Geoscience Reference
In-Depth Information
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Easting (m)
fIGURe 21.7
Perpendicular (PRP) electrical conductivity contours at the Muirfield Village Golf Course
MVGC green.
indicate secondary drains. Drainage is to the northeast; the southwestern portion of the green is the
least conductive, suggesting that it is also driest.
The HCP contours of Figure 21.8 are similar to the PRP contours, but with less contrast and
spatial detail.
Measurements at the MVGC tee (Figure 21.9 and Figure 21.10) were made along north-south
traverses. Unlike the results at the greens, the PRP contours of Figure 21.9 do not show a regular
area of low conductivity, which suggests that the tee has no sand-layer beneath it. Instead, PRP
conductivities decrease below 30 mS/m toward the southern edge of the tee. A corresponding but
subtler decrease in HCP conductivities (Figure 21.10) suggests that the soil texture of the uppermost
0.3 m near the southern edge of the tee is relatively coarse.
Toward the northern edge and the northwest corner of the tee, HCP conductivities rise to their
highest values, and PRP values remain more moderate. In these areas, the diverging conductivities
reveal that the earth beneath 0.5 m depth is increasingly conductive.
The PRP conductivities and, to a lesser extent, HCP conductivities show a linear low extending
along 7 N between 7 E and 14 E. A drainage trench runs under the tee at about 7 N, and the conduc-
tivity low may indicate the local effectiveness of the trench in draining the soil.
21.6 ConClUSIonS
A 1 m EM instrument that incorporates HCP and PRP arrays, with 1 mS/m accuracy, can provide
ground-level measurements with sufficient resolution for mapping features on golf courses. Where
