TM 5-803-12
CHAPTER 6
GENERAL SITE PLANNING GUIDELINES
AND ARCHITECTURAL CHARACTER
6-1. General.
pling or bear the weight of continuous vehicular
traffic without becoming compacted into a con-
This chapter provides general guidelines for
crete-like consistency. Compacted soils resist root
planning outdoor recreation sites and buildings.
growth and become devoid of vegetation, lead-
More detailed guidance for site planning is found
ing to soil erosion. Soils that are easily com-
in TM 5-8035. Detailed building design and con-
pacted constrain recreational use to low density,
struction criteria are also located in the tech-
passive forms of recreation.
nical manuals listed in Appendix B. Other sources
(d) Shallow depth to bedrock, and ston-
of information include state park and recrea-
iness. Shallow soils are easily compacted. Shal-
tion agencies, federal agencies such as the Na-
low depth to bedrock constrains facilities
tional Park Service and U.S. Forest Service, and
development since construction on such soils may
others such as the Tennessee Valley Authority.
require excavation of bedrock which escalates
The National Park and Recreation Association,
the cost of development. Soils with significant
as well as the various associations representing
amounts of rock fragments on the surface are
individual recreation activities, can often pro-
unsuited to use for certain types of recreation
vide useful guidance.
such as children's play areas or picnic grounds.
(e) High water table. Soils in lowlands or
6-2. Environmental constraints
on level to gently sloping uplands that have low
and opportunities.
permeability or a fragipan may hold water for
long periods after rainfall and remain satu-
a. Certain aspects of the environment of an
rated, limiting their use for recreation.
installation may serve to constrain outdoor rec-
(f) Low weight-bearing capacity. Steep
reation development in one way or another. The
slopes composed of weak soils with low weight-
most common environmental or physical con-
bearing capacity are prone to mass movements
straints include soils limitations; unstable or
such as mudflows, slides and soil creep. Con-
unsuitable geologic formations; rare, threat-
struction of recreation facilities such as access
ened or endangered flora or fauna; air quality
roads or support buildings is prohibited unless
limitations; water quality limitations; and cul-
the weak soil materials is brought in. This, of
tural features such as archaeological or historic
course, greatly escalates the costs of develop-
sites.
ment.
(1) Soils limitations. Common soil-related
(g) Slow permeability. Soils that do not
constraints include:
percolate sufficiently may constrain develop-
(a) Slope. Slopes are important consid-
ment that requires sewage disposal by means of
erations in outdoor recreation planning both
a septic tank and lateral drain field system or
from the viewpoint of the environmental con-
that requires construction of a sewage lagoon
straints they pose and the environmental im-
or an overland-flow irrigation disposal system.
pact related to their alteration. Steep slopes in
(2) Unstable geologic formations. The most
an area designated for recreation use increase
common unstable geologic formations in most
the difficulty and the cost of establishing rec-
portions of the continental United States are
reational facilities and decrease the density of
soluble limestones and plastic clay shales. Sol-
use that the area could otherwise sustain. Dis-
uble limestones underlie karst topography which
turbance of steep slopes is associated with the
is characterized by the presence of numerous
potential for erosion and/or slope failure.
sinkholes. Karst areas may have large subsur-
(b) Erosion potential. Soils on steep
face caverns or voids beneath them, and con-
slopes, with light vegetative cover or where veg-
struction of recreational support buildings in
etation has been removed, and composed of loose
such areas should be preceded by subsurface in-
soil materials are conducive to erosion. Areas
vestigations to ascertain the absence of such
having soils with high erosion potential can sus-
voids. Plastic clay shales on steep to moderately
tain only low-density, passive forms of recrea-
steep slopes become unstable when wet. Devel-
tion use.
opment on slopes underlain by shale is prone to
(c) Compaction. Certain soils, particu-
slumping and sliding following periods of heavy
larly clay soils, cannot withstand repeated tram-
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