TM 5-814-7
normal, mean and extreme values for long periods of record
rial. All facilities must be designed for specialized problems
and climatic maps of the United States. Design data directly
such as seismic shaking in seismically active areas, o
available from the US Weather Bureau include isobars for 24-
expansive soils.
hour rainfalls and for average annual lake evaporation.
e. In addition, numerous theories, empirical correlations,
3-4. Climatic elements
modeling procedures and charts have been developed for
defining and predicting the impact of climatic elements on
a. Climatic
conditions,
particularly
design. Those useful in designing land disposal facilities
evaporation, temperature, and wind, can significantly influence
include equations for infiltration and run off, rainfall and wind
the selection, design and operation of land disposal facilities.
erosion, and wind waves; depth of freezing indices; and
Adverse climatic conditions can, for example:
evaporation/evapotranspiration calculations. State and local
(1) Prevent use or operation of
agencies have used available climatic data to develop charts
Surface Impoundments practicing evaporative
and tables which can be used in these predictive calculations-
disposal of wastes, if annual precipitation is greater
including the rainfall and storm recurrence tables and rainfall
than annual evaporation.
intensity/duration charts used for run-off calculations.
Land Treatment facilities, if soils in the treatment area
are frozen or saturated.
3-5. Impact of site conditions on selection of disposal
(2) Restrict operation of--
Surface Impoundments, where heavy rainfall reduces
method
storage capacity.
a. Most regulations dealing with disposal to land clearly
Land Treatment facilities, where lower temperatures
reflect the sensitive relationship between waste type, disposal
will decrease biodegradation rates.
method, and potential for natural or engineered protection of
Landfills, where (1) freezing soil or wastes interfere
the environment at the proposed disposal facility. Sites that
with proper placement of compaction of wastes, soil
are designed to accept only solid, generally inert substances,
cover or earthfills, (2) accumulation of snow may
obviously require fewer natural containment features than do
require clearing, or (3) snow melt may increase the
those intended for liquid hazardous waste. Similarly, siting of
moisture content of the waste.
waste piles or land treatment facilities may be far less
(3) Impact closure practices at impoundments and
restrictive than siting of impoundments.
landfills
b. Site conditions which obviously prohibit development
Disruption of the compacted soil zone through frost
of a disposal site of any type are wetlands and locations in
heave (water migration and freezing in layers, lenses
critical aquifer recharge areas. Site conditions that impact
or veins of ice).
selection of disposal methods fall into three basic areas (1)
Sliding resulting from thawing of a shallow, saturated
ability for ground-water protection, (2) potential for surface
zone of soil cover.
water contact with wastes, and (3) availability of materials
Rainfall erosion of the soil cover.
required by each disposal method. Almost any negative site
b. Generalized climatic data are available from the
condition can be overcome by engineering designs; however,
National Climatic Center of the National Oceanic and
these engineering solutions can often result in unacceptable
Atmospheric Administration and the National Weather Service.
economic impacts and/or regulatory monitoring requirements.
Local meteorological data is often available at Army
(1) In selecting a disposal method, two key elements
installations that have air fields. In addition, some states have
regarding ground-water protection must be considered: (1)
official weather observation stations that offer climatic data.
vertical separation of wastes from the uppermost ground-
Selected publications which provide recorded data, frequency
water, and (2) permeability of the subsurface material
and duration analyses, and general charts for various climatic
providing the hydraulic separation. These two elements are
elements are listed in the references (appendix A).
interrelated. Far less separation between waste and ground-
c. Another source of information is the US Weather
water can be tolerated in a low permeability clay environment
Bureau, whose 300 first-order weather stations provide data
than in a site underlain by sand and gravel. However, design
on:
considerations of the natural ground-water setting can be
greatly influenced by regulations mandated by 40 CFR 264
Daily and monthly temperature
requiring the placement of impermeable liners beneath
Dewpoint
landfills, impoundments and waste piles.
Precipitation
Pressure
Wind
Sunshine and cloud cover
Solar radiation
d. Weather stations also publish climatic tables of
3-4
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