South Bay Salt Ponds: Alviso - Island Ponds A19, A20, A21 (Phase 2)

Status In-progress County Santa Clara
Project Type Non-mitigation Location 37.46652° N, -121.96770° W Map
Project Area (Acres) 1,249 Last Updated 5 March 2020
Project Abstract The goal for Phase 2 is to enhance and accelerate marsh development in these 3 ponds by doing some additional breaching and lowering of levees.
Project Groups San Francisco Bay Restoration Authority (Eligible) | San Francisco Bay Restoration Authority (Funded) | South Bay Salt Ponds | South Bay Salt Ponds: Initial Stewardship Plan | South Bay Salt Ponds: Phase 2

Project Identification

732 JV - Record Number

Habitat Plan

ActivitySubActivitiesHabitatSubHabitatAcresActivity StatusWater Regime
Enhancement Bay Habitat (SFBJV Only) Tidal marsh 265.0 In-progress/Implementation Unknown/Unspecified
Restoration (unspecified) Unspecified Bay Habitat (SFBJV Only) Tidal marsh 984.4 Completed Fully tidal

Related Habitat Impacts

HabitatAcres LostType of Loss
No Data


Alviso Island Ponds In-progress/Implementation 764.0
Pond A19 Completed 276.4
Pond A20 Completed 66.81
Pond A21 Completed 142.2


DateTypeDescriptionSite Name
2018-10-30 Permit The CEQA/NEPA processes for these Phase 2 pond modifications were complete in 2016; permitting was completed in 2018. Construction of the additional levee breaching, lowering, and removal is planned to take place in 2020.
2016-04-22 Report Final Environmental Impact Statement/Report, Phase 2 Alviso and Ravenswood Ponds
2012-01-01 Project start date
2006-03-01 Levee breach Breached the levees of Ponds A19, 20 and 21.


Contact Anne Morkill USFWS - San Francisco Bay National Wildlife Refuge Complex Not applicable/Unknown
Contact Dave Halsing State Coastal Conservancy Not applicable/Unknown


Enhancement SFBRA San Francisco Bay Restoration Authtority - Measure AA

Related CRAM Assessments

Visit DateVersionSite NameWetland TypeIndex Score
2007-06-22 4.6 Coyote Creek Lagoon estuarine perennial non-saline 70
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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 ( 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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