If the soil is not trampled down while it is being back filled, the compaction and bulk density of
the backfill will be considerably less than the native undisturbed soil around it. After a few
months, the backfilled soil will begin to compact on its own and return to a steady state bulk
density. The Hydra Probe will effectively be residing in two soil columns. The tines will be in
the undisturbed soil column, and the head, cable and conduit will be in the backfill column that is
undergoing movement. The compaction of the backfilled soil may dislodge the probe and thus
affect the measurement volume of the probe. After the probes are installed, avoid foot traffic and
vehicular traffic in the vicinity of the probes.
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