Geoscience Reference
In-Depth Information
fIGURe 27.2
Green No. 2 located at the Hickory Ridge golf course, Carbondale, IL.
pattern. Spacing between the lateral lines was about 3 to 5 m (USGA Green Section Record, 1993).
The blueprints of the drainage system of both greens were available for comparison.
27.2.2 s
e l e c t i of n
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n t e n n a
In mapping the golf green drainage system, a Subsurface Interface Radar Model SIR 2000 (man-
ufactured by Geophysical Survey Systems Inc., Salem, NH) was used. Both 400 and 900 MHz
antenna were tested (Boniak et al., 2003). The 400 MHz antenna was good for a deeper soil but
provided less resolution. The 900 MHz antenna had a higher resolution for a shallow soil that would
seem ideal for the golf green. Prior to measurement, the GPR was calibrated and standardized to
select the best viewing parameter settings. The adjustment included maximum depth range, posi-
tion of ground surface reflection, and proper signal amplification. In the calibration, the depth of the
image was set to a subsurface truth object such as the gravel layer. It is best not to apply frequency
filters in the field because it may remove critical data that may be needed later.
27.2.3 s
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R e P a R a t i o n
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R i o R
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M
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A two-person team worked together in conducting the experiment. Prior to scanning, a 1 × 1 m grid
pattern was overlaid on the entire green. In the establishment of the grid pattern, the sprinkler heads
around the green were used as reference points. The sprinkler heads were selected because they are
stationary and easily located. If sprinkler heads are not readily available, stakes may put into the
ground for permanent reference points. The grids were flagged at every meter on both sides of the
green (Figure 27.3). Due to the irregular shape of each green, marking the green boundary is critical
for identifying the location of the drainage tile.
27.2.4 M
e a s u R e M e n t
Initially, a 900 MHz antenna was used because of its ability to examine shallow subsurface features
with high resolution. However, a large amount of unexpected noise appeared in the image. This
might be attributed to the granular fertilizer applied to the green earlier. High salt index in the
