TM 5-803-14
grading can be described by the following catego-
ries:
(a) Minimal: removing topsoil and estab-
lishing finished grade with only a minor transition
between existing grade and constructed facilities.
(b) Moderate: requiring cuts and fills
greater than one foot in more than 50% of the
constructed site.
(c) Massive: requiring cuts deep into subsur-
face material and/or rock together with fills which
cover the entire building or site area. The transi-
tion between existing grade and constructed facil-
ities occurs at maximum slopes.
(3) Hydrology.
(a) Subsurface. Subsurface hydrology deals
with the storage and movement of groundwater
through aquifers. Subsurface information may be
obtained from USGS maps. Increasingly, Federal,
state and local agencies regulate the quantity and
quality of water allowed to infiltrate the ground
surface. Shallow, perched and fluctuating water
tables can all impact development. If a site is in a
groundwater recharge area, there may be restric-
tions upon the amount of impermeable surface and
upon the minimum water quality allowed for
infiltration.
(b) Surface. Surface hydrology, or runoff,
increases as development decreases the area of
infiltration. Surface conditions affecting site de-
sign are existing drainage patterns, flood plains,
and man-made structures (e.g., dams or channel-
ized drainageways.) Where soils are naturally sub-
ject to erosion and sedimentation, care may be
necessary to avoid increasing slopes, concentrating
runoff, or increasing impermeable surface. Devel-
opment may be precluded altogether. Water bodies
(e.g., ponds, lakes, streams or rivers) will be
examined and evaluated. Figure 3-5 illustrates a
combined topography and hydrology analysis for
the candidate site for the battalion complex.
(4) Soils. Soil types and locations will be
identified. The geotechnical investigation prepared
for each project will determine the type of founda-
tion design for buildings. Soils influence the kind
of activities and location of facilities on a site. The
most common soil problems affecting site develop-
ment are the following:
(a) Expansive soils can cause damage to
structures and paving.
(b) Unstable soils do not withstand pres-
sure. They require foundations with a larger bear-
ing area or foundations installed into a stable
substrate.
(c) Corrosive soils can affect materials used
in buildings and utility systems.
Figure 3-4. Slope Categories.
3-8
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