Gutter Shapes Explained


Product(s):StormCAD, CivilStorm, SewerGEMS
Version(s):CONNECT Edition, V8i
Area:Modeling

Background

The following shapes are available to select when modeling a gutter at a catchbasin:

This article explains the assumptions and use of each.

Conventional Gutter

A conventional gutter begins at the curb and extends to the roadway centerline. The HEC-22 manual declares two types of Conventional shaped gutters: uniform and composite. Gutters having irregular cross sections have a gutter cross slope uniform to that of the road cross slope. A conventional gutter where the section nearest the curb is depressed compared to the roadway slope should be modeled as a composite gutter section.

Uniform (depressed gutter = false)

Composite (depressed gutter = true)

Where:

Q = flow rate (m^3/sec, ft^3/sec)
Kc = 0.376 SI, 0.56 US Customary
n = Manning's coefficient
Sx = Pavement cross-slope (m/m, ft/ft
SL = Longitudinal pavement slope (m/m, ft/ft)
T = Width of flow/spread (m, ft)

See more in Help chapter "Conventional Gutters"

Trapezoidal Gutter

Where:

W = Bottom Width (Ditch)

SL = Left side slope

SR = Right side slope

Parabolic Gutter

Where:

H= Gutter Height
B = Width (Parabolic Gutter)
a = linear term coefficient derived with equation: a = 2H/B
b = quadratic term coefficient derived with equation: b=H/B2

See Hydraulic Engineering Circular No. 22, Third Edition Urban Drainage Design Manual (2009) for more details. 

V-Shaped Gutter

The Equivalent cross slope (Sx) for V-Shaped gutter is found with the formula:

where:

  • Sx1 = Curb side slope
  • Sx2 = Gutter cross slope
  • Sx3 = Road cross slope

See more details in the Help topic "V-Shaped Gutter Cross Section"

See Also