Open vegetated swale materials specifications.
Link to this table

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

This page was last edited on 4 August 2022, at 16:49.