Martis Valley Groundwater Management Plan - Placer County Water ...

Martis Valley Groundwater Management Plan Section 2
Figure 2-7. Stratigraphic Column showing Primary Hydrostratigraphic Units
Stratigraphic interpretations shown in Figure 2-7 and in Section 2.4.3 (below) are consistent with
published geologic maps of the basin (Birkeland, 1961; Birkeland, 1963; Saucedo, 2005; Melody,
2009), and delineate four primary water-bearing stratigraphic units that make up the aquifer, and
underlying rocks that are considered to be relatively water-limited (see Figure 2-9). The primary units
shown in Figure 2-7 include a number of subunits mapped by previous investigators and shown on
Figure 2-9 and noted in parenthesis with the descriptions below. When available, information regarding
potentially confining (fine grained) or water-bearing (coarse) subunits are also delineated. Following well
log interpretation, three representative geologic cross-sections were located and developed. Figure 2-9
shows the cross-section locations; Figure 2-10 shows cross-section A-A’; Figure 2-11 shows cross-section
B-B’, and Figure 2-12 shows cross-section C-C’.
It should be noted that Figure 2-9, a geologic map of the MVGB and surrounding areas, is based on
published geologic mapping by Saucedo (2005), Melody (2009), and Saucedo and Wagner (1992). The
Saucedo and Wagner (2009) mapping was completed at a statewide scale and is therefore, less precise
than other portions of the map and geological cross-sections. Accordingly, portions of the geologic map
in Figure 2-9 do not correspond to the more detailed geological mapping and cross-sections.
DRAFT for review purposes only. Use of contents on this sheet is subject to the limitations specified at the end of this document.
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