Pringle

Birdwatchers in the Strawberry area have dubbed these bald eagles Freedom (right) and Glory. Photo by Connie Mettier

Over this past winter our national bird became a local attraction, with numerous sightings of beautiful adult bald eagles in the lower Corte Madera Creek watershed. Eagle-eyed drivers northbound on Hwy 101 in January may have seen a large, white-hooded female perched atop a redwood tree next to the freeway just before Lucky Drive. Such sights as these promise to become an unremarkable thing as the national resurgence of bald eagles spreads throughout Marin. The return of these majestic birds may be hastened thanks to a historic courtship that has resulted in a pair of local eagles being joined for life, with a good chance they will be raising their offspring in southern Marin.

From a 1960s continental U.S. population of fewer than 500 breeding pairs, the bald eagle population has rebounded to over 10,000 breeding pairs today. They inhabit a variety of habitats, generally close to the lakes, rivers, and bays where they hunt fish and waterfowl. They prefer perching sites, where they will rest while hunting, on the edge of these waterbodies, while nesting and roosting (sleeping) sites can be miles away.

While bald eagles have been seen in Marin for years, only in the last four years have eagles have been seen with regularity in southern and central Marin. One bird in particular, a seven or eight-year-old female, is presumed to be the same pioneer eagle that has been returning around December to the Strawberry peninsula for the past four years. It was this eagle that could be seen perched above the freeway near Lucky Drive. She has been dubbed Freedom by local eagle fans.

In the previous three years Freedom had left the area in February, but this year she remained around through April, using the time to court and pair off with a four- to five-year-old male eagle, named Glory. As eagles mate for life, this was an important event in Freedom’s life and provided an extraordinary thrill for eagle watchers in Strawberry, where the romance unfolded. The nesting season in California runs November through April. While no one spotted a nest belonging to Freedom and her mate, there are high hopes that next year this pair will return to nest in southern or central Marin.

This mated pair put on some stunning displays of hunting prowess. They would leap off their respective perches and soar down toward an unfortunate grebe. Talons outstretched, Freedom would make a sweeping lunge at the grebe, which would submerge and pop back up seconds later, in time to see Glory zooming in to make a pass. Flying in a circle, the eagles, if their timing was right, would ultimately tire the bird and be able to grab it. If the timing was off, and the bird had enough time between attacks, it could fly off. There was also a number of sightings in Tiburon near Keil Cove, including of an eagle pair. These were almost certainly not the Strawberry eagles. One of those eagles was also seen hunting in Richardson Bay, flying back to Keil Cove with kills.

While there were many eagle sightings reported in Corte Madera this winter, no reports surfaced about eagles hunting. This may be due to the fact that Corte Madera bay is mostly removed from roadways, so viewing is limited. It may also be a less ideal hunting ground than Richardson Bay. But with eagle numbers increasing every winter, it may be only a matter of time before eagles become a regular sight on the creek and the bay. And eaglets, too, if Freedom and her mate select a tree in the watershed for their first nest.

The perch along Hwy 101 that Freedom was using in January is located a few hundred feet north of Shorebird Marsh. In Strawberry, the best viewing areas are the east side of the Strawberry peninsula in the vicinity of Aramburu Island. The eagles perch in a select few trees above the island and will launch hunts from there, often consuming kills on the east shore of the island.

Fire-wise Landscaping with California Natives

by Laura Lovett

After the firestorms of October 2017 in Sonoma and Napa, fire awareness has come to Marin County. While all of us know the necessity to reduce fuels and thin vegetation on our property, a recent guest from San Diego passed along some highly useful knowledge on how to create an attractive, fire resistant landscape—knowledge learned the hard way. The San Diego area was hit by major firestorms in 2003 and 2007, long before those of us in the north were contemplating such disasters.

Greg Rubin is founder of California’s Own Native Landscape Design in Escondido, near San Diego—one of the largest native landscape contractors in the state. He established the company after working for many years as an aerospace materials engineer. Greg’s career change is to our great benefit: to his logic-based engineering mind it made no sense that native plants were frequently failing to thrive in suburban landscapes, while being completely successful on the hills behind our homes. Greg has made it his life’s work to bridge this gap of understanding and share what he has learned.

A fire-wise garden by California’s Own Native Landscape Design. Photo courtesy of Greg Rubin

Of the three dozen landscapes his company had installed that were in fire zones during 2003 and 2007, none of the owners lost their homes, although neighbors did. Greg’s years of experience as an aerospace engineer enabled him to understand the thermodynamics of fire in the landscape and to realize that clearing all vegetation around a home actually sets up the perfect conditions for ember-laden winds to blow right against the house. It’s also an ecological disaster. We need the beauty, shade and moisture that plants provide. Here are a few of the key steps he takes to create thriving native landscapes that are fire resistant:

• Planting plans focus on evergreen native shrubs. These comprise 60–75% of the landscape planting, with showier bulbs and perennials placed closer to walkways and windows. These shrubs stay green year-round, eliminating the dried-up look of summer-dormant plants while providing quality habitat in all months.
• The three or four feet closest to the home is kept free of plants; use this space for walkways, patios and decks. (And avoid the temptation to use this space to store flammable things like firewood and propane for the grill.)
• Don’t fertilize. Native plants don’t need it and it encourages bacteria, which introduce diseases.
• Thin existing areas with thick chaparral and undergrowth, but don’t clear them. Thinning them by half removes 70% of the fuel load. Open naturalistic paths between clumps of plantings, allowing both gardeners and firefighters access.
• Once cleared, immediately cover these areas in several inches of mulch to keep weeds out. Pull the weeds that do show up. If annual grasses are allowed to fill in, an even more flammable situation has been created.
• California native landscapes should then be irrigated with overhead spray heads, not drip lines, at a rate of 4/10ths of an inch per hour using MP Rotators, 2–3 times per month, year-round. This is key, especially in hot, dry climates. It is the equivalent of a summer thunderstorm, but just this small amount of water allows the plants to stay hydrated. Most homes are lost when flying embers lodge in flammable material and catch fire. If they lodge in hydrated plants, more than likely they will burn out before the plant catches fire.
• Plants from non-Californian Mediterranean climates like Chile and South Africa will need about twice this amount of overhead irrigation to achieve the necessary hydration. Non-native plants require at least four times as much.
• This irrigation/hydration regime takes precedence over installing a list of non-flammable plants. Greg has found that some of what have been declared the most flammable native plants simply smolder once they receive this minimum hydration.

We all want to keep our homes safe in the event of fire, while having a lovely green landscape to enjoy in the meantime. These landscaping principles, tested in the southern California wildfires, are equally applicable here in Marin County and should enable us to have both beauty and safety.

Where Will All That Water Go?

by Sandy Guldman

Flood Zone 9 (FZ9), the collaboration of the Marin County Water Conservation and Flood Control District, together with the towns of Fairfax, Ross, and San Anselmo and the City of Larkspur, is implementing the Ross Valley Watershed Program (RVWP) by moving forward on several fronts to reduce the risk of flooding. The focus is on completing design and environmental review of identified projects and obtaining additional funding from outside sources where necessary. Here’s a rundown, starting at the top of the watershed.

The San Anselmo Flood Risk Reduction Project will reduce the risk of flooding in Ross Valley by implementing projects on two parcels along San Anselmo and Fairfax creeks: one to remove a channel-constricting building and another to construct a flood diversion and storage basin. Marin County purchased the building at 634–636 San Anselmo Avenue and is working with the owners of the businesses to relocate by the end of 2019. The businesses continue to operate as of mid-2019. The basin property is a 7.7-acre parcel located along Fairfax Creek at the former location of the Sunnyside Nursery growing grounds. A depression to accommodate diverted creek water will be created to temporarily reduce downstream flooding. The Environmental Impact Report (EIR) for this project was certified in September 2018 and final design work is underway for both components. Construction is scheduled to begin in mid-2020 and be completed by late 2021. This project is funded by RVWP fees and a grant from the California Department of Water Resources (DWR).

Existing concrete structures at the Saunders Avenue bridge cause multiple problems for people, property and migratory fish. Photo by Charles Kennard

Planning is underway for various bridge replacements that will reduce the risk of flooding. The Town of Fairfax plans to replace the Azalea Avenue bridge by the end of 2021. The Town of San Anselmo expects to replace the Madrone Avenue and Nokomis Avenue bridges by the end of 2020. The more complex planning involved to design replacements for the Bridge Avenue, Sycamore Avenue, and Center Boulevard bridges results in an expected completion date of late 2024. The Town of Ross plans to replace the Winship Avenue bridge by the end of 2020. All of the bridge work is funded by Caltrans with local contributions from the towns and support from RVWP funds. Another bridge, the Saunders Avenue bridge at San Anselmo Creek, was recently declared deficient by Caltrans; this bridge causes local flooding and structures in the creek represent a major barrier to fish passage. Friends is helping the Town raise $25,000 to prepare the application necessary for Caltrans to add Saunders to the list of bridge replacement projects eligible for Caltrans funding.

The Corte Madera Creek Flood Risk Reduction Project has a long and complicated history. It was intended to complete the US Army Corps of Engineers (USACE) Project, begun in the 1960s. Fast forwarding several decades and skipping the many false starts, the USACE presented a series of alternatives to reduce the risk of flooding along Corte Madera Creek in Ross and Kentfield. These alternatives were presented to the public in September 2018 when a draft environmental document was released. This document was intended to serve both as an Environmental Impact Statement (EIS) required by the National Environmental Policy Act and an EIR to satisfy the California Environmental Quality Act (CEQA). The only project that met USACE criteria was not favorably received by the local community. Typical of USACE work from the 1960s, this project was authorized with the single purpose of reducing the risk of flooding; the alternatives did not consider other benefits. In addition, the joint EIS/EIR was not considered adequate by CEQA standards and reviewers had a number of substantive comments. Another major problem was the unwillingness of the USACE to address fish passage problems in the concrete channel downstream of its preferred project; this would have made it challenging for the USACE project to receive permits from wildlife agencies. When the USACE declared that it could not continue work on the project because its authorization provided neither adequate funding nor time to deal with extensive revisions to the draft EIS/EIR, Marin County decided to suspend the agreement with the USACE. At this time, FZ9 staff, in consultation with local stakeholders, is developing a new project description and a new set of alternatives, with a new EIR to follow. Recent field work on this project has included taking core samples to evaluate the condition of the ~50-year-old concrete channel and conducting land surveys to identify the right-of-way. The current schedule indicates that construction of the new project will be completed by the end of 2023 using funding from DWR and the RVWP.

Fish passage in the concrete channel is a key issue for wildlife agencies. To facilitate permitting of the Corte Madera Creek Flood Risk Reduction Project, Friends submitted a proposal to the Coastal Conservancy for the conceptual design of measures that would modify the concrete channel to meet fish passage criteria for salmonids. The proposal, prepared in cooperation with FZ9, would use the results of the recent concrete borings to inform the design. The work would also be done in collaboration with engineers developing the flood risk reduction measures for the concrete channel, so that an integrated design would be prepared. Construction to address fish passage issues throughout the concrete channel likely will need additional funding above and beyond work that will be funded by the DWR grant. That funding will be sought from programs that specifically address fish passage.

Concrete channel removal has been a goal of Friends since the organization’s beginning, but it always seemed a distant prospect. However, Friends funded the preparation of conceptual designs for removal of the right side (viewed looking downstream) of the concrete channel on the College of Marin campus downstream of the SMN Bridge. The left side of the channel would stay in place to protect a large sewer that was installed at the same time the concrete channel was constructed. In cooperation with the College of Marin and FZ9, Friends submitted a proposal for funding to prepare final designs for a project downstream of Stadium Way in Kentfield. If the proposal is successful, the design work would be funded by the Marin Community Foundation. With the final design in hand, FZ9, Friends, and the College could seek funding for construction. We expect to pursue additional funding opportunities for other work in Kentfield in collaboration with FZ9, and the College of Marin. Drawings of the concrete channel conceptual designs are posted on Friends’ website under pulldown menus for Restoration Projects–More FCMCW Projects–Kentfield and Larkspur.

The 1998 dredging of Corte Madera Creek immediately downstream of the concrete channel required the building of two temporary dams. Photo by Charles Kennard

Dredging in the lower reaches of Corte Madera Creek is a perennial topic of discussion. Unfortunately, dredging as a solution to flooding in this reach is not sustainable. Sedimentation rates are high, dredging is expensive and unfunded, permits are challenging to obtain, and there are limited disposal options for dredged material. Furthermore, sea level rise will increasingly dominate flooding in the downstream portion of the watershed. Engineers with the Flood Control District are working to evaluate the feasibility of what is called a geomorphic dredge. This would identify a channel that could be maintained by the natural flow tides and upstream contributions to flow with very limited dredging.

Levees may be one component of adaption to sea level rise. With funding from DWR, the RVWP is evaluating locations in Kentfield and Larkspur where levees could serve to protect residential areas. Results are expected by late fall 2019.

Pump stations are sometimes necessary to deal with stormwater that accumulates in low-lying areas. One pump station will be constructed to drain the Hillview neighborhood in Larkspur, work being done in conjunction with replacement of the Bon Air Bridge currently underway. Another pump station will likely be needed in Granton Park, in Kentfield. Although a wall will be built to protect this neighborhood from creek overflows, this low-lying neighborhood accumulates stormwater.
Stay tuned for news from the RVWP and Friends as work progresses on these many projects. On-the-ground results will soon be seen throughout the watershed.

What a Difference Some Glorious Mud Makes!

by Sandy Guldman
Flanders and Swan, a British comedy duo, wrote over 100 comic songs including the Hippopotamus Song, which extols the virtues of mud, glorious mud. This took on new meaning as we searched for mud to replace poor soil at Creekside Marsh.
Creekside Marsh at Hal Brown Park was restored in the mid-1970s by contouring the fill dumped there in the late 1960s. The standard tale was that the material was dredged from the natural channel of Corte Madera Creek and its surrounding tidal wetlands when the wide earthen channel was dug by the US Army Corps of Engineers. However, large bare areas persisted even after all these years and as we literally began to dig around in the marsh, we found what appeared to be material from road construction or cleared land-slides—rough, rocky material that had never been smoothed and sorted over time in a creek bed.
To grow native plants in these bare areas, we needed to replace the poor soil with what geologists call Young Bay Mud, the soil that supports healthy tidal marsh vegetation around San Francisco Bay. However, finding it is easier said than done. After a long search, we were lucky to find a project at Corte Madera Eco-logical Reserve where Marin Audubon was restoring a filled parcel and digging a new channel through Young Bay Mud. Marin Audubon and their contractor offered us the mud and the search was finally over. By then, we felt it truly was glorious mud! The mud had roots of native cordgrass, saltgrass, and pickleweed, all of which began to grow. Then we were given hundreds of pickleweed plants by Marin County Parks, which
volunteers from Cal State East Bay and Friends planted this spring. This newly restored area is transformed—thanks to mud.

Young Bay Mud is composed of soft water-saturated estuarine deposits less than 10,000 years old that underlie present and former marshlands that border San Francisco Bay.

Friends board member Cindy Lowney introduced dozens of young pickleweed plants to their new home. Photo by Ann Thomas

The earthen channel under construction in the 1960s, near Bon Air Road. Photo courtesy of Richard Torney

New Technologies Being Used to Study Erosion of Corte Madera Marsh

by Laurie Williams
In the fall of 2018, scientists used a drone (otherwise known as an unmanned aerial vehicle) to survey baseline elevations in the Corte Madera Marsh in order to study marsh erosion and resiliency to sea level rise caused by climate change. Follow-up survey efforts in 2019 will measure how much the marsh has eroded over the winter. The project, which is funded by a grant from the Marin Community Foundation, is overseen by San Francisco State University with involvement from San Francisco Estuary Institute (SFEI).
The study seeks to understand detailed mechanisms of marsh erosion that will help engineers restore mudflats and marshes that can reduce wave energy and decrease marsh erosion. If we want our marshes to keep pace with climate change, we need to understand the forces that build up and erode marshes and the potential impacts of increased numbers and intensities of storms on marshes in Corte Madera and around the Bay.
One of the main benefits of the drone survey is that scientists did not have to access the sensitive marsh by foot, as with traditional survey methods. This is important in sensitive habitat that supports listed species such as Ridgway’s rail and salt-marsh harvest mouse.
In order to proceed with the flights, researchers needed approval from the California Department of Fish and Wildlife (DFW), which owns the land. To protect birds and wildlife, the drones were flown higher than usual, at 200 feet instead of 100 feet. A DFW land manager closely monitored the drone flights and used a bird scope to observe the behavior of the birds to ensure that the drone was not disturbing them. Pete Kauhanen of SFEI remarked that the “drones did not appear to disturb the wildlife, and scientists noted that in a few instances, foraging birds approached the drone as it was taking off and landing.”
The article “Drones: An Asset or a Menace?” in a previous issue of Creek Chronicles, and now archived on Friends’ website, describes regulations affecting the recreational use of drones. Friends of Corte Madera Creek Watershed does not support the recreational use of drones where such use may harass wildlife or disturb the enjoyment of nature.

A drone’s eye view of a section of Corte Madera Marsh. Photo courtesy of San Francisco Estuary Institute