Historical SWMM 5 and SWMM 4 Engines and Examples

Subject:  Historical SWMM 5 and SWMM 4 Engines and Examples

The web site has http://swmm5legacycode.ning.com/  historical SWMM 5 installs, SWMM 5 input file examples and SWMM 4 input files and engines.   The SWMM 4 engines go back to SWMM 3.5 engines from the 1980’s.

Link Iterations in the SWMM 5 Dynamic Wave Solution

Subject:   Link Iterations in the SWMM 5 Dynamic Wave Solution

Link Iterations in the SWMM 5 Dynamic Wave Solution by dickinsonre Subject:   Link Iterations in the SWMM 5 Dynamic Wave Solution Each of the links in the SWMM 5 network can use up to 8 iterations to reach convergence during a time step in the dynamic wave solution of SWMM 5.  The rules governing the number of iterations are: 1.       A minimum of 2 iterations per time step with the 1st iteration NOT using the underrelaxtion parameter of 0.5 (Figure 1) 2.       If both the downstream and upstream nodes are converged then the link drops out of the iteration process during the time step (Figure 2) 3.       The number of iterations for each link can vary over the simulation from 2 to 8 depending on how fast the flow is changing. Figure 1.  A minimum of two and up to eight iterations per time step in the SWMM 5 dynamic wave solution. Figure 2.  The number of iterations for each link vary through out  the simulation with less iterations being used for constant flows. via Blogger http://www.swmm5.net/2013/08/link-iterations-in-swmm-5-dynamic-wave.html

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?

How is the St Venant Equation Solved for in the Dynamic Wave Solution of SWMM 5? by dickinsonre 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. via Blogger http://www.swmm5.net/2013/08/how-is-st-venant-equation-solved-for-in.htm

SWMM 5 Precipitation Options

Subject:  SWMM 5 Precipitation Options

SWMM 5 Precipitation Options by dickinsonre Subject:  SWMM 5 Precipitation Options You can have design storms, monitored storms of any length of the time from minutes to centuries, use intensity, volume or cumulative precipitation, use both rainfall and snowfall in the same rain gage depending on temperature, use both time series or external files for the rain gage and have unlimited rain gages with the limitation of one rain gage per subcatchment . via Blogger http://www.swmm5.net/2013/08/swmm-5-precipitation-options.html

SWMM 5 Leaping Weir Example

Subject:  SWMM 5 Leaping Weir Example

SWMM 5 Leaping Weir Example by dickinsonre Subject:  SWMM 5 Leaping Weir Example The attached example shows one way how SWMM 5 RTC Rules can be used to have the low flow go down a leaping weir orifice and the high flow go over the weir to the downstream section of the sewer.  via Blogger http://www.swmm5.net/2013/08/swmm-5-leaping-weir-example.html

Force Main Friction Loss in InfoSWMM and the Transition from Partial to Full Flow

Force Main Friction Loss in InfoSWMM and the Transition from Partial to Full Flow by dickinsonre Subject:  Force Main Friction Loss in InfoSWMM and the Transition from Partial to Full Flow You can model Force Main friction loss in InfoSWMM using either Darcy Weisbach or Hazen Williams as the full pipe friction loss method (see Figure 1 for the internal definition of full flow).   A function called ForceMain in InfoSWMM whose purpose is to compute the Darcy-Weisbach friction factor for a force main using the Swamee and Jain approximation to the Colebrook-White equation .  No matter which method you use for full flow the  program will use Manning's equation to calculate the loss in the link when the link is not full (see Figure 2 for the equations used for calculating the friction loss – variable dq1 in the St Venant equation for InfoSWMM).   The regions for the different friction loss equations are shown in Figure 3.      There is no slot in InfoSWMM for the full pipe flow as a surcharged node in InfoSWMM uses this point iteration equation (Figure 4):  dY/dt = dQ / The sum of the Connecting Link values of  dQ/dH  where Y is the depth in the node, dt is the time step, H is the head across the link (downstream – upstream), dQ is the net inflow into the node and dQ/dH is the derivative with respect to H of the link  St Venant equation.  If you are trying to calibrate the surcharged node depth, the main calibration variables are the time step and the link  roughness:  1.   Mannings's N 2.   Hazen-Williams or 3.   Darcy-Weisbach  The link roughness is part of the term dq1 in the St Venant solution and the other loss terms are included in the term dq5.  You can adjust the roughness of the surcharged link  to affect the node surcharge depth.   The point iteration continues until the sum of the flow in the node is zero – basically the new depth in the node either increases or decreases the friction loss in the force main so that net flow at the node is zero.  This is why it is important to use the right time step to ensure that the net flow is zero when the pumps turn on and off.   Figure 1.  How the full pipe condition is defined in InfoSWMM - both ends have to be full Figure 2:  Friction equations used in SWMM 5 for a Force Main.  Figure 3:  Regions of Friction loss equations in SWMM 5. Figure 4.  The Node Surcharge Equation is a function of the net inflow and the sum of the term dQ/dH in all connecting links. Generally, as you increase the roughness the value of dQ/dH increases and the denominator of the term dY/dt = dQ/dQdH increases.  via Blogger http://www.swmm5.net/2013/08/force-main-friction-loss-in-infoswmm.html

Dry lands getting drier, wet getting wetter: Earths water cycle intensifying with atmospheric warming

http://www.sciencedaily.com/releases/2012/05/120521104631.htm

May 21, 2012

ScienceDaily (May 21, 2012) — A clear change in salinity has been detected in the world's oceans, signalling shifts and an acceleration in the global rainfall and evaporation cycle.
In a paper just published in the journal Science, Australian scientists from the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and the Lawrence Livermore National Laboratory, California, reported changing patterns of salinity in the global ocean during the past 50 years, marking a clear fingerprint of climate change.
Lead author, Dr Paul Durack, said that by looking at observed ocean salinity changes and the relationship between salinity, rainfall and evaporation in climate models, they determined the water cycle has strengthened by four per cent from 1950-2000. This is twice the response projected by current generation global climate models.
"Salinity shifts in the ocean confirm climate and the global water cycle have changed.

"These changes suggest that arid regions have become drier and high rainfall regions have become wetter in response to observed global warming," said Dr Durack, a post-doctoral fellow at the Lawrence Livermore National Laboratory.

With a projected temperature rise of 3ºC by the end of the century, the researchers estimate a 24 per cent acceleration of the water cycle is possible.

Scientists have struggled to determine coherent estimates of water cycle changes from land-based data because surface observations of rainfall and evaporation are sparse. However, according to the team, global oceans provide a much clearer picture.
"The ocean matters to climate -- it stores 97 per cent of the world's water; receives 80 per cent of the all surface rainfall and; it has absorbed 90 per cent of the Earth's energy increase associated with past atmospheric warming," said co-author, Dr Richard Matear of CSIRO's Wealth from Oceans Flagship.

"Warming of the Earth's surface and lower atmosphere is expected to strengthen the water cycle largely driven by the ability of warmer air to hold and redistribute more moisture."

He said the intensification is an enhancement in the patterns of exchange between evaporation and rainfall and with oceans accounting for 71 percent of the global surface area the change is clearly represented in ocean surface salinity patterns.

In the study, the scientists combined 50-year observed global surface salinity changes with changes from global climate models and found "robust evidence of an intensified global water cycle at a rate of about eight per cent per degree of surface warming," Dr Durack said.

Dr Durack said the patterns are not uniform, with regional variations agreeing with the 'rich get richer' mechanism, where wet regions get wetter and dry regions drier.

He said a change in freshwater availability in response to climate change poses a more significant risk to human societies and ecosystems than warming alone.

"Changes to the global water cycle and the corresponding redistribution of rainfall will affect food availability, stability, access and utilization," Dr Durack said.

Dr Susan Wijffels, co-Chair of the global Argo project and a co-author on the study, said maintenance of the present fleet of around 3,500 profilers is critical to observing continuing changes to salinity in the upper oceans.

The work was funded through the Australian Climate Change Science Program, a joint initiative of the Department of Climate Change and Energy Efficiency, the Bureau of Meteorology and CSIRO.

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The above story is reprinted from materials provided by CSIRO Australia.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:

1. P. J. Durack, S. E. Wijffels, R. J. Matear. Ocean Salinities Reveal Strong Global Water Cycle Intensification During 1950 to 2000. Science, 2012; 336 (6080): 455 DOI: 10.1126/science.1212222

Saving an Output Relate in InfoSWMM directly to Excel using Arc Tool Box

Subject:  Saving an Output Relate in InfoSWMM directly to Excel using Arc Tool Box

Saving an Output Relate in InfoSWMM directly to Excel using Arc Tool Box by dickinsonre Subject:  Saving an Output Relate in InfoSWMM directly to Excel using Arc Tool Box The following shows how to make an Excel file directly from a feature table in InfoSWMM Step 1.  Download the Arc Tool box add on Table to Excel You can download the python script from here   http://resources.arcgis.com/gallery/file/geoprocessing/details?entryID=95009B25-1422-2418-7FB5-B8638ECB2FA9 Step 2.    Add the Tool to Arc Toolbox and then use the tool to create an Excel CSV File Step 3.  You can export any of the features in InfoSWMM to CSV    via Blogger http://www.swmm5.net/2013/08/saving-output-relate-in-infoswmm.html

Example DUPUIT-FORCHHEIMER APPROXIMATION FOR SUBSURFACE FLOW Model in SWMM 5

Subject:   Example  DUPUIT-FORCHHEIMER APPROXIMATION FOR SUBSURFACE FLOW Model in SWMM 5

Example DUPUIT-FORCHHEIMER APPROXIMATION FOR SUBSURFACE FLOW Model in SWMM 5 by dickinsonre Subject:   Example  DUPUIT-FORCHHEIMER APPROXIMATION FOR SUBSURFACE FLOW Model in SWMM 5  This example was created from an older SWMM 4 model from 1988 using the SWMM 4 to SWMM 5 converter.  The values for the coefficients in this case are A1 = A3 = 4*K/L^2, A2 = 0, B1 or the exponent or B1=2 or from Appendix X in the SWMM 4 manual from OSU (http://eng.odu.edu/cee/resources/model/mbin/swmm/swmm_6.pdf)   via Blogger http://www.swmm5.net/2013/08/example-dupuit-forchheimer.html

Example Groundwater Model in SWMM 5

Subject:   Example Groundwater Model in SWMM 5

Example Groundwater Model in SWMM 5 by dickinsonre Subject:   Example Groundwater Model in SWMM 5  The attached model shows three ways in which the groundwater model of the SWMM 5 subcatchments interact with the node depths of the hydraulic network.  The hydraulic network interaction can be either:  1.       At a fixed water surface elevation, 2.       At a time varying water surface elevation based on the inflow and geometry of the node and 3.       At a threshold node water surface elevation.  via Blogger http://www.swmm5.net/2013/08/example-groundwater-model-in-swmm-5.html

Example SWMM 5 Snowmelt Model

Subject: Example SWMM 5 Snowmelt Model

Example SWMM 5 Snowmelt Model by dickinsonre Subject: Example SWMM 5 Snowmelt Model  Attached is a simple sample snowmelt model in SWMM 5 that has built in snowfall and temperature in a one subcatcment model with snowmelt.   You define the separation of precipitation into snowfall and rainfall by setting a base temperature in the Snow Pack Editor.   The precipitation that falls with when the air temperature is below the base temperature is stored in a snow pack where it eventually will melt when the temperature rises or is moved via plowing.  You can have an initial snow cover, final snow cover and runoff from the melting snow long after the snowfall occurs. via Blogger http://www.swmm5.net/2013/08/example-swmm-5-snowmelt-model.html

Runoff Routing Options Example in SWMM 5

Subject:   Runoff Routing Options Example in SWMM 5

Runoff Routing Options Example in SWMM 5 by dickinsonre Subject:   Runoff Routing Options Example in SWMM 5 There are six options for runoff routing in SWMM 5:  ·         All Runoff to an Outlet Node ·         All Runoff to another Subcatchment ·         All Runoff to the Pervious Area of the Subcatchment or other Subcatchment ·         All Runoff to the Impervious Area of the Subcatchment or other Subcatchment ·         Partial Runoff to the Pervious Area of the Subcatchment or other Subcatchment ·         Partial Runoff to the Impervious Area of the Subcatchment or other Subcatchment  The attached example SWMM 5.0.022 file has three catchments in a chain, the 1stSubcatchment Routes to the Pervious area of the 2nd Subcatchment and the 2ndSubcatchment routes the runoff to the Impervious area of the 3rd Subcatchment which routes all runoff to an outlet node.  via Blogger http://www.swmm5.net/2013/08/runoff-routing-options-example-in-swmm-5.html

Example FM SWMM 5 model with and without Surcharge Depth

Subject:   Example FM SWMM 5 model with and without Surcharge Depth

Example FM SWMM 5 model with and without Surcharge Depth by dickinsonre Subject:   Example FM SWMM 5 model with and without Surcharge Depth  You need to use the surcharge depth for a Force Main in SWMM 5 to allow the engine to find the right point on the pump curve and pump up the rising main.  If you do not use a surcharge depth then the flow MAY be very small in the rising main due to a small head difference.  Of course the flow in the force main depends on the pump curve you have entered but having the right downstream head of depth for the link matter as well.  The attached model was created in SWMM 5.0.022   via Blogger http://www.swmm5.net/2013/08/example-fm-swmm-5-model-with-and.html

How to Edit the Subcatchment Polygons in InfoSWMM with Arc Map

Subject:  How to Edit the Subcatchment Polygons in InfoSWMM with Arc Map

How to Edit the Subcatchment Polygons in InfoSWMM with Arc Map by dickinsonre Subject:  How to Edit the Subcatchment Polygons in InfoSWMM with Arc Map You can edit the polygon boundaries of the Subcatchments in Arc GIS by using the Editor command and either editing the vertices or by using the Reshape Feature Tool to adjust the boundaries or snap to the polygon lines or vertex points.    You should start the editing session by right mouse clickining on the Subcatchment Feature layer Vertex Editing and Reshape Feature Tool   via Blogger http://www.swmm5.net/2013/08/how-to-edit-subcatchment-polygons-in.html dickinsonre | August 4, 2013 at 11:43 pm | Tags: Blogger, H2oMAP SWMM, IFTTT, InfoSWMM,swmm5 | Categories: H2OMAP SWMM, InfoSWMM, swmm5 | URL: http://wp.me/pnGa9-2Do Comment    See all comments    Like