Types of Manholes in SWMM 5 and InfoSWMM

Subject:   3 Types of Manholes in SWMM 5 and InfoSWMM 

 There are three types of interior manholes in SWMM 5 and InfoSWMM as regards water surface elevations above the Node Rim Elevation:

1st Excess Water leaves the Node as flooded water if the water surface elevation equals the Rim Elevation (Figure 1 and Gravity Mains),

2nd Excess Water is  stored in the manhole as pressurized depth if the Node Surcharge Depth is used (Figure 2 and Force Mains)

3rd Excess Water is stored above the Node Rim Elevation (Surface Ponding and Figure 3)

Figure 1.  The default node in SWMM 5 and InfoSWMM has just the Manhole Invert Elevation, the program calculated elevation of the highest connected link and the Node Maximum Depth or Rim Elevation.  If the Water Surface Elevation exceeds the Rim Elevation then any excess flow is lost as flooded flow.

Figure 2.  A force main or pressure in SWMM 5 and InfoSWMM has the Manhole Invert Elevation, the program calculated elevation of the highest connected link, the Node Maximum Depth or Rim Elevation and the Node Surcharge Depth.  If the Water Surface Elevation exceeds the Surcharge Elevation then any excess flow is lost as flooded flow but this allows more the links to have more pressure and hence more flow.

Figure 3.  The flooded Node option in SWMM 5 and InfoSWMM has just the Manhole Invert Elevation, the program calculated elevation of the highest connected link, the Node Maximum Depth or Rim Elevation and Node Ponding.  If the Water Surface Elevation exceeds the Rim Elevation then any excess flow is NOT lost but stored in the ponded area.  The depth of the ponded area is a function of the ponding area and the excess inflow.  If the water surface elevation goes below the Rim Elevation then the ponded volume flows back into the network.

 

InfoSWMM and Arc GIS Layer Properties for Force Mains and Gravity Mains

Subject:  InfoSWMM and Arc GIS Layer Properties for Force Mains and Gravity Mains

 An important advantage of using InfoSWMM is the ability to use all of the Arc GIS layer and programming tools.  For example, you can use the layer properties in the Table of Contents to color and create symbols for the force mains and gravity mains in InfoSWMM.  The Force Main variable (which is a Yes/No parameter) is selected as the field value in the Symbology Tab of Layer Properties which allows you to color and size the link based on the Force Main property of is you do a Layer Join the link property and simulation results.

InfoSWMM Note About Pump Wet Wells

Subject:  Wet Well Maximum depths and Pump Start and Pump Off Depths

  The Wet Well has

·         An invert elevation and

·         A Maximum Depth

The Pumps have

·         Pump On Depth

·         Pump Off Depth

·         Pump Head – Discharge Curve or

·         RTC Rules

The Links have a

·         Invert Elevation into the Wet Well and

·         Invert Elevation into the Downstream Force Main

·         Crown Elevation

Detention Pond Infiltration and Evaporation Losses

Subject:  Detention Pond Infiltration and Evaporation Losses

 

You can also add a storage pond infiltration and surface evaporation losses to the pond.  The surface evaporation is added to the infiltration (computed from the green ampt parameters); a storage volume summary listing the average and maximum volume and the percent loss from the combined infiltration and evaporation from the ponds.  The pond infiltration loss during a time step is basd on the areal weighed average depth, the Green Ampt infiltration and the Area of the pond.

 

Figure 1.  Pond Infiltration Loss Assumptions

Figure 2. SWMM 5 Storage Summary listing Evaporation

 

  

Figure 3.  Infiltration Pond Data is entered in the Property Sheet for the Node.

 

infiltration_detetention_pond.inp Download this file