Open vegetated swale materials specifications.
Link to this table

Parameter Specification Size Note
Dry swale soil USCS; ML, SM, SC n/a soil with a higher percent organic content is preferred
Dry swale sand ASTM C-33 fine aggregate concrete sand 0.02” to 0.04”
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
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
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
Pea gravel diaphragm and curtain drain ASTM D 448 varies (No. 6) or (1/8” to 3/8”) use clean bank-run gravel
Under-drain gravel per pre-cast manufacturer 1.5” to 3.5”
Under-drain ASTM D-1785 or AASHTO M-278 6” rigid Schedule 40 PVC 3/8” perf. @ 6” o.c.; 4 holes per row
Rip rap per local criteria size per requirements based on 10- year design flow