The Soils of The Regional Municipality of Ottawa=Carleton

In this survey, boundaries were periodically checked in the
field, but mainly they were interpreted from aerial photographs
. At least one site inspection consisting of soil material
and surface feature assessments was made in most map delineations.
Soil materials were examined in vertical sections by
using a probe, auger, or shovel . Average depth of examination
was to about 1m. At each site, on-site slope as well as surrounding
slopes, surface stoniness, and surface rockiness were determined
.
The soil maps included in this survey thus provide informationat
a level of detail which is most suited for making general
land assessments and decisions related to use on an overall
map delineation basis . They are not suitable for making land
assessments or land use decisions for site specific or small land
areas within map delineations, such as potential building sites
or fields within individual farms . In such cases, an on-site
examination of soil characteristics is recommended .
The Mapping System
The mapping system employed in the survey is similar to
the system employed in the surveyofthe Ottawa Urban Fringe
area (1) . In each survey, a categorical system is used to define
landareas atdifferent levels of detail . Such asystem allows naturally
occurring landscape patterns to be identified and
mapped at the scale of the survey. Categories employed in this
survey to define land areas are shown in Figure 12 .
The broadest category in the system differentiates a
mappedland area into one ofthreebasic types . Ifthe land area
consists of recognizable soils, those soils are defined in a par
ticular soil association . The soil association is a mapping convenience
which groups soils on the basis of similarities in
physiographic factors and soil parent materials (1) . Thirty soil
associations have been defined for different types of soils
occurring in the survey area . Iftheland area consists mainly of
unique land features such as materials that cannot be classified
as soils, those areas are defined in a particular land type . Four
landtypes were defined, with an example being Rockland (RK)
in which extensive rock outcropping occurs . Finally, if undisturbed
soils or recognizable land features do not occur, those
land areas were defined as miscellaneous land . An example
would be land areas which have been altered by man, such as
urban land (U) .
Soil associations and land types have been subdivided into
a number of landscape descriptors, each of which defines an
individual land area . These descriptors are called soil land
scape units andland type units, and compose the next category
in the mapping system . Each defines a basic landscape pattern
in terms of the range of topographic conditions and the types
of soils or land features which are present . Soil landscape
units, and to a lesser extent land type units, are the most important
land descriptors in the mapping system .
An area on the soil maps enclosed by a boundary line and
defined byone or more symbols is called a map delineation . A
map delineation encloses a particular type of land area, or it
may enclose a combination of two separate and distinct types
of land areas . Combinations of land areas often had to be
included in one delineation due to the map scale. Most often,
these combinations involve two soil landscape units .
Each type of land area represented within a map delineation
is defined by a map unit . A map unit represents discrete
soil/land elements and is represented by the following : (1) a
soil landscape, land type, or miscellaneous land unit symbol
which defines the type of land area ; and (2) additional descriptor
symbols which define such elements as surface slope, surface
stoniness, or rockiness . A map unit including a soil
landscape unit as itsprimary component always has additional
descriptors, whereas map units composed ofland type or miscellaneous
land units usually do not have additional descriptors.
Since a map delineation may representone or two types of
land areas, then one or a combination of two map units are
shown to define the land area or areas . The entire amalgama
tion of symbols shown within the map delineation, which may
portray either a single map unit or a combination of two map
units, is called the map unit symbol . Ifonemap unit composes
the symbol, that symbol is a simple map unit symbol . If two
map units compose the symbol, then that symbol is a compound
map unit symbol . Some examples of map unit symbols
are given in Figure 13 . Further explanations of these are given
in the section "Definitions of Terms Associated with the Soil
Maps and Legend", and definitions of specific symbols are
given in Appendix 1 . Definitions and explanations are also
givenonthe maps as well .
Soil series were recognized and correlated in accordance
with the Canadian System of Soil Classification (22) . In the
survey, however, large areas of land had to be delineated in
which related but significantly different series often occur.
Under this circumstance, series information served as an aid in
mapping, but was not used as a basis to delineate land areas .
Soil association descriptions, therefore, reflect a range in soil
characteristics which may comprise a number of different soil
series . In all site assessments made during mapping, emphasis
was first placed on the nature of the soil materials and then
their geologic origin . Thus, the Jockvale association for example,
comprises soils developed on both marine and fluvial origin
parent materials .
Conventions Used in Mapping
Standard soil classification guidelines outlined in "The
Canadian System of Soil Classification" (22) and "The Canadian
Soil Information System" (24), were applied in this sur
vey. These publications defined the limits employed for slope,
surface stoniness and rockiness classes as well as texture and
drainage classes . Component classes used to differentiate soil
map units are fully defined in Appendix 1 .
In addition to the standard classification guidelines
employed, a number of conventions were followed in this survey.
These are primarily related to the portrayal of landscape
information at the map scale, andthe survey objective ofcorrelating
as closely as possible with the survey of the Ottawa
Urban Fringe area. Aspects of the survey and a brief explanation
ofthe conventions pertaining to them are as follows :
Soil variants A soil variant in this survey is a soil which has
characteristics similar to soils included in a particular soil association,
but is different in at least one major characteristic .
Four types of soil variants were recognized and identified on
the soil maps by separate soil landscape units defined for some
soil associations . These are :
(1) Soils having significant layers of finer or coarser-textured
materials within the profile. An example is the NG5 soil
landscape unit of the North Gower association, in which
layers ofcoarser-textured silt, silt loam, or fine sandy loam
occur within the profile.
(2) Soils in which underlying materials which occur within 1
m of the surface are significantly different from those
materials which normally compose the association . An
example would be the 14 landscape unit of the Ironside
association, in which Leitrim till rather than Grenville till
materials underlie fine sand and loamy fine sand materials.