Download User's Guide - Equal Parenting

Additional Width
Stone Cover
Stone
Base
Rise
Stone Fill
Arch
Pipe
Span
Figure 8.11 Underground storage arch pipe dimensions
Stone Fill
This check box is used to denote whether additional stone fill is used around
the sides of the underground storage arch pipes. By default, no additional
stone fill is provided.
If stone fill is defined, then the stone fill is assumed to extend outward from
the arch pipe to a total width equal to the pipe span (base width) + additional
width, as with a rectangular “box-style” excavation (or galley) containing both
the underground storage arch pipe and stone fill.
If no additional width is specified, then the stone fill extends out equal to the
arch pipe span (base width).
Stone Cover
This entry specifies the cover thickness (ft/inches or m/cm) of the stone fill
(pea gravel or equivalent fill material) that is constructed above the
underground storage arch pipe and header (if defined), as shown in
Figure 8.11. This stone cover is assumed to be as wide as the span (base width)
of the underground storage arch pipe and overlays both the arch pipe and any
headers (if defined). If an ADDITIONAL WIDTH is specified, then the stone cover
width is increased by this amount. This stone cover is then used in calculating
the available detention storage area and volume.
Stone Voids
This entry specifies the void space within the stone fill (pea gravel or
equivalent fill material), in percentage. For example, 40% void space means
that within 1 ft3 cubic volume of stone fill material, 0.40 ft3 is available for
storing stormwater. The default void space is 40%.
Underground Storage Chambers
Underground stormwater storage chambers, as shown in the following figure, are
designed as an open bottom, interlocking, high-density polyethylene infiltration
chambers which function in both permeable and non-permeable soils for
subsurface retention or detention of stormwater runoff and for a water quality
Storage Curves | 305