Hamilton Wetlands Restoration

Status Completed County Marin
Project Type Non-mitigation Location 38.05765° N, -122.50654° W Map
Project Area (Acres) 1,180 Last Updated 5 March 2020
Project Abstract This project restored close to 1,000 acres of tidal and seasonal wetlands, provided a beneficial reuse of 24 million cubic yards of dredged materials, and converted a former military base into a treasured public resource.

Project Identification

M05-23 BCDC - Permit Number
70 JV - Record Number

Habitat Plan

ActivitySubActivitiesHabitatSubHabitatAcresActivity StatusWater Regime
Monitoring & Evaluation Bay Habitat (SFBJV Only) Tidal marsh 744.0 In-progress/Implementation Fully tidal
Restoration (unspecified) Sediment Management, Vegetation, Water Management Bay Habitat (SFBJV Only) Tidal marsh 989.5 Completed Fully tidal
Restoration (unspecified) Buffer area None 34.00 Completed
Restoration (unspecified) Depressional Wetland Unknown/Unspecified 156.0 Completed

Related Habitat Impacts

HabitatAcres LostType of Loss
No Data


Phase 1: Hamilton Army Airfield Completed 744.0
Phase 2: North Antenna Field Completed 435.5


DateTypeDescriptionSite Name
2014-12-15 Levee breach Hamilton Airfield restored to tidal action
2014-04-25 Phase end Levee breach Phase 1: Hamilton Army Airfield
2013-12-31 Phase end Phase 2: North Antenna Field
2006-04-10 Permit BCDC Record number issued
2006-04-10 Project start date Estimated date
2002-01-01 Phase start Phase 1: Hamilton Army Airfield
1996-01-01 Phase start Phase 2: North Antenna Field


Contact Jeff Melby State Coastal Conservancy San Francisco Bay Area Project Manager
Contact Jessica Davenport State Coastal Conservancy Not applicable/Unknown


Restoration (unspecified) BCDC - San Francisco Bay Conservation and Development Commission
Restoration (unspecified) U.S. Army Corps of Engineers $75,257,921
Restoration (unspecified) SCC State Coastal Conservancy $25,725,313

Related CRAM Assessments

Visit DateVersionSite NameWetland TypeIndex Score
2007-09-12 4.6 Hamilton oversample estuarine perennial saline 62
Name File Type Submitted On Submitted By
Hamilton Airfield Levee Breach Other 2018-09-05 Liz Duffy, SFBJV
Hamilton/Bel Marin Keys Wetlands Restoration Project Background Other 2018-09-05 Liz Duffy, SFBJV
US. Army Corps Project Site - Hamilton Wetlands Restoration Other 2018-09-06 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 (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.

Display Habitat Development Curves For Wetland Type:

CRAM Site Scores