SWMM-USERS Digest - 15 Dec 2009 to 17 Dec 2009 (#2009-138)

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Dec 18, 2009, 12:05:17 AM12/18/09

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There are 3 messages totalling 211 lines in this issue.

Topics of the day:

1. modeling a pipe crossing a culvert (3)

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Date: Thu, 17 Dec 2009 14:51:26 -0500
From: "Keene, Marla" <MKe...@VHB.COM>
Subject: modeling a pipe crossing a culvert

Hello,
I'm attempting to model a large box culvert, 12'w x 9'h, with a 15" corruga=
ted metal pipe sleeve crossing it near, but not at, the top. The culvert i=
s about 50' long, to give you an idea of scale. Could anyone suggest how t=
hey would go about modeling the interruption due to the pipe sleeve? The c=
ulvert is fully submerged and under pressure flow during average high tide =
and is nearly dry under average low tide, so I'm seeing a full range of flo=
w regimes in the culvert.

Thanks!

Marla H. Keene
Water Resources Engineer
VHB | Vanasse Hangen Brustlin, Inc.
Transportation | Land Development | Environmental Services
101 Walnut Street
Watertown, MA 02472
Phone: 617.924.1770 x1357 | Fax: 617.924.2286

mke...@vhb.com<mailto:MKe...@VHB.com>
www.vhb.com<http://www.vhb.com>

This communication is confidential and intended only for the recipient(s). =
Any other use,
dissemination, copying, or disclosure of this communication is strictly pro=
hibited. If you
have received this communication in error, please notify us and destroy it =
immediately.
Vanasse Hangen Brustlin, Inc. is not responsible for any undetectable alter=
ation, transmission
error, conversion, media degradation, software error, or interference with =
this transmission.
Vanasse Hangen Brustlin, Inc. | 101 Walnut St | Watertown, MA 02472 | 617.9=
24.1770

------------------------------

Date: Thu, 17 Dec 2009 12:25:11 -0800
From: "Gregory, Mike" <Mike.G...@AECOM.COM>
Subject: Re: modeling a pipe crossing a culvert

you could treat this obstruction as an equivalent gate opening (i.e.,
rectangular orifice, offset = 0 [bottom of pipe], with orifice height as
the depth from pipe bottom to low chord of the sleeve, and set orifice
width to match equivalent area in flow below the sleeve).

it sounds like there might also be flow over the top of the sleeve - you
could model that as a weir. if culvert was always submerged you could
just add the flow area to the equivalent gate; a weir covers the low &
high tide conditions.

Regards,
mike g.
AECOM-Kitchener, Canada

-----Original Message-----
From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of
Keene, Marla
Sent: Thursday, December 17, 2009 2:51 PM
To: SWMM-...@listserv.uoguelph.ca
Subject: [SWMM-USERS] modeling a pipe crossing a culvert

Hello,
I'm attempting to model a large box culvert, 12'w x 9'h, with a 15"
corrugated metal pipe sleeve crossing it near, but not at, the top. The
culvert is about 50' long, to give you an idea of scale. Could anyone
suggest how they would go about modeling the interruption due to the
pipe sleeve? The culvert is fully submerged and under pressure flow
during average high tide and is nearly dry under average low tide, so
I'm seeing a full range of flow regimes in the culvert.

Thanks!

mke...@vhb.com<mailto:MKe...@VHB.com>
www.vhb.com<http://www.vhb.com>

This communication is confidential and intended only for the
recipient(s). Any other use,
dissemination, copying, or disclosure of this communication is strictly
prohibited. If you
have received this communication in error, please notify us and destroy
it immediately.
Vanasse Hangen Brustlin, Inc. is not responsible for any undetectable
alteration, transmission
error, conversion, media degradation, software error, or interference
with this transmission.
Vanasse Hangen Brustlin, Inc. | 101 Walnut St | Watertown, MA 02472 |
617.924.1770

------------------------------

Date: Thu, 17 Dec 2009 16:26:54 -0400
From: "Wilson, Alexander" <alexa...@CBCL.CA>
Subject: Re: modeling a pipe crossing a culvert

Hi,
How about trying to model it as an orifice (lower portion), and a weir
(upper portion)?
When looking at the effect of a circular obstruction in the path of a
current (like piers in the ocean), the Morison's equation is used.
You could apply it for your flow rate, then calculate the equivalent K,
and perhaps get a better value that way.

Just a couple of ideas.

Alexander.

Alexander T. Wilson, M.Eng, P.Eng.
Water Resources Engineer
CBCL Limited, Consulting Engineers

-----Original Message-----
From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of
Keene, Marla
Sent: Thursday, December 17, 2009 3:51 PM
To: SWMM-...@listserv.uoguelph.ca
Subject: [SWMM-USERS] modeling a pipe crossing a culvert

Thanks!

mke...@vhb.com<mailto:MKe...@VHB.com>
www.vhb.com<http://www.vhb.com>

This email and any files transmitted with it are provided for convenience only. They are to be considered confidential
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please notify the sender immediately. CBCL Limited assumes no responsibility for data transmitted electronically.
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End of SWMM-USERS Digest - 15 Dec 2009 to 17 Dec 2009 (#2009-138)
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