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Project: Development of the California Rapid Assessment Method (CRAM)

Background and Objectives

The California Rapid Assessment Method (CRAM) for wetlands was developed to provide consistent, scientifically defensible, affordable information about the condition of wetlands and riparian habitats throughout California. CRAM is designed to cost-effectively assess the performance of wetland restoration and mitigation projects, as well as the ambient condition of existing wetlands within watersheds, regions, and for the state as a whole. To achieve this goal, the method needed to be standardized, cost-effective, scientifically defensible, and broadly applicable to the variety of wetland types found across California.

The purpose of this project was for SCCWRP to collaborate on the method development and calibration of CRAM, as part of a statewide core team of scientists and environmental agency staff. SCCWRP scientists led the southern California regional team, which provided review and input on the applicability of CRAM for southern California wetlands.


This project was conducted from 2002 to 2005.


Development of CRAM consisted of nine steps with distinct products. These were organized into three phases: basic method design, calibration, and validation (Table 1).

Table 1. Phases and steps of CRAM development.

CRAM was developed for application among different wetland types, including estuaries, lagoons, wadeable and non-wadeable streams and rivers, depressions, seeps, springs and lakes. Wetland mapping protocols  were developed using the standard methods and conventions developed by the US Fish and Wildlife Service National Wetland Inventory (NWI). An additional hydrogeomorphic classification developed specifically for California wetland and riparian habitats was also developed.

In southern California, the wetland and riparian mapping protocols developed for CRAM were applied in a pilot project in the San Gabriel River Watershed in 2005. This project, conducted in collaboration with the Los Angeles and San Gabriel Rivers and Mountains Conservancy, NWI, and the Resources Agency, involved initially mapping wetland and riparian habitat across 27 quads. Based on that experience, the mapping protocols were refined and finalized. CRAM was then used to comprehensively map the remainder of the quads in the region, and applied statewide for estuarine and riverine wetland assessment.

Many different wetland types can be assessed using CRAM.


Project activities resulted in a completed and verified CRAM User Manual, with individual modules for perennially tidal estuarine, seasonally tidal estuarine, riverine, lacustrine, depressional, slope/seep, and vernal pool wetlands. CRAM manuals can be accessed at


This project was conducted in collaboration with San Francisco Estuary Institute, San Jose State University Foundation, the Humboldt Bay Harbor Recreation and Conservation District, US EPA Region IX, and scientists and agency staff from the statewide Core Team and Regional Teams.

For more information on Development of the California Rapid Assessment Method (CRAM), contact Eric Stein at (714) 755-3233.
This page was last updated on: 8/30/2011