Petaluma River

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Coordinates: 38°6′38″N 122°29′15″W / 38.11056, -122.4875
Petaluma River
river
none The river flowing through Petaluma. View is to the southeast.
The river flowing through Petaluma. View is to the southeast.
Name origin: Coast Miwok
Country United States
State California
Region Sonoma and Marin counties
Tributaries
 - left Lichau Creek, Lynch Creek, Washington Creek, Adobe Creek
 - right San Antonio Creek
City Petaluma, California
Source
 - location 1.5 mi (2 km) southwest of Cotati, California
 - elevation 332 ft (101 m)
 - coordinates 38°18′18″N 122°43′3″W / 38.305, -122.7175 [1]
Mouth San Pablo Bay
 - location 5 mi (8 km) east of Novato, California
 - elevation 0 ft (0 m)
 - coordinates 38°6′38″N 122°29′15″W / 38.11056, -122.4875 [1]
Length 18 mi (29 km) [1]
Discharge for Petaluma (USGS gage station 11459000) [2]
 - average 17 cu ft/s (0 m³/s)
 - max 64 cu ft/s (2 m³/s)
 - min 0 cu ft/s (0 m³/s)
The mouth of the Petaluma River on San Pablo Bay. View is to the northeast.
The mouth of the Petaluma River on San Pablo Bay. View is to the northeast.

The Petaluma River is a river in the California counties of Sonoma and Marin that becomes a tidal slough near its mouth. It springs from farmlands southwest of Cotati and flows generally southward through Petaluma's old town and 10 mi (16 km) of marshes to end at San Pablo Bay.

The western slopes of Sonoma Mountain drain to the Petaluma River by way of tributaries such as Lichau Creek, Lynch Creek, Washington Creek, and Adobe Creek. In the marshes west of Lakeville, the river joins San Antonio Creek, at which point it becomes the boundary between Marin County and Sonoma County. The river flows under State Route 37 at Green Point and enters San Pablo Bay just north of Petaluma Point.

While the river's source lies over 300 ft (100 m) above sea level, it descends to 50 ft (15 m) within about 0.4 mi (600 m). The river is fully tidal 11 mi (18 km) from its mouth, indicating its slight gradient through the marshes below Petaluma. The United States Army Corps of Engineers dredges this section to keep it navigable by gravel barges and pleasure craft.

Contents

[edit] Habitat and pollution

The marshes provide an important wildlife habitat and fish hatchery. However, since the onset of intensive European immigration in the mid-1850s, the water quality has diminished, partly due to overgrazing and other agricultural uses. Pollutants present in the river include nitrates, phosphates, petroleum hydrocarbons, pesticides and sediment.[3] Urban runoff, particularly from the City of Petaluma, adds heavy metals and hydrocarbons to the river.[4] Starting about 1990, material steps were taken to mitigate the pollution. However, continuing population growth makes it difficult to attain the State of California's water quality goals.

[edit] Bridges

Bridges span the Petaluma River at the following locations: State Route 37, U.S. 101, Corona Road, Petaluma Boulevard North, and four places in Petaluma (D Street, Payran Street, Washington Street, and Lakeville Street). The longest of these, the 4-lane State Route 37 bridge, is 2,183 ft (665 m) long and was built in 1958. The oldest bridge, built in 1925, is a 114 ft (35 m) concrete triple span carrying two lanes of Petaluma Boulevard North.[5]

[edit] See also

[edit] References

  1. ^ a b c USGS GNIS: Petaluma River
  2. ^ Flow: Monthly Average Petaluma River at Petaluma 1949-1963. Retrieved on 2007-12-10.
  3. ^ Petaluma River Water Quality Profile
  4. ^ Kay Ransom, C. Michael Hogan, Ballard George et al., Environmental Impact Report for the Petaluma General Plan, prepared by Earth Metrics Inc. for the city of Petaluma (1986)
  5. ^ National Bridge Inventory Database.

[edit] External links