Agriculture Reference
In-Depth Information
spot elevation at the bottom of the wall where the wall meets pavement,
or the ground, in the case of a planting area. Where walls with sloping
top surfaces are designed, a spot elevation is given for the start and end
of each sloping section of a wall. If a sloping wall is not divided with
stepped sections, then a top-of-wall spot elevation is provided at the
start and end of the wall. Spot elevations are given at the beginning and
end of the sloped ramp (item C). Detailed sections and elevations would
accompany the site-grading plan to provide the contractor with greater
detail of the wall and ramp design intent of the designer.
The image in Figure 10.9 shows the critical grading documentation
features of a wall and step combination. Item A is the bottom eleva-
tion of the stairs, item B is a note indicating number of stairs and riser
height, and item C is the spot elevation at the top of the stairs. Item D
gives the height of the wall, with the second item C giving the elevation
of the top wall, and item F the elevation of the lower wall. TW is a com-
mon abbreviation meaning "top of wall."
4. rim elevations for drain inlets (catch basins or French drains):
Catch
basins and French drains are shown in site-grading plans. Several
elevations are associated with the detailing of these drainage elements.
A spot elevation is given for the rim elevation of each catch basin and
the drainpipe where the water is being carried away underground. In
addition, technical details are provided giving the dimensions and con-
struction details of the entire catch basin unit, including sections show-
ing inlet and outlet pipes that take water from a catch basin or drain
in the system to the municipal storm water system, or, in the case of
on-site disposal, to a detention/retention pond. See Figure 10.10.
5. Beginning and ending of swales:
With intermediate spot elevations
when slope changes occur.
Spot elevations are provided at the beginning and end of drainage
swales. Intermediate spot elevations may be needed when the slope
along the swale changes (becomes steeper or more shallow). In Fig-
ure 10.11, point A represents the beginning of the drain swale in the
lawn area, and the arrow indicates the direction of water flow with a
percent of slope provided. At point B there is a change in percent of
