SWMM-USERS Digest - 5 Nov 2009 to 16 Nov 2009 (#2009-117)

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1. Subsurface drainage solutions with horizontal flow (8)

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Date: Mon, 16 Nov 2009 12:23:08 +0100
From: Jaime Palalane <jaime.p...@UEM.MZ>
Subject: Subsurface drainage solutions with horizontal flow

As part of my master thesis work, I would like to simulate two subsurface
drainage solutions, infiltration trenches with a perforated pipe (also know
as French drain) and a soakaways (also known as infiltration pits)
associated with a collector drain. One important aspect of my study area,
which is a peri-urban informal settlement of Maputo in Mozambique with not
well defined and unpaved streets, is the high ground water level during the
rain season, meaning that there will be some horizontal infiltration into
the trenches and soakaways.

I did the LID Application Exercise available at EPA's webpage as part of my
preparatory work but it only considers vertical infiltration and horizontal
infiltration is ignored. So, I would like to know if anyone has any
experience or suggestion about how to model this two subsurface drainage
solutions in areas with a high ground water level where horizontal
infiltration will be important during and after the rainfall.

If I treat my infiltration trench as a subcatchement how can horizontal flow
be considered (in order to have interaction with the groundwater) and how
can I simulate the perforated (or not) pipe drain which will take the flow
out from the infiltration trench?

Kind regards,

Jaime Palalane

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

Date: Mon, 16 Nov 2009 07:46:26 -0500
From: "Dorsey, Jay" <Jay.D...@DNR.STATE.OH.US>
Subject: Re: Subsurface drainage solutions with horizontal flow

Jaime,

The DRAINMOD model developed by Wayne Skaggs at North Carolina State
University is an excellent tool for 2-D modeling of subsurface drainage
hydrology:

http://www.bae.ncsu.edu/soil_water/drainmod/

It may allow you to model some aspect of your system that SWMM cannot,
or the documentation may provide some guidance of how to model lateral
outflow as a function of head/depth in SWMM.

Jay

Jay Dorsey, P.E., Ph.D.
Water Resources Engineer
ODNR, Division of Soil and Water Resources
(614) 265-6647

-----Original Message-----
From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of
Jaime Palalane
Sent: Monday, November 16, 2009 6:23 AM
To: SWMM-...@listserv.uoguelph.ca
Subject: [SWMM-USERS] Subsurface drainage solutions with horizontal flow

As part of my master thesis work, I would like to simulate two
subsurface
drainage solutions, infiltration trenches with a perforated pipe (also
know
as French drain) and a soakaways (also known as infiltration pits)
associated with a collector drain. One important aspect of my study
area,
which is a peri-urban informal settlement of Maputo in Mozambique with
not
well defined and unpaved streets, is the high ground water level during
the
rain season, meaning that there will be some horizontal infiltration
into
the trenches and soakaways.

I did the LID Application Exercise available at EPA's webpage as part of
my
preparatory work but it only considers vertical infiltration and
horizontal
infiltration is ignored. So, I would like to know if anyone has any
experience or suggestion about how to model this two subsurface drainage
solutions in areas with a high ground water level where horizontal
infiltration will be important during and after the rainfall.

If I treat my infiltration trench as a subcatchement how can horizontal
flow
be considered (in order to have interaction with the groundwater) and
how
can I simulate the perforated (or not) pipe drain which will take the
flow
out from the infiltration trench?

Kind regards,

Jaime Palalane

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

Date: Mon, 16 Nov 2009 14:28:33 +0100
From: Jaime Palalane <jaime.p...@UEM.MZ>
Subject: Re: Subsurface drainage solutions with horizontal flow

Dear Jay,

Thank your for your attention. I am trying to see if it is possible to model
it in SWMM as I am going to use other drainage infrastructures and model
features which are well described in SWMM. For sure, I will go through the
documentation which sounds interesting. I guess it will inspire and help me
to have a clear picture about how to model lateral flow.

Best regards,

Jaime

2009/11/16 Dorsey, Jay <Jay.D...@dnr.state.oh.us>

> Jaime,
>
> The DRAINMOD model developed by Wayne Skaggs at North Carolina State
> University is an excellent tool for 2-D modeling of subsurface drainage
> hydrology:
>
> http://www.bae.ncsu.edu/soil_water/drainmod/
>
> It may allow you to model some aspect of your system that SWMM cannot,
> or the documentation may provide some guidance of how to model lateral
> outflow as a function of head/depth in SWMM.
>
> Jay
>
> Jay Dorsey, P.E., Ph.D.
> Water Resources Engineer
> ODNR, Division of Soil and Water Resources
> (614) 265-6647
>
>
> -----Original Message-----
> From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of
> Jaime Palalane
> Sent: Monday, November 16, 2009 6:23 AM
> To: SWMM-...@listserv.uoguelph.ca
> Subject: [SWMM-USERS] Subsurface drainage solutions with horizontal flow
>
> As part of my master thesis work, I would like to simulate two
> subsurface
> drainage solutions, infiltration trenches with a perforated pipe (also
> know
> as French drain) and a soakaways (also known as infiltration pits)
> associated with a collector drain. One important aspect of my study
> area,
> which is a peri-urban informal settlement of Maputo in Mozambique with
> not
> well defined and unpaved streets, is the high ground water level during
> the
> rain season, meaning that there will be some horizontal infiltration
> into
> the trenches and soakaways.
>
> I did the LID Application Exercise available at EPA's webpage as part of
> my
> preparatory work but it only considers vertical infiltration and
> horizontal
> infiltration is ignored. So, I would like to know if anyone has any
> experience or suggestion about how to model this two subsurface drainage
> solutions in areas with a high ground water level where horizontal
> infiltration will be important during and after the rainfall.
>
> If I treat my infiltration trench as a subcatchement how can horizontal
> flow
> be considered (in order to have interaction with the groundwater) and
> how
> can I simulate the perforated (or not) pipe drain which will take the
> flow
> out from the infiltration trench?
>
> Kind regards,
>
> Jaime Palalane
>
> **********************************************************
> * To sign off, email to: list...@listserv.uoguelph.ca *
> * In the body of the message type: signoff swmm-users *
> **********************************************************
>
> **********************************************************
> * To sign off, email to: list...@listserv.uoguelph.ca *
> * In the body of the message type: signoff swmm-users *
> **********************************************************
>
> --
> This message has been scanned for viruses and
> dangerous content by MailScanner, and is
> believed to be clean.
>
>

--
Jaime Palalane
+258 82 70 56 990

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

Date: Mon, 16 Nov 2009 09:17:52 -0500
From: Lewis Rossman <Rossma...@EPAMAIL.EPA.GOV>
Subject: Re: Subsurface drainage solutions with horizontal flow

Jaime,

You can use SWMM's groundwater module to model sub-surface seepage flow
into your collection drains. Aside from the usual collection of aquifer
soil parameters, to simulate Dupuit-Forcheimer seepage the values of the
constants used in the GW outflow equation should be: A1 = 4*CF*Ks/L^2,
A2 = 0, A3 = -A1, B1 = 2, and H* = 0, where Ks is the soil's saturated
hydraulic conductivity, L is the horizontal distance between the point
of highest GW elevation under the subcatchment and the receiving node,
and CF is a units conversion factor (e.g., in/hr to cfs/acre or mm/hr to
cms/ha). The derivation of these coefficient values was presented in the
old SWMM 4 Users Manual.

Note that since SWMM only computes a spatially averaged water table
elevation beneath the overlying subcatchment, the length L can be
considered an adjustable parameter whose initial guess might be the
subcatchment's center.
--------------------------------------------------------------------------------------

Lewis Rossman
Environmental Scientist
Water Supply and Water Resources Division
U.S Environmental Protection Agency
email: rossma...@epa.gov

From: Jaime Palalane <jaime.p...@UEM.MZ>

To: SWMM-...@listserv.uoguelph.ca

Date: 11/16/2009 08:46 AM

Subject: Re: [SWMM-USERS] Subsurface drainage solutions with horizontal flow

Dear Jay,

Thank your for your attention. I am trying to see if it is possible to
model
it in SWMM as I am going to use other drainage infrastructures and model
features which are well described in SWMM. For sure, I will go through
the
documentation which sounds interesting. I guess it will inspire and help
me
to have a clear picture about how to model lateral flow.

Best regards,

Jaime

2009/11/16 Dorsey, Jay <Jay.D...@dnr.state.oh.us>

> Jaime,
>
> The DRAINMOD model developed by Wayne Skaggs at North Carolina State
> University is an excellent tool for 2-D modeling of subsurface
drainage
> hydrology:
>
> http://www.bae.ncsu.edu/soil_water/drainmod/
>
> It may allow you to model some aspect of your system that SWMM cannot,
> or the documentation may provide some guidance of how to model lateral
> outflow as a function of head/depth in SWMM.
>
> Jay
>
> Jay Dorsey, P.E., Ph.D.
> Water Resources Engineer
> ODNR, Division of Soil and Water Resources
> (614) 265-6647
>
>
> -----Original Message-----
> From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of
> Jaime Palalane
> Sent: Monday, November 16, 2009 6:23 AM
> To: SWMM-...@listserv.uoguelph.ca
> Subject: [SWMM-USERS] Subsurface drainage solutions with horizontal
flow
>
> As part of my master thesis work, I would like to simulate two
> subsurface
> drainage solutions, infiltration trenches with a perforated pipe (also
> know
> as French drain) and a soakaways (also known as infiltration pits)
> associated with a collector drain. One important aspect of my study
> area,
> which is a peri-urban informal settlement of Maputo in Mozambique with
> not
> well defined and unpaved streets, is the high ground water level
during
> the
> rain season, meaning that there will be some horizontal infiltration
> into
> the trenches and soakaways.
>
> I did the LID Application Exercise available at EPA's webpage as part
of
> my
> preparatory work but it only considers vertical infiltration and
> horizontal
> infiltration is ignored. So, I would like to know if anyone has any
> experience or suggestion about how to model this two subsurface
drainage
> solutions in areas with a high ground water level where horizontal
> infiltration will be important during and after the rainfall.
>
> If I treat my infiltration trench as a subcatchement how can
horizontal
> flow
> be considered (in order to have interaction with the groundwater) and
> how
> can I simulate the perforated (or not) pipe drain which will take the
> flow
> out from the infiltration trench?
>
> Kind regards,
>
> Jaime Palalane
>
> **********************************************************
> * To sign off, email to: list...@listserv.uoguelph.ca *
> * In the body of the message type: signoff swmm-users *
> **********************************************************
>
> **********************************************************
> * To sign off, email to: list...@listserv.uoguelph.ca *
> * In the body of the message type: signoff swmm-users *
> **********************************************************
>
> --
> This message has been scanned for viruses and
> dangerous content by MailScanner, and is
> believed to be clean.
>
>

--
Jaime Palalane
+258 82 70 56 990

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

Date: Mon, 16 Nov 2009 09:32:25 -0500
From: Bill Lucas <wlu...@INTEGRATEDLAND.COM>
Subject: Re: Subsurface drainage solutions with horizontal flow

Lew,

I had just drafted a similar response, but then I ran into the issue of how
to link the outflow from a storage node into an aquifer. Are you suggesting
that you create another dummy storage node with the relevant geometric
storage and porosity parameters of the aquifer, and then write the equation
as a rating table to determine outflow as function of Delta H etc?

Hate to admit my ignorance in this regard, but I think others would
appreciate your wisdom here.

Regards,

Bill

William Lucas, Principal
Integrated Land Management, Inc.
3 Lucas Lane
Malvern, PA 19355
610-644-0606
610-644-6583 (f)
484-995-6840 (m)
wlu...@integratedland.com

-----Original Message-----
From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of Lewis
Rossman
Sent: Monday, November 16, 2009 9:18 AM
To: SWMM-...@listserv.uoguelph.ca
Subject: Re: [SWMM-USERS] Subsurface drainage solutions with horizontal flow

Jaime,

Lewis Rossman
Environmental Scientist
Water Supply and Water Resources Division
U.S Environmental Protection Agency
email: rossma...@epa.gov

From: Jaime Palalane <jaime.p...@UEM.MZ>

To: SWMM-...@listserv.uoguelph.ca

Date: 11/16/2009 08:46 AM

Subject: Re: [SWMM-USERS] Subsurface drainage solutions with horizontal
flow

Dear Jay,

Thank your for your attention. I am trying to see if it is possible to
model
it in SWMM as I am going to use other drainage infrastructures and model
features which are well described in SWMM. For sure, I will go through
the
documentation which sounds interesting. I guess it will inspire and help
me
to have a clear picture about how to model lateral flow.

Best regards,

Jaime

2009/11/16 Dorsey, Jay <Jay.D...@dnr.state.oh.us>

> Jaime,
>
> The DRAINMOD model developed by Wayne Skaggs at North Carolina State
> University is an excellent tool for 2-D modeling of subsurface
drainage
> hydrology:
>
> http://www.bae.ncsu.edu/soil_water/drainmod/
>
> It may allow you to model some aspect of your system that SWMM cannot,
> or the documentation may provide some guidance of how to model lateral
> outflow as a function of head/depth in SWMM.
>
> Jay
>
> Jay Dorsey, P.E., Ph.D.
> Water Resources Engineer
> ODNR, Division of Soil and Water Resources
> (614) 265-6647
>
>
> -----Original Message-----
> From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of
> Jaime Palalane
> Sent: Monday, November 16, 2009 6:23 AM
> To: SWMM-...@listserv.uoguelph.ca
> Subject: [SWMM-USERS] Subsurface drainage solutions with horizontal
flow
>
> As part of my master thesis work, I would like to simulate two
> subsurface
> drainage solutions, infiltration trenches with a perforated pipe (also
> know
> as French drain) and a soakaways (also known as infiltration pits)
> associated with a collector drain. One important aspect of my study
> area,
> which is a peri-urban informal settlement of Maputo in Mozambique with
> not
> well defined and unpaved streets, is the high ground water level
during
> the
> rain season, meaning that there will be some horizontal infiltration
> into
> the trenches and soakaways.
>
> I did the LID Application Exercise available at EPA's webpage as part
of
> my
> preparatory work but it only considers vertical infiltration and
> horizontal
> infiltration is ignored. So, I would like to know if anyone has any
> experience or suggestion about how to model this two subsurface
drainage
> solutions in areas with a high ground water level where horizontal
> infiltration will be important during and after the rainfall.
>
> If I treat my infiltration trench as a subcatchement how can
horizontal
> flow
> be considered (in order to have interaction with the groundwater) and
> how
> can I simulate the perforated (or not) pipe drain which will take the
> flow
> out from the infiltration trench?
>
> Kind regards,
>
> Jaime Palalane
>
> **********************************************************
> * To sign off, email to: list...@listserv.uoguelph.ca *
> * In the body of the message type: signoff swmm-users *
> **********************************************************
>
> **********************************************************
> * To sign off, email to: list...@listserv.uoguelph.ca *
> * In the body of the message type: signoff swmm-users *
> **********************************************************
>
> --
> This message has been scanned for viruses and
> dangerous content by MailScanner, and is
> believed to be clean.
>
>

--
Jaime Palalane
+258 82 70 56 990

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

Date: Mon, 16 Nov 2009 11:06:44 -0500
From: Lewis Rossman <Rossma...@EPAMAIL.EPA.GOV>
Subject: Re: Subsurface drainage solutions with horizontal flow

Hi Bill,

No, my suggestion was to add a Groundwater object to each subcatchment
that is capable of allowing infiltrated rainfall to flow into a French
Drain (or even a seepage pit - maybe). I was not suggesting that one use
the infiltration feature of conveyance system storage nodes. With the
groundwater approach one can implement the standard textbook solution
for lateral subsurface flow into a drainage channel (which is where the
expressions for A1, B1, etc. in the GW outflow equation come from).

I don't think you can do this with a dummy storage node because you
loose the ability to determine how the surface infiltrated rainfall
affects the water table level which in turn affects the lateral
subsurface flow rate into the drain.
--------------------------------------------------------------------------------------

Lewis Rossman
Environmental Scientist
Water Supply and Water Resources Division
U.S Environmental Protection Agency
email: rossma...@epa.gov

From: Bill Lucas <wlu...@INTEGRATEDLAND.COM>

To: SWMM-...@listserv.uoguelph.ca

Date: 11/16/2009 09:45 AM

Subject: Re: [SWMM-USERS] Subsurface drainage solutions with horizontal flow

Lew,

I had just drafted a similar response, but then I ran into the issue of
how
to link the outflow from a storage node into an aquifer. Are you
suggesting
that you create another dummy storage node with the relevant geometric
storage and porosity parameters of the aquifer, and then write the
equation
as a rating table to determine outflow as function of Delta H etc?

Hate to admit my ignorance in this regard, but I think others would
appreciate your wisdom here.

Regards,

Bill

William Lucas, Principal
Integrated Land Management, Inc.
3 Lucas Lane
Malvern, PA 19355
610-644-0606
610-644-6583 (f)
484-995-6840 (m)
wlu...@integratedland.com

-----Original Message-----
From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of
Lewis
Rossman
Sent: Monday, November 16, 2009 9:18 AM
To: SWMM-...@listserv.uoguelph.ca
Subject: Re: [SWMM-USERS] Subsurface drainage solutions with horizontal
flow

Jaime,

----------

Lewis Rossman
Environmental Scientist
Water Supply and Water Resources Division
U.S Environmental Protection Agency
email: rossma...@epa.gov

From: Jaime Palalane <jaime.p...@UEM.MZ>

To: SWMM-...@listserv.uoguelph.ca

Date: 11/16/2009 08:46 AM

Subject: Re: [SWMM-USERS] Subsurface drainage solutions with
horizontal
flow

Dear Jay,

Thank your for your attention. I am trying to see if it is possible to
model
it in SWMM as I am going to use other drainage infrastructures and model
features which are well described in SWMM. For sure, I will go through
the
documentation which sounds interesting. I guess it will inspire and help
me
to have a clear picture about how to model lateral flow.

Best regards,

Jaime

2009/11/16 Dorsey, Jay <Jay.D...@dnr.state.oh.us>

> Jaime,
>
> The DRAINMOD model developed by Wayne Skaggs at North Carolina State
> University is an excellent tool for 2-D modeling of subsurface
drainage
> hydrology:
>
> http://www.bae.ncsu.edu/soil_water/drainmod/
>
> It may allow you to model some aspect of your system that SWMM cannot,
> or the documentation may provide some guidance of how to model lateral
> outflow as a function of head/depth in SWMM.
>
> Jay
>
> Jay Dorsey, P.E., Ph.D.
> Water Resources Engineer
> ODNR, Division of Soil and Water Resources
> (614) 265-6647
>
>
> -----Original Message-----
> From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of
> Jaime Palalane
> Sent: Monday, November 16, 2009 6:23 AM
> To: SWMM-...@listserv.uoguelph.ca
> Subject: [SWMM-USERS] Subsurface drainage solutions with horizontal
flow
>
> As part of my master thesis work, I would like to simulate two
> subsurface
> drainage solutions, infiltration trenches with a perforated pipe (also
> know
> as French drain) and a soakaways (also known as infiltration pits)
> associated with a collector drain. One important aspect of my study
> area,
> which is a peri-urban informal settlement of Maputo in Mozambique with
> not
> well defined and unpaved streets, is the high ground water level
during
> the
> rain season, meaning that there will be some horizontal infiltration
> into
> the trenches and soakaways.
>
> I did the LID Application Exercise available at EPA's webpage as part
of
> my
> preparatory work but it only considers vertical infiltration and
> horizontal
> infiltration is ignored. So, I would like to know if anyone has any
> experience or suggestion about how to model this two subsurface
drainage
> solutions in areas with a high ground water level where horizontal
> infiltration will be important during and after the rainfall.
>
> If I treat my infiltration trench as a subcatchement how can
horizontal
> flow
> be considered (in order to have interaction with the groundwater) and
> how
> can I simulate the perforated (or not) pipe drain which will take the
> flow
> out from the infiltration trench?
>
> Kind regards,
>
> Jaime Palalane
>
> **********************************************************
> * To sign off, email to: list...@listserv.uoguelph.ca *
> * In the body of the message type: signoff swmm-users *
> **********************************************************
>
> **********************************************************
> * To sign off, email to: list...@listserv.uoguelph.ca *
> * In the body of the message type: signoff swmm-users *
> **********************************************************
>
> --
> This message has been scanned for viruses and
> dangerous content by MailScanner, and is
> believed to be clean.
>
>

--
Jaime Palalane
+258 82 70 56 990

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

Date: Mon, 16 Nov 2009 17:13:43 +0100
From: Jaime Palalane <jaime.p...@UEM.MZ>
Subject: Re: Subsurface drainage solutions with horizontal flow

Dear Lewis,

As I understood, using the groundwater module I will get a sub-surface
seepage flow for a certain subcatchment area (e.g. cms/ha). Trying to
integrate this in my modeling plan there are two possibilities to represent
soakaways and infiltration trenches.

1st) Considerer the receiving node as my soakaway or infiltration trench,
receiving water from the contributing subcatchment. For this case, how can I
account for different soakaways and infiltration trenches dimension and
shapes?

2nd) Considerer a minor subcatchment as soakaway or infiltration drain,
receiving water from the surrounding drainage area (a major subcatchment)
and draining it to a node which will be the start of an outlet pipe. For
this case, is there any interaction between the groundwater levels and
groundwater flows from the major subcatchment to the minor subcatchment
representing the soakaway or infiltration trench?

I hope I not confusing or complicating myself.

Kind regards,

Jaime

2009/11/16 Lewis Rossman <Rossma...@epamail.epa.gov>

> Jaime,
>
> You can use SWMM's groundwater module to model sub-surface seepage flow
> into your collection drains. Aside from the usual collection of aquifer
> soil parameters, to simulate Dupuit-Forcheimer seepage the values of the
> constants used in the GW outflow equation should be: A1 = 4*CF*Ks/L^2,
> A2 = 0, A3 = -A1, B1 = 2, and H* = 0, where Ks is the soil's saturated
> hydraulic conductivity, L is the horizontal distance between the point
> of highest GW elevation under the subcatchment and the receiving node,
> and CF is a units conversion factor (e.g., in/hr to cfs/acre or mm/hr to
> cms/ha). The derivation of these coefficient values was presented in the
> old SWMM 4 Users Manual.
>
> Note that since SWMM only computes a spatially averaged water table
> elevation beneath the overlying subcatchment, the length L can be
> considered an adjustable parameter whose initial guess might be the
> subcatchment's center.
>
> --------------------------------------------------------------------------------------
>
>
> Lewis Rossman
> Environmental Scientist
> Water Supply and Water Resources Division
> U.S Environmental Protection Agency
> email: rossma...@epa.gov
>
>
>
> From: Jaime Palalane <jaime.p...@UEM.MZ>
>
> To: SWMM-...@listserv.uoguelph.ca
>
> Date: 11/16/2009 08:46 AM
>
> Subject: Re: [SWMM-USERS] Subsurface drainage solutions with horizontal
> flow
>
>
>
>
>
>
> Dear Jay,
>
> Thank your for your attention. I am trying to see if it is possible to
> model
> it in SWMM as I am going to use other drainage infrastructures and model
> features which are well described in SWMM. For sure, I will go through
> the
> documentation which sounds interesting. I guess it will inspire and help
> me
> to have a clear picture about how to model lateral flow.
>
> Best regards,
>
> Jaime
>
>
>
> 2009/11/16 Dorsey, Jay <Jay.D...@dnr.state.oh.us>
>
> > Jaime,
> >
> > The DRAINMOD model developed by Wayne Skaggs at North Carolina State
> > University is an excellent tool for 2-D modeling of subsurface
> drainage
> > hydrology:
> >
> > http://www.bae.ncsu.edu/soil_water/drainmod/
> >
> > It may allow you to model some aspect of your system that SWMM cannot,
> > or the documentation may provide some guidance of how to model lateral
> > outflow as a function of head/depth in SWMM.
> >
> > Jay
> >
> > Jay Dorsey, P.E., Ph.D.
> > Water Resources Engineer
> > ODNR, Division of Soil and Water Resources
> > (614) 265-6647
> >
> >
> > -----Original Message-----
> > From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf Of
> > Jaime Palalane
> > Sent: Monday, November 16, 2009 6:23 AM
> > To: SWMM-...@listserv.uoguelph.ca
> > Subject: [SWMM-USERS] Subsurface drainage solutions with horizontal
> flow
> >
> > As part of my master thesis work, I would like to simulate two
> > subsurface
> > drainage solutions, infiltration trenches with a perforated pipe (also
> > know
> > as French drain) and a soakaways (also known as infiltration pits)
> > associated with a collector drain. One important aspect of my study
> > area,
> > which is a peri-urban informal settlement of Maputo in Mozambique with
> > not
> > well defined and unpaved streets, is the high ground water level
> during
> > the
> > rain season, meaning that there will be some horizontal infiltration
> > into
> > the trenches and soakaways.
> >
> > I did the LID Application Exercise available at EPA's webpage as part
> of
> > my
> > preparatory work but it only considers vertical infiltration and
> > horizontal
> > infiltration is ignored. So, I would like to know if anyone has any
> > experience or suggestion about how to model this two subsurface
> drainage
> > solutions in areas with a high ground water level where horizontal
> > infiltration will be important during and after the rainfall.
> >
> > If I treat my infiltration trench as a subcatchement how can
> horizontal
> > flow
> > be considered (in order to have interaction with the groundwater) and
> > how
> > can I simulate the perforated (or not) pipe drain which will take the
> > flow
> > out from the infiltration trench?
> >
> > Kind regards,
> >
> > Jaime Palalane
> >
> > **********************************************************
> > * To sign off, email to: list...@listserv.uoguelph.ca *
> > * In the body of the message type: signoff swmm-users *
> > **********************************************************
> >
> > **********************************************************
> > * To sign off, email to: list...@listserv.uoguelph.ca *
> > * In the body of the message type: signoff swmm-users *
> > **********************************************************
> >
> > --
> > This message has been scanned for viruses and
> > dangerous content by MailScanner, and is
> > believed to be clean.
> >
> >
>
>
> --
> Jaime Palalane
> +258 82 70 56 990
>
> **********************************************************
> * To sign off, email to: list...@listserv.uoguelph.ca *
> * In the body of the message type: signoff swmm-users *
> **********************************************************
>
> **********************************************************
> * To sign off, email to: list...@listserv.uoguelph.ca *
> * In the body of the message type: signoff swmm-users *
> **********************************************************
>
> --
> This message has been scanned for viruses and
> dangerous content by MailScanner, and is
> believed to be clean.
>
>

--
Jaime Palalane
+258 82 70 56 990

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

Date: Mon, 16 Nov 2009 12:22:15 -0500
From: Lewis Rossman <Rossma...@EPAMAIL.EPA.GOV>
Subject: Re: Subsurface drainage solutions with horizontal flow

I'm no expert in this area -- I was just suggesting what capabilities
SWMM offers. However, the "standard" approach would follow your 1st
option. The drains and trenches form a conveyance network that transport
exfiltrated groundwater to some outfall point. The flow rates and depths
of flow in these elements, which will determine the shape of the final
outfall hydrograph, are determined by their slopes and dimensions. And
although in reality the lateral GW flow into these channels is
continuous along their length, in SWMM they must be modeled as point
inputs that occur at user-defined nodes along the conveyance system.
Also note that I'm assuming that any direct infiltration from these
drainage elements is negligible compared to the GW inflow, since right
now SWMM doesn't have the ability to model infiltration along a
conveyance channel.

One fine point to mention is that when the A3 term of the groundwater
equation is zero, SWMM will allow outflow from a conveyance system node
back into the GW zone that it connects to if its head is higher than the
water table elevation. So in a sense, this can model infiltration from
the conveyance system back into the soil. The "textbook" parameters I
gave earlier for lateral drainage were derived for one-way flow only
(exfiltration of GW) since A3 was non-zero. But you could use a more
empirically defined set of parameters (with A3 = 0) to simulate this
two-way flow capability.

And to answer your other question, SWMM cannot directly allow
groundwater interaction between two or more subcatchments. The only GW
interaction that is allowed is between a given subcatchment and a given
conveyance system node.
--------------------------------------------------------------------------------------

Lewis Rossman
Environmental Scientist
Water Supply and Water Resources Division
U.S Environmental Protection Agency
email: rossma...@epa.gov

From: Jaime Palalane <jaime.p...@UEM.MZ>

To: SWMM-...@listserv.uoguelph.ca

Date: 11/16/2009 11:26 AM

Subject: Re: [SWMM-USERS] Subsurface drainage solutions with horizontal flow

Dear Lewis,

1st) Considerer the receiving node as my soakaway or infiltration
trench,
receiving water from the contributing subcatchment. For this case, how
can I
account for different soakaways and infiltration trenches dimension and
shapes?

2nd) Considerer a minor subcatchment as soakaway or infiltration drain,
receiving water from the surrounding drainage area (a major
subcatchment)
and draining it to a node which will be the start of an outlet pipe. For
this case, is there any interaction between the groundwater levels and
groundwater flows from the major subcatchment to the minor subcatchment
representing the soakaway or infiltration trench?

I hope I not confusing or complicating myself.

Kind regards,

Jaime

2009/11/16 Lewis Rossman <Rossma...@epamail.epa.gov>

>
>
> Lewis Rossman
> Environmental Scientist
> Water Supply and Water Resources Division
> U.S Environmental Protection Agency
> email: rossma...@epa.gov
>
>
>
> From: Jaime Palalane <jaime.p...@UEM.MZ>
>
> To: SWMM-...@listserv.uoguelph.ca
>
> Date: 11/16/2009 08:46 AM
>
> Subject: Re: [SWMM-USERS] Subsurface drainage solutions with
horizontal
> flow
>
>
>
>
>
>
> Dear Jay,
>
> Thank your for your attention. I am trying to see if it is possible to
> model
> it in SWMM as I am going to use other drainage infrastructures and
model
> features which are well described in SWMM. For sure, I will go through
> the
> documentation which sounds interesting. I guess it will inspire and
help
> me
> to have a clear picture about how to model lateral flow.
>
> Best regards,
>
> Jaime
>
>
>
> 2009/11/16 Dorsey, Jay <Jay.D...@dnr.state.oh.us>
>
> > Jaime,
> >
> > The DRAINMOD model developed by Wayne Skaggs at North Carolina State
> > University is an excellent tool for 2-D modeling of subsurface
> drainage
> > hydrology:
> >
> > http://www.bae.ncsu.edu/soil_water/drainmod/
> >
> > It may allow you to model some aspect of your system that SWMM
cannot,
> > or the documentation may provide some guidance of how to model
lateral
> > outflow as a function of head/depth in SWMM.
> >
> > Jay
> >
> > Jay Dorsey, P.E., Ph.D.
> > Water Resources Engineer
> > ODNR, Division of Soil and Water Resources
> > (614) 265-6647
> >
> >
> > -----Original Message-----
> > From: SWMM-USERS [mailto:SWMM-...@listserv.uoguelph.ca] On Behalf
Of
> > Jaime Palalane
> > Sent: Monday, November 16, 2009 6:23 AM
> > To: SWMM-...@listserv.uoguelph.ca
> > Subject: [SWMM-USERS] Subsurface drainage solutions with horizontal
> flow
> >
> > As part of my master thesis work, I would like to simulate two
> > subsurface
> > drainage solutions, infiltration trenches with a perforated pipe
(also
> > know
> > as French drain) and a soakaways (also known as infiltration pits)
> > associated with a collector drain. One important aspect of my study
> > area,
> > which is a peri-urban informal settlement of Maputo in Mozambique
with
> > not
> > well defined and unpaved streets, is the high ground water level
> during
> > the
> > rain season, meaning that there will be some horizontal infiltration
> > into
> > the trenches and soakaways.
> >
> > I did the LID Application Exercise available at EPA's webpage as
part
> of
> > my
> > preparatory work but it only considers vertical infiltration and
> > horizontal
> > infiltration is ignored. So, I would like to know if anyone has any
> > experience or suggestion about how to model this two subsurface
> drainage
> > solutions in areas with a high ground water level where horizontal
> > infiltration will be important during and after the rainfall.
> >
> > If I treat my infiltration trench as a subcatchement how can
> horizontal
> > flow
> > be considered (in order to have interaction with the groundwater)
and
> > how
> > can I simulate the perforated (or not) pipe drain which will take
the
> > flow
> > out from the infiltration trench?
> >
> > Kind regards,
> >
> > Jaime Palalane
> >
> > **********************************************************
> > * To sign off, email to: list...@listserv.uoguelph.ca *
> > * In the body of the message type: signoff swmm-users *
> > **********************************************************
> >
> > **********************************************************
> > * To sign off, email to: list...@listserv.uoguelph.ca *
> > * In the body of the message type: signoff swmm-users *
> > **********************************************************
> >
> > --
> > This message has been scanned for viruses and
> > dangerous content by MailScanner, and is
> > believed to be clean.
> >
> >
>
>
> --
> Jaime Palalane
> +258 82 70 56 990
>
> **********************************************************
> * To sign off, email to: list...@listserv.uoguelph.ca *
> * In the body of the message type: signoff swmm-users *
> **********************************************************
>
> **********************************************************
> * To sign off, email to: list...@listserv.uoguelph.ca *
> * In the body of the message type: signoff swmm-users *
> **********************************************************
>
> --
> This message has been scanned for viruses and
> dangerous content by MailScanner, and is
> believed to be clean.
>
>

--
Jaime Palalane
+258 82 70 56 990

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

End of SWMM-USERS Digest - 5 Nov 2009 to 16 Nov 2009 (#2009-117)
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