SW3190201_Email RE O'Reilly Auto Parts Stormwater Permit_20190509

Georgoulias, Bethany
From: Anen, Steven C
Sent: Thursday, May 09, 2019 5:42 PM
To: Daniel Renckens
Cc: Michael Theberge; Daniel Hines; [e-mail]
Subject: RE: [External] RE: O'Reilly Auto Parts Stormwater Permit SW3190201
Daniel,
I reviewed all of the routing calculations and I had a few comments:
• The calculations show that the peak elevation during the 1" storm is above the first weir, resulting in a flow of
0.40 cfs through the outlet. The entire 1" storm must by treated by infiltrating through the bioretention media.
• The calculated storage in the bioretention cell should not take into account the porosity of the media.
• The subcatchments were modeled using weighted curve numbers rather than the Discrete NRCS Method in
which pervious and impervious areas are routed separately. This artificially lowers the calculated runoff volume.
• The routing appears to be calculating the flow through the bioretention media using the surface area at
elevation 563 rather than at the surface of the bioretention media. The calculation shows the flow as 0.03 cfs,
whereas it should be 0.007 acres * 1 in/hr * 43560 sf/ac * 1 ft/12 in * 1 hr/3600 s = 0.007 cfs.
• The grading sheet shows the bottom of the bioretention cell at El. 561, whereas the detail and calculations show
it as El. 561.5.
I will be out of the office tomorrow but I'd be happy to discuss these comments with you on Monday.
Thanks,
Corey Anen
Environmental Engineer
North Carolina Department of Environmental Quality
Division of Energy, Mineral & Land Resources Stormwater Program
512 N. Salisbury Street
1612 Mail Service Center
Raleigh, NC 27699-1612
919-707-3649
[e-mail]
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties.
From: Daniel Renckens [mailto:[e-mail]]
Sent: Wednesday, May 1, 2019 9:21 AM
To: Anen, Steven C <[e-mail]>
Cc: Michael Theberge <[e-mail]>; Daniel Hines <[e-mail]>;
[e-mail]
Subject: RE: [External] RE: O'Reilly Auto Parts Stormwater Permit SW3190201

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[e-mail]
Corey,
Perfect. That is how we replied in the comment response letter included within the package. You should be receiving the
package tomorrow.
Hope you're feeling better.
Thanks
Daniel Renckens, P.E., CFM
Bohler Engineering NC, PLLC
1927 South Tryon Street, Suite 310 1 Charlotte, NC 28203
P: 980-272-3400 1 [e-mail]
From: Anen, Steven C [mailto:[e-mail]]
Sent: Wednesday, May 01, 2019 9:11 AM
To: Daniel Renckens <[e-mail]>
Cc: Michael Theberge <[e-mail]>; Daniel Hines <[e-mail]>;
[e-mail]
Subject: RE: [External] RE: O'Reilly Auto Parts Stormwater Permit SW3190201
Hi Daniel,
I've been out of the office sick the past two days, so I just got your email and voicemail. It's ok that it's past the 4/26
deadline that I had originally set. In response to your call, I don't see the erosion calculations as necessary as the inlet
pipe will just be discharging to the riprap and concrete structure.
Corey Anen
Environmental Engineer
North Carolina Department of Environmental Quality
Division of Energy, Mineral & Land Resources Stormwater Program
512 N. Salisbury Street
1612 Mail Service Center
Raleigh, NC 27699-1612
919-707-3649
[e-mail]
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties.
From: Daniel Renckens[mailto:[e-mail]]
Sent: Monday, April 29, 2019 4:41 PM
To: Anen, Steven C <[e-mail]>
Cc: Michael Theberge <[e-mail]>; Daniel Hines <[e-mail]>;
[e-mail]
Subject: RE: [External] RE: O'Reilly Auto Parts Stormwater Permit SW3190201

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report.spamLa)nc.xc
Corey,
We have uploaded the resubmission contents via the website and have sent hard copies to your attention. If you could
please grant us the additional business day past the 4/26 submission deadline, due to the outstanding items we had to
work through below, that would be great.
Please let us know if you have any questions or if you need anything else when the package arrives. We look forward to
your approval.
Thanks
Daniel Renckens, P.E., CFM
Bohler Engineering NC, PLLC
1927 South Tryon Street, Suite 310 1 Charlotte, NC 28203
P: 980-272-3400 1 [e-mail]
From: Daniel Renckens
Sent: Friday, April 26, 2019 3:28 PM
To: Anen, Steven C <[e-mail]>
Cc: Michael Theberge <[e-mail]>; Daniel Hines <[e-mail]>;
[e-mail]
Subject: RE: [External] RE: O'Reilly Auto Parts Stormwater Permit SW3190201
Corey,
Just to quickly recap our call, we will extend the 48" pretreatment manhole 12" below the bottom of the sand media,
leave the bottom of the manhole open, and implement a layer of rip -rap, in order to allow runoff to infiltrate into the in -
situ soil after a rainfall.
We will resubmit the package ASAP and will let you know when we do.
Thank you.
Daniel Renckens, P.E., CFM
Bohler Engineering NC, PLLC
1927 South Tryon Street, Suite 310 1 Charlotte, NC 28203
P: 980-272-3400 1 [e-mail]
From: Anen, Steven C [mailto:[e-mail]]
Sent: Wednesday, April 24, 2019 3:26 PM
To: Daniel Renckens <[e-mail]>
Cc: Michael Theberge <[e-mail]>; Daniel Hines <[e-mail]>;
[e-mail]
Subject: RE: [External] RE: O'Reilly Auto Parts Stormwater Permit SW3190201
Hi Daniel,

Based on the elevations of the piping system I would be very concerned with that design. Runoff would not be able to
drain from the pipes below El. 561, which would cause standing water in all of the pipes and the inlets. I would also think
that maintenance would be very difficult and would have to be performed frequently to remove trash and sediment and
could lead to flooding of the parking lot if it clogged. I would recommend that you look into another option.
Corey Anen
Environmental Engineer
North Carolina Department of Environmental Quality
Division of Energy, Mineral & Land Resources Stormwater Program
512 N. Salisbury Street
1612 Mail Service Center
Raleigh, NC 27699-1612
919-707-3649
[e-mail]
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties.
From: Daniel Renckens [mailto:[e-mail]]
Sent: Tuesday, April 23, 2019 6:08 PM
To: Anen, Steven C <[e-mail]>
Cc: Moore, James <[e-mail]>; Michael Theberge <[e-mail]>; Daniel Hines
<[e-mail]>; [e-mail]
Subject: RE: [External] RE: O'Reilly Auto Parts Stormwater Permit SW3190201
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Corey,
Have you had a chance to look at our below request regarding the inflow pipe below the sand media? We are really
needing to resubmit to avoid a construction delay so your attention to this is very much appreciated.
Thank you.
Daniel Renckens, P.E., CFM
Bohler Engineering INC, PLLC
1927 South Tryon Street, Suite 310 1 Charlotte, NC 28203
P: 980-272-3400 1 [e-mail]
From: Daniel Renckens
Sent: Thursday, April 18, 2019 4:37 PM
To: Anen, Steven C <[e-mail]>
Cc: Moore, James <[e-mail]>; Michael Theberge <[e-mail]>; Daniel Hines
<[e-mail]>; [e-mail]
Subject: RE: [External] RE: O'Reilly Auto Parts Stormwater Permit SW3190201
Corey,
Just wanted to follow up on my recent email and voicemail.

To simplify (since I know you are busy), we can design the system such that all runoff enters the sand media from the
top, it will just stage in an impermeable forebay first. Just looking for confirmation that the pipe can come in below the
media.
Thank you.
Daniel Renckens, P.E., CFM
Bohler Engineering NC, PLLC
1927 South Tryon Street, Suite 310 1 Charlotte, NC 28203
P: 980-272-3400 1 [e-mail]
From: Daniel Renckens
Sent: Wednesday, April 10, 2019 5:31 PM
To: Anen, Steven C <[e-mail]>
Cc: Moore, James <[e-mail]>; Michael Theberge <[e-mail]>; Daniel Hines
<[e-mail]>; [e-mail]
Subject: RE: [External] RE: O'Reilly Auto Parts Stormwater Permit SW3190201
Corey,
We understand and thank you for your response.
We will accommodate the 1"/hr. and reroute the system.
As far as the inflow pipe, the design is intended such that the manhole receiving the flow is separated from media so
that the runoff will stage up in the manhole then spill over the top directly into the sand media. See below detail with
some clarification labels.

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If you'd prefer we remove the rip-rap/geotextile layer and just have the bottom of the manhole be concrete to avoid
short circuiting through the underlain soil, we can happily accommodate that. The sump was implemented due the
inability to get cover over the pipes without raising the site and importing an infeasible amount of dirt.
Please let us know if this is acceptable once you've reviewed.
Thank you.
Daniel Renckens, P.E., CFM
Bohler Engineering NC, PLLC
1927 South Tryon Street, Suite 310 1 Charlotte, NC 28203
P: 980-272-3400 1 [e-mail]
From: Anen, Steven C [mailto:[e-mail]]
Sent: Wednesday, April 10, 2019 4:49 PM
To: Daniel Renckens <[e-mail]>
Cc: Moore, James <[e-mail]>; Michael Theberge <[e-mail]>; Daniel Hines
<[e-mail]>; [e-mail]
Subject: RE: [External] RE: O'Reilly Auto Parts Stormwater Permit SW3190201
Hi Daniel,
6

Sorry it's taken me some time to get back to you. We're short staffed and very busy and I've been out of the office since
Thursday. I looked back at the email chain you included and looked over the plans again. Usually we require that the
actual storage between the planting surface and the outlet be sufficient to hold the entire design storm. This is how the
MDC are usually interpreted. We can allow an alternative design on a case -by -case basis and I would be ok with routing
runoff through the bioretention cell. However, using 16.88 in/hour is far in excess of what we expect to see for long
term infiltration rates through a bioretention cell. The MDC only set a minimum infiltration rate of 1 in/hour through the
bioretention media, so the hydraulic conductivity could drop precipitously without being out of compliance with the
MDC, at which point there would not be sufficient storage room in the media to treat the runoff. Therefore, I would be
ok with determining the maximum ponding depth using routing calculations, but would not allow more than 1 in/hour
to be used for the infiltration rate.
The inlet pipe into the bioretention cell cannot discharge below the surface of the media. The method of runoff
treatment in a bioretention cell is filtration through the media and uptake by vegetation. By discharging directly into the
soil media, runoff would not be allowed to infiltrate through the media and receive the required treatment. Untreated
runoff would likely be discharged directly through the underdrain pipe.
Let me know if you would like to discuss this further.
Corey Anen
Environmental Engineer
North Carolina Department of Environmental Quality
Division of Energy, Mineral & Land Resources Stormwater Program
512 N. Salisbury Street
1612 Mail Service Center
Raleigh, NC 27699-1612
919-707-3649
[e-mail]
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties.
From: Daniel Renckens [mailto:[e-mail]]
Sent: Tuesday, April 9, 2019 9:39 AM
To: Anen, Steven C <[e-mail]>
Cc: Moore, James <[e-mail]>; Michael Theberge <[e-mail]>; Daniel Hines
<[e-mail]>; [e-mail]
Subject: [External] RE: O'Reilly Auto Parts Stormwater Permit SW3190201
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[e-mail]
Corey,
Just following up here as this is our last outstanding permit. Is there a time we can chat about the method of sizing?
Thank you.
Daniel Renckens, P.E., CFM
Bohler Engineering INC, PLLC

1927 South Tryon Street, Suite 310 1 Charlotte, NC 28203
P: 980-272-3400 1 [e-mail]
From: Daniel Renckens
Sent: Tuesday, April 02, 2019 10:55 AM
To: 'Anen, Steven C' <[e-mail]>
Cc: Moore, James <[e-mail]>; Michael Theberge <[e-mail]>; Daniel Hines
<[e-mail]>; [e-mail]
Subject: RE: O'Reilly Auto Parts Stormwater Permit SW3190201
Corey,
Good morning.
Can we please discuss your first comment? We proactively inquired about this in November and Rick conveyed that he
did not see any immediate issues with what we were proposing (please see attached email).
Are you available for a call later today or tomorrow?
Thank you in advance.
Daniel Renckens, P.E., CFM
Bohler Engineering NC, PLLC
1927 South Tryon Street, Suite 310 1 Charlotte, NC 28203
P: 980-272-3400 1 [e-mail]
From: Anen, Steven C [mailto:[e-mail]]
Sent: Wednesday, March 27, 2019 5:48 PM
To: Daniel Renckens <[e-mail]>
Cc: Moore, James <[e-mail]>
Subject: O'Reilly Auto Parts Stormwater Permit SW3190201
Good afternoon,
The Division of Energy, Mineral and Land Resources (DEMLR), received a Stormwater Management Permit Application
for the subject project on February 5, 2019. A review of that information has determined that the application is not
complete. Attached is a letter describing the items that need to be submitted. If you have any questions, please feel free
to contact me. My contact information is listed below.
Thank you,
Corey Anen
Environmental Engineer
North Carolina Department of Environmental Quality
Division of Energy, Mineral & Land Resources Stormwater Program
512 N. Salisbury Street
1612 Mail Service Center
Raleigh, NC 27699-1612

919-707-3649
[e-mail]
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties.
Corey Anen
Environmental Engineer
North Carolina Department of Environmental Quality
Division of Energy, Mineral & Land Resources Stormwater Program
512 N. Salisbury Street
1612 Mail Service Center
Raleigh, NC 27699-1612
919-707-3649
[e-mail]
Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties.