Specify an inlet compliant with HEC-22.
HEC-22 Inlets can be specified with the use of the Gutter and Inlet tabs.
The Size Inlets button opens the Inlets form.
Long. Slope - The longitudinal slope of the road (pavement).
Road Cross Slope - The cross-section slope of the road (pavement).
Gutter Cross Slope - The cross-section slope of the gutter.
Gutter Width - The width of the gutter.
Manning's n - Manning’s n roughness value. Used by the Manning Formula equation.
Inlet Type - The type of inlet: Grate, Curb, Combination, or Slotted. This value will change the Inlet Details section of the form, and the preview image.
Location - The location of the inlet: On Grade, or In Sag.
Inlet Details - Dependant on the inlet type. Depression and Clogging are show for all inlet types.
Grate & Slotted:
Depression - The depth of the depression on the inlet below the gutter.
Clogging - The amount of clogging to be consider on the inlet.
When opened from the Inlets form, HEC-22 inlets have a third tab. This is used to determine the flow into the inlet.
Runoff Type - The runoff type determines the method of calculating flow into the inlet, using one of the following:
Rainfall (Use Plan Data only) - The button will open the rainfall manager. From here an existing or new rainfall file can be edited / created. Once finished in the rainfall manager the drop down list will be populated with rainfall sets. The rainfall selected will be used to calculate the intensity used when calculating the inflow using the Use Plan Data runoff type.
Flow - The flow into the inlet, the method to set or calculate this value is determined by the runoff type.