SW3230601_Sand Filter MDC Quick Questions_20230808

Holland, Brianna
From: David Ledford <[e-mail]>
Sent: Tuesday, August 8, 2023 7:02 AM
To: Holland, Brianna
Subject: Re: [External] Fw: Sand Filter MDC Quick Questions
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Email Chain of questions and answer by Jim Farkus.
Email#2.
If you have any questions feel free to contact me.
Thanks,
David
I David Ledford, RLA
Landscape Architect
2730 Maiden Highway
Lincolnton, NC 28092
704-530-7880
On Thursday, May 25, 2023 at 03:34:05 PM EDT, David Ledford <[e-mail]>wrote:
Jim,
Sounds good.
I will included a rip rap energy dissipater calculations along with a sizing graph.
Thank you for the quick responses.
Have great holiday weekend,
David
I David Ledford, RLA
Landscape Architect
2730 Maiden Highway
Lincolnton, NC 28092
704-530-7880
On Thursday, May 25, 2023 at 03:30:40 PM EDT, Farkas, Jim J <[e-mail]>wrote:
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That design (riser pipe with riprap to disperse flow)will suffice,just make sure that you provide calculations showing that
the riprap is adequately sized.
Jim Farkas
State Stormwater Engineer
North Carolina Department of Environmental Quality
Office: [phone]
Jim.farkasa-deg.nc.go,�: D- E
�
NORTH CAROLINA7.4m Q
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Department of Environmental Quality
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Carolina Public Records Law and may be disclosed to third parties.
From: David Ledford <[e-mail]>
Sent: Thursday, May 25, 2023 3:24 PM
To: Farkas, Jim J <[e-mail]>
Subject: Re: [External] Fw: Sand Filter MDC Quick Questions
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Jim,
Sorry about that. To quick on the send button.
Haver been on a jobsite till now.
See attachments below.
Thanks,
z

david
I David Ledford, RLA
Landscape Architect
2730 Maiden Highway
Lincolnton, NC 28092
704-530-7880
On Thursday, May 25, 2023 at 12:02:28 PM EDT, Lawyer, Mike <mike.lawyera-deg.nc.gov> wrote:
No bother at all. Glad you got your questions answered.
Hope you have a nice holiday weekend as well.
Michael Lawyer, CPSWQ
Stormwater Program Supervisor
Division of Energy, Mineral and Land Resources
North Carolina Department of Environmental Quality
Office: [phone] 1 Cell: [phone]
Email: mike.Iawyera-deg.nc.gov
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look different, but email performance will not be impacted.
oMwru.ca�r«.w..u�ar�rr�`�
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to third parties.
From: David Ledford <idavidledforda-vahoo.com>
Sent: Thursday, May 25, 2023 11:08 AM
To: Lawyer, Mike <mike.lawyera-deg.nc.gov>
Subject: [External] Fw: Sand Filter MDC Quick Questions
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CAUTION: External email. Do not click links or open attachments unless verified. Report suspicious emails with the
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Mike,
Jim actually emailed me back during the time I was send the email to you.
Sorry to bother you. Just thinking it may take a while for Jim.
However, he like always is right on the spot.
Tell him I said thanks.
Have a great holiday weekend,
David
I David Ledford, RLA
Landscape Architect
2730 Maiden Highway
Lincolnton, NC 28092
704-530-7880
----- Forwarded Message -----
From: David Ledford <idavidledforda-vahoo.com>
To: mike.lawyera-ncdenr.gov<mike.lawyera-ncdenr.gov>
Cc: David Ledford <idavidledforda-vahoo.com>
Sent: Thursday, May 25, 2023 at 11:04:20 AM EDT
Subject: Fw: Sand Filter MDC Quick Questions
Mike,
I left a voice mail a little bit ago about a few questions I had about on
MDC for Sand Filters that were not clear in the design manual.
I had sent this below to Jim with the questions but got a automatic response
being a week or more out on response times. Thought you may be able to answer.
See questions below.
Thanks you for any help,
David
I David Ledford, RLA
Landscape Architect
2730 Maiden Highway
Lincolnton, NC 28092
704-530-7880
----- Forwarded Message -----
From: David Ledford <idavidledfordCc�yahoo.com>
To: >
Cc: David Ledford <idavidledforda-vahoo.com>
Sent: Thursday, May 25, 2023 at 10:18:13 AM EDT
Subject: Sand Filter MDC Quick Questions
Jim,
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Been a while since we last talked. Hope everything is well in Raleigh.
I know you are overworked by the sounds of it talking with other designers.
I remember those days with Lincoln County and the volume of plans.
The reason for writing is to get a few MDC answers for a sand filter design.
I haven't submitted to the State in a while, mainly to local municipalities for
review and they have their own additional requirements too.
As always trying to get what's need but not over-design for the heck of it.
Items in Questions:
1) Is there a maximum depth over the sand filter area for the Vt (treatment volume).
I know there is a maximum 6' depth for the sand filter with a mention of peak
attenuation if needed. I'm planning on a 3'Vt depth over the sand filter portion.
2) Is there any peak attenuation requirement for a sand filter with the State.
As above there was only a mention of it with the depth IF NEEDED and the
as-built certification asks about if the bypass device is set at or above the
storage volume (Vt?).
3) What is the minimum depth of the stone or gravel layer on the top of the sand
filter surface. Not labeled in the detail or section but is usually 2" depth in most
municipalities with the requirement.
4) What is the requirement for underdrain protection with regard to the only mention
of the minimum sand layer depth and then the minimum sand layer depth above
the underdrains. The open bottom detail shows sand beside the underdrain no
protection mentioned. Would it be filter fabric, stone layer, or both.
5) Could the even flow distribution be accomplish with a rip rap energy dissipater
added at the end of the perforated riser pipe outlet in the sand filter as allowed
by Mecklenburg County. If not, are there any examples that you have or know
of that have been approved and used for this type of outlet.
6) Is there a checklist for either a sand filter submittal or a typical overall submittal
that you use or is listed on the website somewhere. I like to try to have all the
needed info for a good review package.
Thanks for your time.
David
I David Ledford, RLA
Landscape Architect
2730 Maiden Highway
Lincolnton, NC 28092
704-530-7880
Email correspondence to and from this address may be subject to the North Carolina Public Records Law and may be disclosed to third parties by an authorized
state official.
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