How to make Multiple Storm Events in InfoSWMM and How to Use them in the Scenario Manager

Subject:  How to make Multiple Storm Events in InfoSWMM and How to Use them in the Scenario Manager

Step 1.  Make a new Time Series to hold the data points for your new Rainfall Time Series in the Operation Tab of the Attribute Browser.

 

Step 2.  Populate the Rainfall Distribution with a SCS Type II Hyetograph with a 1 inch rainfall total

 

Step 3.  Now Clone the created Rainfall Distribution and make 10, 25, 50 and 100 year storm events each with 1 inches of rainfall in a cumulative distribution.

 

Step 4.  Now use the Block Edit command and convert each of the newly created hyetographs to 4, 7, 10, 15 and 20 inch cumulative rainfall totals from the original 1 inch rainfall total (for example).

Step 5.  Now create a Raingage for each of the newly created hyetograph time series using the DB Editor under the Raingage Table in Hydrologic Data

Step 6.  Link the Time Series to the new Raingages and define the type (cumulative), units (inches) and hyetograph interval (15 minutes)

Step 7. Make 4 New Scenarios for the different return period hyetographs,  the Base Scenario will use the 5 year or 4 inch SCS II rainfall.

Step 8. Use the DataSet Manager and make 4 new Subcatchment DB Tables in which each Subcatchment Set uses a different return period hyetograph.

Step 9. Run the Batch Simulator for all 5 scenarios including the Base Scenario.

Step 10.  You can  use the Output Report Manager to see the Rainfall for all of the Batch Runs to check if the proper rainfall was used for each Scenario Simulation.

Weirs in InfoSWMM and SWMM5

Weirs in InfoSWMM and SWMM5

Subject: Weirs in InfoSWMM

 Figure 1 shows the relationship between the weir input data and the upstream and  downstream nodes.

·         Height,

·         Crest and

·         Node Invert Elevation

 There are four types of weirs and if the weir becomes submerged downstream the Villemonte weir submergence correction is applied (Figure 2).  You can have flow reversal across the weir unless you use a Flap Gate for the weir (Figure 3). 

Figure 1:  Definition of Weir Terms

Figure 2: Villemonte Weir Submergence Correction

Figure 3:  Flow Reversal in a Weir

A Basic InfoSewer Wet Well, Pump and Force Main System

Note:  A Basic InfoSewer Wet Well,  Pump and  Force Main System

How is the St Venant Equation Solved for in the Dynamic Wave Solution of SWMM 5?

Subject:   How is the St Venant Equation Solved for in the Dynamic Wave Solution of SWMM 5?

An explanation of the four St. Venant Terms in SWMM 5 and how they change for Gravity Mains and Force Mains. The HGL is the water surface elevation in the upstream and downstream nodes of the link. The HGL for a full link goes from the pipe crown elevation up to the rim elevation of the node + the surcharge depth of the node.  The four terms are:

dq2 = Time Step * Awtd * (Head Downstream – Head Upstream) / Link Length or

dq2 = Time Step * Awtd * (HGL) / Link Length

Qnew = (Qold – dq2 + dq3 + dq4) / ( 1 + dq1)

when the force main is full dq3 and dq4 are zero and

Qnew = (Qold – dq2) / ( 1 + dq1)

The dq4 term in dynamic.c uses the area upstream (a1) and area downstream (a2), the midpoint velocity, the sigma factor (a function of the link Froude number), the link length and the time step or

dq4 = Time Step * Velocity * Velocity * (a2 – a1) / Link Length * Sigma

the dq3 term in dynamic.c uses the current midpoint area (a function of the midpoint depth), the sigma factor and the midpoint velocity

dq3 = 2 * Velocity * ( Amid(current iteration) – Amid (last time step) * Sigma

dq1 = Time Step * RoughFactor / Rwtd^1.333 * |Velocity|

The weighted area (Awtd) is used in the dq2 term of the St. Venant equation:

dq2 = Time Step * Awtd * (Head Downstream – Head Upstream) / Link Length

The four terms change at each iteration and time step to determine the new flow (Figure 1) based on the two equations:

Denom = 1 + dq1 + dq5

Q = [Qold – dq2 + dq3 + dq4] / Denom

If you look at a table of the values you will see that the terms add up to zero when the flow is constant and to delta Q or the change in Q when the flow is NOT constant (Figure 2).

Figure 1.  The four terms define the new flow at each iteration in the dynamic wave solution of SWMM5

  

Figure 2.   The magnitude of the four terms determine the flow at the new iteration and ultimately the new Time Step.  If the flow is constant then the value of the term is constant.

InfoSWMM and H2oMAP SWMM Map Display of d/D

Note:  You can use the Output Statistics Manager in InfoSWMM and H2OMAP SWMM to compute the peak d/D for ALL of the links in your network. Once you have calculated the peak d/D using the tool you can copy them using the command Ctrl-C and paste them to a new field in the Conduit Information DB Table.  The pasted mean flow from the Conduit Information table then can be mapped using Map Display.

Step 1:  Use Run Manager and Run the Simulation

 

Step 2:  Use the Output Report Manager and view the Conduit Summary Table

Step 3:  Select the links you want to analyze using the pick tool.

Step 4:  Copy the Peak d/D values using the command Copy after a Right Mouse Click.

Step 5:  Paste the Peak d/D values using the command Paste after a Right Mouse Click in the created DOVERD Field in the Conduit Information DB Table.

Step 6:  Map the Conduit.DOVERD variable from the Conduit Information DB Table.

Step 7:  Now Display the Peak d/D for each link.

Pump / Force Main System in InfoSWMM and SWMM 5 - with Emojis

Subject: 🚀 Pump / Force Main System in InfoSWMM and SWMM 5

Introduction: 💡 The Pump/Force Main system in InfoSWMM and SWMM 5 is a critical component for effective wastewater management. It ensures that wastewater flows smoothly from its source to the desired destination. Let's explore its components and the steps to set it up!

📌 The Basic System:

• Wet Well with its parameters 🕳️
• Pump Type 🔄
• Defined Pump Curve 📈
• Downstream Pressure Node 📍
• Downstream Force Main 🛤️

Figure 1:  The Basic System

Step 1: Wet Well Data 📋

• Input the invert elevation and maximum depth of the Wet Well.
• Define the shape, considering evaporation or infiltration factors.

Step 2: Define the Pump Type 🔄

• The pump's operation is guided by its Pump Curve and the set On and Off elevations.
• The four primary pump types include:
  • Volume - Flow 🌊
  • Depth – Flow 📏
  • Head – Flow 📌
  • Depth - Flow 📊

Step 3: Define the Pump Curve 📈

• Under the Operation Tab, outline the desired pump curve to ensure efficient pump functioning.

Step 3:  Define the Pump Curve in the Operation Tab 

Step 4: Set a Surcharge or Pressure Depth 🌡️

• By setting a positive Surcharge Depth at the Downstream node, you ensure that during the simulation, the node remains pressurized, driving the flow through the Force Main.

• This plot offers a visual representation of the hydraulic gradient line (HGL) for the Force Main System, showcasing the pressure changes within the system.

• Define the downstream conduits emerging from the pump as Force Mains.
• Choose either the Hazen Williams or Darcy-Weisbach coefficient based on your requirements. (This is typically set in SWMM 5 options or InfoSWMM's Run Manager.)

Step 5: Force Main Data 🛤️

Step 6: HGL Plot of the Force Main System 📊

  

Step 7: Pump Summary 📑

• Refer to the RPT File to get a comprehensive summary of the pump's performance and other related parameters.

Conclusion: 🌟 Setting up the Pump/Force Main system in InfoSWMM and SWMM 5 is a meticulous process but ensures efficient and effective wastewater management. Following these steps will ensure a robust system in place! 🚀🌊🛠️

Water Quality Processes in a Subcatchment and Node/Link System of SWMM 5

Subject:  Water Quality Processes in a Subcatchment and Node/Link System of SWMM 5

Manhole Elevations in InfoSWMM and SWMM 5

Subject: Manhole Elevations in InfoSWMM and SWMM 5

Starting from the bottom of the manhole you have these regions of computational interest:

1.   Manhole Invert to the lowest link invert – the node continuity equation is used with the area of the manhole being the default surface area of a manhole,

2.   Lowest Link Invert to the Highest Link Crown Elevation – the node continuity equation is used with surface of the node being normally half of the surface area of the incoming and outgoing links,

3.   Highest Manhole Pipe Crown Elevation to Manhole Rim Elevation – the node surcharge algorithm in which the surface area of the manhole is not used and the surcharge depth is iterated until the inflow and the outflows of the node are in balance,

4.   The region above the Manhole Rim Elevation which can use one of four options to calculate the depth and/or flow out of or into the manhole:

1.   No Surcharge Depth is entered and No Ponding area is used – the excess water into the manhole is lost to the network and shows up as internal outflow in the continuity tables,

2.   A Ponding Area is used and the excess flow will  pond on the surface of the manhole and later go back down into the conveyance pipes.

3.   A Surcharge Depth is used and the depth will continue to be calculated using the node surcharge algorithm in which the surface area of the manhole is not used and the surcharge depth is iterated until the inflow and the outflows of the node are in balance,

4.   A Dual Drainage system is simulated and the excess flow of the manhole is simulated in the street gutters or the actual street,

5.   You use a 1D/2D linkage between the 1D manhole and 1D links to a 2D Mesh and simulate the flow out and the flow into the manhole using a bottom outlet orifice that switches automatically between weir and orifice flow based on the depth on top of the manhole.