### Calculate runoff depth of a subbasin

Hi all,

I am trying to calculate runoff depth for a subbasin from the subbasin peak flow ( collected from SWMM model)by inverting the manning's equation ( as SWMM uses manning's equation for the calculation of peak flow) . In that case, what should be the slope value? For example if the slope of that subbasin is 5%, should I give 5 in the manning's equation or 0.05? Thanks.

### SWMM 5 Water Quality Example Files

SWMM 5 Water Quality Example Files

File Name Description
RUNOFF3_SW5.INP STEVEN''S AVENUE DRAINAGE DISTRICT LANCASTER PA
RUNOFF20_SW5.INP Runoff Example # 20 - PCSWMM 3.2 EXERCISE 5
RUNOFF21_SW5.INP SUSPENDED SOLIDS AND BOD POLLUTOGRAPH SIMULATION
RUNOFF22_SW5.INP RUNOFF EXAMPLE # 22 - SIMULATION OF EROSION
RUNOFF23_SW5.INP A wide parabolic channel between 301 and 401
RUNOFF31_SW5.INP PCSWMM 3.2 EXERCISE 5 - Runoff example 31
RUNOFF41_SW5.INP Runoff example 41 - Input of constant groundwater quality
RUNOFF42_SW5.INP Precipitation quality only
RUNOFF43_SW5.INP BROWARD COUNTY Multi FAMILY SITE - Runoff example # 43
RUNOFF44_SW5.INP HDR STORM USGS STORM # 3 May 5 1977
RUNOFF45_SW5.INP BROWARD COUNTY Multi FAMILY SITE
RUNOFF46_SW5.INP BROWARD COUNTY Multi FAMILY SITE
RUNOFF47_SW5.INP BROWARD COUNTY Multi FAMILY SITE - Runoff example # 47

### Modeling "Leaf" Gates

I am trying to determine the best way to represent "leaf" gates in SWMM5.  The gate consists of two panels that overlap each other.  The top gate serves as an overflow weir and drops as the upstream water level rises.  If the top gate is fully lowered and the upstream water level is still rising, then both gates would be lifted up to create an underflow outlet.  This would then eliminate the overflow aspect.

My thought is to model two separate gates.  The overflow gate would need some kind of timeseries to control (lower) the crest elevation of the overflow gates until the upstream water surface elevation exceeds level X.  At that time, the overflow gate would close and flow goes to zero.

A separate underflow gate would open to full capacity if the upstream water surface elevation exceeds level X.

I welcome your suggestions on how best to tackle this issue.  Thanks.

### DS Bisht

Sem1.zip

Hello Bob,

Please have a look on my model. I could not find the option to attach the zip file there.

### Diversion Sturctures and SSO events in SWMM 5

I'm a new user to SWMM and i'm currently trying to model SSO events at a waste water treatment plant. I've been using dynamic routing and I've been having trouble modeling the diversion structure. Currently I have a storage node acting as a wet well that feeds a type 3 pump. The pump is connected to an orifice which regulates the the pump to 4.0 MGD (anything over that would risk washing out the plant). Also coming out of the wet well i have a weir that is offset from the invert elevation of the storage tank. After some adjusting of that elevation I am able to match the volume of diverted flow for specific events. The problem comes in that very small adjustments of that height (as little as 0.5%) has a major impact of the simulated volume (around 50%) which makes the model impossible to calibrate and useless for a design event. Does anyone have any suggestions on how better model the diversion structure? Any help would be appreciated.

### Innovyze Launches Educational Product Webinar Series

 Innovyze Launches Educational Product Webinar Series

### Running SWMM5 Using .bat files

Hi Robert,

I have a folder with many inp files representing different urbanization scenarios for a watershed in VA. I would like to automate the processing of this files because it is something I'll most probably will have to do again. From my research it looks like something that can be done through .bat files but I have no idea how it would work. maybe there is a reference you can share or you have addressed this issue in previous blogs.

Thank you for all your help!

SDH

### Large data output extraction in SWMM

Hi,

I have developed a model with 33 subcatchments using 1 year hourly  rainfall data. The problem is when I try to get the runoff for all the subcatchments it says '' too many objects to display".

It would be really helpful If you could tell me how can I get the runoff from all the 33 subcatchments together?

Thanks.

### hi, i have every 1h of total 12h rainfall time series data and run for 12h . so i got total precipitation in status report is 108 mm but when i sum up total time series is 112mm which is grater then r

hi,

i have every 1h of total 12h rainfall time series data and run for 12h . so i got total precipitation in status report is 108 mm but when i sum up total time series is 112mm which is grater then report.

moreover when i use design strom for every 10 minute of 2h this value is shown 11.38mm but the sum up of time series data is 86mm.

i am really confuse, please any one help me for how to calculate total precipitation in status report.

### thanks bob for your reply, can you tell me another issues like total precipitation in status report how it is calculated? i am using time series rainfall for 10 minute interval as intensity. total pre

thanks bob for your reply, can you tell me another issues like total precipitation in status report how it is calculated? i am using time series rainfall for 10 minute interval as intensity. total precipitation value and depth in status are not clear to me.

### flood Volume in canal system

hi, how to calculate the volume spilled from
the Khals in SWMM 5.0?
can anyone help on this issue?
In Status report of SWMM, final storage volume is shown after simulation. is this value  my required value? please help on this issues.

# SWMM 1.2.3.4.5+ History

### How to subtract upstream flow to get NET catchment inflow for SWMM

Dear All,

I am trying to update an I&I report done by a consultancy using SWMM5 modelling.

The sewer flow gauged seems to be difficult to be used in SWMM model, because we only gauge flow data including upstream flows. In SWMM, we could only assign junctions with net ADWF for any subcatchments,  I was trying to lag upstream and downstream flows and get net inflow from subtraction of two series of data. However, there is no proper lag time as sewer travel time changes with flow and my flow data for downstream have so many minus value.

### Groundwater Calculations in SWMM

Hello Robert !

I am trying to incorporate groundwater in my model. Right now it is showing high negative groundwater error. Is the groundwater error calculated same as the continuity error ?

The Percent Error = 100.0 * (1.0 - totalOutflow / totalInflow)

What are the components and corresponding equations for inflow and outflow for groundwater ?I think the outflow is calculated as

QGW = A1(HGW - H*)B1 - A2(HSW - H*)B2 + A3(HGW HSW)

But how is the inflow calculated ? There are quite a few parameters used in aquifer data editor and groundwater data editor ( i.e. Conductivity slope, tension slope etc) I want to learn them in details. Can you suggest me any documentation for them?

I am following some of the regional modeling attempts for parameters who used XP-SWMM. And they used a lot of parameters like

' Fraction of evapo-transpiration assigned to upper zone, Maximum depth of significant
lower zone storage, Curve fitting parameter, Initial upper zone moisture , Coefficient for unquantified losses
Average slope of the tension versus soil moisture curve. '

It would be very helpful if I could  use this data in my SWMM model. Are they  denoted differently in SWMM? Please help.

bests,

Shams

### Time series Stage input

Hello,

There is an option of using time series data for outfall stage. Should I include elevation of water or depth of water in this case.

For example,

invert EI =-5 ft

Outlet offset= 0

depth of conduit = 12 ft

depth of water ( stage)  =7 ft

Now, should I  input  stage at outlet = 7ft

or I should input with reference to Invert EI= 7-5= 2ft

I have the same confusion for initial depth of water in junctions. Is it just depth (7ft) or the elevation (2ft)

Thanking you  in anticipation.

bests,

Shams

### MODELING MULTIPLE CONTROL GATE IN A TRANSECT

I am modeling a natural channel with gated spillway. There are two gates as shown in the following figure.

I want to use two different time series for the two gates. How do I model the two gates in SWMM and use time series control rules simultaneously? If I use two different orifice for two gates then wont they superpose on one another? I want to model them to act parallel as shown in the figure and add two different time series for the two gates.

Kindest regards,

Shams

### REPRESENTING THE HEAD LOSS DUE TO FRICTION AND CHANGE IN CONVEYANCE IN ADVERSE SLOPE

HELLO!!

I am trying to model the interaction between stormwater and surface water using SWMM. Flow in the canal I am dealing with is maintained by gated spillways. The canal has very irregular and even  adverse slope i.e. slope against the direction of the flow as shown in the following figure.

If I provide the SWMM model with this exact canal profile against the direction of flow, will it be able to reflect the head loss due to friction and change in conveyance due to adverse slope? ( I am providing the gated spillway upstream to input the necessary head)

What alternative can I use to represent the effect of this adverse slope in a simplified way?

This is stressing the scope of SWMM I understand, but if I can do this,  this will be something very interesting .

I appreciate your help as always. Thanking you in anticipation.

regards,

Shams

### MODELING CONTROL GATE IN A TRANSECT

Hello!

I am modelling a natural channel with a gated spillway. I am using the rectangular orifice option to install the gate .

In SWMM, orifice is added as a link between two nodes and according to the manual "located either at the bottom or along the side of the upstream node."

My question is does SWMM use the geometry ( depth + width) of the orifice to consider it as an usual  conduit for the flow from upstream node to downstram node as it is connected between two junctions  just like the conduis?

or Its just a gate acting at the upstream node though added as a link?

Thanking you in anticipation.

Shams

### Transect data processing in SWMM

Hello,

My model includes a canal and I am using a transect to represent the canal. One of the typical sections is shown in the  figure. I uses the actual elevation data for the transect cross section and hence some coordinate values are negative.

1. The profile view does not show the negative portion. Is there any way I can see the full depth profile view? will there be any problem in SWMM internal calculation if I use negative value ( as shown in the figure).

2. From the transect sections, does SWMM automatically calculate the slope ( using the lowest coordinates) or it uses the section only to calculate area and wetted perimeter. I am asking this because if it considers lowest coordinates than there will be problem from double counting if I input slope through offsets.

3. I will use stage data at outfall. what is the datum SWMM considers for stage data depths given?

Thank you in anticipation.

Regards

Shams

### Modeling bridge with obstruction.

I am modeling a natural channel which has a bridge with two piers in it obstructing the flow. The upstream section  is shown in the image below.

Since I have the coordinates I can add the cross section as a transect in SWMM as I have tried below

I have also added the appropriate conduit code.

1. Will this work?

2. What alternative do I have?

As an alternative I am adding this three sections as three separate links. ( repost from the comment as the images in comment are not clear enough). Please let me know if this is what you suggested.

Kindest regards,

Shams