Wetland Profile: Los Osos Creek

Published 10/30/2004

LOCATION

County

San Luis Obispo

USGS Quadrangle

Morro Bay South

Descriptive Location

Los Osos Creek drains the Los Osos watershed, the southern half of the Morro Bay watershed, and enters Morro Bay via the Morro Bay Salt Marsh.

Longitude & Latitude

-120°49'38" W, +35°20'17" N

Component Names

Eto Lake, Warden Creek, Warden Lake

OWNERSHIP, MANAGEMENT & LOCAL AUTHORITIES

Management Authorities	Source
Management
CA Dept of Water Resources	2
San Luis Obispo County Flood Control District	2
US Geological Survey	2

Group Name	Website	Source
Local Interest Groups
Morro Estuary Greenbelt Alliance	http://www.coastal.ca.gov/publiced/ directory/resdirectory/m_orgs/morro estuarygreenbelt.html	1

LAND USE

On Site Use	Source
Agriculture	3
Open Space	3, 4, 5, 6, 7, 8
Rural Lands	9

Historic On Site Use	Source
Agriculture	3

Adjacent Use	Source
Agriculture	3, 4, 5, 6, 8, 10, 11, 12
Open Space	1, 3, 4, 5, 6, 7, 8
Public Facilities	10
Recreation	4, 8
Residential Rural	4
Residential Single-Family	3, 6
Rural Lands	10

Historic Adjacent Use	Source
Agriculture	12
Open Space	1
Residential Rural	1

Comments	Source
Comments
Cattle grazing and some rural and urban development	10
Agriculture=grazing	8

HYDROLOGY

Tributary Influence	Influence	Gaging Station	Source
Tributary Influence
None		Los Osos 1 - above Eto Lake, Los Osos 2 - Los Osos Valley Road, Los Osos 3 - Clark Valley	2, 11
Clark Canyon			12
Eto Lake	Overflow into creek		2, 7
Los Osos Creek	40 ft3/s-1000 ft3/s	Seasonal	2
Warden Creek	981acre ft/year		2, 5
Warden Lake			2

Alterations	Comments	Contribution / Removal Amount	Date	Source
Wetland Alterations
Discharge Pipe	From Eto Lake			12
Flow Obstructions	Los Osos Valley Road Bridge			2, 8, 12
Groundwater Extraction	Agriculture wells	800 acre ft/yr	00/00/1977	3
Groundwater Extraction	Numerous mapped wells			9
Groundwater Extraction	Wells (extensive map)			2
Non-point Source	Agriculture, Urban Runoff			3
Non-point Source				7, 11
Non-point Source		5000 acre ft/year	1980	5
Non-point Source	Agriculture			4, 8, 10
Non-point Source	Agriculture, Urban Runoff			12
Sediment Removal				4
Seepage from Turri Road dump site				11

WATER QUALITY

Program Name	Parameters	Comments	Website	Source
Monitoring Programs
Central Coast Ambient Monitoring Program	Coastal Confluence Monitoring	At Turri Road	http://www.ccamp.org/ca/3/Sites/310 syb/310SYB.htm	13
Snapshot Day	Numerous	Off Turri Road near South Bay Boulevard; 2002-2004	http://www.coastal.ca.gov/publiced/ snapshot/snapshot1.html	14
MBNEP Volunteer Monitoring Program	Numerous	AtTurri Road near South Bay Boulevard	http://www.mbnep.org/volunt.htm	15

Parameter	Duration	Comments	Source
Water Quality Data
Dissolved Oxygen			9
Dissolved Oxygen	February 19, February 22, March 11, 1992	At Los Osos Valley Road and Turri Road	4
Nutrients			6
Nutrients	1996		7
Nutrients	April 19-July 20, 1996	Nitrate, Phosphate	12
Nutrients	February 19, February 22, March 11, 1992	At Los Osos Valley Road and Turri Road	4
Nutrients	October-December, 1989	Nitrite, Nitrate	5
Stream Flow			9
Stream Flow	1980-1986		8
Temperature			9
Temperature	February 19, February 22, March 11, 1992	At Los Osos Valley Road and Turri Road	4
Turbidity	February 19, February 22, March 11, 1992	At Los Osos Valley Road and Turri Road	4
pH	February 19, February 22, March 11, 1992	At Los Osos Valley Road and Turri Road	4
pH	October-December, 1989		5

SOILS

Comments	Source
Clay layers	3
Dune remnant	9

VEGETATION

Common Name	Scientific Name	Federal	State	Source
Special Status Plants
Swamp gooseberry	Ribes divaricatum	None	None	6

Comments	Source
Vegetation Comments
Plant list	6

ANIMALS

Common Name	Scientific Name	Federal	State	Source
Special Status Animals
Brackish Water Snail	Trytonia imitator	None	None	10
California red-legged frog	Rana aurora draytonii	Threatened	None	10
Giant kangaroo rat	Dipodomys ingens	Endangered	Endangered	17
Southwestern pond turtle	Clemmys marmorata pallida	None	None	10
Steelhead - south/central California coast esu	Oncorhynchus mykiss irideus	Threatened	None	1, 10
Tidewater goby	Eucyclogobius newberryi	Endangered	None	10, 11

Common Name	Scientific Name	Source
Non Native Animals
Bullfrog	Rana catesbeiana	10

Benthic Invertebrates Sources

Bird Sources

Fish Sources

WETLAND IMPACTING ACTIVITIES

Activity	Source
In the Wetland
Active/Severe riparian erosion	5, 12
Agriculture	3, 6, 9, 11
Excavation	6
Hiking	6
Resource extraction	10
Road construction	1, 2, 6, 8, 12, 16
Surface/subsurface drainage	2, 10

Activity	Source
Adjacent to the Wetland
Agriculture	3, 4, 5, 6, 9, 10, 11, 12
Fertilizer application	3, 4, 12
Flood control	3
Grazing	3, 5, 9, 10
Hiking	6
Road construction	1, 2, 3, 8, 12, 16
Septic tank seepage	3
Surface/subsurface drainage	2, 3, 12

SOURCES

Source	Author(s)	Year Published	Document Name
1	Trust for Public Land, Calif.	2001	Morro Bay Watershed: Hollister Peak, Morro Bay Dunes.
2	Yates, E.B. and J.H. Wiese	1988	Hydrogeology and Water Resources of Los Osos Valley Ground-Water Basin
3	Van Vlack, Mark	1989	Geohydrology and management of Los Osos Valley ground water basin, San Luis Obispo County: district report.
4	Brecheisen, Vicki	1992	Survey of Osos and Chorro Creeks with empasis on nitrate and phosphate concentration and their effect on Morro Bay and groundwater quality.
5	Morro Group and Tenera Environmental	1990	Freshwater Influences on Morro Bay
6	San Luis Obispo County, Engineering Dept.	1988	Los Osos Creek bridge replacement on Los Osos Valley Road near the town of Los Osos, County of San Luis Obispo: environmental assessment/initial study and programmatic 4(f) evaluation.
7	Dada, A. Karim	1996	Monitoring nitrate levels in Los Osos Creek and possible dilution effects of Eto Lake.
8	Gamette, Sean A.	1991	Morro Bay watershed: a study of the input of all waters entering Morro Bay.
9	Moore, Briana Lynn	1997	Los Osos Creek study.
10	Worcester, Karen	None	Aquatic Inhabitants of Chorro and Los Osos Creeks: Their Habitat Needs and Status
11	Baiocco, Joseph Carl	1978	Distribution and abundance of fish species found in both San Luis and Los Osos Creek estuaries and a (sic) evaluation of the current status of Eucyclogobious Newberri.
12	Adam, Ian & Marc Barton	1997	Nutrient loading in Los Osos Creek.
13	Central Coast Regional Water Quality Control Board	None	Central Coast Ambient Monitoring Program
14	Snapshot Day	None	None
15	Morro Bay National Estuary Program	2004	Morro Bay National Estuary Program Volunteer Monitoring Program
16	Fricke, Dana	1970	Identification and distribution of the intertidal polychaete fauna of Los Osos Creek, San Luis Obispo County, California
17	Carbone, David Franklin	1977	Incorporation study and environmental impact report of Los Osos.

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