Your Richardson Bay Watershed

Southwest Shore - Sausalito

Starting at the southeast end of the bay is the City of Sausalito. Runoff from the steep slopes both above and below Highway 101 gathers and runs down through the city via Glen Creek, Willow Creek, and two unnamed tributaries. Much of these watercourses have been piped underground, especially the closer they get to the bay, but their upper watersheds beginning in open space and reaching down into the upper urban area still have natural channels. Planning efforts have been made to daylight more of Willow Creek in the urban corridor.

Northwest Shore - Sausalito Canal 

Continuing along the bay shore to the northwest of Sausalito is the Sausalito Canal. The canal is the northwest finger of Richardson Bay and where most of the drainage into Richardson Bay originates. The inlet to Sausalito Canal spans between Waldo Point to the west and Strawberry Point to the east. It then extends under the Richardson Bay Bridge and along Bothin Marsh and Bayfront Park on the west shore, and Bayfront Meadow and Hauke Park on the east shore. The primary drainages to Sausalito Canal include Arroyo Corte Madera del Presidio, Coyote Creek, Sutton Manor Creek, and Marin City.

Arroyo Corte Madera del Presidio

Arroyo Corte Madera del Presidio is a 4.1-mile-long perennial stream with a catchment basin of about 8 square miles that drains the south-eastern slopes of Mount Tamalpais and much of the area in and around the city of Mill Valley. It is the largest subwatershed flowing into Richardson Bay. Beginning in West Blithedale Canyon and running down along W. Blithedale Avenue, Arroyo Corte Madera del Presidio is joined from the west by 2.3 mile long Old Mill Creek at Miller Avenue just south of downtown Mill Valley. 

Old Mill Creek, and its mile long Cascade Creek tributary, both begin high on the south flank of the east peak of Mount Tamalpais and join at the lower end of Cascade Park. Old Mill Creek continues down along Cascade Drive and through Old Mill Park behind the Mill Valley Library. Arroyo Corte Madera del Presidio is then joined from the north near Locust Avenue by Warner Creek, which begins on the eastern slopes of Blithedale Summit, flowing down through East Blithedale Canyon and then through the golf course and Boyle Park. Arroyo Corte Madera del Presidio’s last tributary is Reed Creek that joins from the west at Reed Street. Reed Creek drains all of Homestead Valley and its ridgeline includes Panoramic Highway, along Sequoia Valley Road, and down Edgewood Avenue. Its headwaters run through Stolte Grove, then down along Marin Horizon School, Evergreen Avenue, then Reed Street. Arroyo Corte Madera del Presidio then crosses under Camino Alto and the Mill Valley-Sausalito Path before flowing into Bothin Marsh at the southern end of Bayfront Park.

The Arroyo Corte Madera del Presidio watershed still supports a Steelhead trout run. Old Mill and Cascade Creeks support the healthiest remaining fisheries habitat in the watershed. Due to their seasonal nature, the small creeks draining directly to Richardson Bay do not support sustainable fisheries. It is known to support nine other fish species. Seven are native and two are introduced. Native species include California roach, Sacramento pikeminnow, Coho salmon, Steelhead trout, Threespine stickleback, Staghorn sculpin, and Prickly sculpin. The two introduced species are Rainwater killifish and Western mosquitofish. Recorded observations of Coho salmon date from the 1940s to 1960s but were last seen in the watershed in 1981. 

Coyote Creek

Coyote Creek flows 2.5 miles to the bay at the south end of Bothin Marsh and drains all of Tamalpais Valley. The North Fork of the stream originates at the crest of Shoreline Highway where it meets Panoramic Highway and runs down through Eastwood Park and meets another tributary from the top of Loring Avenue that flows down along Shoreline Highway. The South Fork flows down from Coyote Ridge and runs along Marin Avenue to the north and east. The two forks converge at Ash Street and continue to run east along Shoreline Highway. The creek then briefly curves to south and under the Flamingo Road bridge where it is joined by Nyhan Creek. Nyhan Creek begins in Golden Gate National Recreation Area along the ridgeline separating Tamalpais Valley from Tennessee Valley. As Nyhan Creeks flows northeast it is met by Oakwood Valley Creek coming from the southeast. It then turns north where it is met by Crest Marin Creek from the west at Marin Avenue. At the confluence with Nyhan Creek, Coyote Creek does a big bend back to the northeast where it crosses under Shoreline Highway at Tam Junction and continues out alongside the south end of Bothin Marsh and under the Mill Valley-Sausalito Trail.

Sutton Manor Creek

Sutton Manor Creek is a smaller drainage with headwaters in the Alto Bowl and Horse Hill Open Space Preserves and flowing down through the Alto and Sutton Manor neighborhoods. A portion of the creek’s tributaries under Edna Maguire Elementary School and the residential neighborhood are piped underground and resurface in the Shell Road Ditch before flowing south and crossing under Ashford Avenue. As the creek meets E Blithedale Avenue another piped tributary draining the Alto neighborhood from the east side of Highway 101 joins in. The creek then curves around the Alto Shopping Center and crosses under E Blithedale and into the estuary marsh running south along Mill Valley-Sausalito Path. Just before Sutton Manor Creek crosses under the pedestrian bridge between Sycamore Avenue and Hauke Park, it is joined by Ryan Creek from the west. Ryan Creek is a small tributary draining the local neighborhood on the west side of Camino Alto. After Ryan Creek crosses under Camino Alto, it flows into Elizabeth Terwilliger Marsh and along the north side of Mill Valley Middle School before crossing under Mill Valley-Sausalito Path and into the estuary.

Marin City

The community of Marin City has several small, unnamed tributaries collecting the runoff from the hillsides encircling the community. All the tributaries are piped under both the residential neighborhoods and the Marin Gateway Shopping Center to the pond between the shopping center and Highway 101. From the pond the drainage is piped under the freeway and enters Sausalito Canal at Gate 6 ½ Road just northwest of Waldo Point.

North Shore - Ring Mountain

Ring Mountain creates the north watershed boundary and the divider between Corte Madera and Tiburon. West Creek and East Creek begin on the mountain’s west and south slopes just below the Ring Mountain Fire Road and flow down through the Reed neighborhood. 

West creek flows down along Reedland Woods Way and then on the west side of Blackfield Drive, before crossing under the west end of Cecelia Way, then under Tiburon Blvd, where it flows through Saltworks Canal and enters the bay behind Strawberry Point School. 

East Creek flows down and crosses under Reed Ranch Rd, then parallels Karen Way to the south and Leland Way to the east before crossing under the east end of Cecelia Way. It then flows along the east side of the Cove Shopping Center parking lot and crosses under Tiburon Blvd and Greenwood Cove Drive and into the bay.

East and Southeast Shores – Tiburon and Belvedere

Tiburon has three smaller unnamed creeks draining to Richardson Bay. The first runs down along the north side of Trestle Glen Blvd, crossing under Tiburon Blvd and through Blackie’s Pasture. The second starts at top of Gilmartin Drive and Round Hill Road and flows down the hill passing along the north side of Owlswood Road before crossing under Tiburon Blvd and San Rafael Avenue. The last begins between the top of Mt Tiburon Rd and Sugar Loaf Drive. As it travels down slope it crosses under the lower section of Round Hill Rd and then Kleinert Way where it pipes under Reed Elementary School, Tiburon Blvd, and Lagoon Road and flows into Belvedere Lagoon. Belvedere Lagoon itself has a tide gate linking it to the bay.

There is a fourth unnamed creek on the western slope of Tiburon Peninsula beginning at the top of Old St. Hilary's Preserve. It flows down behind and along the north side of the Tiburon Peninsula Club and Mar W Rd before crossing under the road and into Tiburon Lagoon. This creek however does not flow into Richardson Bay. It instead is piped southeast and flows into Raccoon Straight just to the east of the Tiburon Ferry Terminal. The remaining unnamed creeks in the Richardson Bay Watershed flow from the south and eastern slopes of the Tiburon Peninsula into Keil Cove and the San Francisco Bay.

Historically, the myriad of habitats in the Richardson Bay Watershed were connected to one another through the streams cascading down from Mt Tamalpais. Creeks overflowed onto floodplain marshes and these wetlands transitioned into extensive native forests and grasslands.

Today, the upper slopes and ridges of the watershed remain largely protected from development as public open space and support a rich diversity of plant and wildlife communities. The hills are dominated by Redwood and Douglas fir forest, chaparral, and oak woodlands. These plant communities provide wildlife with natural movement corridors. The diverse vegetation is a reflection of the soils, availability of water and micro-climates in the watershed. The creeks and adjoining forest lands support Steelhead trout and Northern spotted owls.

The baylands and Richardson Bay still support a diverse array of native plants and animals. Great blue heron and great egret nesting colonies are found along the Bay’s shoreline. Bothin Marsh Open Space Preserve protects the largest salt marsh at the northern end of Richardson Bay. Surrounded by cordgrass and pickleweed, the marsh supports many birds including the endangered Ridgway's rail, California black rail, and San Pablo song sparrow as well as the endangered Salt marsh harvest mouse. At higher elevations, northern spotted owl territories occur in wooded areas along several creeks.

On the Tiburon Peninsula, there is a small population of California red-legged frog. The population was discovered in 1997 at a small pond, formerly a lagoon, at Keil Cove.  A second sighting was made in 2000 in coast live oak woodland to the northwest of the Keil Cove sighting. This is probably the last remaining population on the peninsula.

Richardson Bay itself supports the second largest surviving eelgrass bed in San Francisco Bay. Eelgrass beds provide important shelter for fish and shellfish, and a food source for many water bird species. Fish species in the bay include Bay pipefish, Bat ray, Black surfperch, Northern anchovy, Pacific herring, Striped bass, and Threespine stickleback. In the winter, the Bay supports hundreds of thousands of waterbirds including ducks, geese, grebes and shorebirds. 

Remember, storm drains connect streets to creeks. Simple changes can make a big impact. Richardson Bay Watershed is Ours to Protect.