Arroyo Seco (Sonoma County)

For the canyon and creek in Southern California, see Arroyo Seco (Los Angeles County).

Arroyo Seco^[1] is a 6.9-mile-long (11.1 km)^[2] tributary stream to Schell Creek in southern Sonoma County, California, United States. In Spanish arroyo seco means "dry stream." Arroyo Seco Creek drains a portion of the western slopes of the southern Mayacamas Mountains. Its 11.4-square-mile (30 km²) watershed,^[3] along with the entire Mayacamas mountain block, was formed in the Miocene era by volcanic action and with tectonic uplift about 12 million years ago.

Arroyo Seco
Middle reach of Arroyo Seco Creek
Location of the mouth of Arroyo Seco Creek in California
Location
Country	United States
State	California
Region	Sonoma County
City	Sonoma, California
Physical characteristics
Source
• location	4 mi (6 km) northeast of Sonoma, California
• coordinates	38°20′8″N 122°25′3″W[1]
• elevation	1,345 ft (410 m)
Mouth	Schell Creek
• location	4 mi (6 km) south of Sonoma, California
• coordinates	38°14′42″N 122°26′5″W[1]
• elevation	13 ft (4.0 m)
Basin size	11.4 sq mi (30 km2)
Basin features
Tributaries
• left	Haraszthy Creek

Soils of the immediate streambed and its vicinity are classified as the riverwash series, recent deposition of sands and gravels.^[4]

Arroyo Seco Creek springs near the Napa County line about 4 mi (6 km) northeast of Sonoma, California. It flows southward, emerging from near Sonoma Valley Hospital. After a confluence with Haraszthy Creek, it crosses under State Route 12 near Schellville, California, where it flows into Schell Creek. Schell Creek discharges to a network of sloughs that eventually empty into Sonoma Creek, which in turn empties into the Napa Sonoma Marsh and San Pablo Bay.

See also

• California oak woodland
• List of watercourses in the San Francisco Bay Area
• Miwok