Marre Weir (Lower SLO Creek Fish Passage Design and Habitat Improvement Project)

Status Planning County San Luis Obispo
Project Type Repair/Maintenance Location 35.18748° N, -120.72563° W Map
Project Area (Acres) 2.10 Last Updated 1 August 2022
Project Abstract The Marre Weir on SLO Creek has been a migration barrier for Steelhead trout and Pacific lamprey. The project seeks to improve fish passage while preventing salt water intrusion for wells upstream.
Project Groups Creek Lands Conservation
Administrative Region California Department of Fish and Wildlife - Hildie Spautz, CDFW

Project Identification

Q1996028 CDFW - Prop 1 Grant ID

Habitat Plan

Site NamePhaseActivitySubActivitiesHabitatSubHabitatAcresActivity StatusWater Regime
Marre Weir on Lower SLO Creek Preliminary design Enhancement Infrastructure Riverine Wetland Channel 2.10 Planning in-progress Perennial non-tidal

Related Habitat Impacts

Impact Project NameHabitatAcres LostType of Loss
No Data


Marre Weir on Lower SLO Creek Construction planned 2.10


DateTypeDescriptionSite Name
2022-03-31 Project end date
2022-03-15 Report Biological and botanical surveys. This includes General habitat assessment of summary including map of sensitive resources identified and waters and wetland assessment via wetland delineation biological resources assessment report
2021-11-19 Report 65% Design Report Written description of 65% design alternative
2021-03-10 Update Stakeholder Meeting
2021-03-09 Update Fish Passage Meeting 3
2020-12-31 Report Weir Inspection Report which includes imagery, notes, and sketches. 30% Preliminary Design Report and Drawings for three alternatives
2020-09-15 Update Fish Passage Meeting 2
2020-08-30 Report Hydrologic and Hydraulic Analysis. Technical Memorandum summarizing modeling development and results with respect to potential increases in the creek water surface elevation and adherence to fish passage requirements.
2020-05-11 Update Fish Passage Meeting 1
2019-10-19 Project start date


Agency Staff Steph Wald Creek Lands Conservation Not applicable/Unknown


Funding Need: $459,798

Preliminary design Enhancement CDFW Prop 1 - Watershed Restoration Grant Program $459,798
Preliminary design Enhancement City of San Luis Obispo $8,075

Related CRAM Assessments

Visit DateVersionSite NameWetland TypeIndex Score
No Data

No files found.

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 ( 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.

Display Habitat Development Curves For Wetland Type:

CRAM Site Scores