# HEC-22 Inlets in #InfoSWMM and H2OMap SWMM

The Junction inlet data table stores information regarding the inlet at the junction node. Refer to the section on inflow editor for more information on these input data. The following table shows the whole first row of the DB Table on separate rows in the image.

Field |
Description |

Junction ID |
Name assigned to the junction. |

Overland Junction |
Name of the Overland Junction that is the source of the flow to the Inlet |

Inlet Type |
One of five types of Inlets (1) Continuous Grate, (2) Continuous Curb-Opening, (3) Sag Continuous Grate, (4) Sag Continuous Curb-Opening and (5) Sag Combination |

Cross Slope |
Cross slope (Sx) or the road cross slope |

Grate Width |
Width of grate (W) in feet or meters |

Grate Length |
Length of grate (L) in feet or meters |

Splash Velocity |
Velocity where splash-over first occurs (V0) in feet/second or meters/second |

Open Height |
Height of the Curb Opening in feet or meters |

Open Length |
Length of the Curb Opening in feet or meters |

Gutter Depression |
Gutter Depression in feet or meters |

Depression Width |
Lateral width of the gutter depression in feet or meters |

Clear Area |
Clear opening area of grate (Ag) |

Threshold Depth |
Depth up to which gate behaves as weir or the Threshold Depth in feet or meters |

#### Sag Curb-Opening Inlet

The parameters for a Sag Curb-Opening Inlet are:

· Length of curb opening (L) in feet or meters,

· Lateral width of gutter depression (Wd) in feet or meters,

· Height of curb opening (h) in feet or meters,

· Depth up to which gate behaves as weir as the Threshold depth in feet or meters

#### Sag Grate Inlet

The parameters for a Sag Grate Inlet are:

· Cross slope (Sx) or the road cross slope

· Width of grate (W) in feet or meters,

· Length of grate (L) in feet or meters,

· Clear opening area of grate (Ag)

· Depth up to which gate behaves as weir or the Threshold Depth in feet or meters

#### Sag Combination Inlet

The parameters for a Sag Combination Inlet are:

· Width of grate (W) in feet or meters,

· Length of grate (L) in feet or meters,

· Clear opening area of grate(Ag)

· Height of curb opening (h) in feet or meters,

· Length of curb opening (l) in feet or meters,

· Depth up to which gate behaves as weir or Threshold Depth in feet or meters.

#### Continuous Grate Inlet

The parameters for a Continuous Grate Inlet are:

· Cross slope (Sx) or the road cross slope

· Width of grate (W) in feet or meters

· Length of grate (L) in feet or meters

· Velocity where splash-over first occurs (V0) in feet/second or meters/second

#### Continuous Curb Opening Inlet

The parameters for a Continuous Curb Opening Inlet are:

· Length of curb opening (L) in feet or meters,

· Cross slope (Sx) or road cross slope,

To model a depressed inlet, values for the following parameters are also required:

· Gutter depression (a) in feet or meters

· Lateral width of gutter depression (Wd) in feet or meters

# Grate Inlet on Grade from H2OCalc

The dialog box for grate inlet on grade is shown below.

#### Input for grate inlets on grade:

· **Flow Unit** – Select the desired flow unit.

· **Location** – On grade and in sag.

· **Solving Target** – Efficiency or length.

· **Manning’s Coefficient** – Manning’s roughness coefficient for the gutter.

· **Slope** – Longitudinal slope of the street.

· **Discharge** – Flow rate through the gutter.

· **Gutter Width** –Width of the gutter measured from the curb.

· **Gutter Cross Slope** – Slope of the gutter measured perpendicular to centerline of the street.

· **Road Cross Slope** –Slope of the street perpendicular to the longitudinal direction.

· **Grate Type** – Select one of the eight grate types listed.

· **Efficiency** –Interception efficiency of the grate. It represents ratio of intercepted flow to total gutter flow.

· **Grate Width** – Width of the grate.

· **Grate Length** – Length of the grate.

· **Clogging** – Percentage of the grate opening that is clogged by debris, leaves, etc, and is not available to intercept flow.

#### Output for grate inlet on grade:

· **Flow Area** – Wetted area of the gutter.

· **Depth** – Flow depth in the gutter.

· **Gutter Depression** – Local depression of the gutter measured from the point the cross slope line intersects with the curb.

· **Velocity** – Flow velocity through the gutter.

· **Total Depression** – Sum of the local depression and the gutter depression.

· **Intercepted Flow** – The portion of gutter flow that entered the inlet.

· **Bypass Flow** – The portion of the gutter flow that is not intercepted by the inlet. It is total gutter flow less the intercepted flow.

· **Splash Over Velocity** – Velocity where splash over first occurs. Splash over refers to the fraction of frontal gutter flow that is not intercepted by the inlet.

· **Frontal Flow Factor** – The ratio of intercepted frontal flow to total frontal flow.

· **Side Flow Factor** – The ratio of intercepted side flow to total side flow.

· **Grate Flow Ratio** – The ratio of frontal flow to total gutter flow.

· **Active Grate Length** – Portion of grate length (the side that is parallel to the curb) that is not clogged.

· **Spread** – Top width, or width of the gutter at the water surface elevation.

# Curb-Opening Inlet on Grade from H2OCalc

The dialog box for curb-opening inlet on grade is shown below. For methodology click here.

#### Input for curb-opening inlets on grade:

· **Flow Unit** – Select the desired flow unit.

· **Location** – On grade and in sag.

· **Solving Target** – Efficiency or length.

· **Manning’s Coefficient** – Manning’s roughness coefficient for the gutter.

· **Slope** – Longitudinal slope of the street.

· **Discharge** – Flow rate through the gutter.

· **Gutter Width** –Width of the gutter measured from the curb.

· **Gutter Cross Slope** – Slope of the gutter measured perpendicular to centerline of the street.

· **Road Cross Slope** –Slope of the street perpendicular to the longitudinal direction.

· **Efficiency** –Interception efficiency of the inlet. It represents ratio of intercepted flow to total gutter flow. It is an output if selected as a solving target.

· **Curb Opening Length** – Length of the curb-opening inlet (i.e., length parallel to the curb).

· **Local Depression** – Depth of local depression of the gutter measured from the point where the cross slope line intersects with the curb.

· **Local Depression Width** – Width of the local depression.

#### Output for curb-opening inlet on grade:

· **Flow Area** – Wetted area of the gutter.

· **Depth** – Flow depth in the gutter.

· **Gutter Depression** – Local depression of the gutter measured from the point the cross slope line intersects with the curb.

· **Velocity** – Flow velocity through the gutter.

· **Total Depression** – Sum of the local depression and the gutter depression.

· **Intercepted Flow** – The portion of gutter flow that entered the inlet.

· **Bypass Flow** – The portion of the gutter flow that is not intercepted by the inlet. It is total gutter flow less the intercepted flow.

· **Equivalent Cross Slope** – An equivalent cross-slope that has a conveyance capacity equal to that of the compound cross-slope.

· **Spread** – Top width, or width of the gutter at the water surface elevation.

· **Total Interception Length** – Length of the curb required to intercept 100% of the gutter flow.

· **Length Factor** – Ratio of actual curb length to total interception length.

# Combination Inlet on Grade from H2OCalc

The dialog box for combination inlet on grade is shown below. For methodology click here.

#### Input for combination inlets on grade:

· **Flow Unit** – Select the desired flow unit.

· **Location** – On grade and in sag.

· **Solving Target** – Efficiency, equal opening lengths, or curb opening length.

· **Manning’s Coefficient** – Manning’s roughness coefficient for the gutter.

· **Slope** – Longitudinal slope of the street.

· **Discharge** – Flow rate through the gutter.

· **Gutter Width** –Width of the gutter measured from the curb.

· **Gutter Cross Slope** – Slope of the gutter measured perpendicular to centerline of the street.

· **Road Cross Slope** –Slope of the street perpendicular to the longitudinal direction.

· **Grate Type** – Select one of the eight grate types listed.

· **Efficiency** –Interception efficiency of the inlet. It represents ratio of intercepted flow to total gutter flow. It is an output if selected as a solving target.

· **Grate Width** – Width of the grate.

· **Grate Length** – Length of the grate.

· **Clogging** – Percentage of the grate opening that is clogged by debris, leaves, etc, and is not available to intercept flow.

· **Curb Opening Length** – Length of the curb-opening inlet (i.e., length parallel to the curb).

· **Local Depression** – Depth of local depression of the gutter measured from the point where the cross slope line intersects with the curb.

· **Local Depression Width** – Width of the local depression.

#### Output for combination inlet on grade:

· **Flow Area** – Wetted area of the gutter.

· **Depth** – Flow depth in the gutter.

· **Gutter Depression** – Local depression of the gutter measured from the point the cross slope line intersects with the curb.

· **Velocity** – Flow velocity through the gutter.

· **Total Depression** – Sum of the local depression and the gutter depression.

· **Intercepted Flow** – The portion of gutter flow that entered the inlet.

· **Bypass Flow** – The portion of the gutter flow that is not intercepted by the inlet. It is total gutter flow less the intercepted flow.

· **Splash Over Velocity** – Velocity where splash over first occurs. Splash over refers to the fraction of frontal gutter flow that is not intercepted by the inlet.

· **Frontal Flow Factor** – The ratio of intercepted frontal flow to total frontal flow.

· **Side Flow Factor** – The ratio of intercepted side flow to total side flow.

· **Grate Flow Ratio** – The ratio of frontal flow to total gutter flow.

· **Active Grate Length** – Portion of grate length (the side that is parallel to the curb) that is not clogged.

· **Equivalent Cross Slope** – An equivalent cross-slope that has a conveyance capacity equal to that of the compound cross-slope.

· **Spread** – Top width, or width of the gutter at the water surface elevation.

· **Total Interception Length** – Length of the curb required to intercept 100% of the gutter flow.

· **Length Factor** – Ratio of actual curb length to total interception length.

# Slotted Inlet on Grade from H2OCalc

The dialog box for slotted inlet on grade is shown below. For methodology click here.

#### Input for slotted inlets on grade:

· **Flow Unit** – Select the desired flow unit.

· **Locations** – On grade and in sag.

· **Solving Target** – Efficiency and length.

· **Manning’s Coefficient** – Manning’s roughness coefficient for the gutter.

· **Slope** – Longitudinal slope of the street.

· **Discharge** – Flow rate through the gutter.

· **Gutter Width** –Width of the gutter measured from the curb.

· **Gutter Cross Slope** – Slope of the gutter measured perpendicular to centerline of the street.

· **Road Cross Slope** –Slope of the street perpendicular to the longitudinal direction.

· **Efficiency** –Interception efficiency of the inlet. It represents ratio of intercepted flow to total gutter flow. It is an output if selected as a solving target.

· **Slot Length** – Length of the inlet.

· **Local Depression** – Depth of local depression of the gutter measured from the point where the cross slope line intersects with the curb.

· **Local Depression Width** – Width of the local depression.

## Output for slotted inlet on grade:

· **Flow Area** – Wetted area of the gutter.

· **Depth** – Flow depth in the gutter.

**Gutter Depression** – Local depression of the gutter measured from the point the cross slope line intersects with the curb.

· **Velocity** – Flow velocity through the gutter.

· **Total Depression** – Sum of the local depression and the gutter depression.

· **Intercepted Flow** – The portion of gutter flow that entered the inlet.

**Bypass Flow** – The portion of the gutter flow that is not intercepted by the inlet. It is total gutter flow less the intercepted flow.

· **Equivalent Cross Slope** – An equivalent cross-slope that has a conveyance capacity equal to that of the compound cross-slope.

· **Spread** – Top width, or width of the gutter at the water surface elevation.

· **Total Interception Length** – Length of the curb required to intercept 100% of the gutter flow.

· **Length Factor** – Ratio of actual curb length to total interception length.

# Ditch Inlet on Grade from H2OCalc

The dialog box for ditch inlets on grade is shown below. For methodology click here.

#### Input for ditch inlets on grade:

· **Flow Unit** – Select the desired flow unit.

· **Locations** – On grade and in sag.

· **Solving Target** – Efficiency and length.

· **Manning’s Coefficient** – Manning’s roughness coefficient for the gutter.

· **Slope** – Longitudinal slope of the street.

· **Discharge** – Flow rate through the gutter.

· **Bottom Width** – Bottom width of the ditch (channel).

· **Left Side Slope** – Left side slope of the ditch.

· **Right Side Slope** – Right side of the ditch.

· **Grate Type** – Select one of the eight grate types listed.

· **Efficiency** –Interception efficiency of the grate. It represents ratio of intercepted flow to total gutter flow.

· **Grate Width** – Width of the grate.

· **Grate Length** – Length of the grate.

· **Clogging** – Percentage of the grate opening that is clogged by debris, leaves, etc, and is not available to intercept flow.

#### Output for ditch inlets on grade:

· **Flow Area** – Wetted area of the gutter.

· **Depth** – Flow depth in the gutter.

· **Velocity** – Flow velocity through the gutter.

· **Intercepted Flow** – The portion of gutter flow that entered the inlet.

**Bypass Flow** – The portion of the gutter flow that is not intercepted by the inlet. It is total gutter flow less the intercepted flow.

· **Splash Over Velocity** – Velocity where splash over first occurs. Splash over refers to the fraction of frontal gutter flow that is not intercepted by the inlet.

· **Frontal Flow Factor** – The ratio of intercepted frontal flow to total frontal flow.

· **Side Flow Factor** – The ratio of intercepted side flow to total side flow.

· **Grate Flow Ratio** – The ratio of frontal flow to total gutter flow.

· **Active Grate Length** – Portion of grate length (the side that is parallel to the curb) that is not clogged.

· **Spread** – Top width, or width of the gutter at the water surface elevation.

· **Velocity Head** – Energy head due to velocity.

· **Critical Depth** – Depth corresponding to minimum specific energy of the channel.

· **Critical Slope** – Channel slope under critical depth.

· **Specific Energy** – Sum of velocity head and pressure head.

· **Froude Number** – Flow characteristics dimensionless parameter for the ditch.

# Combination Inlet in Sag from H2OCalc

The dialog box for combination inlet in sag is shown below. For methodology click here.

#### Input for combination inlets in sag:

· **Flow Unit** – Select the desired flow unit.

· **Location** – On grade and in sag.

· **Solving Target** – Efficiency, equal opening lengths, or curb opening length.

· **Discharge** – Flow rate through the gutter.

· **Gutter Width** – Width of the gutter measured from the curb to the break in slope of the street.

· **Gutter Cross Slope** – Slope of the gutter measured perpendicular to centerline of the street.

· **Road Cross Slope** –Slope of the street perpendicular to the longitudinal direction.

· **Spread** – Top width, or width of the gutter at the water surface elevation. Could be an output if selected as a solving target.

· **Grate Type** – Select one of the eight grate types listed.

· **Throat Incline Angle** – Angle of the curb opening throat.

· **Grate Width** – Width of the grate.

· **Grate Length** – Length of the grate.

**Clogging** – Percentage of the grate opening that is clogged by debris, leaves, etc, and is not available to intercept flow.

· **Curb Opening Length** – Length of the curb-opening inlet (i.e., length parallel to the curb).

**Local Depression** – Depth of local depression of the gutter measured from the point where the cross slope line intersects with the curb.

· **Local Depression Width** – Width of the local depression.

· **Curb Throat Type** – Horizontal, vertical, or incline.

· **Curb Height** – Height of the curb.

#### Output for combination inlet in sag:

· **Open Grate Area** – Clear area of the grate accounting for clogging, and area occupied by the bars depending on the grate type. Used when the grate acts as an orifice.

· **Depth** – Flow depth in the gutter.

**Gutter Depression** – Local depression of the gutter measured from the point the cross slope line intersects with the curb.

· **Total Depression** – Sum of the local depression and the gutter depression (measured from the point where the street cross slope meets the curb).

· **Active Grate Weir Length** – Portion of grate length and width that is not clogged and not covered by the bars. Used when the grate acts as a weir.

Categories: #INFOSWMM, ARC GIS, H2OMapSWMM (retired), InfoSWMM, SWMM5