Calabazas Creek (Sonoma County)

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This article is about Calabazas Creek in Sonoma County. For Calabazas Creek in Santa Clara County, see Calabazas Creek (Santa Clara County).
Coordinates: 38°21′45″N 122°31′29″W / 38.36250°N 122.52472°W / 38.36250; -122.52472
Calabazas Creek
stream
Calabazas creek above sonoma creek cm hogan.jpg
Calabazas Creek steelhead run area immediately upstream of confluence with Sonoma Creek.
Name origin: Spanish
Country United States
State California
Region Sonoma County
Tributaries
 - left Stuart Creek
City Glen Ellen, California
Source Mayacamas Mountains
 - location 4 mi (6 km) northeast of Glen Ellen, California
 - elevation 530 ft (162 m)
 - coordinates 38°23′54″N 122°28′26″W / 38.39833°N 122.47389°W / 38.39833; -122.47389 [1]
Mouth Sonoma Creek
 - location Glen Ellen, California
 - elevation 236 ft (72 m) [1]
 - coordinates 38°21′45″N 122°31′29″W / 38.36250°N 122.52472°W / 38.36250; -122.52472 [1]
Length 5.2 mi (8 km) [1]
Basin 7.7 sq mi (20 km2) [2]

Calabazas Creek is a 5.5-mile-long (8.9 km)[3] stream in the Sonoma Valley, California, USA, that rises in the southern Mayacamas Mountains and empties into Sonoma Creek near Glen Ellen.

History[edit]

In the Spanish language, calabazas means squash, pumpkins or gourds.[4] The word calabazas is found on a diseño of part of the Agua Caliente land grant in 1840, just west of the Arroyo de los Guilicos. Gudde felt that this stream may be an early record of Calabazas Creek, although the Los Guilicos Warm Springs are a little west of Calabazas Creek.[5][6]

One of Sonoma County's oldest stone arch bridges, from the year 1915, spans Calabazas Creek near Dunbar School.[7]

As of 2007 the Sonoma County Open Space District has acquired 1,290 acres (5.2 km²) in this watershed for conservation purposes, and is currently drawing up plans for future public access.

Ecology[edit]

Calabazas Creek has historically hosted a robust steelhead (Oncorhynchus mykiss) run.[8] As late as 2001 spawning gravel studies were conducted in Calabazas along with Graham Creek, Bear Creek, Carriger Creek and mainstem Sonoma Creek; these studies demonstrated that adequacy of spawning gravels and absence of sedimentation are not limiting factors for anadromous fish propagation.[9]

The upper reaches of Calabazas Creek are relatively pristine with a dense forest canopy of mixed oak woodland, while the lower reaches on the Sonoma Valley floor have considerable encroachment by rural residential development, vineyards and other agricultural uses.

Geology[edit]

Madrone tree in upper watershed of Calabazas Creek, showing shallow rooting due to thin soil mantle.

Up until about twelve million years ago, this location was part of the seabed of the Pacific Ocean. In the Miocene era, precipitated by the combination of tectonic movement due to the seismically active environment and the presence of magma not far below the Earth's surface, a massive period of uplift ensued. This uplift formed the volcanically based Mayacamas Mountains. Residual evidence of these ancient geological features appears in the form of scattered outcrops of basalt and rhyolite as well as local hot springs such as nearby Mortons Hot Springs and Agua Caliente Hot Springs.[10] Some rock quarrying was historically conducted near Nunns Canyon Road in the upper Calabazas Creek watershed.

Course[edit]

Calabazas Creek originates about 4 mi (6 km) northeast of the town of Glen Ellen, California, just north of Trinity Road, at the top of Nunns Canyon.[1] Its headwaters form from the convergence of several unnamed perennial streams.[2] It descends in a westward direction through the canyon, augmented by the waters of Nunns Iron Spring and other tributaries, and parallels Nunns Canyon Road. It emerges into the Valley of the Moon and turns southward, passing under State Route 12 at milepost 29.41.[11] It flows west of the town of Agua Caliente. As it parallels Henno Road soutward into Glen Ellen, it is fed by Stuart Creek. Just after it crosses Arnold Drive, it empties into Sonoma Creek.

Upper reach[edit]

Riparian zone habitat of upper Calabazas Creek.

The upper reach can be defined as the portion of Calabazas Creek north of its crossing of State Route 12, which point lies approximately three miles upstream of the confluence with Sonoma Creek. Initially there are two large ranches on either side of Calabazas Creek: Beltane Ranch to the west and Atwood Ranch to the east. Proceeding upstream for the next mile, there is continuous close viewing of the creek, since Nunns Canyon Road runs near the top of the west stream banks. An abandoned rock quarry is situated about 0.3 miles (500 m) north of State Route 12 on the west bank.

Where Nunns Canyon Road terminates, Calabazas Creek enters into an 1,290 acre (5.2 km²) open space nature preserve owned and managed by the Sonoma County Open Space District; as of 2007, there is no public access to this prior holding of the Beltane Ranch, which has been named the Calabazas Creek Open Space Preserve.[12] In addition to a relatively pristine riparian zone, the upper Calabazas Creek has a high quality California oak woodland, much of which is an undisturbed ecosystem with considerable biodiversity, particularly in the upper 1.7 miles (2.5 km) of the headwaters. Some of the steeply sloped forested areas are characterized as good examples of such woodlands, testifying to the absence of historic grazing or other agriculture.

Besides the riparian habitat, the dominant plant community is the oak woodland, which has a canopy of coast live oak, Pacific Madrone, Douglas fir, Coast Redwood and California laurel.[13] In the oak woodlands, the dominant understory plants are native toyon, blackberry and western poison-oak. Common animals observed include Black-tailed Deer, gray squirrel, jackrabbit, raccoon, skunk and opossum. Less frequently mountain lion are seen. There is abundant birdlife including the scrub jay, Steller's jay, Acorn woodpecker, Black Phoebe and junco. A number of amphibians occur near the creek and its tributary elements, including the Rough skinned newt, Taricha granulosa.

See also[edit]

References[edit]

  1. ^ a b c d e U.S. Geological Survey Geographic Names Information System: Calabazas Creek
  2. ^ a b Leidy, R.A, G.S. Becker and B.N. Harvey, Historical distribution and current status of steelhead/rainbow trout (Oncorhynchus mykiss) in streams of the San Francisco Estuary, Center for Ecosystem Management, Oakland, Ca. (2005)
  3. ^ U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data. The National Map, accessed March 10, 2011
  4. ^ Durham, David L. (1998). California's Geographic Names: A Gazetteer of Historic and Modern Names of the State. Word Dancer Press. pp. page 610. ISBN 1-884995-14-4. 
  5. ^ Erwin Gustav Gudde (1974). California Place Names. University of California Press. p. C-47. Retrieved 2011-08-23. 
  6. ^ "Los Guilicos Warm Springs". Geographic Names Information System, U.S. Geological Survey. 
  7. ^ Historic Bridges of Sonoma County, California
  8. ^ 1961 Stream Survey and Hand-drawn Map: Calabazas Creek, Sonoma County
  9. ^ Sonoma Ecology Center: Summary of Research Projects
  10. ^ Santa Rosa Quadrangle, Fifteen minute series, USGS Quadrangle Map, U.S. Government Printing Office, Washington DC (1958)
  11. ^ "National Bridge Inventory Database". 
  12. ^ Summary of Holdings and Plans of the Sonoma County Open Space District
  13. ^ Ecology of the Southern Mayacmas Range, Lumina Technologies, Santa Rosa, Ca., May 11, 2005