Tolay Lake Regional Park

Status In-progress County Sonoma
Project Type Non-mitigation Location 38.18359° N, -122.48573° W Map
Project Area (Acres) 3,437 Last Updated 2 July 2018
Project Abstract The acquisition of the 1,737-acre Tolay Lake Regional Park allows a much greater degree of public access than ever before. At least 12 known species of "special status" are found on the property.

Project Identification

251 JV - Record Number

Habitat Plan

ActivityHabitatSubHabitatAcresActivity StatusWater Regime
Acquisition/Preservation/Protection Creek and Lake (SFBJV Only) Lake and pond 1,737 Completed Mixed
Restoration Creek and Lake (SFBJV Only) Lake and pond 1,700 Planning/Scoping Mixed

Related Habitat Impacts

HabitatAcres LostType of Loss
No Data


Tolay Lake Regional Park In-progress/Implementation 3,437


DateTypeDescriptionSite Name
2005-09-22 Project start date The property now comprising Tolay Lake Regional Park was purchased in 2005 by the Sonoma County Agricultural Preservation & Open Space District and transferred to Regional Parks


Contact Steve Ehret Sonoma County Regional Parks Department Not applicable/Unknown
Contact Renee Spenst Ducks Unlimited, Inc. Not applicable/Unknown
Contact Elizabeth Tyree Sonoma County Regional Parks Department Not applicable/Unknown


Funding Need: $600,000

Acquisition/Preservation/Protection Sonoma County Agricultural and Open Space District
Acquisition/Preservation/Protection Federated Indians of Graton Rancheria $500,000
Acquisition/Preservation/Protection USFWS North American Wetlands Conservation Act $250,000

Related CRAM Assessments

Visit DateVersionSite NameWetland TypeIndex Score
No Data
Upload files or links
Name File Type Submitted On Submitted By
Tolay Lake Regional Park website Other 2018-07-02 Liz Duffy, SFBJV

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