TM 5-830-3/AFM 88-17, Chap. 3
usually should be at least four times the width of the
1/2 gallon per square yard. Generally, the object to be
dune.
protected should be downwind a distance of-at least
twice the tip-to-tip width of the dune. The center portion
of a barchan dune can be left untreated, or can be
B-7.
Paneling
treated and the unstabilized portions allowed to reduce in
size by wasting. Figure B-6 shows destruction of a
Solid barrier fences of metal, wood, plastic, or masonry
typical barchan dune and stabilization depending on the
can be used to stop or divert sand movement. To stop
area treated.
sand, the barriers should be constructed perpendicular to
the wind direction. To divert sand, the panels should be
B-9.
Vegetative treatment
placed obliquely or nearly parallel to the wind. They may
be single slant or "V" in pattern (fig B-5). When first
erected, paneling appears to give excellent protection.
Vegetative cover is an excellent method of sand
However, panels are not self-cleaning, and the initial
stabilization. The vegetation to be established must
accumulations must be promptly removed by mechanical
often be drought resistant and adapted to the climate
means. If the accumulation is not removed, sand will
and soil. Most vegetative treatments are effective only if
begin to flow over and around the barrier and soon
the supply of new sand is cut off. Upwind and water,
submerge the object to be protected.
Mechanical
fertilizers, and mulch are used liberally. To prevent the
removal is costly and endless. This method of control is
engulfment of the vegetation, the upwind boundaries are
unsatisfactory because of the inefficiency and expense
protected by fences or dikes, and the seed may be
and should be employed only in conjunction with a more
protected by mulch sprayed with a bituminous material.
permanent control, such as planting, fencing, or using
Seed on slopes may be anchored by mulch or matting.
dust palliatives. Equally good protection at less cost is
Oats and other cereal grasses may be planted as -a fast-
achieved by the fencing method.
growing companion crop to provide protection while
slower
growing
perennial
vegetation
becomes
established. Usually the procedure is to plant clonal
B-8.
Bituminous materials
plantings followed by shrubs used as an intermediate
step, followed by the planting of long-lived trees. There
Destruction of dune symmetry by spraying bituminous
are numerous suitable vegetative treatments for use in
materials at either the center or the ends of the dune is
different environments. The actual type of vegetation
an inexpensive and practical method of sand control.
selected should -be chosen by qualified individuals
Petroleum resin emulsion and asphalt emulsions have
familiar with the type of vegetation that .thrives in the
been found to be effective. The desired stickiness of the
affected area Stabilization by planting has the
sand is obtained by diluting 1 part petroleum resin
emulsion with 4 parts water and spraying at the rate of
Figure B-5. Three types of solid fencing or paneling for control of dune formation
B-5
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