20140762 Ver 4_swap PSH with a dissaptor pad_20200312

Wanucha, Dave
From:Patterson, Robert D
Sent:Wednesday, March 11, 2020 2:16 PM
To:Wanucha, Dave
Subject:swap PSH with a dissaptor pad
Ok. I’m fine with it. PSH is more for diffuse flow.

From: Wanucha, Dave
Sent: Wednesday, March 11, 2020 1:36 PM
To: Patterson, Robert D <[e-mail]>
Subject: RE: R-2915 B, Station 165 request to swap PSH with a dissaptor pad

Robert,
The SW plan shows 0.64 ac drainage area, Q10 of 2.5 cfs and V10 0.8 fps for this particular PSH of which is within the
hydraulic range of other proposed PSHs on this project. We reviewed the site several weeks ago and came across the
situation. Several storm events have occurred since the pipe was installed and there is very little erosion/scour at the
outlet. What they are proposing below is fine with me. Making adjustments in the field is part of standard practice in
road construction. And this would be updated in the database I referred to in earlier emails. Do you think we need
anything else from them on this?

From Division 11 DEO:
“Dave – hopefully my interpretation of the site was similar to yours, but let me know if not. Regarding your question
about what changed - I do not know what changed, or why there was a PSH originally planned at the location. The
drainage area is primarily private property, so possibly a private driveway pipe or spring box was altered outside of our
RW. I’m not sure. When asked about the proposed PSH, the NCDOT hydraulic engineer I spoke to said “the site is at the
outlet of a 15” RCP which drains the roadway coming to two 2GI’s. There is very little runoff being discharged at this
location. A rip rap pad should function more than adequately.“ So, that makes me think that possibly nothing changed,
and the request for a PSH was not necessary in the first place. That’s all I have to go on.”

Division of Water Resources
401 & Buffer Transportation Permitting
NC Department of Envirionmental Quality

336-776-9703 office
336-403-5655 mobile
[e-mail]
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NC DEQ Winston Salem Regional Office
450 West Hanes Mill Road, Suite 300
Winston Salem, NC 27106

From: Patterson, Robert D <[e-mail]>
Sent: Tuesday, March 10, 2020 2:36 PM
To: Wanucha, Dave <[e-mail]>
Subject: RE: R-2915 B, Station 165 request to swap PSH with a dissaptor pad

I mean, if they provide a good reason for removing it, ok. But their statement that there isn’t much flow…psh are used
for small flow 15 and 18 inch pipes. I agree with you that it needs better explanation as to what has changed.
Thanks.

From: Wanucha, Dave
Sent: Tuesday, March 10, 2020 1:19 PM
To: Patterson, Robert D <[e-mail]>
Subject: Fwd: R-2915 B, Station 165 request to swap PSH with a dissaptor pad

FYI, I’m inclined to allow it, but would like to see an explanation as to why PSH was originally proposed and what
changed since then. Any thoughts?
Dave Wanucha
Division of Water Resources
401 & Buffer Transportation Permitting
NC Department of Environmental Quality

336-776-9703 office
336-403-5655 mobile
[e-mail]

NC DEQ Winston Salem Regional Office
450 West Hanes Mill Road, Suite 300
Winston Salem, NC 27105

Email correspondence to and from this address is subject to the
North Carolina Public Records Law and may be disclosed to third parties.

Begin forwarded message:
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From: "Hining, Kevin J" <[e-mail]>
Date: March 10, 2020 at 12:08:46 PM EDT
To: "Wanucha, Dave" <[e-mail]>, "[e-mail]"
<[e-mail]>
Subject: R-2915 B, Station 165 request to swap PSH with a dissaptor pad

Hey Dave and Lori,

I have a modification I would like to seek your approval on, regarding a proposed pre-formed scour hole
(PSH) at the outlet of a stormwater pipe on R-2915 B, at Station 165 (Ashe County). Dave visited the site
with us last month. I’ve attached a photo above, and the plan sheet as well, for reference.

The contractor has yet to install the PSH, and currently the pipe outlet is over sand. Despite this, it has
only caused a small depression in the ground, suggesting the pipe carries very little stormwater. Since
the surrounding area is vegetated, we were hoping to replace the proposed PSH with just a dissipator
pad. We could do the latter by placing rock from above the pipe, without having to disturb much of the
surrounding vegetation.

Both our roadside environmental engineer and hydraulics staff in Raleigh were fine with the
modification. In their view, the proposed PSH was not necessary given the minimal amount of
stormwater the pipe carries. So, I’m writing to see what you might need from me in order to swap out
the PSH at this location with a dissipator pad.

Also, you will noticed the pipe needs to be shortened. We plan to remove the excess length of pipe, and
not sure why that wasn’t done in the first place.

If this email is all that is needed to make the modification, then great, but just let me know if you need
more information. Or, if this level of documentation is overkill, then let me know that as well:)

Thanks,

Kevin

Kevin Hining
Division 11 Environmental Officer
North Carolina Department of Transportation

336 903 9129 office
828-386-7202 cell
[e-mail]

801 Statesville Rd.
PO Box 250
North Wilkesboro, NC 28659

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