SWMM-USERS Digest - 26 May 2008 to 27 May 2008 (#2008-97)
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Topics of the day:
1. Pipe Inlet Control (4)
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Date: Tue, 27 May 2008 08:15:26 -0600
From: Mike Kitchen <mi...@MGCL.CA>
Subject: Re: Pipe Inlet Control
I've tried modeling a culvert using HEC-5, though not with control
rules. What I did was to take the performance curve that was generated
by FHWA's Hy-8 program given what I knew about a specific culvert and
apply it as the rating curve for an outlet (representing a culvert
draining a field which acts as a detention pond in wet weather.
This did not account for any additional tailwater effects (e.g.
resulting from additional inflow from a downstream lateral ditch or
tributary area) - only the effects of the discharge from the culvert
into the downstream channel. The flow out of the culvert was completely
dependent on the upstream head (the assumed effect of tailwater due to
the flow in the downstream channel section is accounted for in
generating the Hy-8 performance curve).
If the culvert is just in inlet control (e.g. steep slope or tailwater
far enough below the downstream invert), wouldn't orifice or pipe-flow
equations be adequate to describe its performance? Otherwise, doesn't
SWMM5 allow control rules that alter which rating curve an outlet uses
based on head, flow rate, etc... in a node or link?
Michael A. Kitchen, P.Eng.
Martin Geomatic Consultants Ltd.
255 - 31 Street North
Lethbirdge, AB
T1H 3Z4
Tel: (403) 329-0050
Fax: (403) 329-6594
-----Original Message-----
From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of
Mark Boucher
Sent: Thursday, May 22, 2008 12:54 PM
To: SWMM-...@listserv.uoguelph.ca
Subject: [SWMM-USERS] Pipe Inlet Control
Has anyone developed a method for bringing the pipe inlet control
aspects of culvert capacity into SWMM models?
I've done a side by side simple detention basin model comparison of EPA
SWMM 5 and HEC-HMS. I found quite a difference in the storage needed for
a specific hydrograph. HEC-HMS incorporates the FHWA Hydraulic
Engineering Circular 5 (HEC5) equations used for pipe inlet control. I
tried putting an orifice on the front end of the pipe in SWMM and I get
answers that are closer, but they still are not as close as I'd like to
be.
I have not used the Control Rules before. Could a set if these be
created to apply the pipe inlet control equations?
Mark Boucher, PE
Senior Hydrologist
Contra Costa County Flood Control and Water Conservation District
Martinez, California
PS - I'm resending this because I needed to change the subject title.
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Date: Tue, 27 May 2008 15:43:22 -0400
From: Rob James <r...@COMPUTATIONALHYDRAULICS.COM>
Subject: Re: Pipe Inlet Control
Mike,
>> Otherwise, doesn't SWMM5 allow control rules that alter which rating
curve an outlet uses based on head, flow rate, etc... in a node or link?
To clarify, the control rules can't change which rating curve is assigned to
an outlet, however the control rules can adjust the flow computed from the
assigned rating curve, by varying a multiplier.
Sincerely,
Rob James
Computational Hydraulics Int.
www.computationalhydraulics.com
Tel. 519-767-0197
-----Original Message-----
From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of Mike
Kitchen
Sent: Tuesday, May 27, 2008 10:15 AM
To: SWMM-...@listserv.uoguelph.ca
Subject: Re: [SWMM-USERS] Pipe Inlet Control
I've tried modeling a culvert using HEC-5, though not with control
rules. What I did was to take the performance curve that was generated
by FHWA's Hy-8 program given what I knew about a specific culvert and
apply it as the rating curve for an outlet (representing a culvert
draining a field which acts as a detention pond in wet weather.
This did not account for any additional tailwater effects (e.g.
resulting from additional inflow from a downstream lateral ditch or
tributary area) - only the effects of the discharge from the culvert
into the downstream channel. The flow out of the culvert was completely
dependent on the upstream head (the assumed effect of tailwater due to
the flow in the downstream channel section is accounted for in
generating the Hy-8 performance curve).
If the culvert is just in inlet control (e.g. steep slope or tailwater
far enough below the downstream invert), wouldn't orifice or pipe-flow
equations be adequate to describe its performance? Otherwise, doesn't
SWMM5 allow control rules that alter which rating curve an outlet uses
based on head, flow rate, etc... in a node or link?
Michael A. Kitchen, P.Eng.
Martin Geomatic Consultants Ltd.
255 - 31 Street North
Lethbirdge, AB
T1H 3Z4
Tel: (403) 329-0050
Fax: (403) 329-6594
-----Original Message-----
From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of
Mark Boucher
Sent: Thursday, May 22, 2008 12:54 PM
To: SWMM-...@listserv.uoguelph.ca
Subject: [SWMM-USERS] Pipe Inlet Control
Has anyone developed a method for bringing the pipe inlet control
aspects of culvert capacity into SWMM models?
I've done a side by side simple detention basin model comparison of EPA
SWMM 5 and HEC-HMS. I found quite a difference in the storage needed for
a specific hydrograph. HEC-HMS incorporates the FHWA Hydraulic
Engineering Circular 5 (HEC5) equations used for pipe inlet control. I
tried putting an orifice on the front end of the pipe in SWMM and I get
answers that are closer, but they still are not as close as I'd like to
be.
I have not used the Control Rules before. Could a set if these be
created to apply the pipe inlet control equations?
Mark Boucher, PE
Senior Hydrologist
Contra Costa County Flood Control and Water Conservation District
Martinez, California
PS - I'm resending this because I needed to change the subject title.
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------------------------------
Date: Tue, 27 May 2008 14:11:45 -0600
From: Mike Kitchen <mi...@MGCL.CA>
Subject: Re: Pipe Inlet Control
I see...
Perhaps multiple outlets with multiple rating curve and control rules
that turn the different outlets on and off as different head- and
tail-water conditions present themselves...
Mike Kitchen
-----Original Message-----
From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of
Rob James
Sent: Tuesday, May 27, 2008 1:43 PM
To: SWMM-...@listserv.uoguelph.ca
Subject: Re: [SWMM-USERS] Pipe Inlet Control
Mike,
>> Otherwise, doesn't SWMM5 allow control rules that alter which rating
curve an outlet uses based on head, flow rate, etc... in a node or link?
To clarify, the control rules can't change which rating curve is
assigned to
an outlet, however the control rules can adjust the flow computed from
the
assigned rating curve, by varying a multiplier.
Sincerely,
Rob James
Computational Hydraulics Int.
www.computationalhydraulics.com
Tel. 519-767-0197
-----Original Message-----
From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of
Mike
Kitchen
Sent: Tuesday, May 27, 2008 10:15 AM
To: SWMM-...@listserv.uoguelph.ca
Subject: Re: [SWMM-USERS] Pipe Inlet Control
I've tried modeling a culvert using HEC-5, though not with control
rules. What I did was to take the performance curve that was generated
by FHWA's Hy-8 program given what I knew about a specific culvert and
apply it as the rating curve for an outlet (representing a culvert
draining a field which acts as a detention pond in wet weather.
This did not account for any additional tailwater effects (e.g.
resulting from additional inflow from a downstream lateral ditch or
tributary area) - only the effects of the discharge from the culvert
into the downstream channel. The flow out of the culvert was completely
dependent on the upstream head (the assumed effect of tailwater due to
the flow in the downstream channel section is accounted for in
generating the Hy-8 performance curve).
If the culvert is just in inlet control (e.g. steep slope or tailwater
far enough below the downstream invert), wouldn't orifice or pipe-flow
equations be adequate to describe its performance? Otherwise, doesn't
SWMM5 allow control rules that alter which rating curve an outlet uses
based on head, flow rate, etc... in a node or link?
Michael A. Kitchen, P.Eng.
Martin Geomatic Consultants Ltd.
255 - 31 Street North
Lethbirdge, AB
T1H 3Z4
Tel: (403) 329-0050
Fax: (403) 329-6594
-----Original Message-----
From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of
Mark Boucher
Sent: Thursday, May 22, 2008 12:54 PM
To: SWMM-...@listserv.uoguelph.ca
Subject: [SWMM-USERS] Pipe Inlet Control
Has anyone developed a method for bringing the pipe inlet control
aspects of culvert capacity into SWMM models?
I've done a side by side simple detention basin model comparison of EPA
SWMM 5 and HEC-HMS. I found quite a difference in the storage needed for
a specific hydrograph. HEC-HMS incorporates the FHWA Hydraulic
Engineering Circular 5 (HEC5) equations used for pipe inlet control. I
tried putting an orifice on the front end of the pipe in SWMM and I get
answers that are closer, but they still are not as close as I'd like to
be.
I have not used the Control Rules before. Could a set if these be
created to apply the pipe inlet control equations?
Mark Boucher, PE
Senior Hydrologist
Contra Costa County Flood Control and Water Conservation District
Martinez, California
PS - I'm resending this because I needed to change the subject title.
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------------------------------
Date: Tue, 27 May 2008 15:49:53 -0700
From: Mark Boucher <mb...@PW.CCCOUNTY.US>
Subject: Re: Pipe Inlet Control
The results I get from the orifice are close, but not as close as I'd
like them to be. I think that the orifice might be OK for a steady state
model, but I'm not so sure in an unsteady state model. I am struggling
to make the detention basins I'm working on meet a freeboard
requirement. I've got three detention basins that drain into the same
pipe. I trust the HEC-HMS results for the outlet performance, but HMS
does not do pipe systems. SWMM is great for pipes, but, so far, doesn't
do HEC-5.
I've passed my files on to Lewis Rossman of EPA off line. I'll report
his response.
Mark Boucher
-----Original Message-----
From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of
Mike Kitchen
Sent: Tuesday, May 27, 2008 7:15 AM
To: SWMM-...@listserv.uoguelph.ca
Subject: Re: [SWMM-USERS] Pipe Inlet Control
I've tried modeling a culvert using HEC-5, though not with control
rules. What I did was to take the performance curve that was generated
by FHWA's Hy-8 program given what I knew about a specific culvert and
apply it as the rating curve for an outlet (representing a culvert
draining a field which acts as a detention pond in wet weather.
This did not account for any additional tailwater effects (e.g.
resulting from additional inflow from a downstream lateral ditch or
tributary area) - only the effects of the discharge from the culvert
into the downstream channel. The flow out of the culvert was completely
dependent on the upstream head (the assumed effect of tailwater due to
the flow in the downstream channel section is accounted for in
generating the Hy-8 performance curve).
If the culvert is just in inlet control (e.g. steep slope or tailwater
far enough below the downstream invert), wouldn't orifice or pipe-flow
equations be adequate to describe its performance? Otherwise, doesn't
SWMM5 allow control rules that alter which rating curve an outlet uses
based on head, flow rate, etc... in a node or link?
Michael A. Kitchen, P.Eng.
Martin Geomatic Consultants Ltd.
255 - 31 Street North
Lethbirdge, AB
T1H 3Z4
Tel: (403) 329-0050
Fax: (403) 329-6594
-----Original Message-----
From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of
Mark Boucher
Sent: Thursday, May 22, 2008 12:54 PM
To: SWMM-...@listserv.uoguelph.ca
Subject: [SWMM-USERS] Pipe Inlet Control
Has anyone developed a method for bringing the pipe inlet control
aspects of culvert capacity into SWMM models?
I've done a side by side simple detention basin model comparison of EPA
SWMM 5 and HEC-HMS. I found quite a difference in the storage needed for
a specific hydrograph. HEC-HMS incorporates the FHWA Hydraulic
Engineering Circular 5 (HEC5) equations used for pipe inlet control. I
tried putting an orifice on the front end of the pipe in SWMM and I get
answers that are closer, but they still are not as close as I'd like to
be.
I have not used the Control Rules before. Could a set if these be
created to apply the pipe inlet control equations?
Mark Boucher, PE
Senior Hydrologist
Contra Costa County Flood Control and Water Conservation District
Martinez, California
PS - I'm resending this because I needed to change the subject title.
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**********************************************************
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End of SWMM-USERS Digest - 26 May 2008 to 27 May 2008 (#2008-97)
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