How is the Volume Calculated in the SWMM 5 Groundwater Component?

Subject:   How is the Volume Calculated in the SWMM 5 Groundwater Component?

How is the Volume Calculated in the SWMM 5 Groundwater Component? by dickinsonre Subject:   How is the Volume Calculated in the SWMM 5 Groundwater Component?  The groundwater component of SWMM 5 is found in the gwater.c code.  It (as is all of SWMM 5) is excellently written in small functions by Lew Rossman of the EPA during the SWMM 5 development process.  However, code being code sometimes it is easier to see how the code is functioning.  This blog or note tries to show that function.   The groundwater component consists of groundwater data (gw in the equation) and aquifer data (a) in the equation.  The equation for the groundwater volume is shown in Figure 1.   The volume is the water content (theta) times the upper depth and the porosity of the aquifer times the lower depth (Figure 2).  Figure 1.  Groundwater Volume Calculations    Figure 2.  Lower and Upper Depth of the Groundwater Compartrment   via Blogger http://www.swmm5.net/2013/08/how-is-volume-calculated-in-swmm-5.html

Aquifer and Groundwater Objects in SWMM 5

Subject:   Aquifer and Groundwater Objects in SWMM 5

Aquifer and Groundwater Objects in SWMM 5 by dickinsonre Subject:   Aquifer and Groundwater Objects in SWMM 5  There are two types of data objects in SWMM 5 to describe the Groundwater flow component.  There is a Groundwater data object associated with a Subcatchment that describes flow equations, the interaction between the Subcatchment infiltration and the Groundwater component and an Aquifer data object that describes the characteristics of the Aquifer that may span one or more Subcatchments.  The Groundwater data is specific to one Subcatchment but the Aquifer may    via Blogger http://www.swmm5.net/2013/08/aquifer-and-groundwater-objects-in-swmm.html

Hierarchy of Your Network in InfoSWMM and H2OMAP SWMM

Subject: Hierarchy of Your Network in InfoSWMM and H2OMAP SWMM

Hierarchy of Your Network in InfoSWMM and H2OMAP SWMM by dickinsonre Subject:  Hierarchy of Your Network in InfoSWMM and H2OMAP SWMM In both InfoSWMM and H2OMAP SWMM you can run a subset of the network by using the Facility Manager to make part of thenetwork inactive and not solved.  You can make the output files smaller if you are performing a continuous simulation and save only the results of All, the Domain Only or a Selection Set to the graphical output file (Figure 1).   Figure 2 shows a few ways to query, view, graph and perform statistics for the model run.  Figure 1.  Options for saving the Active Network Data to the Graphical Output Data Set. Figure 2.  Output View, Query and Graphical Options.c. via Blogger http://www.swmm5.net/2013/08/hierarchy-of-your-network-in-infoswmm.htm

al Options.

Import of Sections from SWMM 5 into InfoSWMM and H2oMAP SWMM

Subject:   Import of Sections from SWMM 5 into InfoSWMM and H2oMAP SWMM

Import of Sections from SWMM 5 into InfoSWMM and H2oMAP SWMM by dickinsonre Subject:   Import of Sections from SWMM 5 into InfoSWMM and H2oMAP SWMM A very useful hidden feature of the import SWMM 5 to InfoSWMM and H2OMAP SWMM is the ability to import all of the data or just one section.  For example, you can import the LID data, DWF patterns, control rules, pollutants, transects and other data that is transferable between different networks.   via Blogger http://www.swmm5.net/2013/08/import-of-sections-from-swmm-5-into.html

History of SWMM to the Year 2005

Subject:   History of SWMM to the Year 2005

History of SWMM to the Year 2005 by dickinsonre Subject:   History of SWMM to the Year 2005  Note on the symbols:  The Gator is the University of Florida and the Beaver is Oregon State University.  The connection is they are both associated with water and Dr Wayne Huber.    via Blogger http://www.swmm5.net/2013/08/history-of-swmm-to-year-2005.html

SWMM 5 Loss Term Values for various velocities and K values

Subject:   SWMM 5 Loss Term Values for various velocities and K values

SWMM 5 has three loss terms available for each link:  Entrance, Exit and Other losses.  The Entrance loss uses the upstream link velocity, the  Other loss uses the center link velocity and the Exit loss uses the downstream link velocity.  The general form of the loss term in the St. Venant equation is K*V^2/2g Table 1 shows the loss in feet of head for various combinations of velocity and K value.  If you want to  simulate a little loss of head at each node then a small value of K should be used otherwise the cumulative loss in the whole networks will be many feet of head.

  Loss Term units equals K * V^2/2g = ft/sec * ft/sec * sec^2/ft = ft

Table 1:  Loss in feet of head for various combinations of velocity and K values.

Velocity (ft/sec)	K	K	K	K	K	K
	0.050	0.100	0.250	0.500	0.750	1.000
1	0.001	0.002	0.004	0.008	0.012	0.016
2	0.003	0.006	0.016	0.031	0.047	0.062
3	0.007	0.014	0.035	0.070	0.105	0.140
4	0.012	0.025	0.062	0.124	0.186	0.248
5	0.019	0.039	0.097	0.194	0.291	0.388
6	0.028	0.056	0.140	0.280	0.419	0.559
7	0.038	0.076	0.190	0.380	0.571	0.761
8	0.050	0.099	0.248	0.497	0.745	0.994
8	0.050	0.099	0.248	0.497	0.745	0.994
9	0.063	0.126	0.314	0.629	0.943	1.258
10	0.078	0.155	0.388	0.776	1.165	1.553

SWMM 5 Inlet Control Culvert Equations

Subject:   SWMM 5 Inlet Control Culvert Equations

SWMM 5 Inlet Control Culvert Equations by dickinsonre Subject:   SWMM 5 Inlet Control Culvert Equations  The newer option for SWMM 5 culverts uses three culvert classifications and associated equations to compute the inletcontrolled flow into a culvert using the FHWA (1985) equations.  The culvert code in the culvert.c code of SWMM 5 uses:  1.   Two Equations for Unsubmerged culvert flow, 2.   One Equation for the Transition flow, and 3.   One Equation for Submerged flow. via Blogger http://www.swmm5.net/2013/08/swmm-5-inlet-control-culvert-equations.html

SWMM 5 Culvert Data from FHWA, HDS No. 5, Hydraulic Design of Highway Culverts, 1985

Subject:  SWMM 5 Culvert Data from FHWA, HDS No. 5, Hydraulic Design of Highway Culverts, 1985

SWMM 5 Culvert Data from FHWA, HDS No. 5, Hydraulic Design of Highway Culverts, 1985 by dickinsonre Subject:  SWMM 5 Culvert Data from FHWA, HDS No. 5, Hydraulic Design of Highway Culverts, 1985 If you use the culvert option in later versions of SWMM 5 then when the inlet control equation flow is less than the computed St Venant flow then the FHWA equations will be used for the current iteration in the SWMM 5 Dynamic Wave Solution. via Blogger http://www.swmm5.net/2013/08/swmm-5-culvert-data-from-fhwa-hds-no-5.html

Understanding Your Model Output in H2oMAP SWMM and InfoSWMM

Three Hidden Secrets to Speeding up your SWMM 5, H2OMAP SWMM or InfoSWMM Model

Three Hidden Secrets to Speeding up your SWMM 5, H2OMAP SWMM or InfoSWMM Model by dickinsonre    Minimum Time Step               Average Time Step        Maximum Time Step Minimum Time Step (sec)             0.984 Average Time Step (sec)              9.071 Maximum Time Step (sec)            30.000 Percent in Steady State (%)          0.000 Average Iterations per Time Step  4.821 Use a maximum time that will lower your average iterations per time step to speed up the simulation,decrease the maximum time step to lower the number of iterations, use equivalent conduit lengthening to increase the minimum time step, the model is fastest if the minimum and maximum time steps are not too small or large compared to the average time step.  Adjust the stopping tolerance and the number of iterations if you can to speed up your model You can also decrease the number of iterations or the stopping tolerance to speed up the model or improve the continuity error of themodel.   If you are doing a continuous simulation then you can have a reduced graphical output data set to speedup the simulation    If you have a duo or quad core computer another option to speed up the simulations is to use 1, 2, 3 or 4 cores for the simulation  via Blogger http://www.swmm5.net/2013/08/three-hidden-secrets-to-speeding-up.html

Elevation Interpolation from a Contour in H2OMAP SWMM

Subject:  Elevation Interpolation from a Contour in H2OMAP SWMM

Elevation Interpolation from a Contour in H2OMAP SWMM by dickinsonre Subject:  Elevation Interpolation from a Contour in H2OMAP SWMM The node invert elevation or the node maximum depth can be interpolated if you use the Elevation Interpolation Tool inH2OMAP SWMM. Steps Action 1.   Make a Contour Plot of the Node Invert Elevations. 2.   The Created Contours are now a layer inH2OMAP SWMM. 3.   Recreate the Invert Elevation from the Contourby using the Value Field and Interpolate Field. 4.   You can  also estimate the Maximum Depth of the Node from the Contour and the known Node Invert Elevation.  via Blogger http://www.swmm5.net/2013/08/elevation-interpolation-from-contour-in.html

How to see what you have in the various scenarios of InfoSWMM

Subject:  How to see what you have in the various scenarios of InfoSWMM

  

How to see what you have in the various scenarios of InfoSWMM by dickinsonre Subject:  How to see what you have in the various scenarios of InfoSWMM How to see what you have in the various scenarios – a tool I use a lot is Scenario Explorer which shows you how to see thevarious datasets associated with a data set along with the relationship between the Base and Various Child Scenarios.   via Blogger http://www.swmm5.net/2013/08/how-to-see-what-you-have-in-various.html

How to see the effect of the Pump Setting in the RTC Rules of InfoSWMM and H20MAP SWMM

Subject:  How to see the effect of the Pump Setting in the RTC Rules of InfoSWMM and H20MAP SWMM

Step 1.   Pump Startup and Shutoff Depth

Depths to turn the Pump On and turn the Pump Off.  In this example, the pump will be off when the Wet Well Depth is less than 2 feet, the Pump will be off between a Wet Well Depth between 2 and 5.75 feet if the Pump is currently Off and the Pump will be On between a Wet Well Depth between 5.75 and 2 feet.

Step 2.   RTC Rule for the Pump Setting when the Wet Well Depth is less than 6.25 feet.  We need to add the AND statement so that the setting is only reset when the Pump is On.   You do not want the pump setting to be reset when the pump should be off.

Result 1:  The Pump Speed Ratio tells you the Pump Setting

Result 2:  RTC Control Rules in the RPT File if you click on Show Control Actions

Result 3:   The depth at the Wet Well and the Flow in the Pump

 Result 4:  A mixed graph of the Wet Well Depth and Pump Flow shows the effect of the RTC.

Result 5:  The RTC Rule can also been seen flow to the Pump Curve.

Variable Time Step in SWMM 5

v  The goal of the link lengthening in SWMM 5 it to meet the CFL time step condition for the full link depth and full link velocity at the chosen lengthening time step.  If the link does not meet the CFL condition then this means the time step needed is smaller than your selected lengthening time step.  SWMM 5 will make an hydraulically equivalent longer link with a smaller roughness but the same full flow velocity as the shorter link.

v  If you are running a simulation in which all of the pipes are exactly full – no surcharge in any pipe – and the variable time step then there would be no need for SWMM 5 to use anything other than the minimum of the routing or lengthening time step.  However, since most real networks have a mixture of partial flow, surcharged flow and pressure flow, the actual time step depth, velocity/Froude Number is different than the assumed full depth and full flow velocity.  For example, the depth can be higher at one end of the pipe and the velocity higher than full flow velocity due to the water surface slope being higher than the bed slope.  The only way SWMM 5 can now satisfy the CFL time step condition since the modified length is fixed is to lower the variable time step.