The Soils of The Regional Municipality of Ottawa=Carleton

their agricultural use . The dominantly occurring textures of
those encountered are shown in the legend .
SoilLandscapeUnit A subdivision ofthe soil association representing
a landscape area having specific proportions ofidentified
drainage components and surface slopes which occur
within a defined range and in a set pattern . On the map, this
unit composes part ofthe map unit symbol shown for a delineated
area.
Land 1 rpe Unit A subdivision of the land type representing a
land area having specific soil or land conditions which serve to
distinguish the area from others which may be included in the
land type . For example, the Rockland land type has primarily
been subdivided into land type units on the basis of different
types ofbedrock which occur.
Soil Drainage The rapidity with which water is removed from
the soilin relation to supply. Supply or additions ofwater occur
inthe form of precipitation, groundwater flow, or surface runoff
water from surrounding soils. Removal of water relates to a
number of factors including texture, structure, landscape position,
and length and gradient of slope .
Soil drainage was determined using the drainage classification
guidelines outlined inthe Canadian System of Soil Classification
(22) . In this survey, drainage classes defined in that
system were grouped resulting in five soil drainage descriptions
. These descriptions are as follows : (1) Excessive - very
rapidly or rapidly drained ; (2) Good-well-drained or moderately
well-drained ; (3) Imperfect - imperfectly drained ; (4)
Poor - poorly drained ; and (5) Very Poor - very poorly
drained . Definitions of the seven soil drainage classes which
make up these groupings are given in Appendix 1 .
Dominant and Significant These are terms which refer to
either the relative proportions of land areas which compose a
map delineation represented by acompound map unit symbol,
or the relative proportions of soil drainage components composing
a soil landscape unit used to define a particular land
area . Dominantmeans that more than 4001o of themap delineation
consists of that type of land area, or, more than 40 01o of
the soil landscape unit and therefore land area is composed of
that drainage state. Significant means that more than20% but
less than 40% consists of the land area or drainage state indicated
. Land areas or drainage conditions occupying 20 010 or
U
0
(dark brown)
(dark yellowish brown)
(light yellowish brown)
Figure 14 .
Diagrammatic soil profile of a typical well-drained soil in the
Ottawa-Carleton Region .
E
U
ô
Ap
- Bg1
(very dark gray)
(mottled dark gray)
-Bg2 (mottled gray)
(mottled olive gray)
Figure 15 .
Diagrammatic soil profile ofatypicalpoorly drained soil in the
Ottawa-Carleton Region .
less ofthe map delineation or area defined by a soil landscape
unit are regardedas inclusions and are not identified .
In the soil map legend, many soil landscape units have
only one drainage state which is shown as being dominant . In
such cases, 80 010 or more ofthe unit is composed ofthat drain
age state. Other drainage conditions may be present, but they
do not occur in significant proportions .
Map Delineation An area delineated on the map or enclosed
by a boundary line, and identified by a map unit symbol composed
ofone ortwo map units .
Map Unit A mapped land area defined by one or more symbols
representing various landscape components, and composing
all or part of the map unit symbol shown within a map
delineation. In the survey, many different map units are portrayed
in either simple or compound map unit symbols on the
soil maps .
Simple Map Unit Symbols Map symbols which contain a single
soil landscape, land type, or miscellaneous land unit as
defined in the map legend . Examples of some simple map unit
symbols and an explanation of their components are as follows
:
1 . G1 .S simple map unit symbol representing a single
S1 .3 soil landscape
GI soil landscape unit of the Grenville association
; the soils have good drainage and meet
the material and landform criteria defined
for the Grenville association
S soil phase ; a shallow phase indicating the
soils are only 50 to 100 cm thick over
bedrock, which is shallower than normal for
Grenville soils. When soil phases are not
shown, those soil conditions are not present .
St stoniness class ; stones whichhave a diameter
greater than 15 cm occupy 0 .01 to 0.1% of
the surface (class 1) . In some symbols, a
rockiness class may be shown rather than a
stoniness class (for example R2 instead of
S1) . Rockiness classes identify the amount
of surface which is either exposed bedrock or
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