Modeling RTK Inflows with the Implicit or SWMM solver

  Applies To 
  Product(s):  SewerGEMS, CivilStorm
  Version(s): CONNECT Edition, V8i
  Area:  Layout and Data Input
  Original Author: Mark Pachlhofer, Bentley Technical Support Group

Problem

How do you enter the RTK information into a SewerGEMS or CivilStorm model for either the SWMM or the Implicit solver?

Solution

RTK information is loaded differently depending on whether you are using the SWMM numerical solver or the Implicit numerical solver.

With the Explicit (SWMM) solver, RTK inflows are loaded at manholes and SWMM RTK sets are used to configure RTK parameters.

With the Implicit solver, RTK inflows are loaded at catchment elements and separate Implicit RTK sets are used.

SWMM (Explicit) Solver

Here are the steps to use RTK loads with the SWMM solver:

1) Go to Components > Runoff > SWMM RTK Unit Hydrographs

2) Create a new entry (see red box in the screen shot below) by clicking the new icon and then enter your RTK data in the table (see blue box in the screen shot below)

3) Open the properties of your manholes by double clicking on them and set the property for "Apply SWMM RTK Unit Hydrograph Set?" to "True".  

4) Enter the Sewershed Area value, which is the area of the sewershed that contributes rainfall dependent infiltration to the node.

5) Choose the SWMM RTK Unit hydrograph set that you created in step 2.

Implicit Solver

Here are the steps to use RTK loads with the Implicit solver:

1) Go to Components > Runoff > RTK Tables

2) Create a new entry by clicking the new icon and then enter your RTK data in the table:

3) Open the properties of your catchments, set the "Runoff Method" to "Unit Hydrograph", select "RTK Unit Hydrograph" from the "Unit Hydrograph" dropdown, then select your RTK set. Global edit in the catchment flextable if you need to change multiple catchments. Use a new Hydrology alternative if you want to keep this configuration separate from other scenarios.

4) Enter the Sewershed Area value in the catchment area field. This is the area of the sewershed that contributes rainfall dependent infiltration.

5) For the "Outflow element" catchment property, select the node which will receive the I&I inflow from the RTK catchment (manhole, catchbasin or cross section, typically).

See Also

Tips on Sewer Calibration

Differences between solvers: GVF-Convex vs. GVF-Rational vs. Implicit vs. Explicit (SWMM)

RTK method catchment calculations take a long time to complete (slow performance)

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