DESIGN OF LID SYSTEMS - Low Impact Development and Sustainable Stormwater Management - page 135

2½” pervious paving surface course

1” choker course (AASHTO
No. 57 - washed)

Clean washed
uniformly graded
coarse aggregate,
AASHTO No. 3

6” wide concrete weir,
height varies

Provide 12” sediment trap
(below low-flow orifices)
w/ 1” weep holes,
three per side.

Solid HDPE pipe

PERF HDPE
along bottom

Nonwoven geotextile

Place CB on 6” compacted
2A w/ compacted subgrade Uncompacted bed bottom

Figure 7-6 Storage bed overflow control structure.

Figure 7-7 Porous pavement next to standard pavement in parking lot.

than in the United States, although at least one U.S. system has been constructed
successfully (in Arizona). In Japan and the United States, the application of an
open-graded asphalt pavement of 1 in. or less on roadways has been used to pro-
vide lateral surface drainage and prevent hydroplaning, but these are applied over
impervious pavement on compacted subgrade. This application is not considered
a stormwater BMP.