Wetland Profile: Morro Bay Salt Marsh Published 10/30/2004
LOCATION
County San Luis Obispo
USGS Quadrangle Morro Bay South
Descriptive Location The Morro Bay Salt Marsh is the confluence of Chorro and Los Osos Creeks. It is located on the eastern side of the bay between Morro Bay State Park and South Bay Boulevard. This profile does not include the discontinuous fringe of wetland around the bay. Please see the Morro Bay Profile to learn more about the wetland fringe.
Longitude & Latitude -120°49'50" W, +35°20'43" N
Other Common Names Chorro Salt Marsh, Chorro Delta, Los Osos Delta
Wetland Complex Morro Bay


LAND USE
On Site Use Source
Open Space 1, 2
Adjacent Use Source
Agriculture 1
Open Space 1, 2
Recreation 2
Historic Adjacent Use Source
Agriculture 1


WETLAND & RIPARIAN ACREAGE
Classification Wetland Acreage Date Method Source
Brackish marsh 55 Unknown 1
Degraded riparian 10.5 2003 Field mapping 3
Freshwater marsh 27 Unknown 1
Riparian 16.4 2003 Field mapping 3
Salt marsh 280 1895 Unknown 4
Salt marsh 376 2003 Field mapping 3
Salt marsh 400 Unknown 5
Salt marsh 412 Unknown 1
Salt marsh 421 1951 Unknown 4
Salt marsh 423 1965 Unknown 4
Salt marsh 450 Unknown 2
Salt marsh 472 1966-1967 Unknown 4


HYDROLOGY
Tributary Influence
Tributary Influence Influence Gaging Station Source
Chorro Creek 122 km2 1, 6
Los Osos Creek 73 km2 6, 7
Wetland Alterations
Alterations Comments Contribution /
Removal
Amount		 Date Source
Flow Obstructions Bridge 2
Flow Obstructions Bridge 8
Flow Obstructions Twin Bridges 6
Groundwater Extraction Groundwater monitoring wells 1
Groundwater Intrusion 1
Non-point Source Urban Runoff 8
Non-point Source Urban runoff 2


WATER QUALITY
Water Quality Data
Parameter Duration Comments Source
Dissolved Oxygen 9
Groundwater 10
Groundwater Salinity 1990-1991 1
Salinity 9
Salinity Various-reported from other documents 4
Sediment deposits 1995 Lower Chorro Creek 1/2 mile west of Twin Bridges; 200 yards east of Twin Bridges 11
Soil salinity 10
Temperature 9
Temperature Various-reported from other documents 4
pH 9


SOILS
Comments Source
Fine silt in pools/pans within salt marsh 4
Sandy clay 2
Silt in the fluvial channels, clay in the tidal channels 6
Silt, clay, sand 1
Very fine silt and clay 9


VEGETATION
Special Status Plants
Common Name Scientific Name Federal State Source
California seablite Suaeda californica Endangered None 12
Salt marsh bird's-beak Cordylanthus maritimus ssp. maritimus Endangered Endangered 6
Non Native Plants
The Non-native plant list is not intended to be a representative list of all plants found in the wetland. To learn more about all plants found in the wetland, including natives, please refer to the lists documented in the Vegetation Comments section.
Common Name Scientific Name Source
Bamboo Phyllostachys spp. 1
Black mustard Brassica nigra 12
Castor bean Ricinus communis 1
Hoary cress Cardaria draba 1
Iceplant Carpobrotus edulis 9
Poison hemlock Conium maculatum 12
Wild fennel Foeniculum vulgare 12
Vegetation Comments
Comments Source
Littoral zone vegetation 7
Native plant list 2
Plant community maps 1
Vegetation comparisons between Morro Bay and other Pacific Coast wetlands 7


WETLAND IMPACTING ACTIVITIES
In the Wetland
Activity Source
Active/Severe riparian erosion 6, 8
Excavation 1
Non-native plant invasion 1, 9
Resource protection 1
Road construction 1, 6
Adjacent to the Wetland
Activity Source
Active/Severe riparian erosion 1
Agriculture 1
Camping 2
Excavation 1
Flood control 1
Grazing 1
Non-native plant invasion 1
Recreation (other) 2
Road construction 1, 6, 8, 9


CONSERVATION PROJECTS
Project Name Type Description Source
Restoration of Native Wetland Habitat at Chorro Delta Restoration of degraded habitat Non-native plant removal 1


SOURCES
Source Author(s) Year Published Document Name
1 Josselyn, M. et al. 1991 Chorro Delta Study - Hydrology, Sedimentation, and Hoary Cress Biology
2 Gardner, Glenn H. 1977 Net primary productivity and vegetational zonation of the salt marsh at Morro Bay, California.
3 US Army Corps of Engineers 2003 Ecosystem Restoration Feasibility Study, Draft F3 Conference Report Without-Project Conditions Analysis
4 Calif. Dept of Fish and Game 1974 Natural resources of Morro Bay: their status and future.
5 USDA Soil Conservation Service 1989 Enhancement plan, Morro Bay Watershed: San Luis Obispo County, California
6 Lin, Hsiao-tung 1991 Bank collapse along wetland channels, Chorro Delta, California
7 Hernandez, Rudolph C. 1971 Salt marsh vegetation of Morro Bay, California.
8 Marquardt, George P. 1991 The Chorro Delt Drainage Network (A Thesis)
9 Salopek, Paul and Sharon Lane 1980 Ecological survey of Morro Bay: contrasting environments within the Morro Bay wetlands system.
10 Rienecker, Erich 1991 Control plan for Hoary Cress(Cardaria draba L.) in the Chorro Creek Delta, Morro Bay State Park, Calif.
11 Provencher, James 1995 Nutrient analysis of recent erosion deposits along Chorro Creek.
12 David Wolff Environmental 2004 Personal Communication


The Wetland Profiles are not suitable for any regulatory purpose, and should not be the basis for any determination relating to the natural resource characteristics of any particular site or geographic area as well as impact assessment or mitigation. Please read the CCWGIS disclaimer for more details.