Road slope vs. Gutter slope vs. local depression

  Applies To 
  Product(s):
SewerGEMS, CivilStorm, StormCAD
  Version(s): 08.11.XX.XX
  Area:  Modeling
  Original Author: Mark Pachlhofer, Bentley Technical Support Group

Problem

What is the difference between Road Cross Slope, Gutter Cross Slope, continuously depressed gutter slope and local depression slope?

Solution

In your gutter if the property for "Depressed Gutter?" is set to 'False' then there is a single slope along the side of the road that is equal to the value of the road cross slope (Shown as DE in the screen shot below).

This uniform gutter is depicted in the following diagram:

In your gutter if the property for "Depressed Gutter?" is set to 'True' there is a steeper slope right near the curb, for the entire length of the gutter, which is the gutter cross slope property. There would also still be a road cross slope value, so, in total, there would be two different slopes or a "composite" gutter section. This composite gutter is depicted in the following diagram:

If you have a local depression (a steeper slope only at the inlet location) then there would be a total of 3 slopes (road cross slope, gutter cross slope, local depression slope). The screenshot below depicts the local depression case with three separate slopes.

The program will calculate a composite cross slope based on the slope of the continuously depressed gutter (and locally depressed gutter if present). For more information, see HEC-22 2nd or 3rd edition manual.

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