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Case Studies > Haddam
Demonstration Site > Rain
Garden > Rain Garden Diagram
Rain Garden Diagram
The rain gardens were installed in September 2002 according to specifications
in the rain garden design manual (Prince George's County, 2002). Native soil
at the site was Penwood (Typic Udipsaments) loamy sand (USDA, 1979), and was
adequate to provide the rapid infiltration (3.8 cm/ hr) required for bioretention.
A 1,143 um (45-mil) EPDM liner (Firestone PondGard, Unit Liner Company, Shawnee,
OK) was installed under the two rain gardens. The liner is not normally a component
of a rain garden, however, in this study it was used to seal the bottom and
to allow collection of all percolate water. A 10.2 cm diameter perforated PVC
pipe collected percolate water under each rain garden (above the liner) and
was covered with 15 cm of 2.54 cm round stone. The native soil was re-installed
in both gardens and covered with a layer of shredded hardwood bark mulch approximately
5 cm thick. The physical characteristics (below
diagram) of the media were similar in the two gardens.
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Soil
& Mulch Properties
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