Open vegetated swale materials specifications

Open vegetated swale materials specifications.
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Parameter	Specification	Size	Note	Design application
Dry swale soil	USCS; ML, SM, SC	n/a	soil with a higher percent organic content is preferred	dry swale, step pool
Dry swale sand	ASTM C-33 fine aggregate concrete sand	0.02” to 0.04”		dry swale, step pool
Check dam (pressure treated)	AWPA Standard C6	6” by 6” or 8” by 8”	do not coat with creosote; embed at least 3’ into side slopes	dry swale, wet swale, step pool
Check Dam (natural wood)	Black Locust, Red Mulberry, Cedars, Catalpa, White Oak, Chestnut Oak, Black Walnut	6” to 12” diameter; notch as necessary	do not use the following, as these species have a predisposition towards rot: Ash, Beech, Birch, Elm, Hackberry, Hemlock, Hickories, Maples, Red and Black Oak, Pines, Poplar, Spruce, Sweetgum, Willow	dry swale, wet swale, step pool
Filter Strip sand/gravel pervious berm	sand: per dry swale sand gravel; AASHTO M-43	sand: 0.02” to 0.04” gravel: 1/2” to 1”	Mix with approximately 25% loam soil to support grass cover crop; see Bioretention planting soil notes for more detail	dry swale, step pool
Pea gravel diaphragm and curtain drain	ASTM D 448	varies (No. 6) or (1/8” to 3/8”)	use clean bank-run gravel	dry swale, step pool
Underdrain gravel	per pre-cast manufacturer	1.5” to 3.5”		dry swale, step pool
Underdrain	ASTM D-1785 or AASHTO M-278	6” rigid Schedule 40 PVC	3/8” perf. @ 6” o.c.; 4 holes per row	dry swale, step pool
Rip rap	per local criteria	size per requirements based on 10- year design flow		dry swale, wet swale, step pool