Riparian Corridor Protection
Shown here: Sleepy Hollow Creek constricted by retaining walls; Corte Madera Creek in Ross.

Creek setbacks are generally acknowledged to be essential if creeks are to retain any of their natural functions in a developed area. These include: serving as a wildlife corridor; providing habitat for fish, including the threatened steelhead; allowing for lateral movement; filtering out pollutants by means of riparian vegetation on a sloping creek bank; and conveying flood waters. A natural creek also has an esthetic value and cooling effect readily recognized by any homeowner living by a creek.

Regardless of their value, our creeks and their environs continue to be degraded by structures and paving that are constructed too close to the channel, and by the armoring of creek banks to protect these structures. Armored banks lead to narrower channels, faster flowing flood-waters, additional erosion of creek banks both upstream and downstream, and further armoring. Destruction of native vegetation and water diversions also degrade the riparian corridor. All this destroys the very things we value about our creeks - and may result in bringing about what San Anselmo and Fairfax prevented the Army Corps from achieving in the 1970s: the substantial channelization of San Anselmo, Fairfax, and Sleepy Hollow creeks.

Effective protection measures should be incorporated in city and county codes to cover alterations within the creek channels and improvements on property adjacent to the creeks. An ordinance would have to be flexible enough to fit the varied conditions of lots within the town, while not allowing so many exceptions that it is ineffectual.

We urge the towns to draft riparian corridor protection plans as a basis for establishing ordinances to control development on properties in the vicinity of our creeks, and to ensure that when development occurs, riparian habitat is simultaneously improved.

Friends of Corte Madera Creek Watershed makes the following recommendations for creek corridor management plans and creek protection policies and ordinances:

1. Natural features and functions of a creek corridor should be protected. These include: sloping banks; native vegetation; a riparian zone capable of filtering out pollutants (especially sediment); wildlife habitat and passage; aquatic life; a degree of meandering of the stream; esthetic value; bank cover to reduce erosion; and roughness of banks to attenuate flood waters.

2. "Creek" should be defined as including perennial, blue-line, intermittent, and ephemeral waterways. Smaller waterways can be defined by the presence of a channel and evidence of scour and deposition. Sometimes waterways are defined by the presence of riparian plants.

The definition that follows has been adopted by the City of Berkeley, and is under consideration for use in the Ross Municipal Code:

A "creek" means a watercourse (a) that carries water from either a permanent or natural source, either intermittently or continuously, in a defined channel, continuous swale or depression, or in a culvert that was placed in the general historic location thereof; and (b) the water either merges with a larger watercourse or body of water, or is diverted into an engineered structure that does not follow the general historic course of a creek. A "creek" does not include any part of an engineered structure developed for collection of storm or floodwaters (e.g. a storm drainpipe) that does not follow the general historic course of a creek.

1. A "permanent or natural source" includes a spring, artesian well, lake, estuary, or a rainfall drainage area that covers at least one-third acre (14,520 square feet).

2. The word "creek" is used synonymously with the phrase "natural watercourse" in this chapter.

3. The portion of a creek that is visible above the ground is referred to throughout this chapter as an "open creek."

4. The portion of a creek below ground and contained in an engineered structure or culvert is referred to throughout this chapter as a "culverted creek."

5. A "swale" is a shallow trough-like depression that carries waters mainly during rainfalls and snowmelts.

6. The City of Berkeley may maintain maps and other reliable records, reflecting such creeks for the guidance of the public.

3. Designated creek corridor width should be based on the potential for riparian habitat, and varies from creek to creek. Some definitions of creek corridor width depend on the observed creek profile and character of existing vegetation at a particular site. However, in a developed area, such a definition ignores prior destruction of riparian vegetation and the natural potential of an area. The designated creek corridor is narrower than the setback, and within it property owners are encouraged to enhance riparian habitat.

4. Creek setback. Setbacks are generally measured from the top of the bank or from the creek centerline. The City of Oakland defines the setback as being measured back from the imaginary top of a 2:1 slope from the toe of the bank (i.e., a 26-1/2 degree slope), a definition that more closely approximates a natural condition in alluvial soils. Such a definition also avoids depending on a movable and often artificial starting point; additionally, homeowners who grade back the creek bank could find themselves penalized as the effective setback becomes actually increased. The setback distance could vary from creek to creek, as established in a management plan. Development (e.g., buildings, impervious paving, swimming pools) should be prohibited within the setback. Varying setbacks could be established for different reaches of a creek depending upon the width of the riparian corridor, and potential (or lack of potential) for creek restoration.

5. The term "buffer" may be used to refer to a band of lightly-used land between a defined creek corridor and the setback distance.

6. Uses that are allowed or disallowed within a designated zone must be defined. Improvements such as fences, paving, decks, hot tubs and ornamental plantings must be addressed.

7. Design review should be required in defined circumstances.

8. Variances may be permitted on improved properties, on small lots, and in irremediable situations; however, most situations should be addressed through the specific setback distance established for each creek.

9. The requirement to obtain permits from other regulatory agencies should be included. These agencies may include Regional Water Quality Control Board, California Department of Fish and Game, Army Corps of Engineers, NOAA Fisheries, and the Coastal Commission.

10. Any new creekside project should include a survey of the riparian area and a study of the consequences of any alterations to grade, vegetation or runoff.

11. Habitat enhancement should be encouraged or required as a condition of a permit. New vegetation should be maintained and monitored.

12.Tree protection policies should consider whether a species is native or not. Invasive non-native plant species such as bamboo, giant reed (Arundo), ivy and periwinkle (Vinca) should be prohibited from being planted within protected zones. Only native riparian species should be planted within the designated riparian corridor.

13. Fence design should be considered, to allow for wildlife passage and creek protection.

14. Surface runoff must be managed to increase infiltration and reduce erosion.

15. Best Management Practices for creekside construction should be defined.

16. Biotechnical techniques of bank stabilization should be required, when stabilization is necessary. Any other technique used must incorporate plantings, e.g., crib walls and riprap. Ideally, the bank is sloped back to a gentler grade.

17. Channel water-carrying capacity should be maintained.

18. Flood-plains should be enlarged where possible.

19. Vegetation removal and trimming for flood control purposes must be carried out only as each specific site requires to serve the purpose, following up-to-date practices.

20. Water diversions should be prohibited. Summer pools are critical habitat for young steelhead.

Some guidelines for creek protection can be provided by the following agencies and documents:

• Start at the Source Tools Handbook (2000), by San Francisco Bay Area Stormwater Management Agencies Association (BASMAA); the publication includes excerpts from several towns' ordinances.
• Marin County Stormwater Pollution Protection Program (MCSTOPPP).
• Regional Water Quality Control Board.
• Center for Watershed Protection (www.cwp.org) in Maryland, can provide some guidelines for urban areas.
• County of Marin: Stream Conservation Area for the City Centered Corridor (draft 2003).
• Fairfax: General Zone Regulations.
• Novato: Waterway and Riparian Protection.
• Oakland: Creek Protection, Stormwater Management and Discharge Control Ordinance.
• Ross: Design Review Criteria and Standards
• City of Santa Cruz: City Wide Creeks and Wetlands Management Plan (draft 2002)

A garden may end at the property line, but knowledge of its flowers and berries can extend to the whole neighborhood in the insect and animal world, and this knowledge may even be carried by migrating birds thousands of miles away. Life in a neighbor's yard or in a nearby creek may be influenced by what we plant and add to the soil-fertilizers, pesticides, and water. Within the garden, connections between the soil, microorganisms, plants, wildlife, and our activities are infinitely more closely knit, so any action we take may have many unintended consequences. Planting a thirsty azalea under a native oak may kill the tree; fertilizing a rose may attract aphids to rank new growth, and spraying for aphids in this area may kill insects that control aphids elsewhere in the garden.

If you have the urge to plant a silver birch or a sweet gum that reminds you of your home state, you should realize that it may not thrive in our watershed, and will play a negligible part in the ecology of your garden. In general, choosing plants native to a region of similar climate to ours-and especially choosing those plants native to this area-will lead to easier and lower cost gardening, and can provide the joy of providing a welcoming habitat for butterflies and hummingbirds and other insects and birds. If we also, as much as possible, use natural fertilizers and avoid chemical pesticides, we will be returning a little piece of our valley to nature's realm.

Some visually appealing California native plants that are suitable for gardens in the Corte Madera Creek watershed and attractive to wildlife are listed below.

Trees: black walnut (Juglans californica), buckeye (Aesculus californica), coast live oak (Quercus agrifolia), valley oak (Quercus lobata), wax myrtle (Myrica californica).

Shrubs: California mock orange (Philadelphus lewisii), California rose (Rosa californica), ceanothus (Ceanothus spp.), coffeeberry (Rhamnus californica), creek dogwood (Cornus sericea), elderberry (Sambucus mexicana), flowering currant (Ribes sanguineum), holly-leafed cherry (Prunus illicifolia, Oregon-grape (Mahonia spp.), lupines (Lupinus spp.), manzanitas (Manzanita spp.), ocean spray (Holodiscus discolor), redbud (Cercis occidentalis), silktassel bush (Garrya elliptica), spicebush (Calycanthus occidentalis), sticky monkey-flower (Mimulus aurantiacus), toyon (Heteromeles arbutifolia), twinberry (Lonicera involucrata).

Vines: California pipevine (Aristolochia californica), honeysuckle (Lonicera hispidula).

Flowers: buckwheats (Eriogonum spp.), California fuchsia (Epilobium canum), California poppy (Eschscholzia californica), columbine (Aquilegia formosa), coyote mint (Monardella villosa), Douglas iris (Iris douglasiana), goldenrod (Solidago spp.), matilija poppy (Romneya coulteri), milkweeds (Asclepias spp.), mugwort (Artemisia spp.), seaside aster (Aster chilensis), yarrow (Achillea millefolium).

Suitable non-native plants that have low water needs and attract butterflies and insects that control pests.

Shrubs: buddleia (Buddleia spp.), chaste tree (Vitex agnus-castus), lantana (Lantana spp.), lavender (Lavandula spp.), rose of Sharon (Hibiscus syriacus), rosemary (Rosmarinus officinalis).

Flowers: sweet alyssum (Lobularia maritima), bee balm (Monarda spp.), cosmos (Cosmos bipinnatus), dill (Anethum graveolens), feverfew (Chrysanthemum parthenium), fleabane (Erigeron spp.), flowering tobacco (Nicotiana spp.), Queen Anne's lace (Daucus carota), salvias (Salvia spp.), pincushion flower (Scabiosa spp.), Shasta daisy (Chrysanthemum maximum), St. Catherine's lace (Eriogonum giganteum), verbenas (Verbena spp.).

Nearby nurseries (wholesale and/or retail) selling native plants include: O'Donnell's Nursery (453-0372), Fairfax; and Sunnyside Nursery (453-2701), San Anselmo. Green Jean's (389-8333), Mill Valley; and Mostly Natives (707 878-2009), Tomales. California Flora (707 528-8813), Fulton; North Coast Native Nursery (707 769-1213), Petaluma; Wayward Gardens Nursery (707 829-8225), Sebastopol; and Western Hills Nursery (707 874-3731), Occidental.

Much useful information on good gardening practices, such as mulching, composting, drip irrigation, plant diversity and integrated pest management can be found through Marin County Stormwater Pollution Prevention Program (MCSTOPPP), and through the Garden Education Program at the Marin Art and Garden Center, in Ross.

If you are fortunate enough to live by a creek, you have a great opportunity to benefit local wildlife by planting native trees, shrubs, and groundcovers on the bank. These can also be helpful in stabilizing an eroding bank; some contractors specialize in such bio-technical solutions. Some non-native plants are especially invasive in our creek corridor, and prevent the regeneration of native species, so if possible avoid planting non-native invasive plants in creekside yards. Yard debris should not be deposited on the creek bank, as it smothers vegetation and suffocates fish when it decays in the water, while doing nothing to prevent erosion. Remember that drawing water from the creek or nearby well for irrigation deprives aquatic life of a very scarce resource, and requires registration with the state; it is better to use your MMWD hook-up.

For more information:
PlantIDInvasivePlants.pdf (332 KB)
PlantIDNativeShrubs&Vines.pdf (318 KB)
PlantIDNativeTrees.pdf (344 KB)
Recommended Native Riparian Plants (Word document/332 KB)

Invasive Plants
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Shown here: The weedy spurge Euphorbia oblongata has invaded a San Anselmo hillside.

Plants are at the beginning of the food chain, manufacturing the leaves, roots, flowers and seeds that feed the insects and animals that feed larger animals. For example, the California pipevine with its curiously sculpted flowers grows along our creeks and is the only food plant for the black-and-red pipevine swallowtail caterpillar, that in due course becomes the handsome black and iridescent blue butterfly seen in April. Leaves that fall into the creek and decay become food for insect larvae that feed steelhead.

Non-native plants typically do not support a wide range of insect life, and while the presence of most non-native species is inconsequential, some crowd out or otherwise prevent native species from growing or propagating themselves. English ivy, for example, shades seedlings of other species and so prevents photosynthesis; acacias contribute chemicals to the soil that hinder the growth of other plants; French broom adds nitrogen to the soil, thus changing the nutritional balance in favor of non-native grasses. In the small sloughs of the Corte Madera Creek estuary, a non-native cordgrass colonizes mud flats and so tends to reduce the area of mudflats available for the life forms that depend upon them.

All plants in their native lands are limited in their ability to spread by natural controls-such as insects and competition-but when they arrive in a new ecosystem, a few of them just go wild, literally and figuratively.

The majority of the invasive plants of our creeks originated in gardens as ornamentals. The most troublesome of these are: acacia; bamboo; periwinkle (Vinca); Cape ivy; cotoneaster; English ivy; French broom; giant reed (Arundo; hawthorn; pampas grass; and privet. Others were introduced as food plants, including: blackberry; fennel; fig; mints; onion lily; and cherry plum.

Others were introduced as food plants, including: blackberry; fennel; fig; mints; onion lily; and cherry plum. Harding grass, which grows in robust clumps with flower heads reaching 6 feet high, was introduced from the Mediterranean region for cattle fodder.

At least two of the three non-native cordgrasses found in our salt marshes were misguidedly introduced to the Pacific coast for salt marsh restoration projects, and have since become widespread.

A major aspect of habitat restoration projects is the removal of these invasive species, and eradication in a small area can take years while seeds stored in the ground postpone germination and then awaken to become a young plant. In some cases the removal of invasive species results in the natural return of native species. Along our creeks, alder, ash, bay, oaks, sedges, horsetail and beeplant will often return if the conditions are favorable, but in general, the stock of native plants is so diminished that active revegetation is necessary.

Friends urges residents to participate in invasive plant eradication efforts organized by the Marin County Open Space District, the Marin Municipal Water District and other groups, as well as by Friends of Corte Madera Creek Watershed, and to control or eradicate them on your own property.

When selecting plants at the nursery, please consider whether your choices have a tendency to spread beyond your fence.

For more information:
PlantIDInvasivePlants.pdf (332 KB)
See Habitat Restoration Projects in Projects section

Streambank Erosion
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Shown here: Attempts at erosion control are often undermined.

Erosion is a natural process associated with stream flow. Streams in steep channels tend to cut straight down to bedrock or a boulder bed unless diverted by natural or human-made barriers. In gently sloping areas the shape of a stream channel usually evolves at a leisurely pace, with a tendency to meander and to develop a sequence of pools and riffles. Meandering channels have a natural rhythm, eroding the outside of each bend, and depositing material on the inside of each bend. In general, meanders change shape slowly in response to natural or artificial variations in flow patterns. However, there are exceptions to this behavior: in 1867 an obstruction in San Anselmo Creek near Laurel Avenue closed off the original channel and turned the creek through a right-angle to its present route.

Within the Corte Madera Creek watershed, many stream reaches have been channelized with vertical walls and riprap (large boulders) or have disappeared entirely into culverts in an attempt to improve drainage and control erosion. Such modifications can have unintended and problematic consequences: water is a powerful force and often unpredictable. Minor adjustments in channel shape can sometimes create extreme problems that have far-reaching effects.

A traditional way to deal with stream-bank failure is to armor the bank by placing riprap at the point of erosion. However a subsequent storm flow may dislodge the rocks and carry them downstream of the attempted repair to a location where they cause flooding by partially damming the stream channel. Another common erosion control measure is the construction of retaining walls of wood or concrete; these speed the flow, and can lead to the erosion of downstream banks.

Failure to foresee the possible consequences of drainage modifications has sometimes led to the drafting of public policies that are actually detrimental to property. For example, for many years, pavement construction standards in Marin called for any rain reaching a paved surface to be directed into local creeks through a system of gutters, culverts, and storm drains. The forces of these unimpeded flows continue to contribute to unnaturally rapid erosion of stream banks within the Corte Madera Creek watershed.

In recent years the County, in collaboration with Marin's 11 cities and towns, has taken a more holistic approach to dealing with water flows and erosion control, with the Marin County Stormwater Pollution Prevention Program (MCSTOPPP) taking the lead in informing the public about new policies and recommended techniques. MCSTOPPP provides a wealth of information free of charge. Three of MCSTOPPP's publications provide particularly useful information for streamside settings: Creek Care: A Guide for Urban Marin Residents; Repairing Streambank Erosion; and Controlling Erosion. The Marin County Flood Control District, the Resource Conservation District, the California Department of Fish and Game, and the U.S. Natural Resource Conservation Service are other valuable sources of information.

See Referrals

The Basics of Erosion Control
Shown here: Mud flow in a picnic area in Deer Park, Fairfax, 1998. Natural materials used to stabilize a creek bank at San Domenico School. Project directed by Dan McCormick. Photo by Pamela Cobb.

It is advisable to become familiar with and implement erosion control practices wherever your property is located. For property owners contemplating new construction or alterations to land near stream courses, early attention to erosion control can pay off handsomely in saved money and peace of mind. The following are some of the practices that MCSTOPPP and other authorities promote:

• Examine your property carefully before disturbing the soil. Be aware of the slope, drainage patterns, and soil types.
• Preserve existing vegetation as much as possible.
• Minimize the length and steepness of slopes by terracing or constructing diversion structures such as earthen dikes or temporary assemblages of brush and tree branches to diffuse water flow.
• Use alternatives to impervious concrete. If you are installing a new patio or rebuilding a crumbling walkway, consider using bricks, interlocking pavers, or flagstone. If placed on well-drained soil or on a sand-and-gravel bed, modular pavers allow rainwater infiltration. A layer of landscape fabric beneath the gravel will suppress weed growth between the pavers.
• Limit vehicle and foot traffic in sensitive, sloping areas. The compaction of roads and trails often lead to erosion problems. Compacted soil restricts the root growth that can restrain the soil and maintain the porosity of soil.
• Plant vegetation. Vegetation is the best means of controlling soil loss because it stabilizes soil, intercepts rainfall, and takes up water. Grass provides the cheapest and most effective short-term erosion control. Check with a native plant nursery for varieties suitable to your area. Native perennial bunch grasses, shrubs and trees provide longer-term erosion protection than fast-growing but less-tenacious annuals.
• Use fencing to protect new plants from foot traffic and deer.
• Use erosion control fabric. Mats of jute or coir netting, excelsior, and straw fibers help keep soil in place through rainy weather, giving vegetation time to become established. To be effective, mats must be in close contact with the soil and fastened securely.
• Prevent erosion from roof drainage. Avoid directing downspouts onto bare earth. However, lawns and friable garden soil might be permeable enough to absorb roof runoff if it is distributed over a broad area by means of a dispersion attachment to the downspout. These are sold at home and garden supply stores.

Dealing with Streambank Erosion
Shown here: Recently installed wattles of living willows terrace a bank of San Anselmo Creek.

The first question you might want to ask yourself when contemplating what to do about a streambank erosion problem is: Does this really need to be fixed? Consider how active or stable the situation is and what the potential is for damage to property or surrounding habitat. If plants are growing on the bank, this indicates that recent erosion has been minimal. Is the situation threatening structures, roads, or infrastructure? Does it appear to be caused by human negligence?

Put on your rain gear and observe what happens during a storm. If the problem is due to surface flow, it might be possible to remedy it by dissipating the force, perhaps by securing tree branches or brush along the rivulets to break up the flow. Strategically placed embedded rocks can also help, but keep in mind that you are dealing with a dynamic situation. Check up on the area periodically during the rainy season; you will probably need to make modifications from time to time.

Finding the source of a streambank erosion problem might not be as simple as you first imagine. While you might think that surface flow is the cause, for example, it could be that a thick growth of blackberry or other vegetation is obscuring a groundwater seep that is the true culprit. Seeps frequently surface along streambanks. If you trace the erosion to a seep, consider the possibility that a leaky water line is to blame, particularly if the problem developed recently. It also could be that the problem is not due to a nearby inflow but rather to some alteration in the stream course upstream or downstream, that is affecting your property. Walk up and down the stream and look for signs of recent changes.

If no easy solution becomes obvious you might benefit from assistance from an engineer or an environmental restoration specialist, who should be able to suggest a range of alternatives that incorporate vegetation and do not jeopardize other people's properties. If you see a need for modifications to the stream course, you will need agency permits.

Most stream repair work requires a Streambed Alteration Agreement from the California Department of Fish and Game, and depending on the situation, the approval of other government agencies. The MCSTOPPP pamphlet Repairing Streambed Erosion gives a good overview of erosion-control options and permitting requirements. The county Flood Control District's Groundwork: A Handbook for Erosion Control in North Coastal California is another good source of information.

Pollution in Our Creeks
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Shown here: Sign in the bed of an urban creek in the East Bay

Natural organisms are so attuned to their habitat that virtually anything we add to the environment will have a detrimental effect. The more harmful pollutants are those that tend to remain unchanged in some damaging form, and those that are effective in low concentrations; some combinations of pollutants can also be unexpectedly lethal. On the other hand, if a specific pesticide is used by many people, it may be cumulatively more detrimental to wildlife than if a variety of pesticides is used.

These broad categories of pollutants can be defined:

• Substances that degrade the aquatic environment. Sediment covers spawning gravel, and can reduce plant photosynthesis. Plant fertilizers and the phosphates in some detergents over-stimulate the growth of aquatic plants, that, on dying, deplete the oxygen supply available to fish. Decomposing garden clippings also consume dissolved oxygen.
• Substances that quickly make life unsupportable. Oil and grease destroy the ability of fur and feathers to trap an insulating air layer, and they prevent insects from breathing. Sediment can clog the gills of fish.
• Substances that have a physiological effect. Salt water intruding freshwater habitat, may reverse the flow of liquid across body membranes. Lead and many pesticides debilitate the nervous systems of animals and insects. Detergents irritate the gills of fish; they can be lethal even at low concentrations.
• Substances that upset animal metabolism. Chlorine from swimming pools is transformed in the environment into carcinogenic dioxin. Heavy metals from paint, car batteries and brake pads accumulate in organisms low in the food chain, and cause debilitating sickness in higher species. Some substances disrupt the immune system of animals.
• Substances that undermine the reproductive system. Selenium deforms fetuses. DDT makes birds' egg shells so fragile that they break in the nest. Medicinal hormones survive sewage treatment and can then disrupt fish reproduction.
• Insecticides and herbicides (including swimming pool algaecides) may continue to be lethal when they reach the creek corridor. The elimination of microscopic organisms low in the food chain affects fish and animals that feed upon them. Pesticides survive sewage treatment operations, so they should not be poured down the sink.
• Bacteria and pathogens from sewer leaks, malfunctioning septic systems, and animal waste can spread disease.

In the creeks of our watershed, most of the pollutants come from surfaces exposed to stormwater runoff: roofs, streets, sidewalks, driveways, parking lots, business properties, lawns, and gardens. Runoff from these areas, which cover much of the residential and commercial area, flows into the storm-drain system's network of gutters, catch basins, channels, culverts, and pipes. In some cases-for example at car washes-collected water is treated, but in general it flows directly into local streams and on to San Francisco Bay without treatment to remove pollutants. The storm drain system is separate from the sanitary sewer system, which collects wastewater from households and commercial buildings and sends it to a wastewater treatment plant before discharging it into the Bay.

We can minimize our impact on the watershed by minimizing the use of polluting substances, cleaning up spills immediately and disposing of them properly. Sweep up dry materials such as cement or fertilizer; don't attempt to wash them away with water or bury them. Clean up liquid spills on paved surfaces by using absorbent materials like cat litter, sand or rags. Keep all paint wastes including solvents and paint-stripping residues, paint chips and dust, and sandblasting wastes away from gutters, streets, and storm drains. Dispose of these wastes appropriately, either in the garbage if they are not hazardous, or at a hazardous waste collection point. So-called biodegradable products may take months to break down, so such labeling is no assurance of the product's safety. It is worth remembering that many of the chemicals we are in the habit of using have persistent effects on the environment, and that disposing of them merely passes on the problem to someone else's watershed.

For more detailed information on watershed pollution prevention visit the Marin County Stormwater Pollution Prevention Program web site,www.mcstoppp.org.

Water Diversion
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Shown here: Well head in Fairfax. Photo by Lou Vaccaro
Thirty, forty years ago, there were many more steelhead trout-and coho salmon too-in the Corte Madera Creek watershed than are seen today. There are many reasons for the decline, but without sufficient summer water flow, improvement in other areas will do little good.

The natural summer water supply for our creeks depends upon the discharge from soil saturated by winter rain, and when this flow is reduced by residents and businesses withdrawing water from the creek to water their landscaping, fish and other aquatic life die from lack of oxygen and food, from predation and from over-warm water. More than forty of these 5/8" to 1-1/2" pipes were recorded during a state agency survey in the Ross Valley. Summer low flows for Corte Madera Creek have been estimated at 450 gallons per minute; so if 45 residents were to run small pumps at ten gallons per minute on a Saturday afternoon, theoretically they would suck the creek dry and kill all fish.

Creekside landholders in California may, in general, exercise their riparian rights to use water from the creek. However, the state Constitution and Water Code require that: riparian users do not waste water; they do not store water for more than 30 days; available water is shared among riparian users; and Statements of Use are filed every three years with the State Water Resources Control Board. Recent legal developments have established that just as watering a garden is a "beneficial use" of water, supplying the needs of aquatic and riparian wildlife is also a beneficial use of water, and thus any water withdrawal must not be at the expense of wildlife. Creeks are held in public trust by the state of California, and are regulated in the public interest.

The use of publicly provided water and the planting of less water-consumptive gardens and landscaping are clearly the best way to protect our creeks.

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Photo in logo: Corte Madera Creek in Ross.

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