Notation

m

run of side slopes in channel cross sections (length, but usually expressed as a ratio in relation to rise. e.g. where side side slopes = 1:3.5, m = 3.5)

q

infiltration rate in (length per time, usually mm/hr) (before or after application of safety factor?)

R_a

Existing rise of swale gradient (length, usually m)

R_b

Rise of compensation gradient for an enhanced swale (length, usually m)

SCF

Safety correction factor (dimensionless)

The rate at which stormwater percolates into the subsoil measured in inches per hour.

A shallow constructed channel, often grass-lined, which is used as an alternative to curb and channel, or as a pretreatment to other measures. Swales are generally characterized by a broad top width to depth ratio and gentle grades.

Vegetated open channel, with check dams; designed to convey, treat and attenuate stormwater runoff.