The gutter depression is the height of depression at the curb achieved from the steeper grade of the gutter cross slope relative to the roadway cross-slope. Gutter depression is well defined for conventional and v-shaped gutter section.

Local depression height is the vertical measure of depression at the location of the inlet. It is the additional depression in the depression area nearest to the inlet opening. The height and width of the local depression area can be modeled on a curb or slot inlet opening in the Inlet Catalog. Local depression does not exist within the gutter upstream of, nor downstream of the inlet. Local depression is measured relative to the gutter slope. The depth of surface flow in the gutter, reported at the Catch Basin or Inlet includes any applicable vertical measure of local depression and gutter depression modeled at the inlet opening.

• DE = Road Cross Slope (V:H)
• AD = Slope of Depressed Gutter (V:H)
• CB=Slope of Local Depression (V:H)
• F=Width of Local Depression (ft, m)
• G=Gutter Width, Width of Gutter Cross Slope (ft, m)
• H=Spread, including Local Depression
• I=Height of Local Depression (ft, m)
• J=Gutter Depth, including local and gutter depression (ft, m)