California Rapid Assessment Method for Wetlands - State Water ...

California Rapid Assessment Method for Wetlands v. 5.0.2 – Appendix I
Project
Boundary
Sample
Universe
Figure 1: Diagrams of Project Boundary (dark green line) and Sample
Universe (area shaded light green) showing a grid used to
develop the Sample Frame of candidate AAs. A GIS can be
used to generate the Sample Frame without using a grid.
Step 3: For each Sample Universe, Develop the Sample Frame (Figures 2-4)
The Sample Frame will be a map of all candidate AAs within the Sample Universe. See
the following Table 3.7 from Chapter 3 of the CRAM Manual for a list of recommended
AA sizes for each wetland type.
There are two ways to begin creating a Sample Frame. One way is to overlay the Sample
Universe with a grid having a cell size just large enough to encompass one AA. Another
way is to use a GIS to generate a map of the maximum number of non-overlapping AAs.
At this stage of Sample Frame development, candidate AAs can overlap the edge of the
Sample Universe, although they cannot overlap each other.
Any AAs that do not meet the criteria for an AA as presented in Chapter 3 of the CRAM
Manual must be rejected. The following considerations are especially important.
a. Each AA should not cross any obvious, major physical changes in topography,
hydrology, or infrastructure that significantly control the sources, volumes, rates,
or general composition of sediment supplies or water supplies within the AA at
the time of the field assessment.
b. Each AA can only include one wetland type. No AA can include any portion of
more than one type of wetland, as defined by the CRAM Manual.
c. Reject any candidate AA that is more than 50% outside the Sample Universe.
The remaining AAs comprise the Sample Frame (Figure 3).
102