such as bulldozers and graders. Hand- or power-
felling equipment, explosives, and fire are used when
they make the completion of these operations easier.
CAUTION
Large-scale clearing and grubbing
operations
often produce damaging
environmental effects, such as increased soil
erosion, reduction of atmospheric oxygen, and
destruction of wildlife habitat. Additionally,
introduction of particulate matter into streams
and riverbeds causes increased siltation and
algae growth. Federal regulations may require
an environmental impact statement or
assessment prior to beginning clearing
operations.
To prevent these damaging effects, save as much
vegetation as possible, such as trees, grass, and other
plants, to hold the soil in place. Constructing a shallow
trench or application of plastic barriers or hay bales
around the perimeter of a project will help to contain
water runoff into streams and rivers, preventing
siltation. Burning of scrubs and stumps should be done
only when atmospheric conditions are favorable and
the material to be burned is dry, However, do NOT
use petroleum base fuels to start fires, as fuels do not
burn completely and seep into the underground water
table.
NOTE: A burn permit is required in all burning
operations on NCF projects to prevent wild fires and
production of smog.
When determining the methods of earthwork
operations needed, consider the following factors:
. The
. The
. The
. The
. The
acreage to be cleared
type and density of vegetation
physical features of the land
expected weather conditions
time available for completion of the job
For best results, a combination of methods should
be used in a sequence of operations. Use the method
most suitable and effective for the job.
EQUIPMENT
Knowing your equipment, its limitations, and its
operating characteristics is part of the knowledge you
need to know to be an efficient EO on earthmoving
jobs.
Equipment production must be determined so that
the correct amount and type of equipment is selected
for a project. Equipment production rates are available
in the Seabee Planners and Estimators Handbook,
NAVFACP-405. The handbook provides information
on estimating construction work elements and
material quantities, including equipment and
manpower requirements.
Before you begin earthmoving operations, it is
often necessary to remove overgrowth, boulders, and
other obstructions. Also, you often have to build a
drainage system, so the construction site will drain.
These operations are carried out with bulldozers,
scrapers, graders, and similar equipment.
The load, hauled by a scraper, is usually referred
to as either heaped or struck (fig. 15-63). When
moving earth, take a full, heaped load and make it
Figure 15-63.-Heaped and struck load.
15-38