Ross Valley Watershed Program—What’s Next?

by Sandy Guldman

Providing protection from an event with a one percent chance of occurring in any year (aka the 100-year event) was an original goal of the Ross Valley Watershed Program. Opposition to proposals to achieve this goal from residents of San Anselmo and Fairfax means that it is no longer a realistic goal in the near term. Most of the floodplain is occupied by homes, businesses, and public facilities and many portions of the channel overflow and flood in a 6-year event., turning our communities into detention basins by default.

In the absence of major flood mitigation measures, downtown Fairfax (seen above, in 1982), San Anselmo and Ross become, in effect, detention basins for flood water. Photo by Charles Kennard


The current program has a goal of providing protection from 10- to 25-year events by 2027 when the current storm drainage fee ends. It includes projects with plausible funding that are being designed and un-der environmental review, discussed below. Other program components (e.g., creek cleanups; webcams, stream gauges, and warning systems; and some limited assistance for land-owners) are described on the Ross Valley Watershed Program website.

Corte Madera Creek Flood Risk Management Project: This is the old US Army Corps of Engineers (USACE) project, revived with the goal of finally completing it. The Environmental Impact Statement/Environmental Impact Report (EIS/EIR) is in preparation and the draft should be available by spring 2018. Funds for the construction of the USACE project depend on congressional authorization, which may not be forthcoming. To speed implementation of some actions, the project has been divided into phases.

Phase 1 includes the Frederick Allen Park Riparian Corridor, removal of the fish ladder in Ross, and construction of a floodwall along Granton Park in Kentfield. Phase 1 reduces flood risk in parts of Ross and Kentfield and will not increase flood risk at downstream locations. Because the Phoenix Lake Integrated Regional Water Management project
is infeasible under the funding and schedule constraints of the funder, the intent is to request reallocation of Phoenix Lake funds to pay for Phase 1. If stakeholders involved in Phase 1 work collaboratively and promptly agree to submit the project to the funder for approval as a substitute for the Phoenix Lake project, design and permitting for Phase 1 can continue. If the schedule slips, then it is unlikely that other grant funding could be obtained and Phase 1 would have to be delayed until Congress provided funding for construction of the entire USACE project.

Friends of Corte Madera Creek Watershed funded the preparation of conceptual plans, described in the last issue of Creek Chronicles, for partial removal of the concrete channel on the College of Marin (COM) campus. That design is being evaluated in the EIS/EIR and, with completed environmental review in hand, we plan to work with the Flood Control District and COM to seek funding for it from sources other than the USACE so that it can be implemented concurrently with replacement of the Student Center and Student Learning Center at COM. If this schedule can be met, it would be-come Phase 2 of the overall project.

San Anselmo Flood Risk Reduction Project: This project would use funding originally intended for the Memorial Park Detention Basin to provide equivalent flood risk reduction and environmental benefits, but in different locations. The pro-posed detention basin would be located west of Fairfax on the former site of the Sunnyside Nursery growing grounds, which is now owned by the County of Marin. It would reduce the flood risk in Fairfax and, to a lesser extent, San Anselmo. This project also includes removal of the building at 634-636 San Anselmo Avenue, where floodwater first leaves the channel in downtown San Anselmo. The Draft EIR will be re-leased in early 2018.

Bridges: Bridges at Azalea Avenue in Fairfax, Madrone and Nokomis avenues in San Anselmo, and Winship Avenue in Ross are considered structurally or functionally deficient by Caltrans and will be redesigned and replaced by the end of 2020, with most of the funding sup-plied by federal highway funds administered by Caltrans. The funds are already committed. All of these bridges currently contribute to flooding. Some measures, such as low walls, may be needed to protect downstream property from the increased flow under the bridges.
The complex intersection at Bridge and Sycamore avenues is being evaluated. A range of alternative designs is expected, with a Draft EIR, in late 2019. The design for this project, but not its construction, is funded by federal highway funds. If federal funding for bridges remains available, construction could occur in 2021.

What Not to Plant

by Laura Lovett

Pride of Madeira. Photos by Laura Lovett


If you love to garden, Marin County is a great place to live. Cold freezes are rare, winters are short, low hills provide wind protection and rains fall more frequently here than inland, making hospitable growing conditions for a huge variety of plants. Those same conditions, how-ever, make it a good host for what are known as “invasives.”

Since settlers arrived in California, we have been importing and growing plants here from all corners of the world, especially those that thrive in similar Mediterranean cli-mate zones. The majority of these are well-behaved visitors. Invasive plant species are those with characteristics such as fast growth and multiple methods of propagation. When combined with a lack of natural predators and diseases, these plants can spread from gardens and take over major areas of land and water, forcing out native plants and creating monocultures. This ability to suffocate and replace native vegetation—degrading the environment—makes a particular plant an invasive weed.

Some invasive species were introduced with good intentions and then ran wild, and there are several that we still bring home from nurseries and plant in our garden that subsequently spread rapidly beyond them. If you live along a stream or in an area that’s foggy and damp, the potential for uncontrolled spreading is increased. While you may be a careful gardener, wind, floods, birds and other animals can spread plants to where they cause havoc. Here are a few of the plants that we hope are not in your garden and some suggestions on what else to plant that will grow to a similar size and form.

Cotoneaster (Cotoneaster lacteus, Cotoneaster pannosus) This pretty shrub produces thousands of berries each year, and those seeds are widely dispersed by birds, small mammals, water, and humans. Cotoneaster has an aggressive root system that displaces native plants. It appears quickly in disturbed sites and becomes established before native shrubs like coffeeberry (Frangula californica) and toyon (Heteromeles arbutifolia), which provide far more ecological value to the habitat in sunnier locations. Good options to use in shadier spots include pink-flowering currant (Ribes sanguineum var. glutinosum) and snowberry (Symphoricarpos albus).

Highway Ice Plant (Carpobrotus edulis) This vigorous groundcover forms impenetrable mats that compete directly with native vegetation. It regenerates through seed and from small fragments that spread by wind and water. Introduced as an ornamental plant, ice plant now inhabits our coastal scrub, grasslands and bluffs, and covers large areas of Point Reyes dunes and beaches. Instead, try trailing ice plant (Delosperma cooperi), a non-invasive ice plant with smaller succulent leaves and brilliant violet-pink flowers that’s salt tolerant and fire resistant. Although this plant is not native, it is a good alternative to its aggressive cousin. Native options include beach strawberry (Fragaria chiloensis), seaside daisy (Erigeron glaucus), and dwarf coyote bush (Baccharis pilularis) ‘Twin Peaks’ or ‘Pigeon Point’.

Pride of Madeira (Echium candicans) Very little will grow under an established Echium candicans. It is especially problematic in damp areas and along watercourses, where abundant moisture enables it to spread. It should not be planted near natural open space—new seedlings can sprout as much as 30 feet from the parent plant. Cut off the flower stalks before seeds mature to avoid this. But why would you plant some-thing from across the Atlantic when you can enjoy a lovely native Ceanothus ‘Concha,’ Cleveland sage (Salvia clevelandii, try varieties ‘Pozo Blue’ or ‘Winifred Gilman’), island bush poppy (Dendromecon harfordii) or flannel bush (Fremontodendron californicum)? All of these are gorgeous shrubs in their own right.

Mexican feather grass (Stipa tenuissima) A feathery and attractive grass that’s easy to grow, this pest appears in gardens all over Marin. It is particularly problematic in gardens near waterways as the seeds are easily dispersed by water. Seeds are also carried by livestock, humans, and wind; they adhere to clothing and fur; and can lie dormant for more than four years. This plant is now found in all types of landscapes around the county. Recommended alternatives include blue grama grass (Bouteloua gracilis ‘Blonde Ambition’), prairie dropseed (Sporobolus airoides), red fescue (Festuca rubra), and slender hairgrass (Deschampsia elongata).

Pampas grass in Corte Madera


Pampas Grass (Cortaderia selloana) This plant was introduced to California for ornamental use; then it took over many areas of the state. The fluffy plumes produce 100,000 seeds (or more) that blow away in the wind, making it nearly impossible to control. It tolerates winter frost, warmer summer temperatures, moderate drought, and produces significant amounts of extremely flammable biomass, increasing both the frequency and intensity of fire. For a substitute with the same striking stature, try giant sacaton (Sporobolus wrightii), which grows up to 10 feet tall and has showy, feathery seed heads in late summer. Also try Lindheimer’s muhly grass (Muhlenbergia lindheimeri) or giant wild rye (Elymus condensatus).

Giant Reed Grass (Arundo donax) This bamboo-like grass is a serious problem in damp areas and along streams. Its dense growth crowds out native plants, damages habitat, and creates a fire and flood hazard while providing little shade for fish populations in the stream. Giant reed threatens riparian ecosystems by modifying the hydrology of the river, retaining sediment, and constricting flow. Alternatives include Lindheimer’s muhly grass (Muhlenbergia lindheimeri), deer grass (Muhlenbergia rigens), arroyo willow (Salix lasiolepis), and giant wild rye (Elymus condensatus).

Running bamboo in Larkspur


Running Bamboo (usually Phyllostachys species but also Pseudosasa, Chimonobambusa, Arundinaria, Semiarundinaria, etc.) Technically a giant grass, running bamboo is one of the world’s most invasive plants. Once established, it is next to impossible to control. Many homeowners plant bamboo to create a fast-growing privacy screen. Before you do, however, keep in mind it will not stay on your property but will also invade much of your neighbor’s. Bamboo grows particularly vigorously when near irrigated lawns and gardens. Bamboo barriers eventually break. If you already have it on your property, use a back-hoe to remove as much root and soil as possible, then comb through the remainder for root fragments.

Better options include island mountain mahogany (Cercocarpus alnifolius) which makes an evergreen shrub 4 to 6 feet wide and 12 feet tall; holly-leaf cherry (Prunus ilicifolia), also evergreen with white flowers and red fruit in fall that birds love; or California cypress (Cupressus goveniana), very drought tolerant, to 15 feet tall and evergreen.

Woodland Forget-me-not (Myosotis sylvatica) This charming little plant grows like wildfire in shady, moist areas. Pull or hoe the plants before they go to seed as they spread by seeds and by roots at the leaf nodes. Good replacements include the similar native woodland phacelia (Phacelia bolanderi), western columbine (Aquilegia formosa), creeping snowberry (Symphoricarpos mollis), and miner’s lettuce (Claytonia perfoliata).

English Ivy (Hedera helix) This European import shows up along roadways, on the coast, and outcompetes almost everything in California’s forests as well. Ivy can smother understory vegetation, kill trees, and inhibit regeneration of understory plants, including new trees and shrubs. Replace it with any native groundcover and you’ll immediately increase the biodiversity of your gar-den. Excellent choices include groundcover varieties of Ceanothus like ‘Centennial,’ ‘Anchor Bay’ or ‘Carmel Creeper,’ bearberry (Arctostaphylos uva-ursi), beach strawberry (Fragaria chiloensis), and yerba buena (Satureja douglasii).

Periwinkle (Vinca major) Periwinkle has trailing stems that root wherever they touch the soil. Riparian zones are particularly sensitive. Fragments of periwinkle vines can break and wash downstream, spreading it rapidly in shady creeks and drainages where it smothers the native plant community. Any alternatives suggested for English ivy will grow where periwinkle has been re-moved. If you have a sunny site, try Bee’s Bliss sage (Salvia ‘Bee’s Bliss’) or seaside daisy (Erigeron glaucus).

Native plants may not seem as showy as your favorite roses or hydrangeas, but they are essential to our natural world. These plants have had millennia to adapt to our region’s local climate and soils, co-evolving with insects, fungi, and microbes to form complex relationships that create the foundation of our ecosystem. Imported invasives that push these plants out create “green deserts” that do not provide any resources for pollinators or food for birds or wildlife. State agencies, parks and regional groups spend more than $82 million a year to control them. We encourage you to help this effort to conserve our natural biodiversity by making thoughtful choices for your home garden. Visit calscape.org for a handy tool to help you pick the right plants.

The Dirt on Hal Brown Park

by Charles Kennard

It was a text-book case of a quick response to an invasive weed—except that the text book was still being written.

Last September several truck-loads of soil were brought to Hal Brown Park from Candlestick Point in San Francisco, to replace stony soil that had been dumped into the marsh decades ago and was inconducive to the growth of marsh plants. The recent action was part of a project implemented by Marin County Parks to compensate for the impacts to tidal marsh habitat during construction of the pedestrian/bicycle bridge across East Sir Francis Drake Boulevard, officially the Central Marin Ferry Connection.

In preparation for a volunteer workday at the park, Kirk Schroeder of Marin County Parks noticed that the area where the dirt had been stockpiled before its use in the marsh was bristling with a patch of three-foot-high plants that had sprung up and were unknown to him. One of his colleagues identified the plant as an invasive weed originating in Eurasia with the delightfully expressive name five-horned smotherweed, or Bassia hyssopifolia. Over the years it has been accidentally introduced to many parts of the western half of the continent, and is also recorded from Ignacio, along the railroad—a typical habitat for weeds, that have an advantage in disturbed and well-travelled routes.

The very next day, a volunteer crew of Salesforce employees was put to work pulling and bagging the weed, to prevent it from spreading.

Volunteers from Salesforce at Hal Brown Park pull up five-horned smotherweed before it can spread around the marsh. Photo by Kirk Schroeder

Such an “Early Detection and Rapid Response” to invasive plants is the model of programs being developed by public land managers around the Bay Area, on the principle of a stitch in time saves nine. One ecologist has calculated that the financial benefit of catching weeds early is actually more like 1 to 34. In Marin, the Tamalpais Lands Collaborative (TLC, or OneTam) has developed a protocol for surveying, re-cording and monitoring the occurrences of invasive plants, especially new populations. In the long term, it is more effective to eradicate these than to attempt to tackle, say, an established five-acre patch of French broom. So the TLC has drawn up a list of 21 priority small-population or anticipated invasive plants that have the potential to cause a big problem if they are not dealt with rapidly, and another list of 40 invasive plants that are already well-established and very hard to make a dent in. Examples in the first group are Chinese tree-of-heaven, Portuguese broom, gorse, large-flowered St. John’s wort, and several grasses. A few of those in the second group are black acacia, pampas grass, French broom, cotoneaster, fennel, English ivy, and many other familiar species.

Of course, the detection of these invasive plants must be followed by effective treatment to eradicate or control them, and this is where volunteers can be most useful. In our watershed, MMWD and Marin County Parks have well-developed programs for volunteers; the San Anselmo Open Space Committee has embarked on a broom-removal and trail project on Red Hill; and Friends has periodic workdays on its restoration sites.

The recent events at Hal Brown park have an aspect of déjà-vu. Forty years ago, a cordgrass was brought from Humboldt Bay to the marsh at Hal Brown Park, intentionally, as part of a restoration project. It turned out to be an invasive species, Spartina densiflora, native to Chile, and Friends has spent much time and money over the past decade, sup-ported by the bay-wide Invasive Spartina Project, to rid our estuary of the plant. We have had considerable success, but it would have been so much easier if the problem had been spotted at its inception.

Fake Turf News

by Charles Kennard

As artificial turf playing fields proliferate around Marin, the debate around artificial vs. natural grass largely revolves around installation and maintenance costs, the experience of human contact with materials, and year-round usage of the surface.

However, the environmental consequences of switching to artificial turf are considerable, and the long-term effects of emissions from the constituent materials have been little studied. The typical anatomy of artificial turf is this: at the bottom, a water-impermeable layer is created with clay and fabric; above it is a layer of rock, threaded by pipes that quickly drain the field; next is a fabric anchoring the synthetic blades of polyethylene or polyethylene blend; after all this has been assembled, the spaces between the blades are filled with recycled rubber crumbs, or with a cork and natural fiber mixture, to make the blades stand up and to provide cushioning.

Hydrology Natural turf fields in our area require approximately three-quarters of the wet season rainfall on them to sustain them through the summer, and this water must be captured in reservoirs elsewhere. However, water applied to natural turf fields can recharge local aquifers and provide some summer base flow to local creeks. Artificial fields require no water, but quickly shed rainfall into creeks and storm drains, contributing to flooding, and precluding groundwater recharge. This is important because less groundwater means lower summer flows in creeks.

Toxicity A study prepared for the Santa Clara Valley Water District in 2010 identified zinc released from recycled tires into drain water as a potential toxin to rainbow trout and to plant growth. On the other hand, pesticides and fertilizers applied to natural turf may well spread beyond the immediate area.

Disposal Artificial turf fields must be replaced about every 10 years (as was done at Drake High School in 2017), and the top layers of synthetic material added to a landfill. If the field is to revert to natural grass, then the potentially zinc-contaminated rock must also be dis-posed of safely. Even during the life-time of the artificial field, rubber particles spread to the surroundings.

Habitat Value Artificial turf fields have zero habitat value, and on hot days increase local air temperature. Natural mown grass provides at least a minimal opportunity for soil organisms, invertebrates, and some foraging or resting for birds.

Friends’ policy on playing fields in general can be found on our web-site under Reports and Policies

Concrete Action to Clean the Creek

by Gerhard Epke

The problem of concrete debris in our creeks, particularly around downtown San Anselmo, has been written about previously in Creek Chronicles—it constricts the channel, inhibits fish movement and is an eyesore. Last September Friends of Corte Madera Creek Watershed and the San Anselmo Public Works Department spent a week removing concrete from the creek and disposing of it properly. By directing $10,000 of mitigation money to help pay for labor, we helped expand the Town’s effort, which ultimately re-moved more than 10 tons of rubble.

This debris, only part of which was removed, includes cinder blocks, fence post foundations, old water heaters, metal pipes, but mostly it is broken pieces of old sidewalks and driveways that were at some point repurposed as creek bank stabilization. The creek also contains large amounts of cobble- and boulder-sized rocks that were imported to stabilize banks. Unfortunately, the concrete pieces and rocks weren’t large enough to withstand fast-moving water and ended up being carried into and down the channel.

After some trial and error, we have learned that surprisingly large pieces of concrete can be removed from the creek quite easily as long as they are not embedded in the bank or cemented to bedrock. A few strong bodies with long pry-bars dis-lodge the concrete from the creek bed and either roll it into an impro-vised sled or wrap it with a chain. Then comes the one crucial piece of equipment, which is a backhoe like the one owned by San Anselmo DPW. Operated from the top of the bank, the backhoe can drag and hoist the debris straight out of the creek and into a dump truck.

This is the second year in a row that San Anselmo has undertaken this effort. Both times the Marin County Flood Control District helped coordinate permits with state and federal regulatory agencies and Conservation Corps North Bay helped with heavy lifting. In 2016 concrete removal took place between Sir Francis Drake Boulevard and the former Sunnyside Nursery. This year it took place between Creek Park and the former Great Acorn building at 800 San Anselmo Avenue.

Some very big pieces of concrete remain in this reach of the creek in San Anselmo—footings of over-hanging buildings, ill-conceived earthquake retrofits, foundations of structures long-gone. An interesting presentation to the San Anselmo Town Council from October 25, 2016 can be viewed online. It goes into some detail on the flood reduction benefits if these larger pieces of concrete could be removed, but these are large projects without any secured funding or approval. In the meantime, we will try to support San Anselmo to keep this program going. If all goes well, maybe this effort can continue upstream next year. The bridges at Nokomis, Sais, Saunders, Taylor all have plenty of accumulated debris to keep us busy.

A concrete pier has just been lifted from the bed of San Anselmo Creek, for disposal. Photo by Gerhard Epke