Agriculture Reference
In-Depth Information
and accuracy. In time, you will become increasingly adept as you gain
confidence through practice and by challenging yourself to discover more
aesthetically exciting and innovative site-grading solutions.
Figure 9.1-a
A pen mirrors slope of a steep
embankment
Figure 9.1-B
A landscape that was altered by a
farmer with a variety of slopes, from steep to level
Slope in site grading refers to the angle or degree of the surface of a
landform (such as the side face of a hill or the steepness of a river valley
or drainage swale) or a paved surface (such as walkway or tennis court).
The drawing pen in Figure 9.1-A is tilted so as to mirror the sloping sur-
face of a constructed earth embankment. As you can see, the face of the
embankment is quite steep; probably impossible to walk straight up on
without considerable difficulty. The degree of steepness is expressed as
a percent of slope, with slopes of 25 or 30 percent following in the steep
range. Slopes of 2 or 5 percent are considered shallow or even almost
level of surfaces that are 1 percent. In Figure 9.1-B the terrain is highly
varied with steep to shallow sloping earth surfaces and everything in
between. More on slope and angle of slopes will be discussed below.
introducinG caLcuLation of SLope
Contour lines and spot elevations are the primary tools to modify the
terrain of an existing project landscape. Used in combination, the manip-
ulation of contours and establishment of spot elevations are the primary
means to create level areas for buildings and sloping areas to direct water
runoff, and to sculpt project terrain to accommodate safe circulation for
