Los osos creek wetland reserve

Status Completed County San Luis Obispo
Project Type Non-mitigation Location 35.32599° N, -120.81252° W Map
Project Area (Acres) 111.0 Last Updated 11 August 2016

Project Identification

No Data

Habitat Plan

ActivityHabitatSubHabitatAcresActivity StatusWater Regime
Acquisition/Preservation/Protection Riverine Wetland Riparian area 111.0 Construction completed

Related Habitat Impacts

HabitatAcres LostType of Loss
No Data


Los Osos Creek/Warden Creek Construction completed 111.0


DateTypeDescriptionSite Name
2009-10-01 Project entered Project entered into database
1995-01-01 Groundwork start Estimated date Los Osos Creek/Warden Creek


Contact Unknown Coastal San Luis Resource Conservation District Not applicable/Unknown


Acquisition/Preservation/Protection SCC State Coastal Conservancy

Related CRAM Assessments

Visit DateVersionSite NameWetland TypeIndex Score
2008-06-18 5.0.1 Los Osos Creek Wetland Reserve riverine non-confined 64

Performance Criteria

StatusDetailsEvaluation Date
No Data

Project Description

This is phase II of the Morro Bay Watershed Enhancement Plan. This 144 acre site is located at the confluence of Los Osos and Warden Creeks just upstream of the Morro Bay estuary. The agricultural land is owned by George Martines. The USDA Natural Resources Conservation Service and the Coastal San Luis Resource Conservation District (CSLRCD) have purchased permanent wetland reserve easements on the property. The State Coastal Conservancy provided funding for the CSLRCD easement. The easements were acquired and 111 acres of flood plain and riparian habitat was to serve as a sediment deposition area, trapping sediment before entering Morro Bay. Thirty-three acres are permanently protected in an agricultural easement. One key component of the plan is to provide a sediment trap on Los Osos Creek near its confluence with Morro Bay. Historically the site was a freshwater wetland and riparian forest. In the 1900s the site was converted to agricultural use. The creek bed was altered and levees were constructed for flood control. It was farmed continuously until 1995, but has since been allowed to revert back to wetland habitat. The floods of 1995 did a great service by rupturing the levees and spreading over the area millions of willow cuttings. Today, the site is functioning as a sediment trap and is outstanding wildlife habitat.
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How to Use the Habitat Development Curve

Habitat Development Curves (HDCs) are used to determine the developmental status and trajectory of on-the-ground projects to create, restore, or enhance California wetland and stream habitats. Each HDC is based on assessments of habitat condition for different age areas of one habitat type that in aggregate represent the full spectrum of habitat development. The assessments of condition are provided by expert applications of the California Rapid Assessment Method (CRAM). Visit the CRAM website for more information about CRAM.

For each HDC, reference condition is represented by areas of a habitat that consistently get very high CRAM scores, have not been subject to disruptive management practices, and exist within landscapes that are protected and managed for their natural conditions. The horizontal lines intersecting the top of an HDC represent the mean CRAM score and standard deviation of scores for 25 qualifying reference areas.

The age of a project is estimated as the elapsed time in years between the groundwork end date for the project and the date of the CRAM assessment. To add or update a groundwork end date, use the Project Events form in Project Tracker (ptrack.ecoatlas.org). The minimum age in years of a non-project area, including any natural reference area, is estimated from all available local information, including historical maps and imagery, historical written accounts, and place-specific scientific studies of habitat development.

An HDC can be used to address the following questions:

  1. At what time in the future will the area of assessed habitat achieve the reference condition or other milestones in habitat development? The HDC can answer this question if the CRAM score for the assessed area is within the confidence interval of the HDC. The answer is the time in years along the HDC between the current age of the assessed area and the future date corresponding to the intersection of the HDC and the reference condition or other milestone.
  2. Is the area of assessed habitat likely to develop faster, slower, or at the same pace as most other areas of the same habitat type? The habitat area is likely to develop faster, slower, or at the same pace if the CRAM score for the area is above, below, or within the confidence interval of the HDC, respectively.
  3. What can be done to improve the condition of the habitat area or to increase its rate of development? HDCs by themselves cannot answer this question. Possible answers can be inferred by the following analysis that involves HDCs:
    1. Examine the HDC for each of the four CRAM Attributes;
    2. Identify the Attribute(s) scoring below the HDC;
    3. For any low-scoring Attribute, examine the component Metric Scores (note: the Metric Scores for any public CRAM assessment in the CRAM database can be obtained through EcoAtlas);
    4. Assume the low score of an Attribute is due to its low-scoring Metric(s);
    5. Consider modifying the design or management of the habitat area in ways that will sustainably increase its score(s) for the low-scoring Metric(s).

For more information about CRAM Attributes and Metrics, including their scientific rationale, see the CRAM Manual.

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