Lake Basin Characteristics and Morphometry
5
fractions and of directional location of subdivisions of a section, as illustrated in
Figure 1.2. The designation of the 10-acre (4.05-hectare) plot in the upper right of the
section would be as follows:
SE-.b NEi, NEi, Sec, __ , T __ (N or S), R __ (E or W) of the __ th principal
meridian.
Because of the necessity of making new surveys in isolated regions opened for
settlement, particularly in the west, it was not always possible or expedient to conduct
the work in a systematic manner from a few well-chosen initial points. Large errors in
geographic position and in the bearings of lines thus were allowed to develop so that,
when the various isolated surveys were finally joined to more reliable work, the errors
were found to be too large to adjust by approved means. There are, likewise, a number
of areas where small groups of townships do not fit into the regional system of
numbering, and it is difficult, if not impossible, to determine from maps the base lines
and meridians used in the original surveys.
In Canada, the scheme ofland subdivision is very similar to that used in the United
States, except that there are fewer irregularities in the Canadian surveys. Townships are
subdivided into sections 1 mF, but the numbering starts in the southeast corner and
ends in the northeast. Sections are subdivided into 16 parts, called legal subdivisions,
which are numbered from 1 to 16, starting in the southeast corner of the section and
ending in the northeast. Each legal subdivision in a regular section contains 40 acres.
Townships are numbered from south and north from the international boundary in
western Canada, and ranges are designated east and west from the principal meridian.
Shore Lines of Lakes and Streams
A reasonably accurate hydrographic survey is essential for the evaluation of basic
morphometric characteristics of lakes and sections of streams. Such surveys can be
performed with a minimum of equipment, although the work can be facilitated and
made more accurate when simple surveying equipment is available.
Often the general outline of the lake or stream in question can be obtained from
aerial photographs. The shore line then is measured and formulated, section by section,
until the entire area is circumscribed. It is sometimes easier to make shore line surveys
during the winter, when the lakes or streams are frozen than during the open-water
season, especially if the margins are swampy or heavily wooded.
Most shoreline surveys use the traverse method, in which a series of points are
connected by straight lines of known lengths and angles from each other. Computerized total station surveying instruments are also available with automatic data
collection capability (e.g., Lietz Co., Overland Park, KA). The use oftransit or alidade
surveying equipment is necessary for the construction of bathymetric maps for research
investigations. Sophisticated methods of point location and survey are possible by use
of the Global Positioning System, where coordinates are determined from triangulation from satellites. The principles, however, of the morphometric characteristics can
be obtained with a simple compass and measuring tape, but at considerable sacrifice of
accuracy. The rudiments of such surveying techniques are elaborated on in a number of
surveying manuals; application to lakes and streams is detailed in Welch (1948) and
Hakanson (1981). Several methods are outlined in the exercises proposed later in the
text.
5
fractions and of directional location of subdivisions of a section, as illustrated in
Figure 1.2. The designation of the 10-acre (4.05-hectare) plot in the upper right of the
section would be as follows:
SE-.b NEi, NEi, Sec, __ , T __ (N or S), R __ (E or W) of the __ th principal
meridian.
Because of the necessity of making new surveys in isolated regions opened for
settlement, particularly in the west, it was not always possible or expedient to conduct
the work in a systematic manner from a few well-chosen initial points. Large errors in
geographic position and in the bearings of lines thus were allowed to develop so that,
when the various isolated surveys were finally joined to more reliable work, the errors
were found to be too large to adjust by approved means. There are, likewise, a number
of areas where small groups of townships do not fit into the regional system of
numbering, and it is difficult, if not impossible, to determine from maps the base lines
and meridians used in the original surveys.
In Canada, the scheme ofland subdivision is very similar to that used in the United
States, except that there are fewer irregularities in the Canadian surveys. Townships are
subdivided into sections 1 mF, but the numbering starts in the southeast corner and
ends in the northeast. Sections are subdivided into 16 parts, called legal subdivisions,
which are numbered from 1 to 16, starting in the southeast corner of the section and
ending in the northeast. Each legal subdivision in a regular section contains 40 acres.
Townships are numbered from south and north from the international boundary in
western Canada, and ranges are designated east and west from the principal meridian.
Shore Lines of Lakes and Streams
A reasonably accurate hydrographic survey is essential for the evaluation of basic
morphometric characteristics of lakes and sections of streams. Such surveys can be
performed with a minimum of equipment, although the work can be facilitated and
made more accurate when simple surveying equipment is available.
Often the general outline of the lake or stream in question can be obtained from
aerial photographs. The shore line then is measured and formulated, section by section,
until the entire area is circumscribed. It is sometimes easier to make shore line surveys
during the winter, when the lakes or streams are frozen than during the open-water
season, especially if the margins are swampy or heavily wooded.
Most shoreline surveys use the traverse method, in which a series of points are
connected by straight lines of known lengths and angles from each other. Computerized total station surveying instruments are also available with automatic data
collection capability (e.g., Lietz Co., Overland Park, KA). The use oftransit or alidade
surveying equipment is necessary for the construction of bathymetric maps for research
investigations. Sophisticated methods of point location and survey are possible by use
of the Global Positioning System, where coordinates are determined from triangulation from satellites. The principles, however, of the morphometric characteristics can
be obtained with a simple compass and measuring tape, but at considerable sacrifice of
accuracy. The rudiments of such surveying techniques are elaborated on in a number of
surveying manuals; application to lakes and streams is detailed in Welch (1948) and
Hakanson (1981). Several methods are outlined in the exercises proposed later in the
text.